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Video

WSSC Proactively Avoids Water Main Breaks Using Acoustic Fiber Optic Technology

Carla Reid, General Manager and Chief Executive Officer of WSSC, lets us know how Acoustic Fiber Optic (AFO) Technology has helped the water utility to avoid several catastrophic main breaks since installing the system.

Video

GLWA implements proactive condition assessment on their transmission system

Sue McCormick, CEO for Great Lakes Water Authority, talks about how a proactive condition assessment program on their transmission systems will allow them to significantly reduce the investment needed to improve their system while avoiding breaks and unscheduled repairs that greatly affect their customers.

Video

Helping the city of Houston extend capital dollars through force main condition assessment

Robert Castillo from Omega Engineers talks about how using condition assessment technologies (SmartBall and PipeDiver) will help the city of Houston extend the capital improvement dollars by identifying and planning repairs of the city’s force main network.

Video

Louisville Water uses condition data from inline inspections to schedule repairs and avoid breaks

Tim Kraus, Vice President and Chief Engineer at Louisville Water talks about being able to make smart decisions using condition assessment data to make targeted repairs for 1/10 the cost of a water main failure.

Case Study

In order to reduce replacement costs and failures, a mid-size Mid-Atlantic utility engaged Xylem for help developing a machine learning approach to building a focused and cost-effective pipeline renewal strategy.

A mid-sized Mid-Atlantic utility with a reputation for taking a proactive and focused approach to continuously improving service reliability to their 270,000 customers was facing all too common situation. More than 1,000 miles of water mains across their system, with an average age of about 50 years. This had led to an increase in water main breaks, and so they started seeking innovative strategies that would improve service reliability while minimizing repair and replacement costs.

THE CHALLENGE

With water main breaks increasing, the customers served by the utility were challenged with unpredictable service outages and costly repairs as well as highly disruptive road closures. They desired to take a more proactive approach to prevent main breaks and improve their customer level of service (LoS) by focusing on the pipes that needed the greatest attention.

Previous experience in working with Xylem to manage their PCCP (prestressed concrete cylinder pipe) inventory led the utility to seek out a better replacement prioritization strategy than traditional techniques such as age and break history.

What solutions did Xylem and the utility come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Will help the utility lower their annual costs related to pipeline replacement from $90 million to just $20 million while achieving a dramatic four-fold reduction in failures.

Developed a plan to reduce customer outages and improve service reliability, while cutting replacement spending by over 70% compared to other prioritization methods.

Developed a real-time, field mobile tracking application to improve break record accuracy that reduces labor time required to update their Computerized maintenance management system (CMMS) and their geographic information system (GIS), as well as improve the output of the AI model

Services Provided

• Pipeline failure and risk analysis
• Mobile field data collection application
• Data integration with the utility’s existing systems

Case Study

In order to maximize their existing capital assets, reducing overflows and optimizing overall operation efficiency, the Metropolitan Sewer District of Greater Cincinnati (MSD) engaged Xylem in utilizing BLU-X, a drainage network optimization solution that uses a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

Cincinnati’s sewers discharge an average of 11.5 billion gallons of combined sewage every year into the Ohio River and its tributary streams within Cincinnati’s urban watershed.

In 2002, the EPA entered into a federal consent decree with MSD, mandating the elimination of sanitary sewer overflows and significant mitigation of combined sewer overflows into receiving waterways. Engineers estimated the cost to mitigate the sewer overflows at $3.1 billion, an unacceptable capital expense to pass along to MSD’s customers.

THE CHALLENGE

Recognizing the generally inadequate stormwater management capabilities of their existing combined sewer system, MSD prepared a comprehensive wet weather improvement plan. MSD recognized that full sewer separation and deep tunnel construction are massive capital investments that have a very low return on investment because they create only episodic benefits during peak flow events and are single-use assets with little additional community wealth creation.

Instead, MSD’s objective was to maximize existing capital assets — such as sewer interceptors, storage and treatment facilities, and pump-stations — to reduce overflows and gain system-wide benefits through advanced control logic that will optimally operate MSD’s urban watershed.

What solutions did Xylem and MSD come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Overflow volumes reduced by 247 million gallons annually

More than a 90% reduction in cost compared to initial capital work estimated at $38 million

CSO mitigation achieved at a price of less than$0.01/gallon

Services Provided

• BLU-X real-time decision support system (RT-DSS) to manage storage and conveyance
• RT-DSS integrated into MSD’s existing SCADA and IT networks
• All sensor data presented on one unified platform

Case Study

In order to get a better understanding of the infiltration and inflow into their newly separated sanitary sewers, Grand Rapids engaged Xylem in utilizing BLU-X, a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

Grand Rapids, MI is a community that has garnered accolades in the clean water industry for taking significant proactive steps to improve its sewer system. In the early 1990s, “River City” took the initiative to invest in transforming its collection system from a combined sewer system to separate storm and sanitary sewers. By moving from a single pipe for both stormwater and wastewater conveyance to separate pipes, the City avoided the introduction of sewage into its waterways, reducing overflows and subsequent pollution into the landmark Grand River that flows to Lake Michigan 40 miles downstream.

THE CHALLENGE

After nearly 25 years, Grand Rapids finished retrofitting its combined sewer overflow system to a separate sanitary and stormwater system, completing its long-term control plan (LTCP) in 2015. But now, the City needed to get a better understanding of the infiltration and inflow into these newly separated sanitary sewers to ensure compliance with a mandate from the Michigan Department of Environmental Quality (DEQ). This mandate allowed them zero overflow events of any kind, except as part of a wet weather event of a magnitude in excess of a 24-hour, 25-year storm.

For compliance purposes, the City needed analytic data to certify performance and understand how the system behaved during a wide variety of wet and dry weather conditions. While gathering this information, the City was also presented with a hydraulic report stating that areas of the community were experiencing excessive surcharging and flooding. They suspected otherwise, but needed proof to answer regulators, as mitigation to eliminate the surcharging and flooding was estimated to cost much as $1 billion; a capital expense the city could ill afford.

What solutions did Xylem and Grand Rapids come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Data demonstrated that the infiltration and inflow problem could be solved for $30-50 million as opposed to the original $1 billion estimate

Real-time decision support system brought in to help the Environmental Services Department for the sanitary system separation

City has expanded the sensor network to more parts of the system

Services Provided

• BLU-X real-time decision support system (RT-DSS) deployed to help characterize infiltration and inflow performance on sanitary lines
• All sensor data presented on one unified platform
• Integration into Grand Rapids’s existing IT networks

Case Study

In order to better understand the realities of their overflow problems and, ultimately, help the city avoid flooding, the city of South Bend, Indiana engaged Xylem in utilizing BLU-X, a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

The Saint Joseph River has long shaped South Bend’s economy, especially during the mid-20th century, when the river was the conduit to heavy industrial development such as Studebaker and the Singer Sewing Company. To reduce the 1-2 billion gallons of polluted water dumped in the Saint Joseph River annually, and the huge environmental, social, and economic costs associated with the ongoing issue, the City embraced a way to harness intelligent watershed technology to optimize its existing sewer system, without the need to build costly new grey infrastructure.

THE CHALLENGE

Prior to 2008, virtually every time it rained heavily, the City of South Bend faced sewer overflows into the landmark Saint Joseph River because the City`s aging sewer system could not handle the excess discharge, an average of some 1-2 billion gallons annually. In 2011, the City — under the leadership of Public Works Director Eric Horvath — entered into a consent decree, agreeing to a long-term control plan (LTCP) of their sewer overflow estimated at more than $860 million. For South Bend, with a population of just over 100,000, this equated to a burden of nearly $10,000 per citizen, which is economically unfeasible given that the average annual household income is around $32,000.

What solutions did Xylem and South Bend come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Estimated $500 million in capital work savings

$1.5 million per year in operations and maintenance cost-savings

Over 70% reduction in combined sewer overflow volumes (roughly 1 billion gallons per year)

All sensor data presented on one unified platform, and integrated into South Bend’s existing IT networks

Services Provided

• BLU-X real-time decision support system (RT-DSS) for optimizing sewer infrastructure
• 165 networked sensors and software agents optimally operating 13 gates and valves city-wide
• All sensor data presented on one unified platform
• Integration into South Bend’s existing IT networks
• Real-time alert system to identify grit, FOG, sewer collapse & blockages

Utilities can save their communities substantial amounts of money, reduce the need for unaffordable rate increases or financing arrangements, and improve the environmental sustainability of their operations – all while maintaining and enhancing system control.

Around the world, critical valves are in poor repair, or even inoperable. When critical valves fail, managers have effectively lost control of their system, increasing vulnerability to water main breaks or any other system hazard. Once valves have failed, utilities have traditionally sought to replace them, often at great cost, both in terms of time and expense.

But what if there were another way? It turns out there is a far more economical, less risky, and more sustainable option: preventative maintenance, repair, and rehabilitation. High performing utilities are turning away from the wasteful practice of replacing valves that can be restored to full function, instead engaging experts in asset renewal to extend the life of those assets at a substantially lower cost.

This white paper will highlight:

  • identifying the true cost of large valve replacements
  • understanding the cost savings of a repair vs replace strategy
  • the benefits of performing routine critical valve assessments
  • what to look for in a valve assessment partner

With advancements in technology and a willingness to develop proactive pipeline integrity programs, utilities can successfully reduce failures, mitigate risk, reduce capital expenditures, and increase confidence in the overall operation of their force mains.

New standards of best practice for force main management involve a variety of methods and technologies to provide data and information with which to make decisions. Utilities can now often perform a detailed condition assessment while the force main remains in service.

There is no “one-size-fits-all” way of assessing force mains. Any approach should be tailored to risk tolerance, material, diameter and past failure history. Savvy utility managers are turning to programs that reduce damage to assets, prioritize investment to minimize community impact of asset failure, and reduce the consequence of failure by enabling system control.

This white paper will highlight:

  • how to develop a risk-based program
  • the most common modes of failure for force mains
  • how to define which of the three approaches to proactively assessing force mains best fits your goals and risk-tolerance
  • how utilities are finding success using these approaches to: prevent failures, reduce capital expenditures, mitigate risk, optimize budget allocation, and increase confidence and level of service.

Case Study

In order to proactively address the ongoing challenge of apparent water loss and make intelligent decisions regarding rates and capital expenditures, Clayton County Water Authority (CCWA) engaged Xylem to evaluate their entire metering operation.

As one of Georgia’s smallest counties in terms of land size area (only 143 square miles), Clayton County’s location near the top of a regional watershed means it has little area to gather precipitation into streams and rivers. With limited water supplies available in its own catchment area, CCWA is increasingly recognized as an industry leader for proactive water management approaches. Recently CCWA demonstrated this proactive mindset by instituting a program that would harness the power of data analytics to achieve benefits such as increased revenue, better customer care and wiser capital spending — all by targeting an invisible source of system leakage: apparent water loss.

THE CHALLENGE

Located in a state with some of the strictest efficiency and water conservation regulations in the country and a growing population, CCWA has been addressing water loss across its entire system. Apparent water loss (defined as water that is consumed, but not properly measured, accounted for or paid for) is a significant source of revenue leakage for many utilities. On average, about 5 percent of retail water is not registered at the meter, or unbilled for, representing approximately 2 percent of a utility’s top-line revenue.

In looking for an innovative solution to address these issues, CCWA was open to exploring new solutions using intelligent monitoring and management tools that allow them to undertake a prioritized, economically-justified meter replacement program. They refused to follow the status quo of random or time-based meter replacement and instead were driven to identify customer metering accuracies, quantify the apparent water loss and improve operational efficiencies — all without raising rates.

What solutions did Xylem and Clayton County Water Authority come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Over $1 million of recoverable revenue identified through meter inaccuracies over a four-year period

Identified average revenue loss of $6 (residential) to $67 (non-residential) per meter per year

Meter under-registration identified as largest contributor to apparent water loss

Realized short-term gains possible by concentrating on non-residential meters

Services Provided

• Intelligent meter management
• Apparent water loss management
• Lost revenue recovery

Case Study

The Champlain Water District utilized a variety of methods, including high-resolution inline leak and air pocket inspection, transient pressure monitoring (TPM), and a structural design check to ensure a critical transmission pipe’s design was sufficient for current operational conditions.

Champlain Water District (CWD) is an award-winning regional municipal organization that supplies drinking water to 12 municipal water systems in Vermont. As the largest water supplier in the state, CWD serves approximately 75,000 residential, commercial and industrial users. CWD draws water from Lake Champlain, and three high-value water transmission mains supply water to the user municipalities. When evidence of corrosion-related breaks was revealed in nearby distribution mains, CWD became concerned that a critical metallic water main in their system could be next.

THE CHALLENGE

After conducting their own risk prioritization plan, Joe Duncan, Chief Engineer for CWD, and his team kept with the proactive mindset and began a transmission main asset management program.

While the transmission system is relatively “young” and had no real break history, visual feedback from crews showed distribution mains in the vicinity of the transmission mains were experiencing corrosion-related breaks and in some instances looking like “Swiss cheese”. Due to the high importance of the transmission pipeline, CWD wanted to understand its condition and forestall potential corrosion issues.

What solutions did Xylem and Champlain Water District come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

VIDEO CASE STUDY

Project Highlights

Design check confirmed that the pipe design was sufficient for current loading

Acoustic monitoring identified no leaks or gas pockets

Transient monitoring revealed no harmful pressure surges

Anticipated repair funding was re-allocated to other capital work projects

Project Details

Solutions
SmartBall acoustic leak detection
Transient pressure monitoring
Strucutral analysis
Pipe Material
Ductile Iron (DIP)
Inspection Length
1.8 miles (2.9 km)
Diameter
24 inches (600mm)
Transmission Type
Water

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Whitepaper:
Metallic Pipeline Condition Assessment

Case Study

The Town of Flower Mound, Texas (Town), worked closely with Pure Technologies to conduct a leak and gas pocket detection survey of approximately 1.91 miles of potable water mains, which included nearly 1.4 miles of metallic pipelines. The Town is home to 70,000 residents and manages both the water and sewer utilities within Flower Mound.

THE CHALLENGE

In 2001 the Town suffered an uncontrolled leak and lost pressure to a third of their system for a two-day period due to a valve that could not be located. This led to an asset management program, and through this program, the 3.5 mile potable water main was identified in 2015 as a main due for inspection.

Inspecting metallic pipelines has been a challenge for utilities because historically there have been few assessment solutions available. Utilities often used indirect methods of assuming the condition of the pipeline or replaced based on age and consequence of failure, not on the actual condition of the infrastructure. The Town enlisted the help of Pure Technologies to provide a comprehensive condition assessment of key sections of their steel, ductile iron and BWP pipes in order to make balanced and accurate decisions and improve the reliability of service within the system.

How was Pure Technologies able to help the town of Flower Mound address this challenge? Find out and explore the results we achieved together by downloading the full case study below.

VIDEO CASE STUDY

Project Highlights

17 sections with defects identified

1 leak found

1 air pocked identified

1 undocumented outlet located

1 defect validated and replaced

Project Details

Services
PipeDiver® electromagnetic inspection

Sahara® acoustic leak and gas pocket detection & visual inspection

Structural design review

Transient pressure monitoring

Timing
September 2015 – December 2015
Pipe Material
Steel, Ductile Iron, Bar Wrapped
Inspection Length
3.5 miles (5.6 kilometers)
Diameter
20-30 inches
Transmission Type
Water

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Whitepaper:
Metallic Pipeline Condition Assessment

Infographic

Case Study

In order to avoid the cost associated with large valve replacement, the city of Grand Rapids engaged Xylem to assess the true condition of 20 large valves and determine if they could be rehabilitated or repaired instead.

The City of Grand Rapids is the second largest water system in Michigan and delivers clean drinking water to the Grand Rapids area using Lake Michigan as its water source. The Grand Rapids Water System operates about 1,250 miles of pipelines, 31,000 system valves, and over 1,300 large system valves (16 inches and larger). Over the last few years, the operation and maintenance of the large valves had declined due to focus being placed on other critical priorities. Without a consistent exercise routine for critical valves, the utility found that many of these valves were inoperable and, as a result, began to seek funding for valve replacements.

THE CHALLENGE

Grand Rapids was aware of a long segment of transmission line that could not be isolated due to inoperable valves. To regain control of the line, the City replaced five large valves at an average cost of $125,000 per valve, each taking an average of one week to replace. This amount of work and cost was a wake-up call that compelled Grand Rapids to find alternate methods of rehabilitating their valve assets.

Xylem’s experience has shown that on average, 60 percent of valves in a water system are operable, meaning that 40 percent are either inoperable, not locatable, or in the wrong position. Statistically, this meant that with 1,300 valves in Grand Rapids’ system, around 500 of them could have some sort of issue. With limited information on which ones required attention and a limited capital budget for asset replacement, the City would need a more focused approach help them make repair or remediation decisions.

What solutions did Xylem and Grand Rapids come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

The City saved more than $800k by assessing and repairing infrastructure rather than replacing – a cost savings of over 90%

8 critical valves restored to full operability for less than the cost of replacing just one valve

60% of the assessed valves were working properly, allowing operational expenditures to be allocated elsewhere

Services Provided

• Valve assessment – assessed 20 large valves in the transmission system
• Valve repair – repaired and restored eight critical valves to full operability
• Valve rehabilitation – rehabilited one inoperable 36″ gate valve

Case Study

In order to better understand the condition of their buried pipeline network and proactively address potential water loss issues, the city of Park City, Utah engaged Xylem in creating a condition assessment program utilizing acoustic and transient pressure monitoring.

While the Park City Municipal Corporation set a goal for Park City to become the “The Best Resort Town in America,” its relatively small Public Utilities Department is also gaining accolades for its forward-thinking approach to leak detection and to addressing water loss in a city which receives about half as much rainfall as the national average. The city chiefly relies on melting snow to recharge the groundwater system, and the next viable source is much more expensive. The city also realized that rapid residential and commercial developments near Park City are placing increased demands on groundwater resources — and as the population swells, more expensive water sources will have to be pursued.

THE CHALLENGE

Jason Christensen serves as Water Resources Manager for Park City, which has more than 120 miles of pipe in its distribution network. Many of the pipes are more than 60 years old and are covered in mineral soil that is corrosive in nature. By reviewing SCADA and Sensus AMI consumption data, as well as results from a previous leak detection survey, Christensen was aware of leaks in their system that attributed to a loss of 100 GPM.

Park City engaged Xylem to deploy their intelligent sensor hardware and monitoring solutions as part of a condition assessment program to understand their system and reduce non-revenue water. The project involved monitoring 6 pressure zones and reporting on anomalies such as leaks and bursts and identifying assets that are likely to fail through predictive analytics.

What solutions did Xylem and Park City come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

VIDEO CASE STUDY

Project Highlights

$50,000 reduction in operating costs

Deployed 20 stations capable of measuring pressure and acoustics

7 previously unknown leaks detected (water loss of 200 gallons per minute)

Program costs expected to be repaid in under 3 years from water savings alone

Project Details

Solutions
Acoustic leak monitoring
Transient pressure monitoring
Pipe Material
Steel (transmission main) Ductile Iron & PVC (distribution mains) HDPE (service lines)
Inspection Length
13 miles (4.8 km)
Diameter
1-in (25mm) to 12-in (300mm)
Transmission Type
Water

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Whitepaper:
Metallic Pipeline Condition Assessment

Case Study

To manage remaining useful life of a critical metallic force main, City of Cape Girardeau deploys SmartBall® as screening tool for condition assessment to identify gas pockets and high likelihood areas of internal corrosion.

Desktop studies commonly incorporate data such a pipe material, class, age, and failure history to assist in preliminary condition assessment programs without someone necessarily ever seeing the pipeline. Utilities often use desktop data as an initial step to help shape a management strategy.

For a higher level of condition assessment data, the health of a pipeline can be determined by combining desktop studies with an inline SmartBall leak and gas pocket survey, leading to focused test pits in areas where gas pockets indicate potential internal corrosion, the most common cause of ductile iron force main failure.

As proof of concept, Pure Technologies used the free-flowing SmartBall platform as part of a recent DIP force main condition assessment for City of Cape Girardeau, Missouri.

Project Details

Services
SmartBall leak and gas pocket survey

Condition assessment aided by SmartBall gas pocket location

Field service verification

Ultrasonic Thickness (UT) Testing for structural evaluation

Remaining Useful Life (RUL) analysis

Pipe Material
Ductile Iron Pipe (DIP) HDPE
Inspection Length
3 miles (4.8 km)
Diameter
20-in (500mm) & 24-in (600mm)
Transmission Type
Wastewater

Project Highlights

3 miles total distance inspected

26 gas pockets detected

5 pipes excavated, visually inspected and wall thickness measurements obtained

RUL data determined failures may occur within 2 years where gas pockets detected and 15 to 30 years where gas pockets were not present

THE CHALLENGE

The City of Cape Girardeau (Cape G) proactively manages 550 miles of water and wastewater pipelines for a population of nearly 40,000.

In January 2017, Cape G retained the services of Pure Technologies to field verify and further assess the condition of the Riverfront Force Main, a three-mile pipeline comprised of 20 and 24-inch ductile iron pipe (DIP), with a few replacement sections of HDPE.

Cape G had experienced a failure on Riverfront Force Main on the Memorial Day weekend of 2016. As the force main is relatively new (installed in 2000) and runs along the Mississippi River, the condition assessment of the non-redundant main was critical for the City.

What solutions did Pure Technologies and Cape G come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

pipe_diver

On Thursday May 17, thought-leaders, leading utilities, and other industry experts, came together for Xylem’s Modernizing Water Infrastructure Workshop in Laurel, MD. Like Infrastructure Week, the event served as a platform for innovators to connect, discuss, and inspire water industry professionals to solve the problems associated with managing water infrastructure. If you were unable to attend, here are some of the highlights of the day.

From Manure To Modern

The morning session focused on utilities, and began with a keynote presentation from industry visionary, George Hawkins, who provided an energetic analogy on how the manure crisis of the 1800s compares to our current water crisis. While the common person only saw the problem of horse manure, the engineers of the 1800s saw the potential for change and created the car, which eliminated the problem while increasing productivity and reducing costs. That’s what we, as an industry, need to focus on as we modernize water infrastructure — seeing the potential for greatness and improvement through innovation.

Hawkins went on to discuss how we report efficiency. If everything is measured in a productivity approach, seeking additional funding becomes easier. Money has gone farther than ever before in the water infrastructure industry because of the advancements in technology that allow us to work more efficiently and accurately. People are prepared to invest in something that matters to them, especially when they understand that the current monies are going further, and you can prove it. Listen to part of Hawkins’ presentation:

100 Years of Continuous Improvement

Following Hawkins’ passionate keynote address, we heard from Glen Diaz, Division Manager of Water/Wastewater Systems Assessment at WSSC. As WSSC (Washington Suburban Sanitary Commission) celebrates their 100-year anniversary, Diaz reflected on the advancements in technology through the years.

Even in the past 10 years, things have greatly improved in the water industry. Diaz cited the 66” water main break in Bethesda, MD in 2008 and how current technology can aid in preventing future incidents. Diaz went on to discuss how most PCCP failures are due to broken wires and how noisy pipes are typically problem pipes.

However, now, WSSC workers receive mobile alerts, through the implementation of Pure Technologies AFO system, as soon as wire breaks occur so they can address any cause for concern. This system has already helped WSSC avert 20 failure events to date, a $21 million dollar savings on the conservative side! See Diaz’s presentation here:

With Challenge, Comes Major Opportunity

After hearing from WSSC, we heard from Jody Caldwell, Asset Management Director for Great Lakes Water Authority (GLWA), on building an asset management program from the (under) ground up.

Caldwell began with an overview of some of the organizational challenges GLWA is experiencing being a relatively new utility. He talked about the process GLWA went through putting together a 10-year strategic roadmap focused on continuous improvement to overcome the challenges and build a utility for the future. Caldwell went on to discuss GLWA’s pipeline risk management strategy, which uses a quantitative, risk-based analysis to drive decisions. This tiered approach allows them to easily calculate their risk return on investment and ultimately, become a best-in-class pipeline management system. Catch the end of Caldwell’s presentation, as well as the Q&A session.

Extreme Preparation for Extreme Weather

After a brief networking break, there was a roundtable discussion that focused on how leading utilities dealt with the extreme weather conditions this past January. The roundtable featured (from left to right) Joseph Mantua, Deputy General Manager Operations at WSSC; Carlos A. Espinosa, Chief of the Office Of Asset Management at Baltimore City Department of Public Works; and Buddy Morgan, General Manager at Montgomery Water Works (Alabama). Who said the South doesn’t experience cold weather.

The discussion began with the question, “Were there particular pipe materials you found to be problematic during the extreme winter, and if so, what were they?” For the City of Montgomery, AL, cast iron mains had the most problems. Baltimore City was no different, reporting that 98% of the water main breaks were in cast iron pipes, the majority of which were 12” or smaller. WSSC confirmed the cast iron trend, with the majority of breaks occurring in 6 or 8 inch diameter pipes.

In order to prepare for next winter, the utilities agreed for the need to ensure that all their equipment is in working order ahead of time, and have conversations with their crews and contractors to make sure they’re prepared to respond, and recognize the need for additional support services and how to best utilize them. Additionally, the panel agreed that social media played a crucial role in real-time communications with customers, aiding them in being proactive with the media, and helping to communicate status updates. Watch the beginning portion of the roundtable discussion:

The discussion moved on to how to keep employees engaged during extreme weather conditions. Aside from the generous overtime benefits, WSSC brought hot meals to workers, while Alabama Water Works limited hours per week to 65 with 24 hours off before coming back. They also held celebratory cookouts once the weather warmed up.

Be Best-In-Class

After lunch, the afternoon sessions focused on technologies and management best practices. Pure’s very own Mike Higgins, Senior Vice President, Americas, talked about buried infrastructure philosophies utilities can use to manage their most valuable assets. Mike kicked-off his presentation by sharing statistics from the 2017 Infrastructure Report Card from the American Society of Civil Engineers (ASCE).

Following these eye-opening numbers, Higgins shared his insights on success for professionals in the water industry.
Key questions utilities need to answer include:

  • Why do you want to assess your pipeline?
  • What are the goals for your project or program?

 

Typically, the answers should focus on one or more of the following areas:

1) Averting pipeline failure
2) Reducing pipeline risk
3) Extending the life of an asset
4) Increasing sustainability
5) Optimizing CAPEX/TOTEX (capital/total expenditure)

Higgins then shared his secret recipe for the 10 key ingredients to be a best-in-class utility:
1) Focus on operations excellence
2) Coordinate with all key stakeholders
3) Perform necessary Public Relations
4) Create a clearly defined team across departments and disciplines
5) Always aspire towards total pipeline management
6) Prepare for emergencies, they will occur
7) Be opportunistic
8) Continue to innovate
9) Understand limitations of innovative approaches
10) Keep your boots on the ground (maximize the amount of inspected pipe)
 
He concluded his presentation talking about the importance of monitoring key performance indicators (KPIs) and keeping senior leadership engaged. Watch Higgins’ presentation:

The 4th Industrial Revolution

Richard Loeffler IV, Client Solutions Architect at Emnet, then reminded us that the number one criteria for where cities locate is the access to water. Loeffler also stated that we are in the midst of a 4th industrial revolution—IoT (Internet of Things) is changing the way we live, work, and play, and is transforming the fundamental economic cost structure of water and related civic works.

He used the example of South Bend, IN, to illustrate just how effective IoT and RTDSS (real-time decision support systems) can be. Ultimately, it’s all about environmental stewardship — it’s not just about saving money, but about doing the right thing for the world that we live in. View Loeffler’s presentation:

Smart Water

Following Loeffler’s informative presentation, Bridget Berardinelli, VP Product Management And Continuous Improvement for Xylem, stated how smart meters and applying analytics can help utilities generate real results. Berardinelli began by explaining how Sensus develops advanced technology solutions that enable the intelligent use of critical resources.

She covered Advanced Metering Infrastructure (AMI) and explained how to leverage it in order to increase operational efficiencies and improve scalability and flexibility. By delivering machine learning and analytics using a programmatic approach, Sensus is able to inform operational interventions that transform how water utilities operate. View her presentation:

Our Newest Solution

Concluding Berardinelli’s presentation, we heard from Pure Technologies Area Regional Manager, Susan Donnally, on how to manage large diameter water transmission mains. She began her presentation with a discussion on pipeline risk prioritization, stating that using data to drive decisions is a quintessential part of moving towards a proactive asset management approach. She then dove into why pipes fail; noting that age alone is a poor indicator of pipe condition. While there is no singular technology that can identify all of the indicators of pipe deterioration, a holistic, risk-based approach can help.

Donnally then moved on to highlight some of Pure’s latest technology innovations:

  • SmartBall® – in addition to leak and gas pocket detection, the tool now provides mapping, which combines data collected during an inspection with known, aboveground locations and pipeline drawings to create a field-generated GIS map of a pipeline.
  • PipeDiver® – Pure’s free-swimming condition assessment tool is now available with video and can easily correlate the data you’re getting from electromagnetics with actual footage.

 

Additionally, Donnally had a huge reveal! She introduced Pure’s newest PipeDiver solution, the PipeDiver UltraTM (currently in the beta testing phase with a couple of clients), which features high-resolution wall condition information for metallic pipes, such as cast iron, ductile iron, and steel, and is as easy to deploy as the existing PipeDiver. Watch her presentation:

You’re Not Going to Start with Perfection

Vice President of PureAnalytics, Travis Wagner, gave the final presentation of the day on managing distribution systems.

He truly engaged the audience by asking attendees to raise their hands if:

  • They saw a need or value in a pipeline renewal program
  • They agreed that a 10-20% efficiency in renewal programs is OK
  • They thought customer affordability was an issue
  • They had trouble with retirements and recruiting

 
Not surprisingly, most hands were raised! From there, Wagner went on to urge everyone to update their approach.

Utilities need to start asking themselves the following questions:

  • What is the current state of my assets?
  • What is my required level of service?
  • Which assets are critical to sustained performance?
  • What are my best O&M and CIP investment strategies?
  • What is my best long-term funding strategy?

 
Wagner concluded this portion of the presentation with a quote that all utilities should follow: “You’re not going to start with perfection, the goal is to build toward becoming better.”

Next, Wagner moved on to discuss risk management, consequence probability analysis, data collection, and risk mitigation. It was truly an eye-opening presentation:

The day concluded with demonstrations of all the latest technology available to utilities, including a 108” PipeDiver, SoundPrint® AFO system, Sensus meters, Visenti software demos, not to mention some great networking.

Want to learn more about our Modernizing Water Infrastructure Workshop? Check out #H2018Workshop on Facebook, LinkedIn, and Twitter.

 

Inspection required divers to retrieve PipeDiver tool from piping outlet located 40 feet beneath the Atlantic Ocean.

For the Township of Ocean Sewerage Authority, proper planning, quick thinking and late night tool modifications keep critical pipeline inspection on track and on schedule.

As every utility manager knows, a critical pipeline inspection can be temporarily derailed for unanticipated reasons. Especially when the assumed pipeline turns out to be composed of a completely different material, with a smaller than expected internal diameter, all of which could affect the condition assessment methods.

If you’re the manager under a time-critical deadline, you face pressure to resolve the issue and successfully move the inspection forward.

Fortunately, with proper planning, quick thinking and an experienced mobilization team in place, an unforeseen challenge like this can turn into an opportunity to gain a better understanding on the state of your linear assets.

Pipeline broken up into 4,000 foot and 2,000 sections by a drop manhole.

Project background

In November 2016, Pure Technologies (Pure) was contracted by Hazen and Sawyer (Hazen), consultant to the Township of Ocean Sewerage Authority (TOSA) in Oakhurst, New Jersey, to conduct a non-destructive evaluation of TOSA’s 36-inch diameter Ocean Outfall Pipeline constructed between 1966 and 1968. The pipeline was (supposedly) a 1.1 mile steel pipe that carries treated effluent to diffuser piping located 40 feet beneath the Atlantic Ocean.

TOSA had sought Hazen’s assistance in exploring ways to help them better understand the wall loss condition of their outfall pipeline in order to evaluate the need for repairs and or reconstruction options using the inspection data.

Prepping the PipeDiver tool for the electromagnetic inspection.

Understanding the pipe material determines inspection methods

In addition, the line is broken up into 4,000 foot and 2,000 foot sections by a drop manhole. According to profile assumptions, the Ocean Outfall Pipeline was thought to be steel. Understanding the pipe material is an important step in the selection and justification of condition assessment methods.

Based on the assumed steel material, Pure recommended the free-swimming PipeDiver® tool to deliver electromagnetic technology for the inspection method. The PipeDiver tool is equipped with Pure’s proven electromagnetic technology, which can be used on metallic pipe materials such as steel and ductile iron to detect cylinder corrosion. Electromagnetic sensors also provide the location and an estimate of the area and depth affected.

“This assessment using the latest in-pipe inspection technology, provided TOSA significant value in cost savings and avoided unnecessary public disruption, all while providing a better understanding of their infrastructure for the long-term management of their ocean outfall. With this understanding comes peace of mind in knowing that the most economical and effective in-kind replacement will be implemented to ensure long-term reliability of this vital asset.” William S. Gettings, P.E., MBA, BCEE, Senior Associate and NJ Office Manager Hazen and Sawyer

Two models of the free-swimming PipeDiver tool were assembled to inspect the various pipe materials, one for steel, the other for PCCP.

As a precaution, two models of PipeDiver tool assembled

Different PipeDiver tools are used for assessment of different pipe material. The optimized 24-detector PipeDiver tool uses electromagnetic technology to locate and identify steel pipes that have indications of wall loss, while the 6-detector PipeDiver tool is designed to identify PCCP pipes that have indications of broken wire wraps, the leading indicator of problematic pipe.

While it was known that the 2,000-foot (Section A) was made of steel pipe, there was no definitive information on the 4,000-foot (Section B) of pipeline material. In response, two models of the PipeDiver tool (a 24-detector tool for steel and a six-detector tool for PCCP were brought on site, assembled and balanced).

The metallic PipeDiver was run through Section B, where data determined that the section was not steel pipe, but rather PCCP, with a small section of cast iron pipe.

That was good call.

Getting the PipeDiver tool ready for the first insertion.

Sections of pipeline 3 inches smaller than anticipated

During the planning stage, it was thought that the pipeline had a 36-inch internal diameter. However, it became apparent after seeing some highly anomalous data sets from the 24-detector PipeDiver tool that the internal diameter was at least 3 inches smaller, which was confirmed at both the inlet and outlet by direct measurement using onsite divers.

This necessitated some late night heroics from Pure’s analysis group, research and development and on-site staff to modify the neutrally buoyant tool to fit into the smaller pipeline.

From here, the inspections went off without a hitch.

In the end, multiple PipeDiver runs were performed over the five-day inspection. On Section A of the steel pipeline, three pipes displayed anomalies indicating wall loss from 30 percent to 50 percent. One pipe contained a single location of wall loss, while two pipes had multiple locations of wall loss.

Analysis of the PCCP data obtained during the inspection determined that one pipe section in Section B displayed an electromagnetic anomaly consistent with five broken wire wraps, and one anomalous signal shift that could be caused by an undocumented feature or a change in pipe property.

A beautiful way to end a successful inspection.

TOSA has a better understanding of their linear assets

Pure worked closely with Hazen and TNJ Marine, Inc. throughout the inspection.  It was recommended that a portion of Section A undergo replacement due to pipe sections with anomalous electromagnetic signals, apparent pipe wall degradation and visible wall loss anomalies. In addition, where five wire breaks were found, it was recommended that a 16-foot length of 36-inch PCCP including plated access port within a sealed access manhole be replaced. Finally, it was recommended Section B undergo re-inspection within the next five years to monitor existing damage and re-evaluate the pipe section with anomalous signal.

All in all, a successful inspection despite the many challenges.

A leak represents not only water loss, but can indicate the potential for pipeline failure.

How proactive utilities are taking the gamble out of finding leaks in order to mitigate failure risk

It takes a lot more than luck and traditional acoustic correlation methods to locate a suspected leak on large critical mains. Not all leaks are obvious, and some leaks can seep for years without visibly surfacing, putting utilities at risk for catastrophic failure.

That is why a proactive leak detection strategy plays such an important role in any asset management program. It allows utilities to obtain the general condition of their mains, since a leak not only represents a real water loss, but can also indicate the potential for pipeline failure.

Recently two water operators — The City of Vancouver, B.C. and The City of Norman, Texas— took measures to mitigate failure risks by implementing a leak detection program for their transmission networks. The utilities deployed various inline leak detection technologies, dependent on such factors as pipe diameter, material, access point availability, and operational constraints.

Acoustic intensity of anomaly and actual leak located

Left: Acoustic intensity of anomaly.   Right: Actual leak located

Inline technologies for leak detection

Inline leak detection technologies use non-destructive methods in which acoustic sensors are inserted into a pressurized pipeline. The “hissing” sound or vibration resulting from a leak in a pipe transmits an acoustic signal collected by the sensor when passing the leak site. The amplitude and frequency of the sound depends on the pipe material and internal pressure, and is easy to distinguish from other pipeline sounds.

Pure Technologies has developed two inline leak detection platforms for large-diameter pipelines of all materials: Sahara® (with a tethered sensor) and SmartBall® (a free-swimming tool).  Both tools are equipped with a sensitive acoustic sensor that can locate very small leaks (as small as 0.1 l/min) with high location accuracy.

SmartBall inside a pipe

The SmartBall tool can be launched while the main remains in operation, limiting disruption to service.

SmartBall leak detection technology

The SmartBall platform is an innovative technique to identify leaks and gas pockets in large-diameter pipelines while the line remains in service, minimizing disruption. The free-swimming ball contains a sophisticated leak detection circuitry and is released untethered into the water flow often through an air valve or hydrant (any 100mm opening). The SmartBall follows the water flow and is tracked by surface mounted sensors as it rolls through the pipe making a continuous recording of the acoustic activity in the pipeline. At a downstream location, the ball rolls into the retrieval device and is extracted from the pipe. The data is then evaluated to report the presence of leaks and gas pockets.

Since the SmartBall is propelled by the water flow, it can be used to survey the subject main for long distances (battery life up to 20 hours) in one deployment. As a result, modifications to the main are significantly reduced.

The tethered Sahara platform provides acoustic data on the presences of leaks and gas pockets and has the ability to map the pipeline alignment.

Tethered Sahara inspection platform

Utilities have long relied on the Sahara leak detection platform for speed, accuracy and real-time results.

The tethered platform identifies leaks and gas pockets by providing acoustic data on the presence of leaks for distances up to 1,800 meters (6,000 feet). The tool also has the ability for mapping the pipeline alignment, and is equipped with CCTV, adding an assessment.

The tool can be inserted into an active pipeline, through almost any tap two (2) inches and greater. As the Sahara tool enters the pipe, the flow velocity of the water inflates a small parachute, which pulls the tool through the pipe, with the probe lighting the way, highlighting any visual defects in the pipeline.

If the Sahara tool encounters any acoustic events – such as a leak – the operator can stop the tool at the exact point of the leak. At the same time, an above ground operator locates the sensor, marking the exact leak location within plus or minus 0.5 meters (18 inches). This enables users to know in real time where leaks are located.

The SmartBall tool was successfully retrieved with the acoustic data intact.

City of Vancouver SmartBall inspection

In March 2016, the City of Vancouver retained the services of Pure Technologies to perform a condition assessment of the Powell-Clark Feeder Main. The pipeline is comprised of concrete cylinder pipe (PCCP/BWP), ranging from 750 to 900m in diameter, installed in 1986-87.

In addition to providing an earlier PipeDiver® electromagnetic inspection to identify broken prestressing wire wraps on the main, Pure Technologies also performed a SmartBall inspection to identify and locate leaks and pockets of trapped gas along the line.

The SmartBall tool was inserted into the pipeline through a flange access and acoustic data was collected and recorded as the tool traversed the pipeline. At a distance of 5.8 kilometers, (470 meters from the end of the inspection run), the tool stopped, which was confirmed by the live tracking software. By analyzing data from the earlier PipeDiver EM inspection, Pure determined that unknown debris likely lodged the SmartBall tool.

The City excavated and modified a tap to allow Pure to access the pipeline with a submersible ROV (equipped with a camera) to retrieve the SmartBall tool and examine the debris, which turned out to be an old tool cart. The cart and SmartBall tool were extracted, and the data considered valid.

Analysis indicated three (3) anomalies characteristic of leaks and zero (0) pockets of trapped gas. Two (2) instances of entrained air were identified as migratory acoustic anomalies, and flagged for future inspection, as they may develop new pockets of trapped air.

When combined with the results from the EM inspection, the condition data will be used as part of the City of Vancouver’s asset management initiative and allow for proactive measures in the management of their infrastructure.

Sahara inspection for City of Norman, Texas 

In December 2016, Pure Technologies performed a leak detection survey on the 30-inch Robinson Street Replacement Water Main (RSRWM) for McKee Utility Contractors (McKee).  The RSRWM is owned and operated by the City of Norman, Oklahoma.

McKee suspected a leak on the pipeline, as the RSRWM was failing to hold pressure during the 150 psi hydrostatic pressure test.  As a result, McKee requested that Pure Technologies inspect 4,248 feet of the RSRWM and pinpoint any leaks in the inspected section.

The Sahara platform was selected for its ability to provide same-day results, and to accurately locate small leaks with sub-meter accuracy. The tethered tool is propelled by a small parachute inflated by the product flow, requiring a flow velocity as little as one foot per second to progress through a water main.

Because the pipeline was not yet in service, the flow was generated with a city connection pushing water into the main, and a 12-inch blow-off spewing it out. The Sahara audio-visual (AV) sensor was deployed to the endpoint using the flow velocity provided by the blow-off.

After the leak was located and marked above ground, McKee quickly excavated around the butterfly valve, tightened the bolts and eliminated the leak on the same day.

Two leaks detected, located and repaired

As a result of the survey, 4,294 feet of the RSRWM was inspected, with two leaks located.

Leak 1 was located 1000 feet from the first insertion. Video from the Sahara tool showed that the leak was located on the mechanical joint securing the inline butterfly valve to the pipeline. The Sahara team located the leak, and marked it above ground and McKee was able to start excavating immediately. After quickly excavating the butterfly valve, McKee was able to tighten the bolts on the BFV, eliminating the leak the same day as the excavation.

A second leak was located, marked above ground, excavated, and repaired the same way as the first. After repairing the two leaks found, the line passed pressure test.

Spokane is touted as one of the most beautiful and future-forward cities in North America.

Replacement programs for risky aging mains are often far more complicated and expensive than anticipated. 

While it may seem like the simplest solution for a utility, replacement programs for risky aging mains are often far more complicated and expensive than anticipated. Seldom is the original estimate close to the final price tag.

As the City of Spokane (City) recently found out, high risk is often driven by a lack of data or poor data. Moreover, age rarely correlates with condition. According to the American Society of Engineers, 96 percent of underground pipe is good condition. Of the remaining 4 percent, only one percent has significant damage that warrants replacement. The challenge is to determine the location of the individual damaged assets.

The City of Spokane recognized this fact going into a condition assessment program for two of their critical aging transmission mains, the 24-inch Manito Transmission Main and the 18/24/30-inch 57Th Avenue Transmission Main, which run through residential and commercial areas, and a historic park. Together, the pipelines service two of the City’s pressure zones, which have a combined annual demand of approximately 21 percent of water to the City’s entire water system.

The mains in question were constructed of steel in the 1960s. For this material, the failure modes are most often related to corrosion, corrosion combined with cyclic loading, manufacturing or construction/third party damage.

The mains assessed were constructed of steel in the 1960s

The mains assessed were constructed of steel in the 1960s.

First step: gathering condition assessment data.

The first step in understanding a pipeline is to evaluate the design of the pipeline under actual internal pressures, external loading and current design standards. Managing these critical assets takes a confident management strategy, which includes gathering condition assessment data and evaluating the results using advanced engineering analytics.

As the scope of the proposed assessment was broad, the City retained the services of Pure Technologies (Pure) to deploy a multitude of technologies to determine the condition of the mains.

24-Detector PipeDiver tool

A 24-detector PipeDiver tool was deployed for an electromagnetic wall thickness evaluation.

Recommended internal inspections consisted of SmartBall® acoustic leak detection and PipeDiver® electromagnetic wall thickness evaluation and video recordings. At the same time, Pure used transient pressure monitoring to determine hydraulic loading conditions of the pipelines.

In addition, Pure performed external observations using Pulsed Eddy Current (PEC) and Ultrasonic Thickness (UT) Gauging technologies during excavations of the 57Th Avenue Transmission Main.

Pure also conducted a structural analysis to determine the wall thickness required if the pipelines were designed today under actual internal pressures and external loading. Pure also performed three-dimensional finite element analysis (FEA) performance curves to determine the combination of corrosion depth and length would exceed the Yield Limit of the steel.

Finally, Pure also performed remaining useful life (RUL) analysis of the 57th Avenue Transmission Main to predict wall loss degradation rates and recommend re-inspection intervals, as part of its decision intelligence solutions.

Challenges included nighttime work with traffic control and rain.

Indefatigable crews faced night-time work with traffic control, relentless rain and sloppy conditions.

Project challenges included non-existent lay sheets. 

The project was not without challenges, starting with poor data — an outdated plan and profile drawings and non-existent lay sheets.  For the inspection, crews also faced a survey route with no existing features for tool insertion and extraction, two inline 24-inch butterfly valves, nighttime work with traffic control, and rain. Lots of rain.

While no one could anticipate all the challenges during the planning stage, the engineering experience of the project teams and collaborative dialogue between Pure and the City ensured a working solution for most unforeseen events, with contingencies in place.

Testing the PipeDiver through a butterfly valve

To ensure a smooth execution, the City provided a similar 24-inch butterfly valve to test the PipeDiver passage.

As mentioned, lots of pre-inspection discussion occurred to minimize risk of the free-flowing 24-detector PipeDiver tool getting stuck at the butterfly valves (BFVs). The City was prepared to dewater the line if necessary. To mitigate additional risk, the City provided a pool in their garage to setup and test the inspection equipment. They also provided a similar 24-inch BFV to test the PipeDiver passage.

All the advance planning paid off. The inspection occurred over 10 days and was executed flawlessly, in spite of the damp weather conditions.

Damaged pipe

Pipe damaged from suspected backhoe bucket teeth during previous excavation.

Two pipes excavated to validate inspection results.

For the Manito Transmission Main, 202 pipes were inspected, with zero leaks and zero electromagnetic anomalies detected.

For the 57th Avenue Transmission Main, Pure inspected 282 pipes. Analysis indicated one (1) leak and three (3) pipes with electromagnetic anomalies. Taken as a whole, analysis indicated 99.4 percent of pipes with no corrosion and 0.6 percent of pipes with anomalies indicative of corrosion.

Based on the EM report, two (2) pipes were excavated to validate results and provide data for a Remaining Useful Life analysis. A third pipe was reported to have corrosion anomalies but was not excavated because of its location the middle of a busy intersection.

Upon excavation, the pipe’s coating was observed to be damaged, which appeared to be caused by bucket teeth from a backhoe during a previous excavation to repair the dresser joint. One of the damaged areas matched the location of the reported EM anomaly perfectly and Pulsed Eddy Current measured 17% wall loss while PipeDiver reported 20%. No wall loss was found at the other areas of damaged coating. The City applied a mastic coating to all areas of damaged coating before burying the pipe.

Excavated pipe

Two pipes were excavated to validate results.

Both pipelines originally scheduled for replacement at expected cost of $7 million.

The City of Spokane originally scheduled both pipelines to be replaced at an expected cost of $7 million dollars. After inspection project expenses, the remaining funds can now be applied to other capital projects, which makes this a good news story.

Moreover, with the analysis in, and the repairs made, the City of Spokane now has confident information to plan and move forward with periodic inspections.

 

 

While metallic force mains have been historically difficult to manage, a risk-based approach increases confidence in the condition of the pipeline.

After the Clean Water Act of the 70s required control of wastewater discharge, an increase in force main construction and management across the country was observed. As these assets are now approaching 50 years in age, reducing the risk of failure has become a major regulatory priority. Nothing grabs headline news like the failure of a force main, which can be extremely damaging to the environment and harmful to a utility’s reputation.

Historically, wastewater force mains have been difficult to manage, especially those made with ferrous materials, where the failure method is slow when compared to concrete pressure pipe.

As well, pressurized sewer mains have special operational challenges that don’t apply to gravity sewer mains as they typically cannot be taken out of service for inspection, and due to the presence of solids in the fluid, force mains represent a far more abrasive environment than potable systems such that assessment methods for water mains may not be applicable.

The presence of gas pockets increases the potential of corrosion in metallic pipes.

Gas pockets are of significant concern in force mains.

The primary failure mechanism of ferrous force mains is due to internal corrosion. Gas pockets are of significant concern in force mains, as concentrations of hydrogen sulfide gas within wastewater can be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall. This may cause corrosion and eventual breakdown of the pipe’s wall.

Therefore, a first step in assessing force main condition should be the identification of gas pocket locations within the pipeline.

Pure Technologies has performed an analysis of force mains inspected using acoustic based technologies in order to better characterize the frequency and location of gas pockets. Based on the analysis, it was found that 72% of gas pockets were not at known high points or air release valves, therefore, the most precise way to identify gas pockets within a force main is through the implementation of inline acoustic inspection technologies.

The collection of gas pocket locations alone will not indicate the condition of the pipeline, but instead identifies locations where an increase in corrosion potential is observed. To ascertain the true condition of a pressure pipe, higher resolution electromagnetic technologies are required. These technologies measure pipe wall thickness in ferrous materials and broken wire or bar wraps in concrete pressure pipe.

Once the condition data is collected, advanced analytics can be applied to estimate the pipeline’s remaining useful life.

“Previous analyses involved straight-line assumptions – comparing the pipe wall thickness at installation against what it is today. However this doesn’t give an accurate picture of how pipes degrade…by using statistical modeling we can develop a more predictable degradation rate based off of over 14,000 miles of inspection data Pure has collected over the past 30+ years.”

Jennifer Steffens, Market Sector Leader, Water and Wastewater, Pure Technologies

Desktop studies are not always reliable.

While often the first thought is to replace the aging wastewater assets based on factors such as age and failure history, this option makes neither logical nor financial sense. With so many miles of buried pipelines and such limited capital budgets, utilities don’t have hundreds of millions to spend on replacing pipelines which still have remaining useful life.

At Pure Technologies, we believe there is a better way. A more feasible approach to ensuring the safe operation of force mains is to undertake a risk-based approach to manage their operation. A risk-based approach will provide decision intelligence on which assets require rehabilitation or replacement to extend their useful life. Or which assets can be left alone.

Our approach is to help utilities evaluate the current state of their buried infrastructure and provide them with high confidence condition and operating data.   We then couple this with our years of extensive experience and project history (more than 12,000 kilometers of pressure pipe assessment) to provide utilities with actionable information, which allows them to make informed decisions as to the management of these critical assets.

The value of a risk-based approach to manage force mains.

Utilities that embrace a risk-based approach to manage their force main inventory have found that on average they can safely manage their force mains for roughly 5 to 15 percent of the replacement cost. This pragmatic approach focuses on providing real condition data through assessment, which can be used to selectively renew isolated areas of damaged pipe in lieu of capital replacement.

At Pure, we recommend a risk-based approach to manage wastewater force mains by focusing on four main areas:

  • Preliminary Risk Analysis
  • Internal Corrosion Potential Surveys using Inline Acoustics
  • Pipe Wall Assessment using Advanced Technologies
  • Condition Data Analysis and Advanced Risk Assessment

Some of the common reasons leading to failure on ferrous pipes.

Preliminary Risk Analysis

Preliminary analysis includes collecting the right data to develop a prioritized plan for assessment, including the selection of appropriate technologies. To help make preliminary decisions, Pure collects all available information to understand the history of the pipeline and the likely failure modes.

The data analysis will provide an understanding of the construction and context of the pipeline. Data of interest typically includes pipe characteristics, installation factors, environmental and performance-related data, operational data, and failure data.

Acoutic-based SmartBall® tool locates leaks and gas pockets

Acoustic-based SmartBall® tool locates leaks and gas pockets.

Sahara is an inline tethered tool used to locate leaks and gas pockets in pressurized lines.

Internal Corrosion Potential Survey.

An internal corrosion potential survey uses inline tools to locate gas pockets that can increase the potential for corrosion and eventual breakdown of the pipe wall. Pure Technologies typically deploys its acoustic-based SmartBall® leak and gas detection tool, as well as its tethered Sahara® leak and gas pocket detection platform to locate gas pockets in pressurized lines of all materials.

Pipe Wall Assessment.

While the presence of gas pockets may indicate areas of potential concern, it will not give a quantifiable answer as to the structural life of the pipe.

Pipe wall assessment is completed using a variety of technology solutions to identify defects and deterioration of the pipe wall in a variety of pipe materials. For pipe wall assessment of metallic force mains, common internal electromagnetic technologies include the PipeWalker® and PureRobotics® platforms, as well as the free-swimming 24-detector PipeDiver® assessment tool, developed to identify electromagnetic anomalies indicating pipe wall loss.

PipeDiver® assessment tool identifies electromagnetic anomalies indicating pipe wall loss.

Condition Assessment Analysis.

Condition data analysis and risk assessment evaluates how to safely renew or extend the life of force mains. The risk evaluation considers not only the probability of failure (condition) of the force main based on inspection data, but also the consequence of failure in order to make sound engineering decisions.

Understanding the risk of the pipeline is an important step in selecting and justifying the appropriate condition assessment methods. As the risk of the asset increases, the value of using high-resolution comprehensive assessment techniques increases. Higher resolution data results in more confident decision making, and would justify and prioritize the application of assessment techniques.

Diagnostic analytics helps utilities move risk assessment forward.

In the past, inspections were done, the data analysed, and the results passed on to the utility. Pure Technologies now offers a more holistic program of diagnostic analytics. This includes analysis of what caused the corrosion problem within the pipe wall, what the impact the corrosion has on the life of the pipeline, and a prescriptive analysis of how it needs to be repaired or rehabilitated.

The next step gathering momentum? Predictive analysis to elongate service life.

 

Case Study

City of Baltimore deploys acoustic optic fiber monitoring to avert potential pipe failure without the expense of excavating the entire line to find it.

Public utilities rarely make headline news unless an unexpected water main break shuts down a road or floods a neighborhood. Then the public swarms negatively all over the story.

In this instance, the opposite happened, and the public responded positively when the City of Baltimore Department of Public Works (DPW) announced that they had averted a “potentially disastrous water main break” in southwest Baltimore because of preemptive monitoring of the pipeline.

Project Details

Services
SoundPrint® Acoustic Fiber Optic Monitoring
Timing
2017
Pipe Material
PCCP
Monitoring Length
16-foot section
Diameter
54 inch
Transmission Type
Water

Project Highlights

AFO hears “pings” on 16-foot segment

15 wire wrap breaks identified over 2-week period

$200,000 repair cost miniscule to the millions a catastrophic failure might have cost

Project Photos

Challenge

The City of Baltimore Department of Public Works operates more than 7,000 miles of water and sewage mains.

In May 2017, analysts from Pure Technologies (Pure) notified DPW that something was wrong with a 16-foot segment of the Southwest Transmission Main that runs beneath Desoto Road (under the Interstate-95) and carries potable water for southwest portions of the City of Baltimore, Baltimore County, and portions of Anne Arundel and Howard Counties. Fortunately, this section of the 54-inch PCCP main was equipped with a SoundPrint® acoustic fiber optic (AFO) monitoring system, the outgrowth of a collaborative project between the city and Howard County in 2007.

The AFO system not only gave DPW an early warning of a distressed pipe section. It also offered them a cost-effective way to pinpoint a potential failure without the time and expense of excavating the entire line to find it.

Solution

Developed by Pure Technologies, the SoundPrint acoustic fiber optic monitoring technology is an industry leading system that tracks and records pipeline deterioration on prestressed concrete cylinder pipes (PCCP), the material of the pipe of which the Southwest Transmission Main was constructed.

Once installed in a pipeline, the SoundPrint AFO system remotely detects the acoustic signature of wire wrap breaks or “pings” and records their specific pipe location. If break activity increases, utility staff are alerted and can intervene on the deteriorating pipe in advance of a failure, much like DPW did with the Southwest Transmission Main.

Unlike electromagnetics, which identifies the number of wire breaks that exist at a point in time, acoustic monitoring identifies the number of wire breaks that occur during the monitoring period, effectively identifying the location of active deterioration for the lifespan of the asset.

Results

In the case of Desoto Road, “our monitoring system reported an alarming 15 wire breaks over a two-week period, raising concerns of a failure and potentially catastrophic water main break,” DPW spokesman Jeffery Raymond said.

The “pings” from the snapped wire wraps, recorded by the acoustic monitors, set off alarm buttons at the Office of Asset Management formed by Public Works Director Rudy Chow.

“I created this office precisely to collect and utilize data that can help us stop problems before they happen,” explained Chow. “Our team moved quickly to prevent what could have been a disastrous water main break,”

The best option for fixing the pipe segment, it was determined, was to utilize high-strength tendon cables. The process called for excavating around the distressed section of pipe, then installing the tendon cables around the pipe’s circumference.

While the cost of repairs the Southwestern Transmission Main cost DPW $200,000, that amount is miniscule compared to the millions of dollars that unplanned emergency repairs can cost a utility. In this instance, an ongoing preventive maintenance program certainly did pay off for the agency.

As a footnote, repair of the Southwest Transmission Main project won the 2017 CEAM Small Project of the Year Award for the City of Baltimore.

“Our monitoring system reported an alarming 15 wire breaks over a two-week period, raising concerns of a failure and potentially catastrophic water main break.”

Jeffery Raymond

DPW spokesman

Pure Technologies completes longest single day pipeline inspection to date using PipeDiver® technology.

From the Colorado town of Buena Vista, the views of the distant Rocky Mountains are deceptively stunning. Up close, the terrain is hilly, inhospitable and extremely remote. With no roads and little access, this is helicopter, snowmobile and 4-wheel-drive country. As might be expected, the logistics of inspecting a water pipeline that runs through this unforgiving territory makes the inspection extremely time consuming and hazardous for everyone.

Until now.

An early start to a long but successful day.

For the Homestake Water Project, the manned electromagnetic (EM) inspection that previously shut down the critical 44-mile (77 km) pipeline for at least one month annually over five years, was now completed in one day, thanks in part to an enhanced PipeDiver® EM tool developed by Pure Technologies.

From 5 months using tradition dewatering and manned entries to a single day. Now that’s progress.

“Amazing,” said Tom Hankins, Supervisor for Homestake Water Project, in describing the Otero pipeline inspection run. “With the PipeDiver tool travelling through the pipeline at three feet per second, we can do what we previously did in five months, [over a five-year period] in just one day…”

Background

Colorado Springs and the City of Aurora are the second and third largest communities in the state of Colorado. The Homestake Water Project (Homestake) is a joint venture between the two cities to collect and transport water from the mountains to the communities that serve almost 1 million people.

The Homestake Water Project includes a collection system, a series of reservoirs, a tunnel that brings water through the continental divide and a pump station that delivers up to 120 million gallons of water per day through the pipe.

The Pure Technologies team mobilizing for the day ahead.

One of the pipelines managed by Homestake includes the 44-mile Otero Discharge Pipeline, a large diameter (66-inch) non-cylinder prestressed concrete pipeline (PCP) built in the early 60s by the Cities of Aurora and Colorado Springs. In the past several years, the pipeline has suffered a few major breaks and non-surfacing leaks. The critical pipeline, which provides 60 to 70 percent of Colorado Springs’ and Aurora’s water, is in a high-risk location, with few roads and steep inclines, and recently the pipeline has suffered catastrophic failures.

Variety of methods used to inspect the pipeline

Over the past ten years, Homestake has deployed a variety of methods to inspect the pipeline. This includes visual, above ground, manned electromagnetic cart, and inline leak detection using the SmartBall® platform, of which Homestake has been a licensee for more than six years. Homestake conducts their own SmartBall inspections, analysis and leak verification of the pipelines they manage.

Beginning ten years ago, over a five-year period, Homestake shut down the Otero Discharge Pipeline each September to perform a condition assessment on certain sections of the pipeline. The shutdown included two weeks just to drain the pipeline to prepare it for a manned electromagnetic (EM) inspection tool, and another two weeks to perform the inspection.

“This task is hazardous,” says Tom Hankins, “not just to the mobilization crews, but also to the inspection teams inside the pipe who required rope support on the steep slopes.”

Because Homestake enjoyed a good relationship with Pure Technologies and knew of its innovative inspection technologies, when Pure broached the subject of using an enhanced PipeDiver electromagnetic tool on the remote 44-mile Otero District pipeline, without the need for dewatering, Homestake became keenly interested. Especially as Pure Technologies was able to develop a new exciter for the PipeDiver tool, which could be used on non-cylinder PCP and deliver higher resolution data than in the past.

Getting the star of the show (aka. PipeDiver) ready.

PipeDiver platform collects EM data and operates while pipeline remains in service

The PipeDiver platform is a versatile, free-swimming condition assessment tool that collects electromagnetic data on the prestressing wires, and operates while the pipeline remains in service. The tool has specialized electromagnetic sensors to identify and locate prestressing wire wraps, which are the main structural components of PCP and PCCP, and the primary indicators that the pipe will fail.

And so the planning began. The purpose of Homestake long distance PipeDiver inspection was to locate and quantify the amount of the prestressing wire wraps on all 44 miles in one run, identify the individual pipe sections with distress growth, and drive repair/replacement decisions. A long, tall order, indeed.

Final deliberations before the big event.

High-risk inspection not without its challenges

The proposed inspection was a technically challenging, high-risk project. The teams put more than six months of planning into the inspection logistics, and Pure Technologies worked closely with Homestake to ensure existing facilities could be used for the tool’s insertion and extraction. Homestake also facilitated a calibration with the new tool prior to inspection, which would help with wire break identification and quantification.

Safety a major issue propelling the inspection

In order to inspect the largest portion of the Otero Discharge Pipeline, the PipeDiver was inserted into a surge tower located 600 feet above the pipeline. This also required a rope crew and a fully-suited diver with an umbilical line to rappel via a sled 600 feet down the 66-inch pipe in order to align the PipeDiver in the proper direction. Once the tool was set in the right direction, the rope team safely hauled up the diver and cart.

The pumps were turned on, and the PipeDiver sailed off without a hitch.

“Safety is a major issue because of the rough terrain as the pipeline slices through the Rocky Mountains with lots of hills, highs and lows, which required lots of ropes to get in and out, with the crews experiencing slips and falls…this way the inspection is conducted inside pipe, which is much safer…it does a better job.”
Tom Vidmar, Superintendent of the Homestake Water Project

In addition, the mobilization team installed 55 tracking sensors along the 44-mile pipeline route to monitor the PipeDiver tool as it traversed the inhospitable and extremely remote pipeline alignment.

No drama, no fuss… just a job done well.

Recognized as longest single day PipeDiver tool run in the history of Pure Technologies

Contingency plans were developed in case the PipeDiver tool got hung up along the 44-mile route, but in the end, less than 24 hours later, the tool successfully sailed into the surge pond, to the applause of the Homestake and Pure crews. The PipeDiver tool was removed from the surge pond and the pipeline data retrieved.

In the end, the PipeDiver electromagnetic inspection, at 44 miles long, was recognized as longest single day run for the tool in the history of Pure Technologies. With Pure Technologies now analyzing the electromagnetic data, Homestake will soon have information on the location and amount of broken prestressing wires on all 44 miles of the pipeline, which in turn, will drive repair/replacement decisions for the proactive water authority.

All in all, not bad for a day’s work.

Technology-based, people-driven.

Case Study

The Washington Suburban Sanitary Commission (WSSC) is the 8th largest water and wastewater utility in the United States, serving over 460,000 customer accounts and 1.8 million residents in Montgomery and Prince George’s County, Maryland (suburban Washington D.C.).

WSSC operates nearly 5,500 miles of water mains, with approximately 145 miles comprised of large-diameter Prestressed Concrete Cylinder Pipe (PCCP) equal to or greater than 36-inches in diameter.

Project Details

Services
SmartBall®
Acoustic Leak Detection
PipeDiver® – Condition Assessment
PureRobotics® – Pipeline Inspection
SoundPrint® AFO – Acoustic Fiber Optic (AFO) monitor­ing
Timing
2014
Pipe Material
PCCP
Inspection Length
145 miles
Diameter
36-inches

Project Highlights

The Assess & Address cost was roughly 6% of the capital replacement estimate of $2 billion

95% of the pipes inspected by Pure Technologies have no deterioration at all

Pure has identified less than 2% of pipes in need of immediate repair

A capital replacement program would have replaced a large amount of pipe in good condition

Challenge

After WSSC began experiencing major PCCP failures in the 1970s, it developed a strong commitment to infrastructure management technology in favor of large capital replacements. Beginning in 2007, WSSC and Pure Technologies began a partnership to create a comprehensive PCCP management program.

Pure Technologies Assess & Address approach to pipeline management is built on extensive research and data from over 8,000 miles of pressure pipe inspection which has found that less than 1 percent of pipelines need immediate repair. Assess & Address programs focus on identifying vulnerable areas of a pipeline and completing selective rehabilitation and replacement in favor of full-scale capital replacement, often saving the utility millions of dollars.

Solution

Pure Technologies uses several solutions for WSSC’s PCCP management program that effectively inspect the pipeline for leaks, gas pockets, and structural deterioration. Pure also provides real-time monitor­ing of the pipelines to alert the WSSC when indi­vidual pipe segments experience prestressed wire breaks and are approaching a high risk of failure.

Pure’s SmartBall® Acoustic Leak Detection Technol­ogy is used to identify leaks and pockets of trapped gas, allowing for proactive repair. The SmartBall inspection tool is a non-destructive, free-swimming technology that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. Early identification and repair of leaks and gas pockets reduces water loss and structural deteri­oration and is crucial in understanding the baseline condition of a pipeline. Pure Technologies regularly deploys SmartBall leak detetction as part of the pro­gram having identified several major transmission mains leaks within WSSC’s system to date.

WSSC Pipelines are also inspected for structur­al deterioration using several of Pure’s platforms. Manned visual and sounding inspections of dewa­tered pipes help identify visible structural damage like corrosion, delamination, and cracking. Pure also uses PipeDiver® and PureRobotics® Electromagnet­ic (EM)Technology Platforms to locate and quantify broken prestressing wires in each pipe section.

Information from these inspection techniques are combined to provide actionable information (including structural modeling and analysis), which allows WSSC to safely manage their PCCP inventory while minimizing renewal projects.

In addition to regular condition assessment, WSSC began using Acoustic Fiber Optic (AFO) monitoring in 2007. Ultimately, the program will monitor up to 145 miles of 36-inch and larger PCCP within WSSC’s system.

AFO technology monitors the condition of PCCP by tracking the amount of wire breaks in each pipe section. The system allows WSSC to monitor pipe­line deterioration and see at-risk pipes before they fail. As wire breaks occur, the data is analyzed and reported to WSSC by e-mail and advanced GIS and web-based reporting systems, allowing for real-time management of WSSC’s system.

Results

While WSSC’s PCCP program is one of the largest and most advanced infrastructure management programs in the industry, the cost of Pure Technologies Assess & Address model is roughly 6 percent of the $2-billion capital replacement estimates.

To date, Pure Technologies inspections have shown that about 95 percent of WSSC’s pipes are in “like new” condition and less than 2 percent require any immediate rehabilitation or replacement. By identifying select distressed areas, WSSC was able to avoid a full replacement program and avoided massive capital replacement costs by rehabilitating the identified sections.

Since the program’s inception, no PCCP failures have occurred for any transmission main managed under the program.

Case Study

The Trinity River Authority of Texas (TRA) owns and operates 8.5 miles of 30-inch BWP and PCCP that supplies raw water from Lake Arlington to the Tarrant County Water Supply Project Water Treatment Plant in Euless, Texas.

The 30-inch pipeline, in conjunction with a parallel 54-inch pipeline, conveys raw water to the Authority’s 87 mgd WTP. Treated water produced at the WTP is supplied to five cities in the mid-cities region between Dallas and Fort Worth including Bedford, Colleyville, Euless, Grapevine and North Richland Hills.

Project Details

Services
SmartBall® Leak Detection
PipeDiver® Condition Assessment
Transient Pressure Monitoring
C303 Bar-Wrapped Pipe structural performance curves
Timing
November 2012 – July 2013
Pipe Material
Bar-Wrapped Pipe and PCCP
Inspection Length
8.5 miles (14 km)
Diameter
30-inch (750mm)
Transmission Type
Raw Water

Project Highlights

SmartBall survey identified 4 leaks and 3 air pockets

Only 1% of BWP sections identified as distressed

TRA verified and repaired 3 high-risk BWP sections

Cost was roughly 4% of the replacement estimate of $25 million

Challenge

TRA had originally planned to replace this pipe­line, but chose to assess and selectively rehabili­tate the pipeline by finding solutions that could identify the most distressed areas. The pipeline spans about 8.5 miles and is made up primari­ly of BWP, although there are some sections of PCCP. It was constructed in 1973.

Solution

In November 2012, TRA began a condition assessment program that included transient pressure monitoring, acoustic leak and gas pocket detection, internal electromagnetic inspection, and structural condition assessment including finite element analysis.

For the leak and air pocket assessment, TRA used SmartBall® technology. The SmartBall inspection tool is a non-destructive, free-swim­ming technology that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. When acoustic anomalies are present, the data is analyzed to determine if it is a leak, gas pocket, or just an external sound.

Regular leak detection inspections can help util­ities identify leaks that may not be visible at the surface. By repairing leaks, utilities can reduce their non-revenue water and prevent pipeline failures, as leaks are often a preliminary indi­cation of pipeline deterioration. Location and elimination of air pockets is also beneficial as it reduces pressure on pumps that are attempting to pump water past a gas pocket.

For the structural inspection, TRA used PipeDiver®, a free swimming electromagnetic tool that identifies wire breaks in PCCP and bar breaks and broad areas of cylinder corrosion in BWP using electromagnetic technology. The tool oper­ates while the pipeline remains in service.

Although BWP looks similar to Prestressed Con­crete Cylinder Pipe (PCCP) in cross section, their design and materials are significantly different. PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water membrane. With BWP, the cylinder plays a much larger role in the structural integrity of the pipe. BWP is essentially designed as a steel pipe with mild steel used to manufacture the steel cylinder and steel bars.

As a result, the bar in BWP and wire in PCCP respond differently to environmental conditions that facilitate corrosion. The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage. The mild steel bars in BWP are thicker in diameter and wrapped under less tension, therefore corrosion takes sig­nificantly longer to lead to breakage.

The engineering services portion of the project was completed to identify optimal operating conditions for the pipeline and determine the structural performance of the pipe materials. This included creating performance curves for TRA’s BWP, as well transient pressure monitor­ing.

The BWP structural performance curves allowed TRA to determine which pipe sections to exca­vate and verify. By determining the bar break yield limit for the specific pipe material, TRA was able to identify which pipe sections should be immediately addressed and which could remain in safe operation.

Results

The SmartBall® survey identified four leaks and three gas pockets. Although the four identified leaks were small (less than 2 gallons per minute), one was located in the front yard of a brand new church building and could have caused signif­icant water damage had it not been repaired immediately by TRA. Water from this leak was visible at the surface 325 feet away from the actual leak location.

The structural inspection using PipeDiver® iden­tified four PCCP pipes with electromagnetic anomalies resembling wire breaks. The inspec­tion of the BWP identified 14 pipes with bar break damage and 72 pipes with electromagnet­ic anomalies resembling cylinder defects out of 1,284 inspected pipes.

TRA has verified and repaired three sections of BWP that were beyond the yield limit deter­mined by the structural performance curves. Upon verification, TRA and Pure determined that distress areas identified in the inspection were accurate and the excavated pipe sections had bar breaks and corrosion.

By repairing specific pipe sections with dete­rioration, TRA was able to avoid replacing the entire 8.5 mile pipeline at a high capital cost. Completing condition assessment has also allowed TRA renew its pipeline infrastructure and continue providing reliable service to cus­tomers in the region.

Case Study

Texas has more than 53,000 bridges, the largest bridge inventory in the United States.

The Texas Department of Transportation (TxDOT) conducts routine inspections of most bridges every two years, ensuring all bridges open to vehicular traffic in Texas are safe and best in class.

Project Details

Services
SoundPrint® Acoustic Monitoring
Monitoring system commissioned in 2002
Operated continuously since commissioning
Bridge Type
Fan arranged cable-stayed bridge
Monitored Length
2473 ft (754 m)
Number of Stays
192
Stay Type
Grouted 15mm x 7 wire strands in HDPE tubes

Project Highlights

System has performed in excess of 98% of efficiency over its life

SoundPrint identified individual wire events in stays ranging from 50 to 193 m in length

Allows TxDOT to establish remaining service life of 192 stays

Challenge

The Fred Hartman Bridge, located in Baytown Texas, opened to traffic in 1995 and is one of the largest cable-stayed bridges in the United States. ­

The cable-stayed bridge portion of the bridge is 2473 ft. (754 m) long, consisting of steel girders and transverse beams, and includes a 1250 ft. (381 m) main span. ­ The bridge consists of two 78 ft. (24 m) wide composite concrete decks suspended from diamond shaped concrete towers using a total of 192 stays. ­The stays are comprised of multiple 0.59 in (15 mm) seven-wire strands grouted inside HDPE tubes.

After the bridge completion, large-amplitude vibrations of the cables were observed. A vibration monitoring program confirmed that the stays are subject to wind/rain-induced vibrations, raising concerns about potential fatigue failure of the strands.

Solution

Following testing by the Ferguson Laboratory at the University of Texas, TxDOT installed a SoundPrint® Acoustic Monitoring System to monitor wire break activity within the stays. ­

The installation consisted of three specially-designed sensors on each stay (one on each anchor and one on the stay approximately 8 ft. (2.5 m) above the deck). ­ These sensors are suitable for cable-stayed bridges and are durable enough to withstand harsh marine environments. ­

The bridge is divided into 16 virtual monitoring zones with sensors from each zone connected to an active junction box using durable coaxial cable. ­ The active junction box outputs are connected to the SoundPrint® data acquisition and management system (“DAQ”) by means of multiple twisted-pair shielded cable. ­ The DAQ is located inside the North-East tower leg at deck level. Data is automatically transmitted from the DAQ through a local Internet connection to the Pure Technologies data processing center in Calgary, where the data is analyzed and classified.

On-demand reports are available to authorized individuals through a secure password-protected area of the SoundPrint® website. As the bridge is located in an area with frequent thunderstorms, the system has been upgraded with state-of-the-art lightning protection technology.

Results

TxDOT personnel have inspected some of the stays based on the reported wire events via anchorage investigations and stay force evaluations. To date, the inspections have not revealed significant changes in the measured stay forces due to the individual wire failures. ­ The rate of wire breaks has given TxDOT confidence in the operation of the stays, as well as the vibration damping system installed to reduce cable fatigue.

Case Study

The Maine Department of Transportation is the office of state government responsible for the regulation and maintenance of roads and other public infrastructure in the state of Maine. The department manages 2,919 bridges and spans in total, inspecting 2,414 in 2014.

Project Details

Services
SoundPrint® Acoustic Monitoring – Bridges

Monitoring system commissioned in 2003

Operated until bridge retired in 2006

Bridge Type
Suspension
Monitored Length
2040 ft (622 m)
Number of Main Cables
9.6 in (244mm) parallel strand cables
Number of Sensors
22

Project Highlights

Rapidly deployed monitoring system allowed resumption of two-way traffic

Identified & located 4 wire break events and 23 wire cut events

Confirmed effectiveness of cable strengthening measures

Estimated economic benefit in range of $25-36 million

Challenge

The Waldo Hancock Bridge, located in the state of Maine, was completed in 1931. Its deck carried one lane of traffic per direction, while two narrow reinforced concrete sidewalks were used for pedestrian traffic.

Partially due to the National Bridge Inspection Standards (NBIS) stipulated by the Federal Highways Administration (FHWA), a number of inspections of the superstructure were carried out starting in the early 1990s. Portions of the main cables were unwrapped and inspected in 1992, 1998, and 2000. Due to signs of stage-3 corrosion during the 1998 small-scale investigation, the 2000 investigation was expanded to include more panel points on the North cable.
This investigation included four openings on the North cable, and one opening on the South cable. The safety factor had originally ranged from 3.0 to 3.2, based on no damage of the main cable. The wire breaks counts observed reduced the safety factor to just below 2.4 at two of the five locations investigated.

Since the cable condition was worse than anticipated, the bridge owner decided to implement a significant rehabilitation program to extend the life of the structure.

The major component was to replace the external main cable protection system. is replacement enabled an extensive visual inspection of the strands, with further wedging performed at select areas. During this exercise, it was discovered that the extent of the corrosion was beyond what the five panel inspection showed. At the worst location, 10 of the 37 strands were not carrying load, with one strand 100 percent corroded. is occurred on the South cable, where previously only one panel was inspected, reducing the calculated safety factor to 1.5 at the posted carrying limit of 12 tons.

Solution
This situation required emergency strengthening measures. First, a SoundPrint® acoustic monitoring system was installed on both main cables. To save installation time, a wireless system with 22 sensors was used. Load restrictions were placed on the bridge, and until the acoustic monitoring system was fully functional, the bridge was restricted to one-way traffi c for a short time. A total of eight supplementary strands were placed above each main cable, connected directly to each cable band with supplementary suspenders. The heavy concrete sidewalk was removed and replaced with a steel-wood combination.
Results

The acoustic monitoring system detected 4 wire breaks in the first 50 days of monitoring the cables (1 on the North cable, and 3 on the more damaged South cable). Once the supplementary cables were installed and the deck lightened, the wire breaks on the main cables stopped. To give all parties confidence, wires were periodically cut to demonstrate the effectiveness of acoustic monitoring system. Nine wires were cut and successfully recorded before the monitoring began, and a further 14 individual wires were cut and recorded over the following two years. In this case, the acoustic monitoring system was used to:

  • Provide utility during the critical period when strengthening measures were required
  • Extend the life of the bridge for an additional three years and four months, until a replacement bridge could be designed and built.

Approximately $1.1 million was spent monitoring the bridge using acoustics over this time period. Client estimated that the economic benefit of removing the load restrictions for heavy trucks, and not fast-tracking the new bridge was in the range of $25-$36 million.

Case Study

The District of Columbia’s water distribution system serves 600,000 residents and 16.6 million annual visitors to the nation’s capital. Local water utility DC Water provides water and wastewater service to the region, with water distribution assets that include approximately 1,300 miles of water pipes, 1,800 miles of sewer lines, 36,000 pipeline valves and 9,300 public fire hydrants.

Project Details

Services
Asset management

Operations improvement

Information services

Engineering support

Timing
2015
Pipe Material
PCCP, LCP, BWP
Inspection Length
4.74 km (2.9 miles)
Diameter
750mm-900mm (29-35 inch)
Transmission Type
Water

Project Highlights

 

Hands-on inspection of all

9,300

fire hydrants in district

 

Program replaces/upgrades about

3,000

most critical hydrants

Program gathers location data, operational capabilities, flow rate and maintenance
History

Possibly first city in U.S. to use Google Earth to display hydrant location & maintenance information

Challenge

Almost half of DC Water’s fire hydrants were antiquated units made at a local prison foundry that closed decades ago, causing problems with their incompatible hose outlet threads, nonstandard hydrant components and the lack of any source for replacement parts.

The other half of DC Water’s fire hydrants included about 24 different hydrant makes and models, but only two of those hydrant types met approved industry standards. Further, the utility was unsure of the precise location of many of their hydrants. They had no reliable information about their maintenance history, their operational flow rate–or even if they worked at all.

Several high-profile incidents involving inoperable fire hydrants at the scenes of major fires in the Washington DC area accelerated a planned DC Water project to inspect, operate and assess the mechanical condition and operational reliability of all the hydrants located within the District of Columbia. To help lead the program, DC Water partnered with the industry leader in hydrant management solutions, Wachs Water Services.

Solution

The project called for a hands-on inspection of all 9,300 public fire hydrants within the District of Columbia, replacing or upgrading about 3,000 of the most critical fire hydrants and installing about 600 new hydrants each year.

The project also required gathering and recording vital hydrant location data, and operational capabilities and flow rate, maintenance history, and current functional status into DC Water’s GIS (geographical information systems) and CMMS (computerized maintenance management systems) so the vital information could be accessed quickly during an emergency response.

Results

The Wachs Water Services team began with an analysis of the utility’s existing records, maps and documentation to help find “cannot locate” hydrants and their connecting valves and pipelines, and enter the correct location data into the utility’s GIS system.

Teamed with DC Water employees, Wachs Water Services field crews methodically located, operated, and flow tested the thousands of fire hydrants and isolation valves, repairing or replacing them as needed, and “color banding” the hydrants to serve as a visual indicator so firefighters are instantly aware of the water flow capacity of a particular hydrant.

As the field technicians operated each hydrant, they also recorded its precise GPS location, and collected critical data describing the operational status of each hydrant, including manufacturer, model, installation data, repair history, flow rate and number of turns to open. This hydrant attribute data was entered into DC Water’s GIS system for quick system-wide retrieval and analysis.

DC Water became one the first US cities to use Google Earth to publicly display hydrant location and maintenance information. DC Water has become a national example of how to comprehensively upgrade and renew an aging water distribution system to better serve the public.

In North America, the material and size of pipes that make up water and sewer networks range widely. Because these pipeline systems are so complex, it requires a strategic approach based on risk and real data for effective long-term management.

Worker inspecting pipe

Historically, however, it has been challenging to gather real data that can shape defensive capital decisions for an entire system. The assessment of metallic pipelines — which make up most water and pressurized sewer networks — differs from prestressed concrete cylinder pipes (PCCP), both in terms of failure modes and in the fact that metallic pipe materials are featured in both transmission and distribution networks.

While PCCP assessment and management have been successfully used by utilities for years, effective assessment solutions for ferrous pipe have only recently been commercialized.

In 2011, Pure Technologies began an initiative to help close the gap in metallic pipe assessment technologies, and focus attention on gathering honest feedback from proactive utilities on what solutions are needed to effectively manage metallic pipe.

Seven years later, Pure Technologies reports that notable progress has been made with the development and advancement of assessment technologies for metallic pipeline networks.

Team of workers with a metallic pipe

Many proactive utilities involved in guiding Pure’s research efforts

Proactive utilities have been involved in the metallic pipe initiative, and instrumental in the development of new inspection tools for metallic pipe, both by providing feedback that helps guide research and development, and by providing opportunities that allow solution testing in live operating conditions. As a result of these efforts, there has been significant improvements to the technologies available to utilities for assessing the condition of metallic pipelines in both transmission and distribution networks.

For large-diameter transmission mains, there is a well-developed business case for assessing these mains as they approach the end of their useful life. These pipelines typically carry a high replacement cost and are higher risk — due primarily to their size and criticality — making it important for utilities to fully understand the condition of the asset.

Armed with real condition data, utilities can make a defensible renewal or replacement decision about the pipeline. Based on well over 14,000 miles of data, Pure Technologies has found that only a small percentage of pipes are in need of immediate renewal.

Small diameter metallic pipe leak

Case for using inline tools for small diameter pipelines

In distribution networks, however, the case for condition assessment is more challenging as smaller pipelines can sometimes be replaced cost-effectively. Despite this, the process for making a replacement decision should be based, whenever possible, on risk and real data.

With the EPA suggesting that between 70 and 90 percent of pipes being replaced have remaining useful life, the case is even stronger for collecting condition data to drive the decision making to help utilities spend their replacement dollars more efficiently and avoid replacing pipe with remaining useful life.

In some instances with smaller diameter pipes, it is often cost-efficient to use inline tools to gather detailed screening data on a pipe-by-pipe basis to determine if replacement is necessary.

A new approach to metallic pipeline management

While there is no silver bullet technology for assessing metallic pipelines, Pure has developed a flexible, risk-based approach to help utilities better understand their infrastructure, gather actionable data and prioritize both short and long-term management efforts.

Over the past few years, Pure has worked along proactive utilities to develop its data-driven Assess and Address® approach, which focuses on four main areas:

  • Understand
  • Assess
  • Address
  • Manage

Through the implementation of programs across North America, Pure has found that the majority of pipelines 16 inches and above can be cost-effectively managed for between 5 and 15 percent of the replacement cost.

Starting an effective pipeline management program

The first step of any pipeline management program is understanding the system-wide risk along with the benefits and limitations of assessment solutions. This allows for the development of a defensible management strategy that can be implemented to maintain and extend the life of the assets.

Many technologies now exist to provide a snapshot of a pipeline condition at various levels of confidence. It is therefore prudent for utilities to approach technology selection and subsequent analysis based on the risk of each pipeline.

A more thorough risk assessment involves estimating the Consequence of Failure (CoF) and the Likelihood of Failure (Lof) of each pipeline based on internal knowledge, operational history and pipeline characteristics. This initial risk assessment determines which areas of the system require further assessment to acquire real condition data and provides the utility with the necessary information to make an informed technology selection.

By using risk to guide management strategies, owners can ensure they are implementing the right approach, at the right time, with the lowest financial impact. The goal of a management program should always be o focus resources on managing the asset while safely getting the most service life out of the pipeline.

Sinkhole in a street

Reducing the Consequence of Failure

Reducing CoF comes down to improving emergency events through field operations efficiency. Studies have shown that the time to shut down a pipeline had more impact on the consequence of failure than the diameter of the pipeline.

Utilities can reduce CoF — and in turn risk — by gaining a better control on their system, which can be achieved two ways:

  • 1. Adding valves and redundancy in the system
  • 2. Knowing the location, condition and operability of control points

For example, if a pipe fails and utility operations staff are unable to locate valves — or the valves are inoperable when they are located — it will take longer to isolate a pipe failure. This will result in greater damage, more water loss and longer outages and repair times as a result of the failure. Implementing a proactive program for control assets that focus on providing better data for field staff reduces CoF by decreasing emergency response time.

Reducing the Likelihood of Failure through condition assessment

Many factors influence the likelihood that a pipeline will fail. Metallic pipelines, specifically, have a variety of failure modes and require a wide array of technologies to accurately assess their condition. Until recently, technologies for metallic pipe assessment have been unavailable or limited in their viability.

As a result, lower risk metallic mains have historically been prioritized for replacement using age, material and break history, while higher risk mains have sometimes been assessed with test pits along the length of the pipeline. After test pitting, statistical methods are used to extrapolate the condition of the test pit locations along the entire pipe length.

Through the development of metallic assessment solutions, condition data shows that pipe distress is often random and localized, meaning that an area of distress identified during the test pit method may inaccurately identify the entire pipeline as distressed, conversely, identify the entire length of pipeline as in good condition.

The development of reliable inline condition assessment tools provides owners with pipe-by-pipe data that gives a more complete picture of the actual condition of the pipeline. This allows for a more targeted management of small sections of pipe instead of generalizing the condition of an entire pipe length. It also allows for the collection of real data to drive pipeline renewal, which allows for more defensible capital decision making.

Case Study

The Milwaukee Metropolitan Sewerage District (MMSD) takes a proactive approach to water management initiatives, as evidenced in the condition assessment of the Franklin-Muskego Force Main.

Ownership of the pipeline is shared between the City of Muskego and MMSD, the government agency that provides water management services for about 1.1 million people in 28 communities in the Greater Milwaukee Area.

In 2015, Pure Technologies (Pure) worked closely with MMSD to perform a detailed condition assessment of the approximately 25-year old ductile iron pipeline. The purpose of the assessment was to identify the structural condition of the metallic force main, and included pressure monitoring, a SmartBall® leak and gas pocket detection survey, and a PipeDiver® electromagnetic inspection of the pipeline.

Project Details

Services
SmartBall® Leak and Gas Pocket Detection
PipeDiver® Electromagnetic Inspection
Transient Pressure Monitoring
Structural Engineering
Timing
2015
Pipe Material
Ductile Iron
Inspection Length
2.9 miles (4.7 kms)
Diameter
20-30 inches (500-750mm)
Transmission Type
Wastewater

Project Highlights

Inspection identified 13 pipe sections with electromagnetic anomalies

Defects ranged from 20-55% wall loss

Transient pressure monitoring indicated pipeline operating within design capacity

Challenge
The Franklin-Muskego Force Main carries wastewater along approximately 3 miles of 24-inch and 30-inch ductile iron pipe (DIP). One of the challenges in assessing DIP is determining if the pipe has undergone any wall thickness loss due to internal or external corrosion, which are the primary causes of failure. DIP in water service with a cement mortar lining generally has fewer internal corrosion failure rates, unless damaged during handling and installation, or later as a result of 3rd party damage. This is not the case when DIP is used in a force main, where internal corrosion is the primary cause of failure.

Gas pockets are of significant concern as concentrations of hydrogen sulfide gas within wastewater may cause corrosion and eventual breakdown of the pipe’s exposed surface. In a force main, identifying internal areas with potential corrosion is challenging, as traditional gravity pipeline inspection techniques are often not applicable to in-service pressurized pipelines.

One method for assessing gas pockets is to locate air release valves (ARVs) or other high points along the alignment and conduct test pit investigations in those areas. While this is a valid method for locating potential gas pocket locations, additional gas pockets may occur due to differential settlement, improper installation or non-functioning ARVs. Desktop surveys may not identify and locate all gas pockets along a pipeline, which is why Pure recommends other more precise survey methods.

Solution
To evaluate the condition of the Franklin-Muskego force main, Pure recommended in-line condition assessment. This included inspecting for the presence of gas pockets, using electromagnetics for assessing the condition of the pipe wall and structural engineering to evaluate the significance of defects found.

In October 2015 Pure performed a SmartBall leak and gas pocket detection survey and a PipeDiver electromagnetic inspection of the Franklin-Muskego Force Main. The SmartBall platform is a free-swimming tool that uses acoustics to detect leaks and gas pockets while the pipeline remains in full service. Pure’s flexible, free-swimming PipeDiver tool collects electromagnetic (EM) data that is used to measure the relative wall thickness of the cylinder – the main structural component of the pipeline. With electromagnetics onboard, PipeDiver can identify localized areas of wall loss in the cylinder of the pipe, and broken bar wraps in BWP, all while the pipeline remains in service.

Results
The results of the C150 design check showed that the pipe’s nominal wall thickness is sufficient for current loading conditions. Transient pressure monitoring indicated that over the period of monitoring, the pipeline operated within its design capacity.

Through the PipeDiver inspection, 13 pipes were found to have a total of 16 electromagnetic anomalies consistent with localized wall loss, ranging between 20 percent to 55 percent wall loss. At the time of writing, MMSD was making plans to excavate and repair one pipe section with three areas of pipe loss ranging from 35 percent to 55 percent wall loss. The results of the condition assessment indicate that the Franklin-Muskego Force Main is in good condition.

While the assessment recognized several areas with an increased likelihood of failure, overall the data was good, and coupled with Pure’s engineering recommendations, gave all stakeholders confidence in the health of pipeline for the near foreseeable future.

Case Study

Following a water main break in 2009 that resulted in the loss of 15 million gallons of treated water, LWC began a Transmission Assessment Program, using various assessment technologies from Pure Technologies.

Project Details

Services
PureRobotics® electromagnetics (EM) condition assessment

PureRobotics HD-CCTV inspection

Inertial measurement unit for GIS component

Risk prioritization

Timing
2015
Pipe Material
PCCP
Inspection Length
3.4 miles (5.5 kms)
Diameter
24-30 inches (610-760mm)
Transmission Type
Water

Project Highlights

EM data identified 17 anomalies warranting further investigation

HD-CCTV identified longitudinal cracks consistent with overloading

One (1) pipe section found to display anomalous EM signals associated with broken wire wraps and wall cylinder loss

Challenge
In the summer of 2015, LWC deployed PureRobotics to assess 3.4 miles of 24 to 30-inch transmission mains in its network. With 4,100 miles of pipeline to maintain, (200 miles of it transmission main) LWC focused its condition assessment on its transmission main system – pipes that would cause the greatest amount of damage in the case of failure. The loss of non-revenue water, either chronically in small amounts or from a catastrophic failure, can result in massive costs to a water utility.

By prioritizing the risk levels associated with their transmission main system, LWC has created an ongoing inspection program to keep a watchful eye on the health of their pipelines. The program utilizes a number of Pure Technologies assessment tools to find active leaks as well as potential future threats.

Solution
In May of 2015, PureRobotics was deployed on the Cross County Header, Ray Lane Easement Pipeline, and Bardstown Road Pipelines. The latest generation robotic crawler is designed to carry sensors and tools up to 1.8 miles (2.9 kilometers) through potable water or wastewater at a speed of 85 feet per minute. For LWC, PureRobotics used CCTV to provide a comprehensive high-definition visual inspection.

The robotic crawler was also outfitted with specialized tools to conduct an electromagnetic assessment on the condition of the pipeline and inertial measurement unit (IMU) for the GIS component. The Inertial Measurement Unit (IMU) deployed with PureRobotics uses a series of Fiber Optic Gyroscopes (FOGs) and accelerometers to track depth, lateral and horizontal movements from a known GPS reference point. The output is a GIS spatial map of the pipeline which depicts elevation changes as well as notable features of interest encountered during the inspection.

Pure’s electromagnetic assessment uses transformer coupling to detect anomalous regions in the pipe cylinder and prestressing wires. This data is correlated with odometer readings from the PureRobotics umbilical tether as well as HD recorded CCTV and IMU to attempt to locate areas of distress in the pipeline.

Results
High definition CCTV inspection results showed a number of longitudinal cracks consistent with overloading. These types of mortar cracks may eventually lead to corrosion of the steel cylinder or prestressing wire and eventually a failure of the pipe.

One pipe section in the Ray Lane Easement pipeline was found to display anomalous electromagnetic signals showing a significant number of broken prestressing wire wrap breaks as well as cylinder wall loss. This was correlated with visual data, showing spalling and exposed steel at the invert of the pipe. LWC intends to investigate this issue at a later date.

Visual assessment also showed a number of pipe sections with spalling. Pure recommended continued monitoring at these locations during future inspections. Electromagnetic assessment also found 11 pipes with anomalous signals not consistent with wire breaks. Investigation performed on one of these anomalous pipes showed a non-standard metal sleeve used in manufacturing. From this information, it was determined that the remaining 10 anomalous pipes could be left in service.

As one of the first utilities to deploy the third generation PureRobotics platform, LWC now has defensible data to move forward with its ongoing rehabilitation program.

A growing number of proactive municipal utilities and power generating operators across North America are reaping the benefits of deploying the latest robotics crawler from Pure Technologies (Pure) to assess the condition of their pipeline networks and save millions of dollars in water loss and prevented breaks.

Unlike slower, limited-distance crawlers, the third generation robotic transporter can quickly navigate up to 1.8 miles (2.9 kilometres) through potable water with ease, and deliver live video and integrity information that can aid in detecting leaks and other anomalies in underground pipes. Since introduction, the latest PureRobotics® platform has delivered data over more than 186 miles (300 km) of pipe and has been deployed for clients including Austin Water Utilities, The City of Ottawa, City of El Paso and Louisville Water.

“We absolutely crushed our previous distance covered in a single day…”

The rollout of our latest generation robot will deliver additional benefits to our clients by providing detailed, real-time, internal condition data in about half the time as the previous generation,” stated Mark Holley, Executive Vice President and Chief Operating Officer of Pure Technologies. “This will reduce our inspection time and correspondingly reduce any facility downtime. In addition, the modular design allows us to customize tools to inspect a broader variety of pipeline sizes and types.


Robot's faster speed important for time-critical shutdowns

 

The PureRobotics pipe inspection system is a modular transporter designed to carry sensors and tools through dewatered pipe or while submerged in depressurized pipes. The advanced robotic crawler is safer than manned inspections, especially where regulations are keeping people out of pipelines in favour of unmanned solutions.

With the new generation of robot, the speed is doubled to 85 feet per minute, which greatly improves efficiency in the field, a huge benefit during time-critical shutdowns.

The standard system features HD digital, pan tilt zoom, closed circuit television for live video streams. The robot can be equipped with a variety of specialized tools including an inertial measurement unit for XYZ mapping geographic information, 3-D LIDAR scanning tools, electromagnetic sensors for assessing the structural integrity of pipelines, or pull condition assessment tools such as 2-D laser technology that can precisely measure a pipeline’s size, shape and level of corrosion.

 

PureRobotics deployed on reclaimed water line for nuclear plant

 

Recently the latest generation PureRobotics platform was deployed during a multi-tool inspection for a reclaimed water line operated by a major U.S. nuclear plant.

Since 1998, the plant has assessed its reclaimed water pipeline using electromagnetic technology(EM) from Pure Technologies to ensure the station continues to operate safely. The inspections cover prestressed concrete cylinder pipes (PCCP) that range from 96 inches to 144 inches in diameter.

The EM inspections are typically performed using the PureRobotics™ delivery platform, or by using manned inspection tools so the pipeline can be visually inspected as well. Electromagnetic inspection provides high quality condition assessment data for understanding the structure integrity of large-diameter pressure pipelines. For the nuclear plant, it is used to assess the number of broken prestressing wire wraps on the PCCP pipeline.

During the latest scheduled EM inspection conducted in 2017, Pure deployed its latest generation robotic crawler.

Robotic crawler beats record and delivers 18,000 feet of condition data in single day

 

What made the inspection so remarkable was the speed of the robot and inspection distance covered during the time-critical shutdown. The inspection set a record for distance covered in a daily inspection, upwards of 18,000 feet of condition assessment footage delivered per day, compared to previous record of 11,000 feet. The robotic inspection covered total distance of nearly 14 miles.

We absolutely crushed our previous distances covered in a single day,” said James Milward, lead developer for the robotic crawler. “The conditions were right, and because we leapfrogged the access points, we finished way ahead of schedule. When you’ve only got a small window of inspection time during a scheduled shutdown, any time saved is a bonus for the client. They were very happy with the outcome.

Good data, faster inspection times, better efficiency, no hiccups, you couldn’t ask for a better inspection project.

Case Study

In early 2015, Pure Technologies (Pure) conducted a condition assessment of Pipeline No. 1 owned and operated by The City of Tacoma (Tacoma Water), as part of their proactive asset management program. Pipeline No. 1 is a critical link in Tacoma’s transmission system, conveying up to 72 MGD of potable water over a 26-mile stretch to the McMillin Reservoir. Tacoma Water provides water service to more than 300,000 residents throughout Pierce and King Counties in Washington.

While the critical pipeline has had previous condition assessment and repairs on targeted sections, the goal of the latest survey was to provide Tacoma Water with detailed assessment information to determine future repair, rehabilitation and re-inspection strategies.

Project Details

Services
PureEM™ manned electromagnetic inspection

Handheld ultrasonic thickness testing

Structural engineering analysis using 3-dimensional nonlinear finite element analysis (FEA)

Remaining useful life projections using Monte Carlo simulation

Timing
48 Hours
Pipe Material
Welded Steel
Inspection Length
917 feet (279 meters)
Diameter
48-52 inches
Transmission Type
Water

Project Highlights

Survey covered 917 feet and spanned 125 pipes

12 pipes identified with electromagnetic anomalies

Defects identified ranged from 15 to 35 percent wall loss

Inspection deployed 48-detector electromagnetic tool

Challenge

By the end of 2013, Tacoma had repaired approximately 15 leaks at 3 locations along the section of Pipeline No. 1 located near Boise Creek. In order to investigate this section of pipeline further, Tacoma decided to excavate the pipe in select locations to observe the condition of the pipeline.

Several areas with minor pitting were identified during the investigation. Due to the critical nature of this pipeline, Tacoma decided to take further action on the main and considered a replacement project.  However, before proceeding, Tacoma wanted to validate the need to replace this section of pipe.

As a result, a comprehensive condition assessment of the main was performed to confirm its condition before initiating an expensive and disruptive replacement project. Owing to the criticality of the line, Pure had only 48 hours to conduct the non-destructive condition assessment, using its proprietary electromagnetic technology (PureEM™) on just over 900 feet of pipe.

Solution

Assessing the condition of metallic pipelines is a challenging task best performed using a combination of assessment methodologies, engineering science and experiential judgment. Pure’s PureEM electromagnetic tool was used to evaluate the condition of the pipe wall and identify localized areas of wall loss. The significance of the results were evaluated through structural engineering, and long-term recommendations were made based on statistical modeling and remaining useful life projections.

As the pipeline could only be taken out of service for 48 hours, this required careful planning and extensive tool preparation. The PureEM tool was inserted through an existing manhole access and assembled in the pipe. During the inspection, technicians gathered electromagnetic data, numbered the pipe, and took detailed notes on the internal visual condition of the pipe. UT thickness measurements were also collected on the pipe in several areas.

A pre-inspection calibration of the PureEM tool allowed for more precise quantification of the defect identified through the EM inspection. This involved destructive testing on an above-ground 52-inch welded steel pipe of similar vintage to calibrate the EM signal changes for this particular type of pipe.

Following the inspections, Pure’s structural engineers used finite element modeling to evaluate the significance of the defect identified. Finally, a Monte-Carlo simulation was employed to estimate the pipe’s remaining useful life.

Results

Analysis of the electromagnetic data obtained during the inspection determined that of the 125 pipes surveyed, 12 pipes had electromagnetic anomalies consistent with wall loss ranging from 15 percent to 35 percent.

The results of the structural analysis indicate that the internal stresses in the subject pipeline are very low compared to the structural capacity of the pipe. None of the detected anomalies are at or near a point of concern, and the pipeline can be operated without immediate rehabilitation.

With the remaining useful life estimated at the pipeline operating without significant risk of structural failure in the next 30 to 50 years, Tacoma Water now has data-driven confidence in the short and long-term management of Pipeline No. 1.

As a result of Pure’s Assess and Address® approach, the City of Tacoma avoided near-term replacement of the main, which was estimated between US$2 to 3 million.

Quote

“With the remaining useful life estimated at the pipeline operating without significant risk of structural failure in the next 30 to 50 years, Tacoma Water now has data-driven confidence in the short and long-term management of Pipeline No. 1.  As a result of Pure’s Assess and Address® approach, the City of Tacoma avoided near-term replacement of the main, which was estimated between US$2 to 3 million.”

Case Study

The Milwaukee Metropolitan Sewerage District (MMSD) takes a proactive approach to water management initiatives, as evidenced in the recent condition assessment of the Franklin-Muskego Force Main.

In 2015, Pure Technologies (Pure) worked closely with MMSD to perform a detailed condition assessment of the approximately 25-year old ductile iron pipeline. The purpose of the assessment was to identify the structural condition of the metallic force main, and included pressure monitoring, a SmartBall® leak and gas pocket detection survey, and a PipeDiver® electromagnetic inspection of the pipeline.

Project Details

Services
SmartBall® leak and gas pocket detection

PipeDiver® electromagnetic inspection

Pressure monitoring

Structural engineering

Timing
2015
Pipe Material
Ductile Iron
Inspection Length
2.9 miles
Diameter
20-inch to 30-inch
Transmission Type
Wastewater

Project Highlights

Condition assessment on

4.7km

of feedermain pipes

Data identified

8

pipes with electromagnetic anomalies consistent with broken pressing wire wraps

HD-CTTV identified

3

pipes with damaged internal mortar and exposed cylinder

Challenge

The Franklin-Muskego Force Main carries wastewater along approximately 3 miles of 24-inch and 30-inch ductile iron pipe (DIP).

One of the challenges in assessing DIP is determining if the pipe has undergone any wall thickness loss due to internal or external corrosion, which are the primary causes of failure. DIP in water service with a cement mortar lining generally has fewer internal corrosion failure rates, unless damaged during handling and installation, or later as a result of 3rd party damage.

This is not the case when DIP is used in a force main, where internal corrosion is the primary cause of failure. Gas pockets are of significant concern as concentrations of hydrogen sulfide gas within wastewater may cause corrosion and eventual breakdown of the pipe’s exposed surface.

In a force main, identifying internal areas with potential corrosion is challenging, as traditional gravity pipeline inspection techniques are often not applicable to in-service pressurized pipelines.

One method for assessing gas pockets is to locate air release valves (ARVs) or other high points along the alignment and conduct test pit investigations in those areas. While this is a valid method for locating potential gas pocket locations, additional gas pockets may occur due to differential settlement, improper installation or non-functioning ARVs.

Desktop surveys may not identify and locate all gas pockets along a pipeline, which is why Pure recommends other more precise survey methods.

Solution

To evaluate the condition of the Franklin-Muskego force main, Pure recommended in-line condition assessment. This included inspecting for the presence of gas pockets, using electromagnetics for assessing the condition of the pipe wall and structural engineering to evaluate the significance of defects found.

In October 2015 Pure performed a SmartBall leak and gas pocket detection survey and a PipeDiver electromagnetic inspection of the Franklin-Muskego Force Main.

The SmartBall platform is a free-swimming tool that uses acoustics to detect leaks and gas pockets while the pipeline remains in full service.

Pure’s flexible, free-swimming PipeDiver tool collects electromagnetic (EM) data that is used to measure the relative wall thickness of the cylinder – the main structural component of the pipeline. With PureEM® onboard, PipeDiver can identify localized areas of wall loss in the cylinder of the pipe, and broken bar wraps in BWP, all while the pipeline remains in service.

Results

The results of the C150 design check showed that the pipe’s nominal wall thickness is sufficient for current loading conditions. Transient pressure monitoring indicated that over the period of monitoring, the pipeline operated within its design capacity.

Through the PipeDiver inspection, 13 pipes were found to have a total of 16 electromagnetic anomalies consistent with localized wall loss, ranging between 20 percent to 55 percent wall loss. At the time of writing, MMSD was making plans to excavate and repair one pipe section with three areas of pipe loss ranging from 35 percent to 55 percent wall loss.

The results of the condition assessment indicate that the Franklin-Muskego Force Main is in good condition.

While the assessment recognized several areas with an increased likelihood of failure, overall the data was good, and coupled with Pure’s engineering recommendations, gave all stakeholders confidence in the health of pipeline for the near foreseeable future.

Case Study

The Foothill Municipal Water District (FMWD) serves approximately 86,000 people through its member agencies located in the foothills of the San Gabriel Mountains, bordered between the City of Pasadena and the City of Glendale. In March 2013, Pure Technologies (Pure) successfully completed in La Canada Flintridge, a 2.2-mile internal inspection and condition assessment of a 24-inch mortar-lined steel force main to identify broad areas of wall loss.

Project Details

Services
PureRobotics™ electromagnetic condition assessment inspection

PureRobotics HD-CCTV inspection

Structural assessment

Engineering services

Risk prioritization

Timing
2013
Pipe Material
Mortar-lined Steel
Inspection Length
2.2 miles (3.55 km)
Diameter
24-inch (610-mm)
Transmission Type
Water

Project Highlights

EM data identified 17 anomalies warranting further investigation

FMWD selected 2 locations to perform test pitting

Results revealed minimal wall loss and continued operation of water main

Challenge

For utilities like FMWD, which has no redundancy in its system, finding a reliable inspection method that provides condition data for the entire length of a steel pipeline is an important aspect of its condition assessment program.

As well, as part of the condition assessment, a structural evaluation was performed to determine whether the force main design satisfies AWWA M11 “Steel Pipe – A Guide for Design and Installation, fourth edition” standards. The results of this evaluation has helped FMWD determine where to focus more detailed inspections in order to make detailed rehabilitation decisions for this force main.

Solution

To complete the inspection, FMWD used PureRobotics electromagnetic condition assessment equipped with electromagnetic technology and high-definition closed circuit television (HD-CCTV). The platform is a non-destructive, in-line assessment tool that provides screening level wall thickness data in the circumferential and axial directions of metallic pipelines.

The robotics tool used was assembled inside the pipeline and controlled remotely by operators on ground level. This allowed FMWD to maximize the HD-CCTV function as internal features could be closely inspected with the camera. By opting for an inline assessment in favor of traditional metallic inspection methods, FMWD has a baseline condition of the entire 2.2-mile water main.

Results

After reviewing the electromagnetic data, Pure Technologies was able to identify 17 electromagnetic anomalies that warrant additional investigation. Using the resulting information, the top 10 anomalies were ranked based on the strength, area and repeatability of signal loss and visually using HD-CCTV.

FMWD selected two locations to perform test pitting to obtain higher resolution data needed to evaluate rehabilitation or repair needs and determine the remaining useful life of the water main.

Results of the two test pits revealed minimal wall loss and resulted in the continued operation of the steel water main with no rehabilitation required. Ranking the anomalies based on size allowed the prioritization of further inspection based on sound and defensible engineering judgment.

Risk prioritization is an important facet of any condition assessment program because it allows the most urgent needs to be addressed first. By proactively managing its pipeline assets, FMWD is able to continue to deliver quality water to its member agencies in a cost-efficient manner to meet their projected demands.

Case Study

Daphne is located along the eastern shore of Mobile Bay, an area served by Daphne Utilities, which provides water, wastewater, and natural gas services to approximately 25,000 residents.

In 1985 the City purchased the Lake Forest Utility, and in doing so, Daphne Utilities took over their existing wastewater treatment plant, which was built in the 1970s.  The facility discharges through the Daphne Outfall, a 6,000-foot, 18-inch ductile iron effluent pipeline that discharges treated wastewater into Mobile Bay. Although the main was critical to the City, little information about it was transferred when Daphne Utilities acquired the facility.  Daphne Utilities later officially named the facility the Water Reclamation Facility.

Project Details

Services
Mapping deliverable

Pipeline alignment

Sahara® leak and gas pocket detection

Timing
One (1) day
Pipe Material
Ductile Iron
Inspection Length
1000 feet (304 meters)
Diameter
18-Inch (457mm)
Transmission Type
Treated Wastewater

Project Highlights

Pipeline assessment hampered by

non-existent plans

Obstacles in pipeline path include

urban development and wildlife sanctuary

Zero (0) leaks

eight (8) gas pockets detected

One (1) day

mobilization
1000ft inspected

Challenge
For many years after Daphne Utilities took over the Water Reclamation Facility the outfall line operated as a gravity discharge line. As the population grew and flows to the plant increased, Daphne Utilities installed pumps to occasionally increase the volume of treated wastewater passing through the discharge line. As development expanded, the situation progressed from a time when the pumps occasionally ran, to the point where the pumps ran almost continuously.

Gravity main transformed into a force main

Now, a pipe designed as a gravity main had transformed into a force main, pumping under pressure at all times, with its location and condition unknown – and with no redundancy.

To proactively manage this critical asset, in June 2015, Daphne Utilities retained the services of Pure Technologies (Pure) for a one-day Sahara® leak and gas pocket detection inspection of the Daphne Outfall, with a mapping deliverable.

The primary purpose of the inspection was to determine the pipeline alignment, since you can’t maintain what you can’t locate.  Since the 18-inch outfall was built, the terrain had changed markedly.  The original shoreline had been extended by hundreds of feet to accommodate the construction of a major highway and several hotels and restaurants.
In fact, based on best guesses and poor drawings, Daphne Utilities suspected that a five-story Hampton Inn had been built on top of the 18-inch outfall!
In short, Daphne Utilities didn’t know the exact pipeline location or its operational conditions.

Solution
To ascertain the alignment and condition of the 18-inch outfall, Daphne Utilities engaged Pure Technologies for a single day inspection.  In addition to the challenge of not knowing the exact pipeline alignment, it also appeared that the pipeline traversed under a swamp sanctuary for hundreds of alligators and other wildlife, in an area known as “Gator Alley.”

To conduct the mapping and assessment survey, Pure recommended the Sahara leak and gas pocket detection platform. Sahara is an inline tethered tool that can assess pipelines 6 inches and larger, without any disruption to service.

Because the sensor tool is tethered, an operator can stop and reverse the tool to investigate acoustic events such as leaks, gas pockets and visual anomalies. At the same time, an above-ground operator locates the sensor above ground, marking the exact location of the pipeline at any point along the pipe with sub-meter accuracy.

The mapping capability of Sahara allows utility owners to determine the exact location of their pipeline at any point, as well as the location of any leaks or gas pockets.

Results
Analysis of the acoustic data identified zero (0) leaks and eight (8) air pockets, which were impacting the efficiency of the line, as gas pockets occupy space within the already maxed-out pipeline. During the inspection, the alignment of the pipeline was determined and recorded from the treatment plant to the edge of the marsh where Mobile Bay starts, confirming the pipeline does indeed pass underneath the Hampton Inn.

In a single day, the Sahara crew determined flow velocity, inserted the tethered tool, inspected 1,000 feet, determined the pipeline alignment, and confirmed its location and the location of 8 gas pockets. As a result, Daphne now knows they have gas pockets and they now know the line location in order to execute a plan to deal with the gas pockets.

Not bad for a day’s work.

Since 2007, utilities all over the world have been using the SmartBall® pipeline inspection platform to save millions of dollars in water loss and to fix leaks before they turn into larger problems.


Developed by Pure Technologies (Pure), the tool is trusted by utilities for two main reasons. One is for condition assessment purposes, and the other is for reducing non-revenue water. From a condition assessment perspective, SmartBall® is a proactive tool that can be used as part of a larger holistic approach to help identify problem areas that require repairs before they turn into bigger issues, and also to help utilities prioritize capital spending.

SmartBall inside a pipe.

Detect and locate acoustic sounds related to leaks and gas pockets

The primary purpose of the SmartBall tool is to detect and locate the acoustic sounds related to leaks and gas pockets.

“Unlike traditional correlators, the SmartBall sensors travel inline along the pipe, inspecting every inch of the water main to detect potential problems such as leaks and gas pockets. Based on thousands of miles of experience, the SmartBall tool has found three to four times more leaks than trunk main correlators, which are traditionally used in smaller diameter pipes, and are less effective for transmission mains and larger diameter pipes.”

Cam White

Business Line Manager, SmartBall

Deployed for long runs in one inspection for water and wastewater pipelines

What makes the SmartBall tool so remarkable is its ability to get into and out of pipelines very easily, and to be deployed for long runs in one inspection for both water and wastewater pipelines. The tool requires only two access points – one for insertion and one for extraction.

For insertion, the foam-shelled SmartBall tool is placed into a claw, compressed, and then lowered into the line through a 4-inch (100mm) or larger tap, all while the line is pressurized. Throughout the survey, Pure’s inspection team constantly monitors the SmartBall’s position as it traverses the pipeline collecting data.

  • An acoustic sensor listens for leaks and gas pockets.
  • An accelerometer and gyroscope measure the SmartBall’s movement, which can later be used for pipeline mapping.
  • A magnetometer measures the magnetic field coming off the pipe wall, data that can be used to find joints and other pipeline features.
SmartBall extraction process

Multiple insertion and extraction options available

There are many alternative options available to get the SmartBall in and out of a pipeline. Having multiple options reduces the money and effort required by utilities to support the inspection.

Once the inspection is complete, the data is extracted from the ball and sent to Pure’s data analysts where they will identify leaks and gas pockets.

As utility owners know, it can be expensive to excavate, and what SmartBall tool does is provide information that’s accurate, so clients can dig up the pipeline and find the leak the first time.

Rideau Canal, Ottawa

For the City of Ottawa, the SmartBall tool is used to locate “leak-where-predicted”

The “leak-where-predicted” scenario recently happened with the City of Ottawa when Pure deployed its SmartBall inspection platform to locate leaks and pockets of trapped gas along a critical transmission main, as part of a long-term condition assessment program for the municipality.

The Baseline Road Water Transmission Main is a high priority 1220mm (48-inch) diameter pipeline comprised of lined cylinder pipe (LCP).

For the City of Ottawa project, five (5) surface-mounted acoustic sensors were placed along the pipeline to track the SmartBall tool during the inspection. The SmartBall device was inserted into the pipeline through a 100mm drain near a hospital. Acoustic and sensor data was collected and recorded as the SmartBall tool traversed the pipeline for more than three kilometers.

From the survey results, Pure detected one (1) acoustic anomaly characteristic of a leak and zero (0) anomalies consistent with pockets of trapped gas.

The “leak-where-predicted” scenario recently happened with the City of Ottawa when Pure deployed its SmartBall inspection platform to locate leaks and pockets of trapped gas along a critical transmission main, as part of a long-term condition assessment program for the municipality.

The Baseline Road Water Transmission Main is a high priority 1220mm (48-inch) diameter pipeline comprised of lined cylinder pipe (LCP).

For the City of Ottawa project, five (5) surface-mounted acoustic sensors were placed along the pipeline to track the SmartBall tool during the inspection. The SmartBall device was inserted into the pipeline through a 100mm drain near a hospital. Acoustic and sensor data was collected and recorded as the SmartBall tool traversed the pipeline for more than three kilometers.

From the survey results, Pure detected one (1) acoustic anomaly characteristic of a leak and zero (0) anomalies consistent with pockets of trapped gas.

SmartBall inside a pipe and working zone map

Ground microphones fail, SmartBall tool succeeds

Although Pure was confident in the SmartBall leak detection data, sometimes it’s worth a try to verify an anomaly with a complimentary technology. In this instance, ground microphones, regarded as a conventional a leak detection tool, were deployed to try and detect leak sounds. Although the suspect area was marked, neither Pure nor the client could pick up leak-related sounds from the ground microphone.

Even though the leak was not picked up by the ground microphone, Pure was confident that the acoustic signature from the SmartBall was caused by a leak, based on more than 15 years of experience identifying leaks. That confidence and experience proved right, and when the suspected area was excavated, the leak was located within a meter of where the data analyst calculated the leak to be.

The results gave the City of Ottawa actionable data regarding the condition of their pipeline, and the City was able to fix the leak reducing non-revenue water loss and any potentially costly damage caused by the leak. It’s a great example of a proactive utility taking efforts to improve the reliability of its services.

What keeps a water utility manager up at night? Getting a phone call from a distraught resident about an unplanned (and unwanted!) ornamental pond developing in the cul-de-sac.

On an already soggy, wet day in early November 2016, water began filling a cul-de-sac in an affluent neighbourhood in the City of Southlake, Texas. To contain surface flooding, Southlake water authorities took immediate remedial action by sequentially shutting down each water line in the area in an attempt to isolate the leak.

“As for using the Sahara tool to find the leak, upon saw cutting the street and excavating, Pure Technologies hit the bullseye yet again for Southlake.” Kyle Flanagan

Water Department Supervisor, City of Southlake

In addition, the City used external listening devices to try and locate the leak – the external listening devices indicated that some kind of leak was present, but the City was unable to pinpoint the location. In the end, the City had to shut down the 42-inch Caylor bar-wrapped potable water main, a low-pressure gravity main passing through the area. This was done to confirm that the 42-inch Caylor Main was leaking.

Sure enough, once the 42-inch Caylor Main was shut down, the water stopped surfacing. When the City reopened the main, the water did not resume surfacing. Despite the inconclusive evidence, the City remained convinced that the 42-inch main was the leak source.

Workers with horses in a field

Soggy ground, horse pasture and and muddy conditions hamper inspection

With uncertainty remaining, the City of Southlake called in Pure Technologies to assist in identifying and locating the leak. Unfortunately, the bad luck continued, as heavy rains and muddy conditions hampered Pure and its mobilization truck from access to the pipeline right-of-way. Even crews from Southlake got stuck when they tried drive the pipeline right-of-way.

One possible additional access point was available through a private owner’s horse pasture, but low-hanging power lines created a safety hazard that would prevent crews from accessing the site by that route.

Disappointed, the crews demobilized to wait for better weather or a better access point.

Sahara device

Sahara® platform selected for speed, accuracy and on-the-spot results

The next day Southlake identified another access point 1,000 feet further upstream, and prepared it for the Sahara inspection.

The Sahara leak detection platform was selected for its ability to provide same day results, and to accurately locate small leaks with sub-meter accuracy. The tethered tool is propelled by a small parachute inflated by the product flow, requiring a flow velocity as little as one foot per second to progress through a water main.

Because the Sahara inline tool is tethered, an operator has complete control, and can closely examine events of interest such as leaks, gas pockets and visual anomalies in real time.

The tool can detect up to four times as many leaks as correlators because the acoustic sensor is brought right to the leak. The Sahara platform also features inline video that allows operators to observe internal pipe conditions, and many times identify the type of leak – indicating if the leak is on a joint, in the pipe barrel, at a feature, and other details helpful for planning a repair before excavating.

Pipe inner surface

Second attempt to find the leak

For the assembled crews, pressure escalated to quickly find the leak location.

Once the Pure mobilization crew set up the installation equipment and inserted the Sahara sensor, the pressure gauge indicated only 36 PSI, not the best scenario for leak detection. Furthermore, the inspection was heading uphill toward the area of interest, and could expect even lower pressure nearer to the suspected leak location area due to loss of head pressure as the pipe ascended the slope.

Further complicating matters, the pipe wall thickness was determined to be about 4 inches, and leak paths that pass through 4 inches of concrete and mortar can often include sharp bends that can muffle leak signatures.

From the insertion point, Sahara inspected a total of 2,400 feet, passing through the cul-de-sac area at around 1,600 feet from insertion.

Sahara platform inside a pipe filled with water

A slow pullback of the tethered Sahara tool to recheck areas of interest

During deployment, review of acoustic data noted a few areas of interest, but nothing definitive. The inspection continued past these areas of interest in the hopes of finding something more conclusive.  When nothing was found, the Pure crew began a slow pullback of the tethered Sahara tool to recheck the areas of interest.

One of the benefits of a tethered tool is that two inspection passes can be conducted on the same section on the same day.

Of the possible leak areas, one acoustic anomaly seemed promising, and that spot was marked above ground.

Since Pure could not get a consistent peak location, and since the audio lacked many classic leak characteristics, it was flagged as an anomaly on site. After review of the acoustic signature off site using advanced sound enhancing software, Pure Technologies was able to resolve the signature as a leak, and reported it as a leak to the City of Southlake.

Because this suspected leak did not, even in post analysis, present with all the elements of a leak signature, and because it lacked a distinctive peak location, Pure Technologies recommended that the City of Southlake check a 7-foot length of the pipe, all the way around the pipe.

Worker digging to reveal the leak

Surprise, surprise, 4 leaks verified

As directed, Southlake crews excavated the indicated areas and found not one but four leaks. The presence of four leaks in close proximity to one another, all at low pressure, explained the difficulty of finding a leak peak.

The four leaks located ranged from pencil-sized to quarter-sized. The sloppy mortar job over an access plate into the 42-inch Caylor Main was just good enough to help muffle the leaks, but not good enough to protect the cylinder from corrosion and eventual leakage.

Small leak before being fixed

In the end, despite difficulties of inspecting small leaks in a low-pressure environment, the inspection was deemed a success, and Southlake was extremely pleased with the accurate results.

Thanks to collaboration between crews from Southlake and Pure, the mystery leak was solved. The inline tethered Sahara tool came through again.

Pensacola view from the air

The introductory meeting was pure happenstance. After a well-timed phone call, two unfamiliar parties – a public utility and a business development team from an engineering technology-solutions firm – agreed to meet, learn about each other, and within weeks, begin to collaborate on a master plan of action to comply with a consent order agreement.

The story begins in late 2015, when staff from Emerald Coast Utilities Authority (EUCA), a progressive utility that services water and wastewater systems of Escambia County and the City of Pensacola, Florida, received a call from Pure Technologies. The inquiry was for permission to set up an educational meeting to discuss the pipeline inspection technologies, solutions and engineering services provided by Pure.

SmartBall in a case with the laptop used to control it.
Coincidental to the consent order, ECUA welcomed the opportunity to hear what Pure could bring to table. ECUA commented, “your timing is perfect, and we appreciate the educational meeting and not a sales pitch.”

That fortuitous encounter set the wheels in motion and led to the partnership between Pure, ECUA and its asset management consulting partner, Arcadis – a three-way cooperative that is now helping ECUA develop a comprehensive risk management program for its wastewater network.

Consent order issued for wastewater division

Backtrack to June 2012, when the Florida Department of Environmental Protection (DEP) issued a consent order to Emerald Coast Utilities Authority, with the agreement citing 24 spill events occurring between 2009 and 2010 that the state deemed avoidable within the utility’s collection of wastewater force mains. These force mains range in size from eight to 30-inches in diameter, and are comprised of cast iron pipe (CIP), ductile iron pipe (DIP) polyvinyl chloride pipe (PVC) and high-density polyethylene pipe (HDPE).

Sanitary Sewer Overflows (SSO), or spills, can result from a break in the pipe, or when the system is overwhelmed by heavy rain events. While spills can be caused by accidental breaks in the pipe, an aging infrastructure, with its inherent inflow and infiltration issues, makes a system all the more susceptible to SSO events.

Emerald Coast Pipe Risk Map

ECUA intrigued by the risk model focus offered by Pure and Arcadis

While ECUA engaged with Arcadis as the lead consultant to assist with the requirements of the consent order, the meeting with Pure Technologies gave ECUA the opportunity to learn about Pure’s expertise in developing a comprehensive risk prioritization plan. It also gave them an introduction to Pure’s suite of condition assessment technologies, which includes the innovative SmartBall® leak detection platform, a free-swimming tool that collects acoustic data associated with leaks and gas pockets.

With more than 315 miles of force mains within its network, it was critical for ECUA to first have the right data to make the right decisions on the prioritization of what assets to first Assess and Address®, in order to make effective use of a limited budget and resources. Pure’s experience indicates that less than 10 percent of pipelines have indicators of distress, while even fewer require repair or replacement to extend their useful life.

All the more reason why ECUA was intrigued by the risk model focus offered by Pure and Arcadis.

Using data-driven decision making as part of a risk management program

Pure recognizes the importance of data-driven decision making as part of an effective, comprehensive risk management program. A Pipeline Risk Prioritization (PRP) is good starting point for a larger proactive program as it helps to focus resources on the highest risk assets and provides justification as to which assets to assess first.

For ECUA, the goal of the PRP is to develop a risk model (likelihood and consequence of failure) to be used as a guide to determine the assets to inspect first, as well as to select the appropriate assessment technique based on risk. ECUA can use this model to put the right amount of money towards the most appropriate asset at the right time. This provides a utility like ECUA with an effective and defensible approach to managing their assets, and it actually defers long-term funding needs by maximizing the life of an asset.

Given Pure’s unique focus on pipeline asset management, its engineers and scientists have developed a risk model that allows for the input of base asset data, operational history and information, as well as condition assessment techniques and technologies. This model, unique to the industry, provides an output that clients can use in their capital and operational budgeting processes.

 

SmartBall inside a pipe.

Latest services include transit pressure monitoring and acoustic leak detection

To date, Pure has been working with Arcadis on a risk prioritization for the ECUA force main network, in which data is collected with transient pressure monitors, as well as from SmartBall acoustic inspections in order to assist in creating a Master Plan for the ECUA wastewater division. ECUA is currently five (5) years into the 15-year calendar agreed to with DEP.

In addition to the transient monitoring, during 2016 Pure inspected approximately 13.6 linear miles of force mains through seven (7) SmartBall deployments, giving ECUA more evaluative information on their aging infrastructure.

As this project is still ongoing, both ECUA and Arcadis have expressed an interest into additional wastewater projects, with the hope to ultimately address the water transmission and distribution system.

And to think, the plan all began with a simple phone call.

Massive pressured water leak

According to AWWA’s 2016 Benchmarking Survey, the average water and wastewater utility has seven breaks per 100 miles of piping every year. Tip-top systems experience just four breaks in that distance, while those at the bottom have 18.

While it’s interesting to note the difference in break rates, it’s unfair to compare one utility to another, as a multitude of factors come into play as to why pipelines can deteriorate to state of failure. Countless sources of stress both inside and outside a pipe related to geographical location, soil-pipe type interactions, age, and construction are among factors that can take their toll on the pipe’s condition.

Worker inspecting pipe

For utilities, the one constant across the spectrum is the acknowledgment that simply replacing pipeline assets is cost prohibitive, and that advanced condition assessment services like those provided by Pure Technologies (Pure) can help utilities confidently make informed decisions that significantly reduce capital and operating costs.

Single-episode blowouts garner all the attention

While single-episode blowouts are quite rare, these tend to garner most media attention, and cause the most obvious blowbacks to the pipeline operator. What the public doesn’t usually notice are the pinhole leaks, hairline cracks, corrosion and leaking gaskets that tend to occur first.

Most catastrophic failures are caused by a sudden unexpected stress such as a water hammer acting on an existing weak point in the pipe. There is a widely held belief that the failure process is a simple one, where a pipe corrodes to the point at which it can no longer withstand the applied internal and external forces, resulting in a main break. However, research has shown that the failure process is more complex than expected.

Corrosion plays a significant role in water main failures, but soil-pipe interactions, manufacturing techniques and human error are also important factors. Failures also take place in multiple stages rather than in a single episode. Early damage not only weakens portions of the pipe, it also allows water to escape, causing corrosion and washing out of the supporting soil.

Broken water pipe on a street

Age alone does not indicate high-risk pipes

Pipes at highest risk are typically constructed using dated materials or methods, running through an area with heavy vehicle traffic. Urban centers typically represent significant loss potential from damage caused by water main breaks as a result of high-density buildings, underground infrastructure, important traffic thoroughfares, and economic loss potential of power, gas, water utilities and legal cases.

The net result is that age alone cannot be relied on as an indicator of a high-risk pipe.

Broken pipe

Types of pipe material and typical cause of failure

Prestressed concrete cylinder pipe (PCCP) has a unique failure mechanism: high strength steel pre-stressing wires that provide strength to the pipe can become distressed and reduce the structural integrity of the pipe. Broken wires can be caused by physical damage to the pipe, corrosion, or hydrogen embrittlement.

Areas of broken wires may be accompanied by leaks, especially in pipelines smaller than 48 inches in diameter, where the internal steel cylinder corrodes at the same rate as the wires or where water escaping through the joint encourages corrosion. Leakage has been proven to be a key indicator of structural condition in lined cylinder pipe, a type of PCCP in which the prestressing wires are placed directly on the steel cylinder. These types of leaks can create voids around the pipe and introduce added stress at an existing weak point.

Cast iron pipes corrode, become brittle and are prone to cracking. Many older North American cities have cast iron pipes that were installed in the 1800s, prior to the existence of pipeline standards, when methods of construction were non-uniform and advanced quality control programs did not exist. Consequently, many pipelines were installed using what are considered poor construction practices by today’s standards.

Ductile iron pipes have failure mechanisms similar to those of cast iron pipes; however they become less brittle and consequently degrade at a slower rate. These pipes may be capable of supporting large leaks for longer periods of time without failing immediately.

Plastic and polyvinyl chloride (PVC) pipes are less prone to corrosion and less brittle than iron pipes. Failures in these pipes are often traced to leaking joints where the escaping water creates voids around the pipeline, causing unplanned stresses on the pipe.

Steel pipes primarily fail due to loss of integrity at welds, and external corrosion causing severe pitting and weakening the pipe wall. Both losses of joint integrity and through-wall corrosion pits lead to leakage long before failure. Older steel pipes in aggressive environments are capable of sustaining massive levels of leakage for decades before failing.

Workers digging with mechanical shovel

Making ongoing condition assessment part of proactive asset management

While pipe material and typical pipe stresses are factors that can contribute to a state of pipe failure, it remains impossible to compare one pipeline to another, and to make generalized statements about remaining service life, especially based on age and depreciation. Instead, it pays to conduct ongoing condition assessment, and then to use that risk-driven asset data collection to reduce the likelihood of replacing pipe that can safely and effectively serve communities for several more years.

Some pipeline inspections are more daunting than others, as Daphne Utilities recently found out. Not only was the planned condition assessment on a critical pipeline hampered by non-existent plans, there were also obstacles in the pipeline path that included urban development atop the pipe and an alligator-infested swamp.

In the end, to map and assess their pipeline, Daphne Utilities opted for the Sahara® leak and gas pocket detection platform, which includes the ability to determine pipeline alignment with sub-meter accuracy.  With the Sahara platform, Daphne Utilities could not only determine the exact pipeline location, but also assess its operation and condition.

Daphne’s Story

Affectionately known as the “Jubilee City”, Daphne was incorporated in 1953 and due to its location, serves as a suburb of Mobile, Alabama. Daphne is located along the eastern shore of Mobile Bay, an area served by Daphne Utilities, which provides water, wastewater, and natural gas services to approximately 25,000 residents.

In 1985 the City purchased the Lake Forest Utility, and in doing so, Daphne Utilities took over their existing wastewater treatment plant, which was built in the 1970s.  The facility discharges through the Daphne Outfall, a 6,000-foot, 18-inch ductile iron effluent pipeline that discharges treated wastewater into Mobile Bay. Although the main was critical to the City, little information about it was transferred when Daphne Utilities acquired the facility.  Daphne Utilities later officially named the facility the Water Reclamation Facility.

For many years after Daphne Utilities took over the Water Reclamation Facility the outfall line operated as a gravity discharge line. As the population grew and flows to the plant increased, Daphne Utilities installed pumps to occasionally increase the volume of treated wastewater passing through the discharge line. As development expanded, the situation progressed from a time when the pumps occasionally ran, to the point where the pumps ran almost continuously.

Satellite view with sewer location

Over the years the gravity main transformed into a force main

Now, a pipe designed as a gravity main had transformed into a force main, pumping under pressure at all times, with its location and condition unknown – and with no redundancy.

To proactively manage this critical asset, Daphne Utilities retained the services of Pure Technologies for a one-day Sahara® leak and gas pocket detection inspection of the Daphne Outfall, with a mapping deliverable.

The primary purpose of the inspection was to determine the pipeline alignment, since you can’t maintain what you can’t locate.  Since the 18-inch outfall was built, the terrain had changed markedly.  The original shoreline had been extended by hundreds of feet to accommodate the construction of a major highway and several hotels and restaurants.

In fact, based on best guesses and poor drawings, Daphne Utilities suspected that a five-story Hampton Inn had been built on top of the 18-inch outfall!

In short, Daphne Utilities didn’t know the exact pipeline location or its operational conditions.

Bridges over a river

Section of the outfall traverses area known as “Gator Alley”

To ascertain the alignment and condition of the 18-inch outfall, Daphne Utilities engaged Pure Technologies for a single day inspection. In addition to the challenge of not knowing the exact pipeline alignment, it also appeared that the pipeline traversed under a swamp sanctuary for hundreds of alligators and other wildlife, in an area known as “Gator Alley.”

Due to the location that the line traverses, extra safety precautions were needed for the inspection crews. Project planning included the deployment of an alligator watchman to watch specifically for a notorious 14-foot alligator known to inhabit the area in the vicinity of the 18-inch outfall.

Sahara inspection technology chosen for accuracy at pinpointing leaks and gas pockets

To conduct the mapping and assessment survey, Pure recommended the Sahara leak and gas pocket detection platform. Sahara is an inline tethered tool that can assess pipelines 6 inches and larger, without any disruption to service.

Because the sensor tool is tethered, an operator can stop and reverse the tool to investigate acoustic events such as leaks, gas pockets and visual anomalies. At the same time, an above-ground operator locates the sensor above ground, marking the exact location of the pipeline at any point along the pipe with sub-meter accuracy.

The mapping capability of Sahara allows utility owners to determine the exact location of their pipeline at any point, as well as the location of any leaks or gas pockets.

Results give Daphne jubilant confidence moving forward

Analysis of the acoustic data identified zero (0) leaks and eight (8) air pockets, which were impacting the efficiency of the line, as gas pockets occupy space within the already maxed-out pipeline. During the inspection, the alignment of the pipeline was determined and recorded from the treatment plant to the edge of the marsh where Mobile Bay starts, confirming the pipeline does indeed pass underneath the Hampton Inn.

Not bad for a day’s work

In a single day, the Sahara crew determined flow velocity, inserted the tethered tool, inspected 1,000 feet, determined the pipeline alignment, and confirmed its location and the location of 8 gas pockets.  As a result, Daphne now knows they have gas pockets and they now know the line location in order to execute a plan to deal with the gas pockets.

As for dealing with alligators, that’s unnecessary now.

Alligator watching to the cammera

With stories of broken mains and aging infrastructure attracting more public attention, pipeline owners face difficult questions about long-term planning for their water and wastewater linear assets. In particular, when and where to focus renewal funding to service these aging networks.

However, as pipeline owners know, precise answers aren’t easy, especially without good data to back up an assumption. Lack of accurate and precise data can lead to an expensive guessing game when trying to identify high risk assets for renewal.

It has been suggested that over 70 percent1 of replaced pipe still has remaining service life. Therefore focusing on collecting the right condition data to make the right decisions at the right time is critical in making the most out of budgets.

Pipeline owners leverage data to make better decisions

We live in an era of big data, and with the help of Pure Technologies, many pipeline owners are beginning to understand how to leverage this data to make better decisions.

Data-based decision making can be used throughout the lifecycle of a pipeline asset to get a clear understanding of the current pipeline condition and its remaining useful life.

Targeted testing results chart

Small amount of sampling data leads to large sampling error and uncertainty

Clear understanding starts with data collection that specifically targets samples along the pipeline. However, not all sampling data is created equal. For example, while a small amount of sampling data gives you some information, it also leads to large sampling error and uncertainty on the true overall condition of your pipeline. This is why so much pipe with remaining service life is replaced, as decisions are made from data with large sampling error and uncertainty.

On the other hand, a large number of samples leads to smaller sampling error, and when you combine less error with more data, higher confidence decisions can be made.

Small amount of sampling data leads to large sampling error and uncertainty

Clear understanding starts with data collection that specifically targets samples along the pipeline. However, not all sampling data is created equal. For example, while a small amount of sampling data gives you some information, it also leads to large sampling error and uncertainty on the true overall condition of your pipeline. This is why so much pipe with remaining service life is replaced, as decisions are made from data with large sampling error and uncertainty.

On the other hand, a large number of samples leads to smaller sampling error, and when you combine less error with more data, higher confidence decisions can be made.

Colored candies and broken pipe

Using coloured candies to understand distribution principle

One way to demonstrate this principle is to examine a bag of colored candies. If you randomly sample a few pieces of candy from the bag, you would be uncertain about the proportion of blues to reds to greens because you don’t know the actual colour distribution.

However, if you were to increase the number of samples, and group this data into color bins, you would begin to have more clarity and understand the distribution of colored candies.

Coloured candies distribution chart

The more samples, the more certainty in the distribution data

In a way, this same principle of sampling applies to collecting pipe condition data. Sample size is important, and the more targeted samples you take, the more certain you are in the distribution of data. This provides owners with more confidence to make good decisions relating to renewal strategies.

That’s where Pure Technologies can help, with innovative technology and expert analysis that delivers precise data. This actionable information helps owners make confident decisions on the management of their pipelines.

Overall, it pays to invest in better data to better understand the true condition of your pipeline. True power lies in balancing the cost of data collection against the cost associated with uncertainty, and the more confident you are in your data, the more certain you are in your decision making, especially when making high-cost pipeline management decisions.

1: Patterson, J. and Phinney, T. (2008). “Assessing aging cast and ductile iron force mains.” Proc., Underground Construction Technology (UCT) Conference, Atlanta, GA, Jan.

Sahara platform inside a pipe filled with water

For more than 15 years, water operators have relied on the Sahara® leak detection platform for speed, accuracy and on-the-spot results required for inspection of complex pipeline networks typically found in urban environments.

The Sahara in-line tethered tool can assess pipelines 6 inches and larger, while the line remains in service. Because it’s tethered, an operator has complete control, and can closely examine events of interest, such as a leaks, air pockets, and visual anomalies.

The tool is propelled by the product flow, requiring a flow velocity of only one foot per second, and is able to navigate in flows up to ten feet per second, with no disruption to service.

Sahara device

Sahara tool can be inserted into almost any existing tap 2 inches and greater

To insert the tool into an active pipeline, almost any tap 2 inches and greater can be used. As the tool enters the pipe, a small parachute or drogue is inflated by the flow velocity of the water. The parachute pulls the tool through the pipe, with the probe lighting the way with its onboard LED lighting system, highlighting any visual defects in the pipeline.

If the Sahara tool encounters any acoustic events—such as a leak—the operator can stop the tool at the exact point of the leak. At the same time, an above-ground operator locates the sensor, marking the exact leak location within plus or minus 18 inches (0.5 meter). This enables users to know in real time where the leaks are, and where repairs are needed.

Worker finding the exact spot for a issue reported during the inspection

Detects up to 4 times as many leaks as trunk main correlators

The tool can detect up to four times as many leaks as trunk main correlators because the acoustic sensor is brought right to the leak – pinholes, cracks, joint leaks – Sahara can detetct virtually any type of leak. In addition, the tool can detect air pockets in the pipeline, both visually and acoustically.

As the Sahara tool inspects the pipeline, it may encounter valves that connect a high pressure zone to a low pressure zone, and if one of those valves is not fully closed, Sahara can also detect the lack of isolation between zones during the inspection.

Visual anomalies detected during inspection

Detect leaks, air pockets and visual anomalies while mapping the pipeline path

The tool can navigate single bends without issue, but is limited up to 270 cumulative degrees of bends in a single survey.

While the video and acoustic inspection is taking place, the tool can also be used to map the pipeline path, providing a clear plan view of the pipeline with sub-meter accuracy. The beauty of the Sahara tethered platform is that it can provide a variety of pipeline condition information in real time, with no disruption to service, on all pipe types.

Houston Skyline

Enwave Houston deploys Sahara tool to quickly locate leak in chilled water line

In December 2015, Pure Technologies (Pure) was retained by Boyer Inc. to perform a Sahara inspection on a 24-inch Chilled Water Supply pipeline (CWS) and on a 24-inch Chilled Water Return pipeline (CWR) operated by Enwave Houston.

The purpose of the inspection was to locate a suspected leak on one of the dual lines that run parallel along the downtown core. Large cities often operate central chilled water plants to cool water that is then sold to building owners for use in air conditioning.

Tools on the surface before starting with the inspection

Insertions completed at night, with no traffic disruption or chilled water disruption

Boyer proposed two separate Sahara insertions during the planning phase. Pure completed both insertions at night over a two-day period for a total of 795 feet of pipeline inspected, with no traffic disruption or chilled water disruption. Acoustic data was collected and recorded during the inspections as the Sahara sensor traversed the main. The data was evaluated on site in real time to identify events associated with leaks and pockets of trapped air.

During the inspections, one (1) leak and zero (0) air pockets were detected. The leak was located 144 feet downstream from the insertion point with sub-meter accuracy. This allowed a pinpoint excavation to be made for repairs, minimizing disruption to downtown Houston traffic, and minimizing the contractor`s cost of excavation and road restoration.

Once again, the Sahara tool proved its worth.

City of Baltimore

Over the past decade, the City of Baltimore has seen vast improvements in control point operability and system sustainability of its water distribution assets. The report card is looking better each year.

The Baltimore City Department of Public Works shoulders a big responsibility. The Department provides 265 million gallons of water daily to 1.8 million people in the greater Baltimore region, and maintains 3,400 miles of water mains, 19,000 fire hydrants and more than 64,000 pipeline valves.

For more than ten years, Wachs Water Services has partnered with Baltimore and surrounding counties to deliver GIS data, coax non-functioning valves and hydrants back to operational life and reduce the probability of failure. The ongoing program is a showcase for Wachs Water Services to demonstrate how its unique approach, field experience and mechanical advantage could give Baltimore new confidence in managing their water distribution assets.

Broken water mains propel utility to investigate distribution system

Many of Baltimore’s water distribution system assets are decades old, with some pipes dating back 100 years and more. Since 2000, large-diameter pipeline failures were occurring more frequently, resulting in extreme flooding in some urban areas. Emergency response was often delayed because of difficult to locate or non-operational valves.

The water utility decided it was time to locate, assess and repair or replace the critical pipeline valves within their distribution system. They turned to the industry leader in valve management solutions, Wachs Water Services, a division of Pure Technologies.

WachsWater Workers

Valve management delivers operational intelligence to mitigate risk

Collaborating closely with field crews from Baltimore Public Works, Wachs Water Services technicians immediately went to work to locate and test the thousands of pipeline valves and water assets within the distribution system.

Valve management involves integrating field-verified valve status details into the GIS system, the vital “operational intelligence” utilities need in mitigating operational risk, and accelerating emergency response to major pipeline failures.

After physically locating each valve, Wachs Water Services field technicians recorded the valves’ precise GPS position, operational and service history, and current functional status into Baltimore GIS (geographical information systems) and CMMS (computerized maintenance management systems), ensuring the vital asset information could be easily accessed during an emergency response.

Damaged or questionable valves were expertly serviced, replaced or updated to verify compliance with industry specifications, and Baltimore field crews were trained to deal with operating valves to respond to an array of emergency situations.

Damaged valve

Valve training pays dividends sooner than expected

The emergency valve training paid dividends much sooner than expected. In September 2009, a 72-inch PCCP water main suffered a catastrophic failure near a busy Baltimore street intersection, flooding the area with 175,000 gallons per minute. Field crews from Baltimore Public Works, Wachs Water Services and emergency service workers converged on the scene as water submerged residential areas and threatened 6,000 homes.

Working closely with Baltimore Public Works, Wachs Water Services provided detailed maps and plans for shutting down the broken pipeline main, including information on all valves involved, and the specific pattern to execute the shutdown in a manageable way.

The utility knew exactly what crews to deploy, where to deploy them, and what they needed when they arrived on location, successfully shutting down all pipelines feeding the ruptured main in a fraction of the time.

Baltimore proves its commitment to municipal water stewardship

Tremendous progress has been made by Baltimore City and surrounding counties, and they have set industry benchmarks for control point operability and system sustainability. In the ongoing program, more than 64,000 valves and 22,000 fire hydrants have been GPS-located and mapped over more than 2,000 miles of mains.

The City has earned high marks, not only for its diligence, but also for its commitment to municipal water stewardship.

Tech analysing data
Hydrant inspection

This large Midwest utility maintains and operates water collection, treatment, and distribution systems, as well as wastewater collection and treatment systems and stormwater management systems for its residential, business and wholesale customers in the region.

To ensure the accessibility and quality of water services to meet the growing needs of the region, the Utility needed to conduct a complete assessment of their water distribution system.  The limited internal resources and need for quick results were more than the department could handle on their own.

To kick-start the process, and ensure success of the project, the Utility needed to identify the most economical solution that would provide the greatest impact on their distribution system in the shortest period of time.

The long-term project called for highly specialized valve maintenance expertise, equipment and technology, and the Utility elected to partner with the industry leader in valve management solutions, Wachs Water Services.

Inserting tools for inspection

Collecting valve status information critical for improving quality of water service

Because of its experience in the field, Wachs Water Services (WWS) was chosen to collect valve status information to assist in operational planning and speed of response, with the ultimate goal to improve the quality of water services in the growing region.

The comprehensive project called on WWS to dedicate an onsite team for the 5-year project, which included water valve assessment, mapping, and data management – including fire hydrant assessments.

During the course of the project, more than 35,000 valves were accessed, assessed and repaired where necessary. During these inspections, WWS discovered almost 2,000 valves with packing leaks, which were subsequently corrected by snugging up the valve to the seal.

Service included raising buried valves to grade to provide easy access

In addition to locating and assessing the valves in the distribution system, the WWS team took 1,065 valves buried in asphalt and raised these to grade in order to provide easy access and shut off during an emergency. Additionally, 5,387 valves buried in non-asphalt environments (dirt-grass-gravel) were raised to grade and are now accessible.

Almost 2,000 damaged or missing operating nuts on valves were repaired or replaced.  This represented by far the largest number of operating nut anomalies that WWS had ever encountered in the field.

This was due, in part, to the use of over-sized tooling.  While some of the operating nuts were over-sized, those that were not (the majority) were damaged by the over-sized tools.

As part of the condition assessment and repairs, more than 10,000 valve boxes were vacuumed and cleared of debris so the valves could be accessed and assessed for damage/need of repairs.

Finally, more than 7,400 fire hydrants were accessed, with a least 20 percent requiring some repairs. Hydrants were also pressure tested, and those with a low-flow reading were corrected.

Inspecting valves

 

System operability increased from 55 percent to 84 percent

Overall, the system operability increased from 55 percent to 84 percent, which added up to an increase of 53 percent more valves now accessible and operable than before the assessment.

The Utility’s GIS was updated to increase the accuracy and include additional attribute information. In addition, WWS provided the Utility with assistance on numerous construction shut-downs for the duration of the contract.

The operating nut repairs eliminated more than 1,300 dead ends caused by inoperable valves, a solution that increased water quality, increased fire-fighting capacity, and corrected system pressure problems.

Wachs Water Service also performed a leak sounding pilot on all the valves accessed during the first 5 months of the program.

Overall, tremendous progress has been made, and the Utility has set industry benchmarks for control point operability and system sustainability.

West Palm Beach Aerial View

The City of West Palm Beach (WPB) makes a concerted effort to engage its citizens.

As one of the three largest cities in South Florida, WPB is a vibrant, growing waterfront community with a population of more than 100,000. Since 1974, WPB has experienced exponential growth in its population and correspondingly, in its wastewater management needs. During this time, WPB has continuously upgraded its pumping and treatment processes based on advances in regulations and technology.

In the evolution of its force main strategy, WPB has undertaken a variety of initiatives to manage its network to reflect the needs of its community. This ties into an overall strategy by dealing with rehabilitation needs proactively to prevent costly system failures while planning the rehabilitation and assessment of an entire system over the long term.

West Palm Beach bucks the trend to replace based on age of system

Historically, management of a force main network has been based on the general age of the system without specific information of the system in relation to its normal and extreme weather operation.

Bucking this trend, WPB takes an enlightened view to the management of its wastewater network, with age of the system not an automatic reason to replace or rehabilitate. While complete replacement would be ideal, the cost associated with full scale replacement is unfeasible. Ratepayers demand fiscal responsibility and are reluctant to sign over blank cheques to their utilities.

As a testament to its proactive stance, WPB has completed the first phase of a condition assessment, design and rehabilitation program of its force main network, which includes a nearly six-mile section of pipeline that conveys wastewater from Lift Station 22 to the East Central Regional Water Reclamation Facility (ECRWRF). Comprised of 42-inch and 48-inch lined cylinder pipe (LCP) and 48-inch embedded cylinder pipe (ECP), this force main, constructed in 1974, is considered the most critical piece of underground infrastructure for the City’s wastewater system.

Staff working at insertion site

In 2007, WPB conducted acoustic monitoring of the ECRWRF Force Main to determine what areas were deteriorating, but the results proved inconclusive.

In 2015, with the evolution of condition assessment techniques, WPB retained Pure Technologies to conduct a follow-up inspection using pressure monitoring and non-destructive inline assessment technologies.

For WPB, the process included examination of the ECRWRF pipeline from a wide variety of parameters. For example, manufacturing standards from the original force main design were structurally analyzed in contrast to current design standards.

The program examined current operational and maintenance practices, monitored air release valves and looked at pressure profiles based on the multiple pumping station connections to the force main. By deploying acoustic and electromagnetic technologies from Pure Technologies, WPB identified high priority areas based on gas pockets and structural stress along the force main route. WPB combined this information with rehabilitation and replacement strategies to define the second phase of the management process.

SmartBall® inside a pipe

First inspection: SmartBall® acoustic leak and gas detection

In February, Pure used its SmartBall inspection platform to conduct acoustic leak and gas pocket detection on the line. Unlike traditional external listening tools with limited success on large-diameter pipes, free-flowing SmartBall technology provides a high degree of accuracy, since as the ball rolls, it can inspect every inch of the main to detect leaks and gas pockets.

The SmartBall tool was inserted into the pipeline through a hot tap and acoustic data was collected and recorded as the tool traversed the pipeline, where it was later retrieved at a bypass grit chamber.

PipeDiver® electromagnetic inspection

Next: PipeDiver® electromagnetic inspection

Subsequently, Pure deployed its free-swimming PipeDiver platform to perform an electromagnetic (EM) inspection to locate broken prestressing wire wraps in the LCP/ECP pipe. Unlike more restrictive assessment tools, PipeDiver is a flexible, free-swimming tool that flows with the product and is able to easily navigate through most butterfly valves, apertures and bends in the pipeline, delivering electromagnetic (EM) data for a variety of pipe type and materials.

EM technology provides prestressing wire-break estimates on each individual section of PCCP, which is the best indicator that this type of pipe will fail. This allows for one deteriorated pipe to be identified within an entire pipeline that is in good condition overall, and also provides the baseline condition on all pipes in the inspected distance.

Results guide the success of the program

During the SmartBall inspection, zero (0) leaks were detected, while 23 recordings were indicative of entrained gas and gas slugs.  Of the 1,682 pipes inspected by the PipeDiver tool, approximately 10 percent of pipes displayed electromagnetic anomalies consistent with broken prestressing wire wraps.

Overall, the condition assessment found the majority of the pipe to be in good condition. Pressure monitoring identified intermittent pressure surges within the design standards of the force main. However, this effort elevated the City’s awareness of the relationships between pressure management and the structural integrity of the pipeline.

Based on the completed assessment, the City implemented a two-year project delivery timeline for extending the service life of the force main for another 40 to 50 years.  The schedule included a comprehensive community outreach program that has residents onboard with the phased-in design and construction approach.

SmartBall extraction and retrieval

Tarrant Regional Water District (TRWD) and Pure Technologies U.S. (Pure) have a long history of working together to keep the water transmission mains in the Dallas-Fort Worth (DFW) area in good operating condition.

The partnership began 17 years ago with mutual development of electromagnetic technology to inspect prestressed concrete cylinder pipe (PCCP). One of Pure’s first electromagnetic inspection prototypes was developed (with funding assistance from American Water Works Research Foundation [now Water Research Foundation (WRF)], commercialized (with assistance from TRWD) and first pulled through TRWD’s pipeline on a little red wagon!

Inspection Prototype

TRWD is one of the largest raw water suppliers in DFW with large-diameter pipelines that transport water from the East Texas Cedar Creek and Richland-Chambers Reservoirs. TRWD provides water to almost two million people and spans an 11-county area in North Texas.

Electromagnetic Inspector

Electromagnetic technology platforms recognized around the world

Since 1999, TRWD has utilized Pure’s advanced inspection and condition assessment services to evaluate than 240 miles of PCCP. Over the years, TRWD has deployed a variety of inspection platforms to determine the condition of their critical supply lines. This includes PipeDiver®, a free-swimming electromagnetic inspection technology, Sahara®, an acoustic leak and gas pocket detection tool, and a manned electromagnetic tool equipped with PureEM® to collect full circumferential data of the pipe wall.

The condition assessment data is compiled with a Geographic Information System (GIS) deliverable, which provides TRWD with detailed information that is used to implement a targeted pipeline repair and replacement strategy.

TRWD utilizes Pure Technologies’ cost-effective Assess and Address® approach to target specific pipes for repair or replacement that are near the end of their service life, as opposed to replacing entire sections of pipe in good condition. In addition, this proactive approach allows TRWD to document significant savings over a complete pipeline replacement strategy.

Since 2000, a total of 271 pipes have been replaced during planned maintenance based on the results from Pure inspections.  As a result, TRWD has noticed a dramatic decline in failures since the late 90s doing a risk-based prioritization and replacement/rehab program, in addition to implementing cathodic protection, pressure transient surge reduction measures, and pipeline protection measures from external loads.

TRWD is extremely proactive when it comes to understanding their pipeline infrastructure. They take pride in their ability to locate and repair leaks, and repair or replace damaged pipes during routine maintenance schedules – rather than in emergency situations.

Tech inspecting a pipe with a tool

Over the past decade, several high profile oil and gas pipeline failures have shown that the consequences of a rupture can be extremely severe for both the environment and human life, and can result in billions of dollars in remediation costs. Because of all these negative consequences, governments have made it mandatory to conduct routine inspections on these assets to prevent catastrophic events.

Today, the most common form of pipeline assessment is inline inspection (ILI) with smart pigs. These pigs flow with the product, collecting data on the condition of the pipe wall. When these tools are operating in a live pipeline, it is important to track their precise location and speed, as a lost or stuck pig can obstruct product flow, cause unwanted service disruptions or damage the pipeline.

A common misconception about pig tracking is that a run always goes as planned.  In the majority of runs, nothing unexpected will occur, but there have been a few cases where a minor event can quickly derail the smoothest of jobs, resulting in cost escalations and unnecessary hassle for the pipeline owner. By taking proper precautions and using advanced tracking technology, pipeline owners can ensure that they are prepared for any unexpected event that may occur.

Traditionally, pigs have been tracked by a single technician equipped with a standard geophone to identify the pig passing. This method can be extremely challenging and unreliable, and can result in a lost pig. In order to mitigate the risks of conventional tracking, owners can use remote tracking technology which provides greater reliability and accuracy.

Remote Tracking Prepares Asset Owners for the Unexpected

Remote tracking combines above ground markers (AGMs) equipped with multiple sensors with remote communication technology. This ensures that the pig is being tracked using more than one sensor, which is significantly more reliable than a standard geophone. In addition to tracking with multiple sensors, pipeline owners and ILI vendors are provided with a record of each passage that is downloaded from the AGMs. This record shows the signal of the pig passage, along with other information such as time and speed. The AGMs provide snapshots into a software where they can be used for real-time tracking of the pig’s position, speed, and estimated time of arrival. Pipeline owners can be sure that the results are accurate because the AGMs constantly record data to confirm pig passages when they are turned on.

If a pig gets stuck, the AGMs will know if the pig has not passed a tracking location, making it much easier for field technicians to retrieve it in a timely manner, so no damage is caused to the pipeline. Remote tracking provides reliable information and when unexpected events occur, enables pipeline owners to be better prepared for any issues that may arise.

To learn more about remote tracking and its benefits, download the white paper below.

Sensor with remote communication technology

*Published in World Pipelines Magazine

Oil and gas pipelines have been around for well over a century, and some of the earliest constructed are still in service today.  Although early pipelines were made of wood, and in the past few decades plastics and composite materials have increased in popularity, the vast majority of pipelines in service today are constructed with steel.

Like any pipe material, steel pipe has its downfalls. Steel has a propensity to dent, buckle, corrode and crack when exposed to the environment.  Steel pipeline’s carrying combustible hydrocarbons are buried underground with typically ~1 meter (3 feet) of cover to protect them.  In order to mitigate corrosion, pipelines are covered with a protective coating, utilize cathodic protection (CP), and have their pressure regulated to reduce crack formation and propagation.

Despite all of the design innovations made over the past century, it has not been enough to prevent failures – even the most recently constructed pipelines.  Weather cycles, frost heaves, and road loadings cause physical damage to the pipeline and protective coating.  Operational errors and material defects cause the steel to succumb after years of relentless pressure cycles from the pipeline product itself.  Therefore, proactive pipeline inspections are needed to identify defects, before they cause a leak or rupture.

Pipeline integrity can be validated and assessed using three primary techniques: hydro-testing, the use of Inline Inspection (ILI) tools, and Direct Assessment.

Hydro-testing

Hydro-testing became common practice for pipelines in the 1940s. The process involves taking the pipeline out of service and purging the product, then the pipeline is pressurized above the maximum operating pressure (MOP) with the intent to determine the ability to operate the pipeline at MOP.  While hydro-testing is still widely used today, there are several drawbacks to the process. The water used in hydro-testing is considered hazardous material after being used, meaning owners incur the additional risk and cost associated with disposing of the water after testing. The information gained from the test is also limited in that it provides no information of the actual condition of the pipe, coating, or surrounding environment.

Hydro-testing can also promote internal corrosion of pipelines, especially if the water used is not properly treated for microbiologically influenced corrosion (MIC) and chlorides. Internal corrosion usually occurs if the pipeline is not properly cleaned and dried after the test.  Hydro-testing can also result in pressure reversals, which worsen the integrity of the pipeline [1].  Finally, the pipeline may be required to be out of service for a significant amount of time, resulting in a significant loss of revenue.

Inline Inspection

ILI tools – which are commonly referred to as smart pigs – were developed in the 1960s and commercialized in the 1970s.  These tools are designed to survey the conditions of the pipeline wall with limited disruption and can identify and quantify the corrosion and cracking in steel pipelines [2].  Magnetic flux leakage (MFL) and ultrasonic testing (UT) are common ILI tools used widely by owners today.

ILI is a significant part of pipeline integrity management, and promote safe, efficient and cost-effective pipeline operation [2].  However, it is important to remember that ILI is just a subset of a family of inspection tools used to verify pipeline fitness for service.  As with any inspection technology, ILI tools have a threshold for detection – the tools are unable to reliably detect anomalies that are below their design specifications’ detection ability. Also, internal pipeline inspections are primarily reactive, requiring the damage or wall loss to occur before defect detection is possible.

Direct Assessment (DA)

The most recently developed solution for pipeline integrity management is Direct Assessment (DA), which is a structured, iterative integrity assessment protocol used by pipeline operators to assess and evaluate the integrity of their pipelines.

Adoption and demand for DA is increasing in modern integrity programs due to more stringent industry regulations, aging pipeline networks, limitations of alternate inspection techniques, and the fact that roughly 70 percent of pipelines within North America are difficult to pig.  Direct assessment surveys provide pipeline owners with important information on both the pipeline’s condition and its surrounding conditions, both of which can lead to degradation and eventual failure.

The Stages of Direct Assessment

It should be noted that geotechnical, dent, and buckle threats are not specifically addressed with any of the DA techniques.  All DA protocols are four-step iterative processes which include a Pre-Assessment, an Indirect Inspection, a Direct Examination and a Post-Assessment.  Inspections involve the integration of as much pipeline available integrity data as possible, which includes physical characteristics and operational history, historical and multiple indirect inspections, and direct pipe surface examinations.

In the pre-assessment step, historic and current pipeline data is collected to determine whether DA is feasible, define DA regions, select indirect inspection tools and determine if additional integrity data is needed.

The second step in DA methodology involves the use of non-intrusive and aboveground techniques. These tools assess the effectiveness of the coating and cathodic protection for pipeline external corrosion assessment (EDCA an ECCDA), and predictive modelling, or critical angle calculations for pipeline internal corrosion assessment (ICDA) to identify and define areas susceptible to internal corrosion.

For external corrosion assessment, the state of cathodic protection, coating and soil resistivity are critical factors in determining high-risk areas. For internal corrosion assessment, fluid flow, mass transfer, solid accumulation, mineral scales, corrosion products, and MIC are critical components [3].  For stress corrosion cracking, critical factors include operating stresses, operating temperatures, distance from a compressor station, age of the pipeline, and coating type.

The direct examination step involves the analysis of pre-assessment and indirect inspection data to select sites for excavation and examination of pipe surface. This process validates the inspection data and provides a first-hand evaluation of the pipe surface and surrounding environment.

Finally, the post-assessment phase involves the analysis and integration of integrity data collected from the previous three steps to assess the effectiveness of the DA process and determine the necessary reassessment intervals.

There are six DA standards developed by National Association of Corrosion Engineers (NACE) and they include:

2002 -NACE SP0502-2010 ECDA (External Corrosion Direct Assessment)

2004 -NACE SP0204-2008 SCC-DA (Stress Corrosion Cracking Direct Assessment)

2006 -NACE SP0206-2006 DG-ICDA (Dry Gas Internal Corrosion Direct Assessment)

2008 -NACE SP0208-2008 LP-ICDA (Liquid Petroleum Internal Corrosion Direct Assessment)

2010 -NACE SP0110-2010 WG-ICDA (Wet Gas Internal Corrosion Direct Assessment)

2010 -NACE SP0210-2010 ECCDA (External Corrosion Confirmatory Direct Assessment)

DA is also covered in ASME B31.8S (Section 6.4).  In the United States, DA is covered in US Code of Federal Regulation CFR 49 Part 192.923 (for natural gas pipelines) and 195.888 (for liquid hazardous pipelines).  It is now one of the three accepted inspections (ILI and Hydro-testing being the other two) allowed for oil and gas pipelines.

Identifying Pipeline Anomalies Using Directing Assessment

When completing a DA inspection, there are three types of anomalies that owners are aiming to identify:

1.         External Corrosion (EDCA and ECCDA)

2.         Internal Corrosion (dry gas, wet gas, and liquid petroleum ICDA)

3.         Stress Corrosion Cracking (SCCDA).

Due to the serious consequences of corrosion and leaks in underground pipelines, external corrosion direct assessment (ECDA), and external corrosion confirmatory direct assessment (ECCDA) – as described in ANSI/NACE SP0502 and NACE SP0210 – were developed in an attempt to proactively prevent external corrosion and ensure the integrity of oil and gas pipelines that are difficult to pig.

ECDA is a continuous improvement process intended to identify and address locations at which corrosion activity has occurred, is occurring, or might occur. For instance, ECDA identifies areas where coating defects have already formed, and can ascertain where cathodic protection is insufficient and corrosion is possible, before major repairs are required.

The success of any ECDA requires strong knowledge of the soil/environment, pipeline material, coating, cathodic protection, and foreign/interference current on the pipeline. Also, the accurate selection of susceptible areas for external corrosion relies on using at least two complementary advanced aboveground inspection techniques. These aboveground indirect inspection techniques may include: direct current voltage gradient (DCVG) or alternating current voltage gradient (ACVG) surveys, a cathodic protection close interval potential survey (CP CIPS), alternating current—current attenuation (ACCA) and side drain (for bare or ineffectively coated pipelines) surveys. Normally these aboveground inspections are used in conjunction with pipe locating.

The development of internal corrosion in pipelines is partly because of its complex nature and interaction between constituents that are found in transported gas and liquid products (e.g., oxygen, carbon dioxide, hydrogen sulfide, chloride, bacteria, etc.). When in the presence of water, these contaminants can lead to conditions conducive to the occurrence of internal corrosion. The susceptible locations for internal corrosion are usually where liquids, solids and gas accumulate. In order to ensure that susceptible locations along the pipeline are prevented from internal corrosion, internal corrosion direct assessment methodology is implemented.

Internal Corrosion Direct Assessment (ICDA) methodology has been developed to verify pipeline integrity, especially for pipelines that are not able to accept inline inspection (ILI) tools. ICDA includes Wet Gas Internal Corrosion Direct Assessment (WG-ICDA), Dry Gas Internal Corrosion Assessment (DG-ICDA) and Liquid Petroleum Internal Corrosion Direct Assessment (LP-ICDA). WG-ICDA (NACE SP110-2010) is used in pipelines that assumes that water, or a combination of water and hydrocarbons can be present in the pipeline. It is intended for onshore and offshore systems where liquid to gas ratio is small. It tends to identify locations in the pipeline where corrosion is expected to be severe. DG-ICDA (NACE SP206-2006) is applicable to pipelines that transport gas that is normally dry, but may suffer infrequent upsets, which may introduce water to the pipeline. LP-ICDA (NACE SP208-2008) is employed to assess the susceptibility of internal corrosion on pipelines that transport incompressible liquid hydrocarbons that normally contain less than 5 percent base sediment and water. The success of any ICDA process is dependent on using an accurate corrosion model to predict a precise elevation profile in order to determine susceptible locations for internal corrosion.

DA technology has also proven successful in stress corrosion cracking direct assessment (SCCDA), offering pipeline operators a comprehensive pipeline integrity management portfolio. SCCDA (referenced in NACE SP0204-2008 and ASME B31.8S) is a proactive structured process that seeks to improve pipeline safety by assessing and reducing the impact of stress corrosion cracking. Stress corrosion cracking can occur at neutral or high pH when susceptible pipeline material is exposed to stress, specific susceptible temperature, and a corrosive environment.

The Benefits of Direct Assessment

Direct Assessment is non-intrusive and inspections can be completed during normal operation of the pipeline.  DA is also a proactive integrity management tool that can find anomalies before they become critical defects, while traditional ILI tools are reactive in that they identify existing pipeline damage.

While hydro-testing and ILI tools are an important part of integrity management, the development of DA provides pipeline owners with another solution to identify at-risk areas of pipe before they become a major problem. A combined integrity approach that employs DA can help pipeline owners ensure containment and prevent costly, reputation-harming pipe failures.

References

1.    Pipeline Research Committee, American Gas Association, NG-18 Report No. 111 (Nov. 3, 1980)

2.    NACE 35100, In-Line Inspection of Pipelines, NACE International, May 2012

3.    NACE Training Course, Direct Assessment, NACE International, November 2012

*Published in World Pipelines Magazine

The oil and gas pipeline industry has been under close scrutiny for a long time. It leads the way as one of the most regulated industries in the world, and for good reason.  With so many safety-related, social and environmental factors at stake, comprehensive regulation ensures rigorous standards for the design, construction, operation and maintenance of O&G pipeline systems.

Global economics and political activism also play a role in shaping today’s conversation about pipelines. In North America, public debates about the Keystone XL Pipeline have dominated much of the recent news, compelling operators to vigorously participate in the discussion and advocate their integrity management programs. Although Keystone has been put on hold, social capital can assist in getting projects of this magnitude on the radar again.

Through it all, much of the dialogue has focused on the industry’s commitment to protecting communities and the environment from risk by means of rigorous pipeline integrity management programs. As a result, the requirement for increased pipeline safety drives innovative research into improving the sensitivity and reliability of inline inspection (ILI) tools.

Most operators already deploy trusted inline technologies that detect structural deterioration and help maintain pipeline integrity. However, with pressure mounting from stricter regulation, increased operational costs, commodity price-driven budgetary pressure, and often limited available resources, operators face an increasing number of challenges, including vigilance from highly engaged consumer groups.

Although the pressure to perform is greater than ever, operators are responding appropriately with greater confidence in modern technologies to assist in the operation and monitoring of their pipeline systems.

Better ILI tools instill better confidence in containment

To have confidence in the pipeline, operators must have confidence in the capabilities of ILI tools to detect small anomalies that could lead to potential failures.  They must also trust the reliability and interpretation of the data, knowing with as much certainly as possible that the depth, size and location of the pipe wall anomaly is correct.

Overall the news is good. Between 2002 and 2013, Canadian Energy Pipeline Association (CEPA) member companies were able to transport oil and natural gas with a 99.999 percent safety record. While that statistic sounds impressive, headline-grabbing pipeline incidents do occur, (in 2014 there were 122 natural gas and liquid releases) and when that happens, the repercussions can undo years of containment management trust and goodwill.

While the oil and gas industry boasts a remarkable safety record, a reliance on conventional tools limit the near perfect record.  As much as the technologies have been refined, regulators have noted that inline inspections don’t pick up all defects, and expedient follow-through often depends on the people analyzing the data and planning repairs, a process that can take months.

“Despite their sophistication, the detection capabilities of inline inspection tools have limitations,” the US National Transportation Safety Board noted in its report on the 3.3-million-liter 2010 spill in Michigan.

Limitations of conventional ILI inline inspection technologies

The oil and gas pipeline industry has access to an extensive toolbox of technologies for robust integrity programs. Some tools address cracks or corrosion issues, while other tools focus on stress, pressure and product containment. Cost, resolution, reliability, data analysis speed – each technology has its own strengths and limitations, with no silver bullet as the single solution for collecting pipeline condition information.

For example, there is a strongly-held belief in hydrostatic testing as a reliable method to test a pipeline’s integrity. One of the earliest inspection techniques, hydrostatic testing determines if a pipeline can hold its operating pressure. A form of destructive testing, hydrostatic inspection involves purging the product, flooding the line with water, pressurizing it to a predetermined level and maintaining the pressure for a period. Based on the results, detected anomalies in pressure, volume and density can be a precursor to leaks.

Critics however, argue and have quite effectively demonstrated that the hydrostatic tests lack the ability to monitor ongoing corrosion or cracking and that the high pressure environment can exacerbate previously small defects, increasing risk of future rupture.

Smart pigs for detecting large cracks and corrosion

Unlike hydrostatic testing, which is often conducted on pipelines for acceptance testing or for pipelines recently rehabilitated, pigging is the more commonly accepted method of testing pipeline integrity.

While newer “smart” pigs have an excellent reputation for accuracy, their efficacy is often limited to detecting corrosion and cracking that exceeds the threshold for detection of the technology.  Small corrosion pits and cracks, especially cracks grouped in a colony, can pose a challenge to most conventional ILI pigging devices.

The various ILI technologies are sensitive to axial or circumferential defects, and each has limitation for minimum aspect ratios or cross sectional wall loss area before the ILI tool can report the anomaly.  It is also possible to have cracks and wall loss pits that are in close proximity to girth welds, long seams, and other features in the pipe, which can mask the defect, preventing the ILI tool from properly identifying and sizing.  As a result, it is possible to have leaking cracks and corrosion pits that are too small to be sized and reported from conventional ILI.

Not all lines are piggable

Some pipes are more suitable for pigging than others. While most oil and gas transmission lines were built in long straight sections suitable for pig runs, sections with small diameter pipe and small bend radius pipe configurations can limit many ILI tools.  Lines with expansion loops and miter bends, and in the case of natural gas lines, those with reduced port valves, are factors that can prohibit or restrict the traversing of online tools.

Mass balance measurement and other leak detection tools

To make up for the limitations of conventional ILI technologies, operators often deploy measurement methods and leak detection technologies to complement their integrity programs.

Mass balance is a means of detecting leaks by measuring the mass of product entering the pipeline compared to the mass exiting the pipeline. The limitation for detecting small leaks is the sensitivity of the mass meters being used (2-4% accuracy for conventional orifice meters and 0.25% for turbine meters), and the fact that the product temperature and pressure changes as it moves through the pipeline.

While mass balance is a means to determine leaks, it is also recognized that making actual measurement of mass from volume (through a meter) at different temperature and pressure going in versus coming out of the pipeline, in real time, is difficult, and not very precise or sensitive to small leaks.

As a result, a leak has to release more product than the total tolerance of the mass balance system before a positive leak/release event is alarmed.

Acoustic leak detection

Minute cracks are often preliminary indicators of potential small leaks that produce acoustic emissions at levels often unrecognizable over background noise.

Acoustic leak detection can be conducted with geophones/hydrophones, comparators and acoustic fiber optic techniques, and each of these acoustic tools is subject to different background noise limitations to determine leak detection thresholds.  Not only can these tools have limitations to prevent small leak detection, the expense from installing permanent acoustic systems may reduce the practicality of these technologies.

Emerging technologies on the horizon

To complement hydrostatic testing, conventional pigging tools, and leak detection technologies, the oil and gas industry is evaluating a growing number of emerging external confirmation of containment technologies. These include vapour-sensor systems, hydrocarbon-sensing cables that change in the presence of hydrocarbons, internal pressure wave based tools and fibre-optic based systems that detect temperature changes and acoustic signals associated with leaks.

While these technologies offer hope for more precise surveys, they have yet to be universally accepted or proven. Many are still under development and often require economically impractical installation requirements.

However, there is an innovative, multi-sensor ILI platform that has been used in integrity management programs since 2006, gaining the attention of major pipeline players who have tested the platform, which has now been used on over 25,000 kilometers of pipeline in total.

Introducing SmartBall® technology for Oil & Gas pipelines

To provide a realistic snapshot of a pipe’s condition, many proactive operators are deploying SmartBall technology,  a free-swimming multi-sensor tool for long inspections of piggable and difficult to pig liquid and gas pipelines 4 inches and larger. This advantage makes the ball-shaped tool an excellent choice for traversing not just standard diameter pipes, but for smaller diameter liquid lines and for gas pipelines with loops and frequent sharp bends and heavy wall fittings.

During an inspection, the SmartBall sensors collect acoustic, pressure, temperature, magnetic and inertial data from inside the pipeline.

Primary applications for the SmartBall tool

SmartBall surveys can be conducted independently, at regular intervals, as part of a routine pipeline integrity management program, or as a value-add to inspection programs along with hydro-testing, ILI, or direct assessment.

The tool is launched and retrieved at existing pig traps and is tracked using proprietary acoustic receivers and/or Armadillo pig tracking boxes (AGMs). The location data from acoustic receivers and tracking boxes is used during data analysis to locate any anomalies.

SmartBall technology has three primary applications, and the multi-sensor tool can provide a variety of pipeline data.

1. Confirmation of Containment

Regular confirmation of containment surveys are an important part of integrity management as leaks are often a preliminary indicator of pipe failure.

Unlike conventional leak detection systems, confirmation of containment with SmartBall supplements these systems. The SmartBall tool directly passes leaks, and is therefore capable of detecting losses as small as 150 mL/min, which can be several orders of magnitude more sensitive than conventional methods.

SmartBall surveys can also complement regular ILI surveys by addressing potential pinhole anomalies that have aspect ratios below the reporting threshold of ILI systems.

2. Pressure and Temperature profiles

As the SmartBall is rolling and not sealing against the pipe ID, as conventional pigs do, the tool can also record precise pressure and temperature profiles. The SmartBall platform can be deployed in gas pipelines, where pressure and temperature profiles can be integrated into flow models to assess the points where water vapor may condense out of the gas.

The tool can also be used to assess the point where high temperatures from pump or compressor output may have affected the pipe coating, as well as in settings to validate and improve SCADA and mass balance systems.

3. Pipe Wall Assessment and Inertial Mapping

During inspection, the SmartBall Pipe Wall Assessment (PWA) tool collects magnetic data that can provide a screening of the pipe wall for stress resulting from features like large cracks, large wall loss, dents and points of excessive loading.  The test can also complement hydrostatic testing, as it can survey the pipeline before and after hydro-tests to identify stress that is indicative of pressure reversals.

In addition, the SmartBall PWA tool can produce a girth weld and joint tally for the pipeline, as well as can confirm locations of bends and general geometry of the pipeline.

Helping operators make better decisions

Admittedly, SmartBall is not designed to compete with high resolution technologies like Magnetic Flux Leakage (MFL), which can provide detailed wall loss data.

What SmartBall can do is complement other integrity tools by providing additional data sets to ensure pipeline integrity. In a single deployment, it can detect anomalies associated with pinhole leaks and stress that doesn’t necessarily involve wall loss; e.g. geotechnical strains.  It can also detect change in pressure and temperatures.

Ultimately, the SmartBall tool can help capture enough data to confirm the integrity of the pipe and give operators enough microscopic knowledge to make better, informed, risk-based decisions on the health of their pipelines.

Georgia Road Sign

Unlike many large, well-funded municipalities, smaller mid-sized communities often lack the financial resources to conduct proactive inspections on their buried infrastructure. Generally it’s a common situation prevalent across much of the United States.

For this reason, when several medium-sized Georgia communities were provided state funding for an inspection and condition assessment on critical sections of their water pipelines, they jumped at the opportunity to have actionable information about their actual pipeline condition.

A baseline condition inspection helps operators make defensible decisions

The Georgia Environmental Finance Authority (GEFA) facilitates programs that conserve and protect Georgia’s energy, land and water resources. In this instance, GEFA provided technical assistance funding for seven mid-sized communities to perform condition assessment on large diameter lines, which for these communities, ranged from 8-inch polyvinyl chloride (PVC) to 24-inch ductile iron pipes.

Pure Technologies was retained to perform condition assessment work for seven (7) Georgia communities, which included Marietta Board of Lights and Water, Paulding County, Haralson County, City of Dublin, City of Valdosta, Spalding County, and Coweta County—whose populations ranged from 10,000 to 100,000.

For the most part, Pure performed a SmartBall® leak and gas pocket inspection and Transient Pressure Monitoring with Fatigue Analysis on the potable water pipelines for the subject communities.

In addition, Pure was also retained to deploy a SmartBall® Pipe Wall Assessment (PWA) on the ductile iron mains for the City of Valdosta Utilities Department and the Marietta Board of Lights and Water.

PWA data

SmartBall PWA technology is used to evaluate metallic pipelines by detecting and measuring the changing levels of the magnetic field, which is related to the stress in the pipe wall. As a screening tool, PWA technology provides an indication of pipe sections exhibiting higher levels of stress, which can be used as a first stage of pipeline condition assessment to help make informed decisions on higher resolution investigations, inspection, data collection and subsequent management or rehabilitation.

SmartBall tool chosen for its ease of use and sensitivity to small leaks

The SmartBall tool was chosen as an inspection platform for its sensitivity to small leaks, minimal pipeline modifications required for insertion and extraction and ability to inspect long distances in one deployment. The free-swimming, acoustic-based SmartBall tool is inserted into the flow of a pipeline, traverses the pipeline, and is captured and extracted at a point downstream.

SmartBall inside a pipe with a net

During inspection, the SmartBall tool’s location is tracked at known points along the alignment to correlate the inspection data with specific locations. As the SmartBall tool approaches a leak, the acoustic signal will increase and crescendo at the point when the tool passes the leak.

Deploying the SmartBall tool allowed each inspection to take place while the mains remained in service, a benefit much appreciated by the communities.

“This was an excellent opportunity to offer mid-sized communities in Georgia with a non-destructive internal inspection of critical pipes within areas where traditional methods may not able to collect this important information. Pure provided very professional service to work with the Utilities and help develop a specific plan to acquire this valuable data.”

Larry Lewison, NRW Analyst, Consultant

Inspection not without its challenges

In general, for most of these smaller communities, condition assessment was a novel concept, which meant lots of communication between Pure and the utilities. Mid-sized utilities, understandably, are often hamstrung by a lack of as-built drawings, geographic information systems (GIS) or other connection and appurtenances information on their pipeline network.

In the end, based on Pure’s many years of inline inspection experience and expertise, obstacles were overcome and the overall inspection program was a positive learning experience for all.

Results from cumulative 11.7 miles of inspection

Immediately after each inspection, the data was downloaded from the SmartBall tool, verified for quality and sent to Pure Technologies for review by the analysis team.

Based on the acoustic results of all the SmartBall inspections, three (3) true leaks and zero (0) acoustic anomalies characteristic of gas pockets were found on a cumulative distance of 11.73 miles of pipe inspected. For the city of Valdosta, which included a PWA inspection, Pure identified 30 specific pipes as having anomalies indicative of stress. For the Marietta Board of Lights and Water, Pure detected 61 stress anomalies along the pipe wall. This indicates a 22 percent anomaly rate, which is average compared to historical data on similar pipelines.

In addition, Pure also performed fatigue analysis for all PVC pipes, and no immediate concerns were noted.

The results indicate that the assessed mains are generally in serviceable condition, and gave the Georgia communities confidence in the overall health their systems, with no need for immediate rehabilitation, except for the three leaks that warranted attention. This process allows the communities to develop a sustainable long-term strategy for managing their critical buried assets.

Insertion and extraction sites

Oil and gas pipeline owners routinely conduct inspections of their assets by using inline inspection pigs. These tools are used to identify defects within the pipeline and need to be tracked throughout an inspection. Pipeline owners have several options to track a pig such as legacy tracking, remote tracking, and batch tracking, which is sometimes considered as a viable alternative to legacy or remote tracking.

Batch Tracking can be Difficult and Risky

Batch tracking involves measuring pump and flow rates to estimate how far a pig has traveled through a pipeline. The data measured is then compared to pipeline drawings to make an estimate of the pig’s location at a given time.

Depending on the tolerance of the metering system and the bypass rates on an individual pig, locating the tool can be very challenging. Batch tracking also does not provide any dynamic information about a pig. For example, an unexpected speed excursion or stoppage will go unnoticed.

Remote Tracking provides a more Reliable Option

Although traditional or remote tracking is more expensive than batch tracking, its cost is far outweighed by the risk of losing a pig. Lost pigs can result in costly, unplanned shutdowns to locate and retrieve the pig, which would ultimately negate any costs saved by using batch tracking. Technological advancements such as remote tracking provide a cost-effective alternative to batch tracking.

Sensor for tracking

Remote tracking can reduce an asset owner’s risk exposure by providing reliable information during an ILI run. Tracking a pig is the best way to ensure your assets are safe and that you can respond to any incident.

Remote tracking uses a combination of above ground markers (AGMs) and remote tracking units (RTUs) to track a pig during an ILI run. Pig passages are detected using multiple sensors to ensure that the pig is being tracked using more than one indicator. In addition to tracking with multiple sensors, pipeline owners and ILI vendors are provided with a record of each pig passage, making it easier to see when passages are not auditable using a standard geophone.

To learn more about advanced pig tracking, download PureHM’s pig tracking whitepaper.

Download full PDF

Oil and gas pipeline owners conduct routine inspections of their pipelines using inline inspection (ILI) tools known as pigs. ILI pigs can identify defects within the pipe wall and need to be tracked when they are travelling through a pipeline.

Pig tracking can be expensive (as much as 25% of the ILI budget) and costs can vary from vendor-to-vendor, especially when you factor in the different methods used to track pigs, such as remote tracking and conventional tracking. In order to ensure that tracking budgets are used efficiently and defensibly, each ILI run should be thoughtfully planned to determine the most appropriate tracking method.

Per Mile Cost Fluctuations

Drawing of a worker

Even after thorough planning, cost estimates can vary from vendor-to-vendor, raising questions about per mile cost fluctuations. To reduce the per mile cost of tracking, service providers often reduce the quality of tracking per mile. In traditional tracking, sending out lesser-trained technicians at cheaper rates, enacting only minimum safety measurements and using only one tracking sensor to identify pig passages are all ways that vendors can reduce per mile tracking costs.

An important consideration for pipeline owners and ILI vendors is determining how much risk they are willing to take when tracking their ILI programs. In most cases reducing the per mile costs by 10 to 15 percent is not worth the risk of using low-quality tracking techniques. A single missed or lost pig can easily negate the savings from using the lowest-cost provider.

In most cases, using remote tracking can decrease both the risk and cost of an ILI run. Remote tracking requires fewer staff and equipment resources than conventional tracking and is much safer.

To learn more about remote tracking and its benefits, download PureHM’s pig tracking white paper.

Download full PDF

City of Milwaukee Skyline

Milwaukee is a water hub, and not just because of its location along the shores of Lake Michigan, which holds 4.3 percent of the world’s supply of fresh drinking water. The City also boasts of global leadership in water technology, having won a U.S. Water Prize for innovative watershed-based approaches toward water sustainability.

The City takes a proactive approach to water management initiatives, as evidenced in the recent condition assessment of the Franklin-Muskego Force Main. Ownership of the pipeline is shared between the City of Muskego and the Milwaukee Metropolitan Sewerage District (MMSD), the government agency that provides water management services for about 1.1 million people in 28 communities in the Greater Milwaukee Area.

Metallic valves

MMSD and Muskego request detailed structural assessment on metallic force main

In 2015, Pure Technologies (Pure) was contracted to perform a detailed condition assessment of the approximately 25-year old pipeline. The purpose of the assessment was to identify the structural condition of the metallic force main, and included pressure monitoring, a SmartBall® leak and gas pocket detection survey, a PipeDiver® electromagnetic inspection, and structural evaluations of the pipeline.

Notably, the latest investigation used electromagnetic technology delivered on the 24-sensor mini PipeDiver platform to validate inspections conducted the previous year along the same lines.

Ductile iron pipe is a challenging material to assess

The Franklin-Muskego Force Main carries wastewater along approximately 1.6 miles of 24-inch and 1.3 miles of 30-inch ductile iron pipe (DIP). A small section of 20-inch DIP force main was also included in the survey.

One of the challenges in assessing DIP is determining if the pipe has undergone any loss of wall thickness due to internal or external corrosion, which are the primary causes of failure. DIP in water service with a cement mortar lining generally has fewer internal corrosion failure rates, unless damaged during handling and installation, or later as a result of 3rd party damage.

This is not the case when DIP is used in a force main, where internal corrosion is the primary cause of failure. Gas pockets are of significant concern as concentrations of hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall.  This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Gravity mains vs pressurized mains

In a force main, identifying internal areas with potential corrosion is challenging, as traditional gravity pipeline inspection techniques are often not applicable to in-service pressurized pipelines.

One method for assessing gas pockets is to locate air release valves (ARVs) or other high points along the alignment and provide pipe wall assessment in those areas. While this is a valid method for locating potential gas pocket locations, additional gas pockets may occur due to differential settlement, improper installation or non-functioning ARVs.

Therefore, these desktop surveys may not identify and locate all gas pockets along a pipeline, which is why Pure recommends other more precise survey methods.

SmartBall with case and insertion tools

SmartBall inspection summary

In June 2014 and October 2015 Pure performed a SmartBall leak and gas pocket detection survey of the Franklin-Muskego Force Main. Acoustic and sensor data was collected and recorded as the free-flowing SmartBall device traversed the pipeline.

During the 2014 survey, Pure detected zero (0) anomalies characteristic of leaks and one (1) anomaly that characterized a fully developed gas pocket.  During the 2015 survey, the SmartBall tool detected zero (0) anomalies characteristic of leaks and four (4) acoustic anomalies characteristic of fully developed gas pockets on the force main.

PipeDiver tool. insertion

24-sensor PipeDiver electromagnetic inspection

In 2014 Pure conducted a PipeDiver electromagnetic inspection, followed by a re-inspection in 2015, utilizing the new, 24-sensor electromagnetic PipeDiver tool. The technology ascertains a magnetic signature for each pipe section to identify anomalies that are produced by areas of corrosion or reduced wall thickness.

During the 2015 electromagnetic inspection using the mini PipeDiver, 13 pipes were found to have a total of 16 electromagnetic anomalies consistent with localized wall loss.

The electromagnetic inspection conducted in the 2015 inspection used an enhanced exciter coil allowing the electromagnetic field to return a more pronounced response. In addition to the enhanced exciter coil, the tool used in the 2015 inspection had a total of 24 receiving sensors, improving the ability of the tool to identify defects.

Confident conclusions

The results of the condition assessment indicate that the Franklin-Muskego Force Main is generally in serviceable condition, which was confirmed after an excavated pipe established a true baseline condition.

While the assessment recognized several areas with an increased likelihood of failure, overall the data was good, and coupled with Pure’s engineering recommendations, gave all stakeholders confidence in the health of pipeline for the near foreseeable future.

Longboat Key Aerial View

When much of your critical sewer pipeline lies buried under a bay of shimmering ocean water, the challenges required to assess its condition may seem daunting. That task faced the Town of Longboat Key, an affluent retirement community located on the barrier island of the same name off the west coast of Florida.

Sensitive to environmental, health and safety issues, the Town has been concerned about their 20-inch ductile iron pipe (DIP) force main installed in 1973. Inspections have been conducted in 1996, 2007 and 2011 with ultrasonic and visual methodologies for assessment.

Aside from being the only wastewater discharge from the island, approximately two miles of the four-mile pipeline runs under the Sarasota Bay before heading to the mainland, where it discharges into the Manatee County Southwest Water Reclamation Facility. The Town designated this force main as a priority pipeline due to the high consequence of failure, and is proactively managing this asset.

With talks of constructing a redundant pipeline, an island resident inquired about the condition of the existing force main and so the Town’s familiar engineering consultant, Greeley and Hansen, contracted Pure Technologies (Pure) as part of the comprehensive condition assessment project.

One of the challenges in assessing DIP is determining if the pipe has undergone any loss of wall thickness due to internal or external corrosion, which are the primary causes of failure.

SmartBall with case and insertion tools

SmartBall® platform provides a variety of condition data in a single deployment

To maximize the amount of actionable information to be gleaned from the force main project, Pure proposed leak and gas pocket detection services coupled with a pipe wall assessment (PWA) utilizing the SmartBall technology platform.

SmartBall is a multi-sensor inspection platform that provides utilities with a variety of pipeline condition data in a single deployment. Because the tool doesn’t disrupt service, it integrates easily into a management strategy to help pipeline owners reduce water loss, screen their network for problem areas and gain a better understanding of the condition of their assets.

SmartBall PWA technology is a screening tool that provides an indication of pipe wall stress on metallic pipes. The technology can be used as a first stage of pipeline condition assessment to help make informed decisions to focus higher resolution investigations, inspections, data collection and subsequent management of the pipeline.

SmartBall was also used to locate leaks and gas pockets in the line. Pipeline leaks are of concern for all pipe materials as they are often found to be the precursor of major failures. A pipeline failure can begin with weakening of the joint or barrel that may include a small leak.

In wastewater pipelines, identifying gas pockets is an important part of safely managing the asset, as concentrations of hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall.  This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Project challenges include underwater tracking throughout inspection

From inception, the biggest challenge was tracking the SmartBall over the 12,000-feet (2.27 miles) subaqueous portion of the pipeline. The Town was very concerned about sedimentation in that section under the bay, and insisted on Pure tracking the SmartBall PWA sensor tool throughout the inspection.

To accommodate the Town’s tracking request, 11 surface-mounted acoustic sensors (SMS) were placed along the pipeline to track the progress of the SmartBall tool during the inspection. SmartBall receivers (SBRs) were connected to the sensors on the pipeline to track the tool during the inspection based on information and drawings supplied by the Town.

Monitoring data collected during inspection

Results from acoustic and electromagnetic anomalies

From the data collected and analyzed, SmartBall detected zero (0) acoustic anomalies characteristic of leaks and zero (0) gas pockets during the inspection. This indicated no leaks within the detection limits of the detection technology.

At the same time, of the 1,133 identified pipe segments, 95 (8.4 percent) showed signals not attributed to known features.  The anomalies identified from the SmartBall PWA analysis included one large anomaly, 18 medium-sized anomalies and 76 small -sized anomalies. The electomagnetic signals associated with 28 of the 76 small anomalies appeared to be similar or repeatable, leading to the likelihood that a manufactured difference in pipe design exists between these 28 pipe sections.

More accurate GIS data revealed

Based on the PWA results, Pure recommended choosing a diversity of pit locations and assessing these with external verification techniques (e.g. high resolution magnetic flux leakage, pulsed eddy current, ultrasonic thickness testing, etc.) to further evaluate the probability of pipeline failure.

As well, Greely and Hansen (and the Town) now have a better handle on the spatial data of the system (GIS) and by statistically analyzing the data, can now develop pipe management strategies for the short-term management and long-term renewal strategies for the force main. By its proactive approach to asset management, the Town sets itself apart as a great example of how a community can plan for its long-term infrastructure needs.

City of Belmont Skyline

To help budget over the next 20 years, the City of Belmont (City) wanted to proactively understand and assess their force mains through a comprehensive condition assessment. Located in the San Francisco Bay area, Belmont serves 26,000 residents and maintains more than 90 miles of sewer mains comprising of 85 miles of gravity mains and 5 miles of force mains, of varying size and material.

To address its goal, the City contracted Pure Technologies (Pure) to deploy a wide range of both proprietary and third-party technologies and techniques to achieve a holistic assessment. The risk associated with a failure was significant, owing to a lack of redundancy, difficulty and cost of bypassing flow and potential for severe consequences to public health and the environment.

Pure provided inspection and condition assessment services on eight of the City’s force mains. The project scope included GAP analysis, condition assessmentengineering analysis, and necessary repair or replacement recommendations to establish a long-term management plan for Belmont’s force main inventory.

Variety of solutions and technologies used to assess inventory

A number of solutions and technologies were used to assess Belmont’s force mains. Phase one involved a GAP analysis, performed by interviewing operations staff and reviewing historic information, GIS maps, and drawings.

Phase two included an assessment of the eight force mains through the use of various technologies, including SmartBall® leak and gas pocket detection, SmartBall Pipe Wall Assessment (PWA), soil corrosion survey, hydrogen sulfide monitoring, transient pressure monitoring, and hydraulic evaluation.

SmartBall with extraction tool and controls

SmartBall leak detection is a free-flowing tool used to locate leaks and gas pockets in pressurized pipelines. The tool is equipped with a highly sensitive acoustic sensor that is able to locate “pinhole” sized leaks. Pipeline leaks are of concern for force mains as these emit illegal discharges to the environment and are often found to be a precursor of major failures. In metallic pipes, gas pockets are of significant concern, as hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall.  This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Pipe wall assessment (PWA) is a screening technology for assessing the condition of metallic pipelines by identifying pipe sections with increased levels of stress. SmartBall gas pocket and leak detection services were used for the 8-12-inch diameter mains.

Transient pressure monitoring and hydraulic evaluation used on the smaller mains

Transient pressure monitoring and hydraulic evaluation was used to evaluate the smaller 6-inch force mains. Hydraulic pressure transients occur in pipelines when steady-state-conditions of the system change due to pressure or flow disturbances. It is important to conduct transient pressure monitoring and hydraulic evaluation because damage from pressure transients can include cracking of mortar coating or lining, crack propagation, movement at joints, and structural fatigue.

During the condition assessment, Pure evaluated the likelihood and consequence of failure criteria and developed a scoring system, placing each force main in one of three categories: low risk, moderate risk, or high risk.

Satellite image with location map

For phase three, Pure conducted a life cycle and financial analysis, outlining the potential life and replacement/repair costs for each force main. By comparing results identified in each assessment phase, the City of Belmont can now move forward and create both a short-term and long-term rehabilitation plan.

“Through innovative technology, comprehensive data gathering and analysis, Pure Technologies helped us to assess condition of our large force mains within budget constraints, to help us plan our future capital improvement program…”

Each main evaluated with an overall risk rating

The GAP analysis included a review of all the information given to Pure at the beginning of the project and included historic information, GIS, and some drawings. During this phase, many of the parameters such as pipe length and material were found to differ from what was originally thought through the process of internal inspections and external excavations.

Pure conducted the SmartBall leak and gas pocket detection survey on four force mains and found 21 unique anomalies. The SmartBall PWA discovered seven indications of stress on the two metallic pipelines.  Hydraulic analysis of all eight force mains revealed that several force mains have a nominal increased potential for failure due to significant pressure swings and a large quantity of pumping cycles. Hydrogen sulfide monitoring was performed on six force mains to quantify the potential for internal corrosion caused by hydrogen gas.

Once all tests were completed, each force main was evaluated by its likelihood of failure and consequence of failure, and then given an overall risk rating.

Assessment includes life cycle and financial analysis

By determining overall risk for each force main, Pure was able to complete a life cycle and financial analysis and provide Belmont with the best data available to make long-term decisions on managing their assets. Each force main was given an estimate of its remaining life as well as a financial comparison of different management option costs. The financial comparison took capital replacement costs into account with Pure’s Assess & Address™ approach in both the best case and worst case scenarios. In both instances, the management options showed costs significantly lower than a full capital replacement option.

Using both the data and short and long-term recommendations provided by Pure, Belmont is now fully equipped to make the best possible decision and budget accordingly over the next 20 years, while continuing to address and mitigate risk.

The most common form of pipeline integrity used by oil and gas pipeline owners is inline inspection (ILI). Inspection pigs are widely used to clean pipelines, as well as identify areas of damage along the pipe wall to ensure the safe delivery of energy products.

Historically, once a pig is deployed in a pipeline, a technician confirms the tool’s arrival time at various tracking locations throughout the planned inspection distance. Once the tool has passed each location, it is out of sight until it reaches the next tracking point. However, recent technological advancements in tracking technology now allow for pigs to be tracked remotely throughout an entire ILI run.

Remote tracking combines the use of above ground markers (AGMs) and Remote Tracking Units (RTUs) that are deployed before an ILI run is scheduled to take place and are used to track the pig from a central location. When a pig approaches a tracking site, the RTU and AGM are activated to track the tool, which eliminates the need to have a field technician to be on site.

Consistent Live Tracking

PureHM has developed a web-based software called LiveMap that tracks a pig throughout the entire ILI run. LiveMap provides real-time updates via email or SMS with the pig’s location, speed, and estimated time of arrival to ensure that there is better visibility for stakeholders during a project. This advanced technology mitigates the risk of unexpected challenges in an ILI run, such as a stuck pig or speed excursion.

Live tracking offers more control throughout an inspection, and can help prevent costly incidents such as lost pigs by providing accurate information on a pig’s location. A lost pig can interrupt or stop product flow in a pipeline, and can lead to pipeline damage and unforeseen service disruptions.

LiveMap drawing

During an ILI run, the time and speed information collected each time the pig passes the AGM is updated and presented in LiveMap. In traditional legacy tracking runs, this is completed and reported by the field tracker, while in remote tracking runs this is completed automatically with a defensible record of the passage.

To learn more about remote tracking, download PureHM’s pig tracking white paper.

Download full PDF

Louisville Water Tower and Pumping Station house the WaterWorks Museum

To many history buffs, “the prettiest ornamental water tower and pumping station” in the U.S. belongs to Louisville Water Company (Louisville Water). In 1860, the water company, which today provides water to more than 850,000 people in Louisville, Kentucky and surrounding communities, built its first water tower and pumping station in the form of a Greek temple complex.

Today, the Louisville Water Tower and Pumping Station house the WaterWorks Museum, and Louisville Water continues to make history using modern technology from Pure Technologies to assess its extensive water network.

Focused on pipes with the potential to cause the most damage

Following a water main break in 2009 that resulted in the loss of 15 million gallons of treated water, Louisville Water began a Transmission Assessment Program, first deploying Pure’s PipeDiver® technology to conduct a practical and cost-effective way to inspect transmission mains. Over the succeeding years, this program has evolved to include with other assessment technologies from Pure’s toolbox.

Transmission Assessment Program utilizes a variety of assessment tools

In the summer of 2015, Louisville Water deployed PureRobotics to assess 3.41 miles of 24 to 30-inch transmission mains in its network. With over 4,100 miles of pipeline to maintain (200 miles of it transmission main), Louisville Water focused its condition assessment on its transmission main system – pipes that would cause the greatest amount of damage in the case of failure. The loss of non-revenue water, either in continuing small amounts or from a catastrophic failure, can result in massive costs to a water utility.

By prioritizing the risk levels associated with their transmission main system, Louisville Water has created an ongoing inspection program to keep a watchful eye on the health of their pipelines. The program utilizes a number of Pure Technologies assessment tools to find active leaks as well as potential future threats.

In May of 2015, PureRobotics was deployed on the Cross County Header, Ray Lane Easement pipeline, and Bardstown Road pipelines. For Louisville Water, PureRobotics used CCTV to provide a comprehensive high-definition visual inspection. The robotic crawler was also outfitted with specialized tools to conduct an electromagnetic assessment on the condition of the pipeline and inertial measurement unit (IMU) for a GIS component.

The Inertial Measurement Unit (IMU) deployed with PureRobotics uses a series of Fiber Optic Gyroscopes (FOGs) and accelerometers to track depth, lateral and horizontal movements from a known GPS reference point. The output is a GIS spatial map of the pipeline which depicts elevation changes as well as notable features of interest encountered during the inspection.

PureEM electromagnetic assessment detects anomalous regions in the pipe cylinder and prestressed wires. This data is correlated with odometer readings from the PureRobotics umbilical tether as well as HD recorded CCTV and IMU to attempt to locate areas of distress in the pipeline.

Anomalous pipe

One of the 11 anomalous pipes excavated.

Due to its mobility, PureRobotics is ideal for multiple isolated inspection runs where a quick setup and breakdown can improve efficiency.  The transporter can be deployed from a number of access styles including valves, open flange, and open pipe. In the case of the Louisville Water inspection, the PureRobotics system was inserted into the pipeline via newly installed vertical gate valves and existing boiler plate style hatches. Inspection lengths varied in length from 70 feet to beyond 2,000 feet.

Staff deploying PureRobotics

Louisville Water deployed PureRobotics to assess its transmission mains.

Results gave Louisville Water the confidence to prioritize its rehabilitation program

High definition CCTV inspection results showed a number of longitudinal cracks consistent with overloading. These types of mortar cracks may eventually lead to corrosion of the steel cylinder or prestressing wire and eventually a failure of the pipe.

One pipe section in the Ray Lane Easement pipeline was found to display anomalous electromagnetic signals showing a significant number of broken prestressing wire wrap breaks as well as cylinder wall loss. This was correlated with visual data, showing spalling and exposed steel at the invert of the pipe.

Visual assessment also showed a number of pipe sections with spalling. Electromagnetic assessment also found 11 pipes with anomalous signals not consistent with wire breaks. Investigation performed on one of these anomalous pipes showed a non-standard metal sleeve used in manufacturing. From this information, it was determined that the remaining 10 anomalous pipes could be left in service.

As one of the first utilities to deploy the third generation PureRobotics platform, Louisville Water now has defensible data to move forward with its ongoing rehabilitation program. For this historic water utility, modern technology really can help.

Historical pipe installation

An archived photo from installation of the pipeline five decades ago.

When your pipeline operates well for five decades, it’s easy to be lulled into a false sense of security about the condition of your buried assets. Out of sight, out of mind.

Then, in an instant, that mindset can change.

For Canadian River Municipal Water Authority (CRMWA), that wakeup call happened after dealing with two unexpected failures in quick succession earlier this year. The failure repercussions quickly introduced CRMWA to Pure Technologies, a leader in technologies for the inspection, monitoring and management of critical infrastructure.

CRMWA provides water to 11 member cities in the Texas Panhandle and South Plains region, near the cities of Amarillo and Lubbock. The water authority, which serves more than 500,000 people, draws water from Lake Meredith through a 358-mile aqueduct system completed in 1966. Comprised of approximately 55 miles of non-cylinder prestressed concrete pipe (PCP) along with approximately 300 miles of reinforced concrete pipe (RCP) and bar wrapped concrete cylinder pipe (BWP), the main aqueduct can deliver up to 118 million gallons of water daily to the 11 member cities.

Digging out failed pipes

One of the pipe failures that caused a blowout.

December 30: First blowout ends flow to 9 cities

The first indication of a problem occurred with a pipe rupture on Dec. 30, 2015, which abruptly ended the flow of water to nine of CRMWA’s member cities, leaving the cities to use precious reserves or their own water.

With the initial failure of a 72-inch (1830-millimeter) diameter non cylinder prestressed concrete pipe (PCP), the water agency lost millions of gallons of water, forcing a temporary pipeline shutdown to make immediate repairs.

January 5: Soon after the first blowout was repaired, an adjacent pipe began leaking

Five days later, on Jan. 5, CRMWA completed repair number one, and started to refill the system when an adjacent pipe began leaking.

This new leak lead to an emergency mobilization from Pure at the request of CRMWA. Pure’s condition assessment technologies have helped clients prevent more than 2,300 failures worldwide, resulting in billions of dollars in savings, and hundreds of billions of gallons in water savings. Pure has also located more than 4,000 leaks on water mains using its leak detection technologies.

Broken concrete pipe exposing the internal anatomy

One of the EM anomalies verified and excavated for repairs.

January 5-6: Pure mobilized to begin a manned electromagnetic survey

The same day, a crew of three mobilized from Dallas to the failure site near Amarillo. The purpose was to conduct a non-destructive evaluation using Pure’s electromagnetic inspection technology on the pipe immediately adjacent to the damaged sections. Over the next two days, Pure scanned 8,822 feet with internal manned electromagnetics.

January 8: Based on expedited EM analysis, Pure informed CRMWA of two large anomalies in two pipes near the first failure.  Over the next two days CRMWA completed the second leak repair, and hoped for more time to conduct a third repair where Pure called a large electromagnetic anomaly.

January 11: After Pure demobilized from the job site, the client turned on the pipeline, and after flowing for 12 hours, a second failure occurred, in the area located where Pure’s EM analysis indicated a potential problem.

January 12-13: Over the next few days, Pure verified five electromagnetic anomalies in three pipes near the failure site while CRMWA completed additional repairs. Based on the verified results, CRMWA requested a total of approximately 47 miles of manned EM inspection, which was completed by mid-March.

“The electromagnetic inspection was well worth the cost. Now we know the condition of our pipelines. We know the locations of our problems. The scan revealed 16 pipes where corrosion had put the lines at risk for developing additional blowouts. Those have been repaired much more cheaply and quickly than the costs of fixing blowouts.”

Kent Satterwhite

General Manager, CRMWA

Preparing the pipeline paid off by finishing ahead of schedule

CRMWA worked around the clock leading up to the inspections to dewater and prepare the pipeline for the internal inspections. The hard work paid off well, with no holdups on the inspection progress. The excellent planning by CRMWA and Pure allowed the inspection to wrap up ahead of schedule. Once the internal inspection was completed, Pure was also able to perform a destructive calibration on a pipe section which CRMWA provided, which was helpful for the analysis of the data collected. CRMWA was also able to repair 16 pipes that were very close to failure as identified by the electromagnetic surveys.

Sometimes one unexpected pipeline problem can compel long term planning and action, as it did with CRMWA. The Water Authority now has a defined plan to assess the condition of their pipeline, giving them the confidence to move forward with greater assurance and peace-of-mind.

Man with fish inside pipe

After a long day,  Pure and CRMWA celebrated with a fish dinner, caught while draining the raw water line.

Fish inside a cooler

In order to mitigate risk, pipeline owners spend approximately $1.5 billion every year on pipeline integrity for the thousands of kilometers of pipe across North America. Pipeline integrity often employs the use of inline inspection (ILI) tools known as pigs. These pigs are inserted into a pipeline and pushed along the pipeline by the flow of product. ILI tools have multiple functions, and can be used to clean and assess the condition of the pipeline, as well as to purge different products in a multiproduct pipeline. There is a risk of the deployed pig getting stuck or lost if it is not tracked properly. Locating a lost pig can be costly to the vendors if it is not found quickly and can cause severe damage to the pipeline.

Many legacy tracking providers do not provide a record of each pig passage to prove a pig has actually passed a location. Instead, this is left to the word of the tracker and sometimes is not a reliable source of information. Trackers are not intentionally misleading stakeholders about where a pig is, but traditional methods often make it difficult to tell if a pig has passed or not.

Traditional legacy tracking providers typically use standard geophones to track and identify a pig passage. It is often difficult to determine if a pig has passed because the signal on the geophone is quick and sometimes difficult to hear. This leads to false positives showing a pig has passed even when it hasn’t.

Using more than one sensor to reduce incidents

Using Advanced Pig Tracking, pig passages are detected using multiple sensors to ensure information is defensible and reliable. Advanced tracking systems are equipped with multiple channels. These sensors work simultaneously and reduce incidents of false positives or missed pigs. Not only do these systems come equipped with multiple sensors, but they also provide stakeholders with a record of each pig passage throughout the run.

Sensor for tracking pigs

The record shows the signal of the pig passage as well as the timestamp and pig speed at the specific location. These snapshots can then be uploaded into LiveMap, and are used for real time tracking of the pig’s position, speed, and estimated time of arrival. Conventional above ground markers (AGMs) rely on triggered passage files unlike Advanced Pig Tracking AGMs, which constantly record data when turned on.

To find out more about the other myths of pig tracking, and how Advanced Pig Tracking is more reliable than traditional methods, click the link below.

Download full PDF

Over the past decade, the world has been gripped by many stories of pipeline failures, especially those with severe consequences to the environment and human life. These failures have resulted in billions of dollars in remediation costs, and understandably, this makes pipelines some of the most regulated assets in the world. The use of inline inspection (ILI) tools, such as pigs, is the most common form of pipeline integrity. Pipeline pigs are tools inserted into a pipeline and pushed along by the flow of product through the pipeline. The tool has multiple functions, and can be used to clean and inspect the pipeline, as well as to purge different products in a multiproduct pipeline. When these tools are operating in a live pipeline, it is important to know their precise location and speed, as they are very expensive to replace. A lost or stuck pig can obstruct product flow, causing unwanted service disruptions, or at worst, pipeline ruptures.
Geophone

When tracking a pig through an oil or gas pipeline, it is often difficult to know if it has passed a tracking location, especially for inexperienced pig trackers. The majority of legacy tracking is done only with a standard geophone, a device which converts ground movement into voltage, and relies solely on the word of the technician tracking the pig. By using only a standard geophone, a technician cannot reassure an ILI vendor when the pig has passed a location. The geophone can give a technician many false positives; therefore, the technician’s word will not inspire much confidence in an ILI vendor.

Lack of experience can lead to tracking challenges

To be able to identify a pig passage with only the use of a standard geophone, an experienced tracker needs to reduce the likelihood of error. Many of the trackers who are sent out in the field are inexperienced and are unable to provide this. By solely relying on a standard geophone, field technicians can easily miss a pig passing through a station, and can lead to problems later in the run. Accurate pig tracking requires the right tools and defensible data. Remote tracking can be a more efficient system and provides more concrete data than legacy tracking systems.

Reliable tools and data

The Armadillo Tracks system uses multiple sensors to track every pig deployed into a pipeline. The sensors work simultaneously and record a snapshot of each pig passage. These snapshots prove when a pig has passed a tracking location and helps ILI vendors with benchmarking and reporting. With more reliable tools and data, vendors can have peace of mind knowing problems during a pig run will be minimized.

Technical map generated by Pure & Armadillo Tracks

To learn more about how remote tracking systems benefit ILI vendors and the other myths of pig tracking, download the White Paper here.

Download full PDF

Houston and Oaklahoma

Sahara® technology is winning accolades from satisfied owners and operators of buried infrastructure the world over. In North America, two recent projects demonstrate the benefits of using this in-line tethered tool for critical leak detection surveys, especially when speed and accuracy are paramount.

Sahara Diagram

Sahara is the first tool designed for live inspection of large diameter mains, and one of the most accurate tools available for detecting and locating real-time leaks, gas pockets and structural defects in complex networks typically found in urban environments.

The tool is inserted via a valved appurtenance, and then moves through the pipeline using the flow of water and a small drag chute – all without interrupting service. Once the sensor tool is inserted, it remains tethered to the surface. This allows for real-time results and maximum control, as the tool can be winched back and forth to immediately confirm suspected leaks and other anomalies. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

Oklahoma City welcomes Sahara leak detection survey on critical main

In March 2015, McKee Utility Contractors (McKee) retained Pure Technologies (Pure) to perform a quick-turnaround leak detection survey on a troublesome 72-inch Transmission Main (TM) in Oklahoma City. The critical TM, which is composed of prestressed concrete cylinder pipe (PCCP) and transmits potable water, is owned and operated by Oklahoma City Water Utilities (OCWU).

In this instance, OCWU suspected a leak along a low point of the line where surface water was noticed. A previous catastrophic failure on the line compelled the utility to call on the prime contractor McKee to dig, locate, and repair the leak.

Thwarted by two days of digging and not finding the leak, McKee called on Pure to assess approximately 4400 feet of pipe and to determine the location of the leak source and any gas pockets using Sahara leak detection technology.

Quick mobilization, short turnaround timing

The planning and execution took place in short order. McKee contacted Pure on Saturday, the project planned on Sunday and by Monday a field crew and equipment were mobilized to the site in Oklahoma City. On Tuesday, a single inspection was performed, and one (1) leak was detected 360 feet downstream from the Sahara insertion point. The leak was classified as a large leak based on the audible range.  The inspection continued for a total inspection distance of 546 feet.  No other leaks were detected at the time of inspection.

By the time Pure began extracting the Sahara tool, McKee had ordered a backhoe enroute, and by afternoon the pipe was excavated, the leak located, and the repairs were able to begin.

Shane McKee, president of McKee was extremely pleased with the accuracy of the Sahara technology and the fast turnaround from the Pure team.

“Based on the results I’ve seen, I’m never again digging up another pipe again without Pure and its technology to help guide the process.”

Shane Mckee

Shane Mckee, McKee Utility Contractors

Sahara Insertion Tool

Houston energy company deploys Sahara tool to quickly locate leak in chilled water line.

Large cities often operate central chilled water plants to cool water that is then sold to building owners for use in air conditioning.

In Houston, Enwave Houston delivers chilled water through 5.4 miles of pipe to air-condition 24 buildings, including Minute Maid Park, home of the Houston Astros. The 27,000 ton system uses ice storage technology to help keep central business district buildings comfortable in spite of summer`s high temperatures and humidity.

In December 2015, Pure was retained by Boyer Inc. to perform a Sahara inspection on Enwave`s 24-inch Chilled Water Supply pipeline (CWS) and also on their 24-inch Chilled Water Return pipeline (CWR). The purpose of the inspection was to locate a suspected leak on one of the dual lines that run parallel along the downtown core.

Data identified events associated with leaks and air pockets.

Boyer proposed two separate insertions during the planning phase. Pure completed both proposed insertions over a two-day period for a total of 795 feet of pipeline inspected. Acoustic data was collected and recorded during the inspections as the Sahara sensor traversed the main. The data was evaluated to identify events associated with leaks and pockets of trapped air.

During the inspections, one leak and zero air pockets were detected. The Sahara sensor was tracked above ground to track the sensor along each pipeline and verify the endpoint of each endpoint. The leak was located 144 feet downstream from the insertion point on the second day with sub-meter accuracy, allowing a pinpoint excavation to be made for repairs, minimizing disruption to downtown Houston traffic, and minimizing the contractor`s cost of excavation and road restoration.

When time and accuracy matter, utilities count on the Sahara platform.

The two case studies demonstrate the efficacy of the Sahara leak detection system. When time and pinpoint accuracy matter, the Sahara platform gets the job done right.

Wachs Water Services – Valve Restoration from Pure Technologies on Vimeo.

For large urban cities, one of the quickest ways to realize an investment return from their network of underground assets is to inventory the water distribution system and assess the overall condition of valves and fire hydrants.

This progressive major southeast U.S. city recognized the value of getting a comprehensive handle on the condition and usability of its aging control assets. The city, which operates a complex water network for nearly one million customers, recently completed a long-term asset management program for its valves and hydrants.

Wachs Water Services, in a joint venture with Brindley Pieters & Associates (WWS-BPA Joint Venture), recently completed the latest phase of this city’s Asset Assessment Program, providing the city with an immediate return on investment by maximizing usability of control assets. The water distribution system consists of approximately 59,000 valves and 24,000 fire hydrants.

Open Hydrant with water flowing

The program also ensured future savings through the development of a geographic information system (GIS) database that contains necessary water system transmission and distribution assets records and global positioning system (GIS) locations to meet water utility asset management and maintenance requirements. The program is projected to save the city a minimum of $77 million over the next ten years.

Estimated $77 million savings from increased control and enhanced management

The $77 million in savings, resulting from the increased control and enhanced management, will be realized even if the city makes no further investments in their system.  This represents three dollars ROI for every dollar invested.  With continued preventative maintenance and further enhancements to their GIS data program, the city could potentially save an additional $65 million over the same 10 year period.

“Every dollar that the utility has invested into this program delivers three dollars of tangible savings from quantifiable system operability improvements and consistent control…”

“Managing an aging water network requires a results-driven approach that achieves both immediate system improvements and long-term sustainability. Every dollar that the utility has invested into this program delivers three dollars of tangible savings from quantifiable system operability improvements and consistent control,” summarized Cliff Wilson, President of Wachs Water Services.

The Valve and Hydrant Asset Assessment Program met two objectives.  The first restored maximum usability to the distribution system, providing immediate system improvements.  The second developed a comprehensive and accurate GIS database, ensuring long-term sustainability.
Valve and Hydrant Asset Assessment

Good news: 95 percent of valves could be located, accessed, and operated within 15 minutes

WWS-BPA evaluated and digitized 82,412 total assets (59,020 valves and 23,392 hydrants).   This process revealed that the city had an initial valve usability of only 27.9 percent.  This low level of control asset usability drastically increased response time and the impact footprint, increasing disruption to customers, increasing traffic rerouting and delays, and increasing collateral damage.   Low usability increases overall costs.

The team rehabilitated over 50,000 assets, including 43,000 valves, most during the initial field assessment.   By the end of the program, 95 percent of valves could be located, accessed, and operated within 15 minutes.

Maximizing usability minimizes costs

City residents and utility crews immediately recognized the benefits.  Field teams can identify and locate assets quickly.  Traffic delays are avoided.  Insurance claims for residents and businesses decreased.   Pre-planned construction shutdowns are more efficient.

To develop the comprehensive GIS database, the WWS-BPA team collected and digitized more than 60 attributes per valve, and over 40 attributes per hydrant, including sub-meter GPS position.  The team digitized 3000 miles of the distribution network, connecting all the assets into an accurate, accessible, and maintainable information system.  The city’s operational crews now have an accurate picture of the system, with exact locations for the control assets along with their usability.  This information is used not only to respond to emergencies, but to manage and maintain the system’s high level of control.

Wachs Water Services is proud to be a part of this project that has set industry standards for large urban cities and demonstrated that efficiencies can be increased through restoration and information rather than replacement.

Flower Mound Sign

Named for a prominent landmark mound with more than 175 species of wild flowers, the Town of Flower Mound is ranked as one of the ten best places to earn a living and raise a family in Texas.

To complement these natural and economic positives, the scenic Town of 70,000 is also known for its municipal water stewardship and proactive approach in maintaining the quality of its buried infrastructure. This includes 430 miles of water mains and 230 miles sewer pipes serving 22,000 residential and industrial connections.

As part of the ongoing program for condition assessment of its buried infrastructure, the Town recently retained the services of Pure Technologies U.S. Inc. (Pure) to conduct a Sahara® leak and gas pocket detection inspection of approximately 21,200 feet of the Potable Water Main (PWM), which connects the Pintail Pump Station to the Waketon Water Tower. Constructed in 1973, the critical section of 20-and 30-inch pipeline is comprised of bar-wrapped (AWWA C303)steel and ductile iron pipe.

“Most pipelines are designed for 50 to 75 years expectancy, and service life can vary depending on factors such as depth, soil conditions and pipe material,” said Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District. “Rather than waiting for breaks to happen, the Town strives to assess the condition of the assets before that happens.”

The Sahara inspection followed a structural assessment using a PipeDiver® inspection of this same pipeline conducted one month earlier and covered many of the identical pipeline sections. FMPW chose CCTV inline video and enhanced electromagnetic (EM) assessment to provide a comprehensive condition assessment.

PipeDiver platform carried to the insertion point

Pure’s free-flowing PipeDiver platform, which preceded the Sahara inspection along the same pipeline, is being carried to the insertion point.

Detecting small leaks with Sahara inspection platform

The Sahara® pipeline inspection platform is one of the most accurate tools available for leak detection, gas pocket detection, and locating structural defects in complex networks of large diameter water and wastewater pipes.

The tethered tool is capable of locating very small leaks typically within 1.5 feet (0.5 meters) of their actual location. The tool also features inline video that allows operators to observe internal in-service pipe conditions.

Added value: Flower Mound inspection included design and installation of taps

The insertion locations for the Sahara inspection were dictated by the previous PipeDiver inspection, which indicated a large number of bends and long distances to cover with less than ideal access.

In light of the limitations, and within a very short time frame, Pure took on the responsibility to manage the tapping process in-house, including the design, excavation and installation of the taps to insert and extract the Sahara tool from the pipes. Although this task was atypical of work normally provided, it is an example of the added value Pure can bring to a project.

Detected: one leak, one large gas pocket, plus improved GIS information

It’s still early in game, and the electromagnetic results have yet to be fully evaluated. Nonetheless, the Sahara inspection detected a leak on an undocumented offtake installed on pipe suspected to have been blanked off and buried, and now leaking.

In addition to pinpointing the leak and gas pocket, the condition assessment located an additional six undocumented outlets the Town was previously unaware of, leading Pure and FMPW to surmise that the outlets were installed and equipped with blind flanges for future expansion. Additionally, during this inspection, sections of pipeline alignment were discovered to be quite different than what FMPW expected.

FMPW now has a true comprehensive condition assessment of their pipeline that includes GIS quality mapping, video inspection and recording of the pipeline interior, leak and gas pocket identification and repair, and assessment of the structural integrity on a pipe-by-pipe basis — allowing for localized verification and repair. Overall, GIS information has been improved, with location and images of possible leaks, defects or anomalies.

“The proactive approach we’re taking allows us to predict water main breaks, which improves our reliability of service,” said Williams. “When you locate a defect, you can schedule a repair, notify people, and get it done at the right time of day, and at a schedule of our choosing. Everybody benefits.”

Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District, talks about the Utility’s approach to condition assessment.

Utilities Complete Condition Assessment Of Bar-Wrapped Pipe With Smartball®, Pipediver®, And Robotic Platform Tools

By the early 1940s, cast iron pipe was losing its historic cachet as the go-to material for new buried infrastructure. Cast iron’s replacement was bar-wrapped pipe (BWP), and it quickly gained acceptance as a reliable, durable and cost-effective pipe material for use in large-diameter transmission and sewer force mains.

Typically, BWP consists of a welded steel cylinder with reinforcing bars wrapped around the cylinder to provide strength. An internal concrete lining and external mortar coating provide corrosion protection to the steel components. The watertight membrane enables the composite pipe to withstand high internal pressures and the effects of external earth and traffic loads.

Until recently, BWP condition assessment proved difficult

Despite early adoption from many pipeline operators, the downside to BWP has been the difficulty to assess the pipe’s condition, where failures are often precipitated by deterioration of the reinforcing bars and long periods of leakage that often go undetected.

It’s now 70 years later, and the methods to assess the condition of bar wrapped pipe have only been recently developed and commercialized. On this forefront, Pure Technologies is recognized for its toolbox of condition assessment technologies that can identify broad areas of cylinder corrosion and bar breaks.

Two Texas cities join forces to assess shared BWP water supply line

In one specific case, the city of Irving and a partnering agency in North Texas joined together to initiate a condition assessment project of their shared water supply line, made up primarily of bar-wrapped pipe. Constructed in 1955, the 48-inch Jamison Water Transmission Main is a critical non-redundant pipeline that conveys potable water to a combined population of 400,000 residences within the Dallas Fort-Worth Metroplex.

The two agencies worked side by side to implement an Assess and Address™ pipeline inspection protocol to determine the condition of the pipeline and to increase the utilities’ reliability of water delivery.

The condition assessment utilized inline acoustic leak and air pocket detection, robotics with high definition CCTV and enhanced electromagnetic detection, transient pressure monitoring and non-linear Finite Element Analysis (FEA) of the steel cylinder corrosion and broken bar wraps.

The results concluded that 97 percent of the 583 pipes inspected had no detectable damage. Less than 3 percent of the total pipes inspected exhibited minor distress, of which 15 (2.5 percent) pipes exhibited thinner steel cylinder.

Through close collaboration, the two agencies were able to effectively manage a shared asset with the goal of preventing disruptive and expensive pipe failures. The information gained from the assessment will allow for the implementation of a cost-effective, long-term management plan to extend the life of the pipeline.

Trinity River Authority of Texas (TRA) evaluates 8.8 miles of critical BWP transmission main

In a second case involving BWP, Pure collaborated with Trinity River Authority on assessing the condition of a pipeline that is a critical link in the reliable delivery of drinking water to five cities within the Dallas-Fort-Worth Metroplex. The aging pipeline was scheduled for replacement due to previous failures and inability to be removed from service for repairs.

To understand the overall pipeline condition, TRA contracted Pure to inspect and evaluate the pipeline by conducting comprehensive hydraulic, leak detection and condition assessment on 8.8 miles of the 30-inch bar-wrapped pipe.

For the leak and air pocket assessment, TRA used the SmartBall® inspection tool, a non-destructive, free-swimming technology that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. Regular leak detection inspections can help utilities identify leaks that may not be visible at the surface.

Increased reliability, reduced capital costs

For the structural inspection, TRA used PipeDiver®, a free-swimming electromagnetic tool that identifies bar breaks and broad areas of cylinder corrosion in BWP using PureEM technology while the line remains in service.

The inspection of the BWP identified 14 pipes with bar break damage and 72 pipes with electromagnetic anomalies resembling cylinder defects out of 1284 inspected pipes. By repairing specific pipe sections with deterioration, TRA was able to avoid replacing the entire pipeline at a high capital cost and continue providing reliable service to customers in the region.

Dallas Water Utilities Discovers Massive Hidden Sinkhole And Achieves Huge Savings Through Annual Leak Detection Program

The year began with the Lone Star state experiencing its fourth year of drought, compelling State Governor Greg Abbott to reissue an Emergency Disaster Proclamation in early May to deal with the declining aquifer levels and severe water shortages. Only a few weeks later, torrential rains flooded so much of the state that the Governor issued another Emergency Disaster Proclamation to prepare for the new crisis. Then, another long stretch of baking heat.

Weather extremes push water utilities to the limit

For most utilities, weather can play havoc with buried infrastructure. While drought can cause the dry brittle ground to shift and pipes to break, excessive rain can result in washouts, loss of bedding and risk for accelerated pipe failures.

In 2015, weather extremes in such a short period taxed water utilities across Texas. Despite the challenging environmental conditions, Dallas Water Utilities (DWU) moved forward to carry out its annual leak detection program. Over the years, DWU has focused its water loss reduction efforts on both its critical large-diameter transmission mains, which have the highest consequence of failure, and on its distribution systems.

Pipe leaking

Detection results include discovery of a large pipe leak near a major roadway

Staff inserting Sahara tool

Crews successfully used the Sahara® tool to locate 10 leaks in 16 miles of inspection.

DWU’s first condition assessment program using electromagnetics was completed in 2001, followed by the use of newer leak detection technologies in succeeding years. The program is now in its 14th year of operation, and DWU has become a showcase utility for proactive pipeline management, a fact recognized by the Texas Water Development Board.

DWU adds 16 miles to its leak detection program in 2015

DWU’s distribution system is one of the largest in the United States, being a regional provider, the utility delivers water service to 2.4 million customers within the Dallas and surrounding city limits. The major distribution system includes over 4,900 miles (7,800 km) of distribution and transmission mains.

DWU’s goal is to continually evaluate, upgrade and replace its water and wastewater assets in order to make its systems operate efficiently. DWU’s long-time partner in this infrastructure endeavour is Pure Technologies (Pure). This year Pure was contracted to perform leak and air pocket detection for 16 miles (25.7 kilometers) of water mains made of a variety of materials, including prestressed concrete cylinder pipe (PCCP), cast iron pipe (CIP) and ductile iron pipe (DIP).

DWU deploys inline detection tools

For inspection of its transmission mains, DWU has long used Sahara leak detection and inline closed circuit video (CCTV) provided by Pure. More recently, DWU has also used SmartBall® technology for longer inspections.

Sahara is the first tool designed for live inspection of large-diameter mains, and one of the most accurate tools available for detecting leaks, gas pockets and structural defects in complex networks typically found in urban environments.

The tool is pulled by the flow of water by a small drag chute while the line remains in service. When the sensor is inserted into a 2-inch tap, it remains tethered to the surface. This allows for real-time results and maximum control, as the tool can be winched back and forth to immediately confirm suspected leaks and other anomalies. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

Detection results include discovery of massive sinkhole near major roadway

The 2015 inspections, conducted over 23 days, challenged the Pure and DWU crews as they faced an environment with temperatures soaring to 104°F (41°C) on many consecutive days.

In spite of the trying working conditions, the crews successfully used the Sahara tool to locate 10 leaks in 16 miles of inspection. This included the unexpected discovery of a very large leak in the barrel of a 12-inch ductile iron water main. DWU’s proactive repair prevented a collapse since the large leak was creating a cavernous sinkhole near a major roadway.

By locating and repairing the leak, which had been seeping water for an estimated year, DWU averted a potential catastrophic crisis and saved the utility at least 893,000 gallons of lost water per year, equivalent to filling 1353 Olympic-sized swimming pools.

Olympic-sized swimming pool

Large leak discovery saved DWU at least 893,000 gallons of lost water annually, equivalent to filling 1353 Olympic-sized pools.

Sahara and SmartBall inspections in Dallas have been extremely successful, locating 160 leaks in 209 miles. The estimated water savings from these leaks is about 4 MGD. For DWU, the reduction in failures has reduced loss claims and service interruptions, as well as reduced treatment and delivery costs.

Whatever the weather, DWU is moving forward.

Though not quite as old as Rome’s ancient aqueduct system, the water and wastewater infrastructure operated by many North American utilities might, to some observers, appear just as antiquated.

For many pipeline operators, failures on pipelines installed decades ago are increasing in frequency, and as large-diameter pipeline assets begin to fail more frequently, the results can be more severe. This ongoing problem leaves utilities between a rock and hard place on whether to maintain or replace their assets.

Pipeline operators might do as the astute Romans did – take a step-by-step proactive approach to manage their transmission systems, enhanced today with the help of modern inline technologies.

The U.S. Environmental Protection Agency and American Society of Civil Engineers estimate the funding costs associated with buried infrastructure ranges from more than $200 billion to $1 trillion over the next 25 years. Pure Technologies is helping utilities manage their buried infrastructure through its Assess and Address® approach to pipeline management. This approach has saved clients hundreds of millions of dollars in capital replacement costs.

Assess and Address the System for Potential Problems

Conventional pipeline management allowed a pipeline to fail multiple times before replacement. While this “three strikes and you’re out” approach may work well for small-diameter distribution pipelines, it isn’t a cost-effective solution for large-diameter pipelines, especially those built without redundancy and without practical options to shut down.

A capital replacement program for large-diameter pressure pipelines not only carries a high price, but also poses significant logistical challenges, especially in urban centers. The headaches get bigger if a section of problematic pipeline runs through the downtown core and is the main source of water for a hospital or office tower.

Through the assessment of more than 8,000 miles of large-diameter pipelines, it is clear that even problematic transmission mains can be managed. In fact, Pure has found that 96 percent of pipe sections do not have any deterioration at all and are in “like new” condition, while less than 1 percent of pipe sections require immediate repair.

Better Understanding Ensures Fewer Surprises

In order to effectively manage a pipeline system, utility operators must first understand their pipeline system. Since many systems were built decades ago, the drawings are often out of date, as features have been added or removed over the years. By completing the knowledge-gathering process before attempting inspections or repairs, utility operators can avoid surprises and create a streamlined pipeline management effort.

By working with a firm that specializes in condition assessment, utility operators can gain a better understanding of their network, and create a prioritized plan for inspection or renewal.

As an example of smart collaboration, Pure Technologies has partnered with Washington Suburban Sanitary Commission (WSSC) in a multi-year program to manage approximately 145 miles of prestressed concrete cylinder pipe (PCCP) water transmission mains that serve nearly 2 million customers outside of Washington, DC. By adopting the Assess and Address model, WSSC has been able to evaluate and actively monitor the condition of its PCCP inventory instead of completing an expensive capital replacement project. To date, over 70 miles of PCCP is being safely managed for approximately 6 percent of the capital replacement cost, saving WSSC nearly $2 billion, which was the estimated capital cost of replacing the assets entirely.

Pure’s fundamental approach to pipeline management programs is to maximize the life of the existing pipeline. Maintaining an existing pipeline though proactive repair and management is in the utility’s economic interest. Our approach identifies deteriorated pipe sections, allowing for isolated repairs that extend the life of a pipeline, rather than making broad recommendations to replace the entire pipeline with capital funds.

Based on the average annual capital spending of large water utilities, it would take decades to replace large-diameter assets entirely, without factoring in the need for other capital renewal projects. Not only is this expensive and time consuming, it is also logistically challenging and disruptive to replace large sections of pipeline.

The Assess and Address Approach Involves 4 Steps

To successfully implement a pipeline management program, utilities can generally follow four key steps:

  1. Understand – Review current pipeline data, complete a risk evaluation, and develop appropriately scaled condition assessment strategies for prioritized pipelines.
  2. Assess – Execute condition assessment using a variety of tools to collect data and evaluate the data to assign condition ratings. This step includes a report of findings and recommendations on how to manage the pipeline.
  3. Address – Problematic locations identified in the condition assessment can be renewed immediately or planned for future re-inspection.
  4. Manage – After rehabilitation, the risk of failure is lower and proactive management measures should be employed to maintain a low risk.

As a result of Pure’s pipeline management programs with clients that range from small towns to major cities, utilities have seen a significant per-mile reduction in costs, while obtaining technically superior data on the real condition of their most critical pipeline assets. With such impressive numbers, it’s something ancient Roman engineers would appreciate.

Across the United States, there are many thousands of water and wastewater utilities that serve populations less than 50,000. Although the majority of attention surrounding aging infrastructure focuses on the challenges of large utilities, these small utilities are often faced with greater challenges.

Smaller utilities often have fewer resources – both financial and personnel – devoted to managing their water and wastewater systems. At times, this can lead to the utility having  less information available about their system, such as pipe drawings, break and leak history and condition data.

Coupled with having fewer resources, small utilities often have primary mains that are non-redundant and represent the sole source of supply or collection for the population, making a leak, rupture or shutdown of any kind very disruptive.

The City of Tarpon Springs, FL serves a population slightly less than 25,000. With limited resources and a mandate to provide both reliable water supply and wastewater collection for its customers, the City decided to assess the condition of one of its primary 14-inch force mains that experienced a failure in summer 2013.

The Dixie Highway Force Main is made of 14-inch ductile iron pipe (DIP) and poly-vinyl chloride (PVC) pipe, which was installed after the failure. In summer 2014, the City decided to complete condition assessment on nearly 1 mile of the force main to identify specific areas of concern before investigating further replacement.

Since internal hydrogen sulfide corrosion is the primary cause of DIP force main failure – and was the cause in 2013 – an inline survey was completed to collect relevant condition data.

For the inspection, the City used the SmartBall® tool, which can locate leaks, gas pockets and pipe wall stress in metallic pipelines. Leaks or failures on wastewater pipelines can have a devastating effect on the environment and can lead to litigation and consent decrees. In addition, gas pockets in force mains are of significant concern as hydrogen sulfide gas within the wastewater can be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Leaking Pipe

The SmartBall PWA tool is removed after the 1-mile inspection.

Sahara Insertion

Staff at Tarpon Springs Water were onsite during the inspection.

While inline leak and gas pocket assessment is a well-developed approach for force main operators, the development of pipe wall assessment (PWA) technology provides a more comprehensive level of condition information – areas of the pipe wall with damage will be under more stress than areas with limited or no damage.

By identifying stress anomalies, it provides operators with a detailed report of areas that warrant a more detailed assessment or testing.

The SmartBall assessment identified no leaks and nine gas pockets along the force main. Three of the gas pockets are located along the PVC section of pipe, indicating that gas pockets re-emerged in the PVC section of pipe in less than a year after replacement. It was recommended that air release valves be installed along the force main to clear gas pockets.

In addition, the PWA survey identified six areas that indicated stress within the pipe wall. One of the stress anomalies corresponds with a transition from buried pipe to exposed pipe, and therefore is caused by the change in load. The remaining five PWA anomalies do not correspond to any known features and could represent pipe degradation. The City during the insertion of the air release valves will be performing some field validation of these pipes.

By assessing the entire force main in advance of replacement, the City of Tarpon Springs is now able to make more informed decisions about its critical asset while avoiding the costly and mostly unnecessary strategy of replacement of the entire force main length. This mentality is an excellent example for other small utilities that are looking for ways to manage aging critical infrastructure, since replacing assets is very expensive within limited capital budgets.

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SmartBall Pipe Wall Assessment

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Frankfort Electric and Water Plant Board Verifies Distress on Ductile Iron Pipe Using Electromagnetics

In June 2013, FEWPB agreed to utilize an electromagnetic (EM) assessment technology on 700 feet of 1974 era DIP after the successful assessment of almost five miles of its prestressed concrete cylinder pipe (PCCP). The 700-foot section of 48-inch DIP runs directly from one of FEWPB’s water treatment plants and connects with the primary transmission main.

Ductile Iron Pipe

Ductile Iron Pipe (DIP)

Introduced into the U.S. marketplace in 1955, ductile iron pipe (DIP) is pressure pipe commonly used for potable water and sewage distribution. The predominant wall material is ductile iron, a spheroidized graphite cast iron, although an internal cement mortar lining usually serves to inhibit corrosion from the fluid being distributed, and various types of external coating are used to inhibit corrosion from the environment.

For water service providers in Texas, providing customers with consistent, reliable access to water is crucial, particularly in the summer months when dry conditions impact the water supply.

In order to ensure that residents receive consistent water supply, the City of Irving and a partnering agency have collaborated in times of need to supply the other with water.

In one specific instance, the City of Irving was able to keep customers of the partnering agency supplied with water from one of its 48-inch transmission mains. The combined effort between the utilities showed excellent organizational cooperation to achieve the most important goal for any utility – finding a way to provide consistent service.

In January 2014, the two agencies teamed up again, this time to assess the critical 48-inch Jamison Main that links the two utilities. The transmission main was constructed in 1955 and is made up primarily of Bar-Wrapped Concrete Cylinder Pipe (BWP). Since its construction, however, the main has had modifications: in 1965 and 1968 sections of Prestressed Concrete Cylinder Pipe (PCCP) were added to accommodate the construction of Texas Stadium, and in 2009, another section of PCCP was added during the reconstruction of Loop 12 Highway.

The Difference Between PCCP and BWP

While BWP and PCCP look similar in cross-section, the pipe materials deteriorate in different ways and therefore are assessed differently.

For BWP, it is important for operators to identify and locate corrosion on the steel cylinder, since it is the main structural component and the bars are made with mild steel and are wrapped under less tension than PCCP; BWP essentially behaves like a mortar-lined and coated steel pipe.

PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water barrier. The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage.

Electromagnetic inspection tool

Electromagnetic inspection tool

Robotic tool insertion

Pure Technologies staff insert the robotic tool for assessment

As the prestressing wires in PCCP begin to break, the pipe becomes weaker and is more likely to fail catastrophically. It is important to locate and quantify the amount of broken wires in PCCP as they are the main structural component.

Because of the differences, the two materials are assessed using electromagnetic (EM) technology that identifies different signs of deterioration in each pipe.

In BWP, inspections identify both the presence of broken bars – which could indicate corrosion on the cylinder – and broad areas of corrosion on the cylinder itself. This approach allows operators to renew pipe sections with an undesirable amount of corrosion that could lead to pipe failure.

In PCCP, EM technology locates and quantifies the amount of broken wires. This method is extremely effective in identifying pipe sections that are suitable for renewal once the number of wire breaks passes a certain limit.

The Condition Assessment Program

For the Jamison Water Transmission Main assessment, the SmartBall® leak detection and PureRobotics® platforms were used to identify deterioration on both the primary pipe material, BWP, and the added sections of PCCP.

Completing a leak detection survey is an important aspect of a condition assessment project, since leaks are often a preliminary indication of a potential failure location. Pre-screening is particularly important in in BWP, since the steel cylinder is the main structural component and the pipe behaves similarly to a mortar-lined and coated steel pipe.

The leak detection survey identified one acoustic anomaly associated with a leak in 2.7 miles of inspection. The screening of the pipeline helps determine the baseline condition of the asset.

The PureRobotics platform was used for the structural assessment portion of the project. The tool is equipped with PureEM™ technology, which can identify distress on both pipe BWP and PCCP, but also features CCTV and above-ground tracking. By completing a structural assessment, damaged areas of the pipe can be targeted for selective renewal.

The Condition Assessment Program

In addition to gaining a valuable baseline condition of the transmission main, the assessment provided both utilities with more information about the location of additions to the critical transmission main.

The CCTV and line-locating feature were used to identify the exact location of two unknown manholes, which in turn were used as additional tracking locations. With more tracking locations during inline inspection, areas of distress can be more accurately located. The CCTV inspection also identified the location of a 48-inch gate valve and 90-degree bends.

Another challenge surrounding this main was accurate mapping of the sections that were added on after the original construction. Additions or alterations to existing pipelines can sometimes lead to inaccurate drawings. By tracking the tethered robotics tool above the ground using a manned sensor, Irving and its partnering agency were able to map out the relocated portions of the pipeline. This provides valuable information for future maintenance, assessment and renewal programs.

Through close collaboration, these two service providers were able to effectively manage a shared asset with the goal of preventing disruptive and expensive pipe failures. The information gained from the structural assessment will allow for the implementation of a cost-effective long-term pipeline management plan and effectively defer the replacement of the pipeline for the foreseeable future.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Case Study

Case Study: Trinity River Authority of Texas

After completing leak detection and structural condition assessment on 8.5 miles of PCCP and Bar-Wrapped Pipe, Trinity River Authority verified the results of inspection, finding three distressed pipe sections.

Technical Paper

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

To proactively address its large-diameter Prestressed Concrete Cylinder Pipe (PCCP) for deterioration, Tampa Bay Water (TBW) completed a leak and gas pocket survey and electromagnetic (EM) condition assessment of the South-Central Hillsborough Regional Wellfield Transmission Main in April 2013. The results of the assessment were verified in 2014 to determine the remaining useful life of the pipeline, which is responsible for delivering 10 percent of TBW’s 24 million gallons of raw water per day.

Based on the EM inspection, only 0.5 percent (11 of 2,177) of pipe sections contained varying levels of distress; subsequent structural and finite element analysis determined that only a fraction of the distressed pipes warranted further consideration. In addition to the structural assessment, the leak and gas pocket survey identified only one small leak.

The results show the critical transmission main is in excellent condition and can be safely managed despite being nearly 30-years-old. Some PCCP users throughout the United States have experienced major failures as their assets approach 40 years of operation.

TBW maintains a large pipeline network that serves the Tampa Bay and St. Petersburg metropolitan area and includes approximately 80 miles of PCCP. The pipeline inspections were completed on 8 miles of 42-, 48- and 54-inch PCCP that convey wellfield supply to the Lithia Water Treatment Facility.

For the leak and gas pocket survey, SmartBall® technology was used as a forerunner for the EM condition assessment and provided TBW with an initial condition of the pipeline.

Early identification and repair of leaks can reduce Non-Revenue Water (NRW), but also helps determine the baseline condition of a pipeline, since leaks can be an indication that a pipeline might fail. In addition, locating and eliminating gas pockets reduces pressure on the pumps that are attempting to push water past a pocket. As pockets grow in size, they can significantly affect the flow of water and capacity of the pipeline if not released.

After the prescreening survey, TBW completed an EM inspection using PipeDiver®, a free-flowing EM tool that is able to accurately locate and quantify broken wire wraps in PCCP. The wire wraps in PCCP act as the main structural component; broken wraps are the main indication that this type of pipe will eventually fail.

TBW’s asset management program allowed them to prioritize and take the first steps in determining the remaining useful life of a critical asset. This will lead to more informed decision-making for the future management of this main through reinspection, monitoring or renewal.

 

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Technical Paper

Beyond the Wires: A Sustainable Approach to Prestressed Concrete Cylinder Pipe Management

While evaluating wire breaks are an important part of PCCP management, it is important to acknowledge additional factors beyond wire breaks. By acknowledging additional condition factors, limitations of wire break assessment, and considering other rehabilitation approaches, there may be a more sustainable PCCP management approach (or combination of approaches).

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

After spending eight years assessing the condition of and monitoring 77 miles of 48-inch and larger PCCP with a variety of methods, WSSC has shifted its focus to 68 miles of 36- and 42-inch mains. Many of these assets have been in the ground for decades and have never been inspected for structural deterioration.

To assess the mains, WSSC is using PureRobotics™ equipped with electromagnetic (EM) sensors. The tool is also equipped with high-definition closed-circuit television (HD-CCTV), which allows WSSC to identify cracks of the inner concrete core and determine joint condition.

WSSC recently produced a video to demonstrate how the tool works and its role within the overall PCCP assessment program.

How the Technologies Work

The EM sensors on the robotic tool identify the quantity and location of broken wire wraps in PCCP pipelines. The wire wraps in PCCP are the main structural component – as wraps begin to deteriorate and break, the pipe section becomes weaker and more likely to fail catastrophically.

By identifying broken wire wraps, WSSC is able to repair or replace specific pipe sections when they reach a wire break limit. The robotics tool used by WSSC also has an inertial mapping unit, which allows damaged pipes to be located with very close location accuracy, usually within 3 feet.

After acquiring a baseline condition of its transmission mains, WSSC plans to install an Acoustic Fiber Optic (AFO) monitoring system to track ongoing deterioration. The AFO system records the sounds of wire wraps snapping, which allows WSSC to intervene and replace a pipe section when too many wire wraps snap in a short span – which indicates accelerating distress – or the amount wire breaks reaches a certain level.

WSSC’s PCCP program is one of the largest and most advanced infrastructure management programs in the industry; however the cost of assessing, monitoring and managing its most critical assets is roughly 6 percent of the $2-billion capital replacement estimates.

To date, WSSC’s inspections have shown that about 95 percent of pipes are in “like new” condition and less than 2 percent require any immediate rehabilitation or replacement. By identifying select distressed areas, WSSC was able to avoid a full replacement program and avoided massive capital replacement costs by rehabilitating the identified sections.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

WSSC Logo

Washington Suburban Sanitary Commission Avoids Critical Failure Through the use of Fiber Optic Monitoring

To prevent critical water main failures, the Washington Suburban Sanitary Commission (WSSC) has installed acoustic fiber optic cable in many of its Prestressed Concrete Cylinder Pipe (PCCP) transmission mains. This technology has prevented a number of major pipeline failures, most recently in Prince George’s County on a 54-inch transmission main.

PureRobotics™ – Pipeline Inspection

Robotic Pipeline Inspection

PureRobotics uses powerful modular robotic pipeline inspection systems that can be configured to inspect virtually any pipe application 12-inches (30.5 centimeters) and larger.

To protect a thriving economy, Californian water utilities require a reliable and predictable supply of clean water; any water lost through leaks not only threatens the ability to provide adequate service, but also represents the waste of a scarce resource.

In order to ensure reliable service delivery and reduce Non-Revenue Water (NRW) – which can be defined as water that is produced for consumption and lost before it reaches the customer – two Californian utilities completed leak detection surveys on their critical water transmission mains in December 2013, while a third utility assessed a force main with a suspected leak.

While reducing NRW can be challenging, one of the most effective methods in reduction is having a well-developed leak detection program for both small- and large-diameter water mains. For large-diameter pipes, the most effective method of identifying leaks is through the use of inline leak detection. This method brings the leak detection sensor directly to the source of the leak, which provides the highest level of accuracy.

Accurately locating and repairing leaks on large-diameter mains is the best way to reduce NRW through leak detection, as almost 50 percent of the water lost through leaks is through large-diameter assets. Identifying leaks also increases service reliability and reduces the likelihood of a pipeline failure, as the presence of leaks is often a preliminary indication of a failure location.

In December 2013, the Los Angeles Department of Water and Power (LADWP) completed an inline leak detection survey on 8 miles of the 45-mile Second Los Angeles Aqueduct, which is made of 76-inch mortar-lined steel.

Identifying leaks on metallic pipe materials is particularly important for water utilities, since leakage is a main indicator that metallic pipes will eventually fail. LADWP’s inspection using SmartBall® leak detection confirmed that this section of the aqueduct is leak-free.

Although addressing NRW is a major priority for utilities, operators of wastewater force mains should also be concerned with leakage. Leaks or failures on wastewater pipelines can have a devastating effect on the environment and can lead to litigation and consent decrees. In addition, gas pockets in force mains are of significant concern as hydrogen sulfide gas within the wastewater can be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

In order to conduct a leak and gas pocket screen on an 18-inch force main, the Vallejo Sanitation and Flood Control District completed a 1.3-mile survey using SmartBall technology. The inspection identified three acoustic anomalies that were associated with pockets of trapped gas.

Through the inline assessment of this force main, the District was able to identify areas of potential concern, which will focus resources and guide future investigations.

Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming inline leak detection technology designed to operate in a live water mains.

Cobb County-Marietta Water Authority (CCMWA) is the second largest drinking water supplier in Georgia, providing vital service to nearly 800,000 people through twelve wholesale customers. With two award-winning water treatment plants and over 200 miles of large-diameter transmission mains, CCMWA can deliver up to 158 million gallons per day. Two of CCMWA’s key objectives are to be financially viable and to reduce vulnerabilities by improving redundancy and implementing a comprehensive asset management program.

However, across the United States critical infrastructure is aging, causing utilities to see an increased number of water pipe failures. While these failures occur most commonly on small pipes – causing only minor disruptions – large-diameter mains do fail, resulting in major delays and enormous repair bills.

A large portion of CCMWA’s large-diameter pipeline inventory is made up of Prestressed Concrete Cylinder Pipe (PCCP). In order to successfully manage PCCP, the water industry has widely adopted the use of condition assessment techniques, which have a proven track record of identifying and averting PCCP failures. PCCP owners and operators continue to use these condition assessment methodologies combined with sound engineering analysis to effectively and safely manage their critical assets.

Cobb County’s Program

In 2012, CCMWA was in a similar situation to many predominant PCCP users; past failures on these critical assets had led to the decision to replace the majority of PCCP assets to avoid the risk of future failures. However, it was determined that replacing large sections of pipeline was not financially or logistically feasible.

Large-scale replacement programs are also unnecessary based on industry research, which confirms that pipe deterioration is not uniform or systematic. Specifically, electromagnetic inspection data (which identifies both the quantity and location of broken prestressing wires – the primary structural component of PCCP) collected by Pure Technologies over more than a decade indicates that less than 4 percent of pipe sections inspected have any level of wire break damage and less than 1 percent require repair – regardless of when it was manufactured.

SmartBall tool extraction

The SmartBall tool is retrieved from the extraction point.

PipeDiver retrieval

Staff remove the PipeDiver tool after the non-destructive assessment.

Therefore, by making the decision to replace entire alignments of PCCP, owners typically remove a majority of pipeline assets that are in like-new condition. A financial evaluation based on the cost of capital replacements compared with PCCP management (inspection, repair, re-inspection, and repairs) for the 48-inch diameter PCCP in CCMWA’s inventory indicates that the pipelines can be managed for approximately 10 percent of the capital replacement costs when extended over 25 years using a net present value calculation (Figure 1).

Capital Replacement vs Condition Assessment

Figure 1: Financial Evaluation of Capital Replacement vs Condition Assessment

Following a repair on a 30- and 42-inch Raw Water Line in 2012, CCMWA decided to manage its critical PCCP assets using condition assessment and engineering analysis as a proactive management strategy. In 2013, CCMWA completed its first full inline condition assessment to identify structural deterioration on its PCCP. The project focused on the 30- and 42-inch main that had previously been found to have defective joints and a deteriorating pipe wall to determine its remaining useful life.

The Inspection Program

The assessment featured two inspections – a leak and gas pocket survey and inline electromagnetic (EM) inspection – on roughly four miles of the 30- and 42-inch PCCP Raw Water Line. The subject pipeline acts as a redundant supply line from Lake Acworth to the Wyckoff Water Treatment Plant. The project also included engineering evaluations including structural analysis and remaining useful life evaluations to make management and renewal recommendations. For the prescreening survey, CCMWA used SmartBall® leak detection, a free-flowing tool that identifies the acoustic anomalies associated with leaks and gas pockets in large-diameter pipelines. Completing a prescreening leak and gas pocket survey is a prudent approach for operators of any pipe material, since leaks are often a preliminary indication of a failure location. For PCCP, leaks are usually located near the pipe joint, which is also a common failure area on PCCP. However, the inspection did not identify any leaks or pockets of trapped gas. For the more detailed structural evaluation, the PipeDiver® electromagnetic (EM) inspection platform was used. The tool uses electromagnetics to identify broken prestressing wires, which are the primary structural component in PCCP. As sections of PCCP begin to deteriorate, the prestressing wires begin to break, which weakens the pipe and makes it more likely to fail. Identifying broken wires is the most effective way of determining the condition of and preventing failures in PCCP. By completing an EM inspection on the PipeDiver platform, CCMWA was able to determine the baseline condition of the pipeline while it remained in service – a major benefit for operators who cannot remove mains from service to complete internal inspection.

The Results

For CCMWA, the inspection identified ten pipe segments amounting to less than 1 percent of the pipeline with evidence of broken prestressing wire wraps. On average, PCCP inspections across the country indicate that approximately 4 percent of the pipe segments have any level of damage. This confirms that the majority of CCMWA’s PCCP inventory is in good condition, with only a small number of pipe sections in need of immediate renewal. However, locating and renewing even one pipe section can help utilities maintain reliable service and avoid an expensive pipe failure. Beyond the prescreening and structural inspections, CCMWA was able to identify limitations in its potable water system through the planning portion of the project. The inspected pipeline is a redundant line which carries raw water to the Wyckoff Treatment Plant; the primary supply line to the plant is a 60-inch line. In order to ensure that the main was being operated safely within its limits, a hydraulic study was completed. This study found that the 30-inch section of the pipeline was incapable of supplying the treatment plant’s required operating flow rate while maintaining a safe operating pressure within the system. Operating the pipeline under the required pressures places the main at a higher risk of failure in the event that the primary raw water line is taken out of service. Based on the study, it was recommended that the approximately 1 mile of 30-inch PCCP be replaced to handle existing and future operating condition requirements of the treatment plant. This discovery allowed CCMWA to make defensible decisions about their 30-inch PCCP main and pumping station while contributing to the prevention of future pipe failures. By upgrading the 30-inch section of the pipeline, the raw water pipeline will remain a safe redundancy line for the main 60-inch line. By managing its PCCP assets using condition assessment, it has also been determined that less than 1 percent of pipe sections on the assessed main have any indication of wire break damage, which is consistent with industry standards. Additionally, the prescreening survey showed that there are no leaks or gas pockets that require maintenance. The results from the inspections will allow CCMWA to cost-effectively manage its PCCP assets in favor of completing a large-scale replacement.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

In Pinellas County – Florida’s most densely populated county – residents and government work together to conserve water. A major component of this water reclamation process is the South Cross Bayou Water Reclamation Facility, which is designed for an average flow of 33 MGD. After a failure in June 2013 on a 42-inch ductile iron pipe in the reclamation facility, the Pinellas County Department of Environmental and Infrastructure rehabilitated and replaced portions of the facility’s pipeline. In September 2013, the Division of Engineering and Technical Support suspected that a small leak (estimated at 19 gallons/hour) had developed on a section of pipeline, originally thought to be in good condition, which was not rehabilitated after the failure. In metallic pipe materials, pipe failure is often preceded by a period of leakage. After already having a significant failure and investing in rehabilitation on a significant amount of pipeline, the County was adamant about identifying the location of any further leaks, which were impacting normal facility operation. After unsuccessfully trying a number of different leak detection techniques, the County turned to inline leak detection to identify the leak on the 627-foot (191-meter) stretch of pipeline. However, one of the challenges was that the pipeline had no flow due to implemented bypass procedures. To locate the leak, the County and Pure Technologies (Pure) took an innovative approach by using a tethered SmartBall® tool.

The SmartBall tool is a free-flowing leak detection technology that identifies the acoustic anomalies associated with leaks and gas pockets. Typically, it travels with the product flow in live pipelines, however, in no-flow conditions it will not move.

To overcome this challenge, the County and Pure temporarily pressurized the pipeline, tethered the tool using a mule tape and winched it through the planned inspection distance 627-feet (191-meters). The County took this approach because the insertion point was in the middle of one of the facility treatment trains– meaning a compact tool was needed to meet the logistical difficulties.

During inspection, the tethered SmartBall tool collects data twice since it is winched back to its insertion point. For this inspection, two runs were completed to confirm the leak size and location accuracy for the County. Upon review of the data and during the actual inspection, a leak was determined to be on a sleeve at the invert near the inline magmeter, which was the downstream limit of our inspection. The area outside of the magmeter vault was difficult and expensive to expose. Therefore, the County filled the area with grout and placed the pipeline back into service.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming inline leak detection technology designed to operate in a live water mains.

Following a significant pipe rupture in December 2012, Tulsa Metropolitan Utility Authority (TMUA) performed a detailed structural assessment on a critical section of one of the city’s major drinking water pipelines in November 2013. This recent work builds upon the TMUA’s rapid response forensics investigation completed in January 2013.

To determine the baseline condition of this major transmission main – which is made of 48-inch (1200-mm) Prestressed Concrete Cylinder Pipe (PCCP) – the city dewatered the pipeline and performed a comprehensive internal inspection using visual and sounding techniques, and electromagnetic (EM) technology.

This specific pipeline was constructed in 1975 and had not experienced a failure before December 2012. The 2012 failure caused major commuter disruptions, evacuations and damage to a local church; in an article published in Tulsa World, City Engineering Director Paul Zachary said that this failure cost roughly $400,000 to rectify. The 2013 inspection will help prevent another failure on this transmission main by identifying pipe sections that have distress and could fail if left in operation.

In total, roughly two miles made up of 688 pipe sections were assessed in November using visual and sounding techniques and EM technology.

Visual and sounding inspections are a reliable method of detecting pipes in an advanced state of distress. The inspections require manned entry to the pipeline and dewatering; any pipes judged to be in a state of incipient failure will be reported to allow for immediate replacement or rehabilitation.

Broken pipe

The failed 48-inch pipe section from December 2012.

Staff inside a pipe working with tool

Pure Technologies staff complete verification work on Tulsa’s PCCP water mains.

EM inspections of PCCP pipelines identify the quantity and location of broken wire wraps. The wire wraps in PCCP are the main structural component – as wraps begin to deteriorate and break, the pipe section becomes weaker and more likely to fail catastrophically.

The inspections showed that 81 of 688 pipe sections had broken wire wraps, indicating some level of distress. Based on a structural analysis, it was recommended that 32 of the distressed pipe sections be replaced immediately. In addition, the pipeline has 120 deteriorating joints that should be repaired in the near term. As a result, the City is moving forward with a rapid response construction project to address the pipeline’s deficiencies in early 2014.

Through the use of comprehensive condition assessment, TMUA has increased service reliability and taken major steps toward ensuring another failure does not occur.

By identifying specific areas of distress along this critical transmission main, TMUA has also avoided completing an expensive and time-consuming replacement project of the entire transmission main. This approach helps to preserve capital budget for other projects by avoiding unnecessary replacement of pipe sections in good condition.

The City of Tulsa supplies drinking water to more than 133,500 metered accounts in the City and more than 500,000 people in the metropolitan area. Tulsa’s two water treatment plants treat between 90 and 190 million gallons of drinking water a day. The TMUA is a public trust organization created by City charter. TMUA’s primary responsibilities are to manage, construct, and maintain Tulsa’s water works and sanitary sewer systems, and to fix rates for water and sewer services rendered within its boundaries.

 

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Pipeline Visual & Sounding Inspection Services

Visual Inspections and Soundings have successfully been used to quickly identify pipes in the state of incipient failure. Issues other than wire breaks can also be identified through visual inspections, such as unusual cracking and poorly detailed or damaged joints.

Electromagnetic Pipeline Inspection

Electromagnetic testing provides the best condition assessment data for large diameter PCCP (AWWA C301) and BWP (AWWA C303) pressure pipelines.

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Around six billion gallons of treated water is lost every day in the United States – this represents about 16 percent of the country’s daily water use. While this represents the loss of a critical resource, it also represents a significant financial burden for end users, since the lost revenue from aging pipes, faulty meters and illegal connections often leads to higher rates – between 1996 and 2010, the cost of water services in the US rose by nearly 90 percent.

In the Great Lakes states (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin), specifically, roughly 66.5 billion gallons of treated water is lost every year. This is enough water to meet the annual water needs of roughly 1.9 million Americans.

In an effort to establish the Great Lakes states as leaders in sustainable water management and develop best practices, the Center for Neighborhood Technology (CNT), a Chicago-based nonprofit focused on sustainable cities, released a report titled The Case for Fixing the Leaks, which is part of a collaborative campaign focused on Great Lakes states, calling for leadership in improved water management.

The report focuses on region-specific challenges to water loss and outlines potential solutions to help utilities manage their water infrastructure in the long term.

Read The case for Fixing the Leaks” Report»

AFO Monitoring
Leaking Pipe

Leaking pipes contribute to the loss of 16 percent of treated water in the United States.

Sahara Insertion

Pure Technologies staff insert the Sahara® tool into a live pipeline.

Leaks Map - CNW

One method that utilities can use to reduce their Non-Revenue Water (NRW) – which can be defined as water that is produced for consumption and lost before it reaches the customer – is having a well-developed leak detection program for both small- and large-diameter water mains.

For large-diameter pipes, the most effective method of identifying leaks is through the use of inline leak detection. This method brings the leak detection sensor directly to the source of the leak, which provides the highest level of accuracy. Non-invasive methods, such as correlators or listening sticks, work very well on small-diameter distribution mains but often lack the accuracy needed to address large pipes as the sound of a leak does not travel as well as pipe diameter increases.

According to one study by the American Water Works Association (AWWA), accurately locating and repairing leaks on large-diameter mains is the best way to reduce NRW through leak detection, as almost 50 percent of the water lost through leaks is through large-diameter pipeline assets. Identifying leaks also increases service reliability and reduces the likelihood of a pipeline failure, as the presence of leaks is often a preliminary indication of a failure location.

To accurately locate leaks, Pure Technologies offers two different solutions that can typically locate leaks within 6-feet (1.8-meters) of their actual location.

The SmartBall® platform is a free-flowing acoustic tool that can survey long distances in a single deployment while a main remains in operation. The Sahara® platform is a tethered tool that provides close control of the acoustic sensor as well as real-time leak detection. Because the tool is tethered to the surface, the operator can closely locate and confirm suspected leaks by winching the sensor back and forth.

Both technologies locate leaks using an acoustic sensor that identifies the unique sound of water leaking from the pipeline and are effective on any pipe material.

With over 2,000 miles of large-diameter pipelines inspected, Pure Technologies has located more than 4,000 leaks for an average of 2.2 leaks per mile using advanced inline leak detection technologies. Locating these large-diameter leaks has significantly reduced NRW, saved millions of gallons of water and helped prevent failures for utilities across North America.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Non-Revenue Water (NRW)

Non-Revenue Water (NRW)

Each day, billions of gallons of water are lost worldwide. Not only does this represent the loss of a precious resource that not everyone has access to; it represents a massive amount of lost revenue for the utilities that provide it.

In March 2013, Louisville Water Company (LWC) will open its “WaterWorks Museum” located in its original pumping station built in 1860. The original pump station and water tower have stood on the banks of the Ohio River for over 150 years and act as a visual icon for the city. Both buildings are now National Historic Landmarks.

The museum will highlight LWC’s considerable archive of historic photographs, films and memorabilia and explore the company’s contributions to water delivery through its innovations in science, engineering and architecture. It will also feature hundreds of photographs, some dating back to 1860, handwritten minutes and customer notes, original architectural drawings, pieces of the original water mains, meters and tools.

Included in the exhibit will be a model of the PipeDiver® tool to commemorate a condition assessment project completed in 2011. The project focused on LWC’s proactive pipeline management approach that addressed deterioration in its Prestressed Concrete Cylinder Pipe (PCCP).

The PipeDiver tool is a free-swimming electromagnetic (EM) platform used to identify and quantify wire breaks in PCCP. The EM sensor collects a magnetic signature reading as the tool traverses the pipeline and identifies anomalies produced by wire breaks. The tool operates while the pipeline remains in service, allowing LWC to avoid shutting down service to assess the condition of its most critical pipelines.

Museum Entrance

The WaterWorks Museum will commemorate Louisville’s commitment to water service delivery.

PipeDiver Model

LWC inspects about 8 to 10 miles of PCCP annually. Typically, between 2 and 4 percent of LWC’s PCCP is found to have deterioration, while less than 1 percent needs to be addressed immediately. This is consistent with industry averages, meaning it is most cost-effective to complete condition assessment and address isolated problems before replacing large sections of pipe, which carries a huge cost.

Pure Technologies’ data from over 8,000 miles of pressure pipe condition assessment indicates that only a small percentage of pipes (less than 5 percent) are in need of repair and therefore have a significant remaining useful life. Condition assessment data also suggests that pipe distress is localized and a significant ROI can be achieved by locating and addressing isolated problems through structural inspection.

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Louisville Water Company Puts PipeDiver Large-Diameter Insertion and Extraction Tubes to the Test

In 2011, Louisville Water Company completed an 8.8-mile non-destructive assessment of a 5-foot PCCP transmission main to determine its baseline condition.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

About half of LWC’s 200 miles of large-diameter transmission mains are made of Prestressed Concrete Cylinder Pipe (PCCP). As PCCP ages, the prestressing wires, which make up the main structural component, begin to break due to a number of factors.

The presence of broken wires in PCCP is the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstates how PCCP typically fails.

How PCCP Fails
AFO Monitoring

Louisville Water completes annual rehabilitation of its large-diameter transmission mains.

MSW article

(Source: MSW Magazine)

In 2009, LWC experienced a large-diameter PCCP failure. Fortunately for LWC, it was in a relatively low-risk location which reduced its repair cost. The pipeline also had redundancy that prevented a long service disruption.

“Had it broken 2,000 feet down the line, the cost of that would probably have been $10 million,” said Keith Coombs, manager of infrastructure planning for Louisville Water in an article for Municipal Sewer and Water. “We considered ourselves very fortunate.”

After narrowly escaping an expensive pipe failure, LWC began a proactive annual condition assessment program that addresses deterioration in PCCP.

For structural assessment, LWC uses PipeDiver® technology, which is a free-swimming electromagnetic (EM) tool used to identify and quantify wire breaks in PCCP. The EM sensor collects a magnetic signature reading as the tool traverses the pipeline and identifies anomalies produced by wire breaks in PCCP. The tool operates while the pipeline remains in service, allowing LWC to avoid shutting down service to assess the condition of its most critical pipelines.

LWC inspects about 8 to 10 miles of PCCP annually. Typically, between 2 and 4 percent of LWC’s PCCP is found to have deterioration, while less than 1 percent needs to be addressed immediately. This is consistent with industry averages, meaning it is most cost-effective to complete condition assessment and address isolated problems before replacing large sections of pipe, which carries a huge cost.

Pure Technologies’ data from over 8,000 miles of pressure pipe condition assessment indicates that only a small percentage of pipes (less than 5 percent) are in need of repair and therefore have a significant remaining useful life. Condition assessment data also suggests that pipe distress is localized and a significant ROI can be achieved by locating and addressing isolated problems through structural inspection.

Read “Continuous Improvement” in Municipal Sewer and Water »

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Industry reports also offer a bleak outlook about infrastructure in the United States; the American Society of Civil Engineers 2013 Report Card on America’s Infrastructure gave water and wastewater infrastructure a ‘poor’ rating and estimated that the cost to renew these systems would range from US $200 billion to US $1 trillion over the next 25 years.

While most of the discussion surrounding American water infrastructure involves pipe failures and the fiscal impact of renewal, water loss from leaking pipes is a major problem for utilities that often goes unnoticed. The U.S. Environmental Protection Agency (EPA) estimate that on average, between 15 and 20 percent of water never reaches the consumer, but is as high as 60 percent in some municipalities.

This loss accounts for a huge financial cost for operators in terms of billing and wasted energy used to pump and treat the water, but also represents the waste of a critical natural resource.

The Challenge for Dallas Water Utilities

In places like Dallas, TX, managing water loss is an important matter for utilities, especially in the summer months when users are affected by severe droughts and forced to restrict consumption. The droughts also bring extreme heat and dryness which dries out the soil and causes pipes to shift. This can lead to the accelerated development of leaks.

To mitigate this problem, Dallas Water Utilities (DWU) has completed an annual summer leak detection program since 2004 on its large-diameter water transmission mains that range in size from 12-inches to 84-inches. The inspection program focuses on a variety of piping materials including Prestressed Concrete Cylinder Pipe (PCCP), Cast Iron Pipe and Ductile Iron Pipe.

To date, DWU has inspected 100 miles of pipe in the program, locating 120 leaks. This has allowed for a major reduction in water loss and helped ensure service reliability.

Staff insert the Sahara® tool into a live pipeline

Pure Technologies staff insert the Sahara® tool into a live pipeline.

Water systems in large metropolitan areas are made up of thousands of miles of pipe varying in size; the distribution system, which delivers water directly to taps, is very large and features small-diameter pipe; transmission mains, which transport high volumes of water throughout an area, are made up of a smaller amount of large-diameter pipe. Because so many areas depend of these pipelines for supply and their high consequence of failure, maintaining transmission mains effectively is a high priority for operators. For DWU, the criticality of these pipelines was a major factor in adopting a leak detection program that focused on its large-diameter pipe.

According to a study completed by the American Water Works Association, leaks on large-diameter pipelines account for roughly 8 percent of the total leaks, but almost 50 percent of the total water lost from leakage. The discrepancy is created because transmission mains have a much higher capacity and operating pressure than distribution mains, meaning small leaks are actually leaking at a very high rate.

By focusing leak detection programs on large-diameter pipes, operators can achieve a much larger reduction in water loss by identifying and repairing evena single leak.

There are several methods of locating leaks on large-diameter pipelines. Non-invasive methods, such as correlators or listening sticks, work very well on small-diameter distribution mains but often lack the accuracy needed to address large pipes, as the sound of a leak does not travel as well as pipe diameter increases.

Conversely, inline leak detection methods aren’t well suited for distribution mains due to pipe size and complexity, but are very effective in accurately locating leaks on large-diameter transmission mains because they bring the leak detection sensor directly to the source of the leak, unlike non-invasive systems.

For inspection of its transmission mains, DWU uses Sahara® leak detection – a tethered platform that combines acoustic leak detection and inline CCTV – offered by Pure Technologies Ltd. The tool is non-destructive and is pulled by the flow of water by a small drag chute while the line remains in service. When the sensor is inserted into a tap, it remains tethered to the surface to allow for immediate confirmation of suspected leaks and gas pockets, internal pipe wall conditions and pipeline features by winching the sensor back and forth from the surface. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

 

How DWU saves water using inline leak detection

“Since introduction to Dallas’ program in 2004, Sahara technology has been a reliable tool for locating and eliminating leaks on larger diameter pipelines,” says Randy Payton, Assistant Director of Dallas Water Utilities. “The program allows the Department to plan and prepare the repair in lieu of responding to a failure.”

The tool is capable of locating very small leaks due the sensitivity of the acoustic sensor. In terms of reducing water loss, small leaks may actually represent the best opportunity for long-term improvement. Leaks on large-diameter pipelines typically form and mature over a period of decades. They tend to grow larger over time, up until a point where the pipe fails or the leak surfaces.

Locating and repairing a large leak prevents it from leaking for the “tail end” of its life, and from failing catastrophically. Catching a leak while it is very small does this as well, but also prevents the decades of sustained water loss that would occur as it grows into a large leak. Using technologies that can locate small ‘pinhole’ sized leaks can identify small leaks early on before they grow into larger leaks or lead to pipeline failure.

In the annual pre-planning stage, DWU identifies the ideal access points needed for the inspections based on their knowledge of the Sahara platform from previous years – there are usually about 30 insertions through 2-inch access points each year. Inspections are usually done during the summer months when most of the leaks are developing, and higher volumes in the pipelines allow longer distances to be inspected. DWU also controls the water flow closely during inspections to optimize the inspection distance. After many years of inspection, DWU staff has become adept at identifying the best insertion points and controlling the flow rate to maximize the tool’s capabilities.

During tethered inspections, there is significant traffic control required when the transmission mains runs beneath busy streets, since the tool is controlled and tracked above the ground by staff members. To avoid major commuter disruptions, the City will reroute traffic and thoroughly plan the insertions to avoid high traffic times – for example, inspections frequently start in the mid-morning when traffic slows as opposed to during morning rush hour. Beyond traffic control, staff from DWU and Pure will often work on weekends when downtown Dallas is less busy.

There are also unavoidable environmental challenges that require adjustments. Sometimes the water main will run under a busy highway or an environmental obstacle like a river, making it impossible for the staff member on the ground to track the tool and mark exact leak locations. In this case, the operator needs to review potential leaks more closely by winching the tool back and forth to determine the exact location.

DWU’s leak detection program has been extremely successful, locating 120 leaks in the 100 inspected miles. The estimated water savings from these leaks is about 7.2 million gallons per day.

The CIty has also seen a 17 percent reduction in catastrophic water main failures, likely as a result of the proactive approach in fixing leaks. Leaks, particularly in metallic pipe materials, are often a preliminary indicator of a failure location as it is a preliminary sign of distress. The reduction in failures has reduced property loss claims and service interruptions, as well as reduced treatment and delivery costs.

“Several factors affect the success of leak detection,” adds Payton. “After nine years, the utility continues to be impressed with its accuracy within the varied environments and piping materials.”

 

Through continued commitment to leak detection on its transmission mains, DWU is improving service reliability and saving significant amounts of water. DWU also completes regular structural assessment of its transmission mains to identify distress that could lead to pipe failure.

 

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Pipeline Inspection and Condition Assessment Services

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Case Study

Case Study: Dallas Water Utilites Leak Detection Program

Dallas Water Utilties anually inspects its large-diameter water transmission mains for leaks using Sahara® technology. Through DWU’s efforts in identifying and repairing leaks, about 7.2 million gallons per day has been saved and major failures have been reduced by 17 percent.

Non-Revenue Water (NRW)

Non-Revenue Water (NRW)

Each day, billions of gallons of water are lost worldwide. Not only does this represent the loss of a precious resource that not everyone has access to; it represents a massive amount of lost revenue for the utilities that provide it.

For utilities like Foothill Municipal Water District (FMWD), which has no redundancy in its system, finding a reliable inspection method that provides condition data for the entire length of a steel pipeline is an important aspect of its condition assessment program.

FMWD covers about 22 square miles in the foothills of the San Gabriel Mountains, bordered between the City of Pasadena on the east and the City of Glendale on the south and west. The District serves approximately 86,000 people through its own member agencies.

In March 2013, FMWD successfully completed a 2.2-mile internal inspection and condition assessment of a 24-inch mortar-lined steel main to identify broad areas of wall loss. As part of the condition assessment, a structural evaluation was performed to determine whether the force main design satisfies AWWA M11 “Steel Pipe – A Guide for Design and Installation,” fourth edition standards. The results of this evaluation will help FMWD determine where to focus more detailed inspections in order to make detailed rehabilitation decisions for this force main.

To complete the inspection, FMWD used PureRobotics™ electromagnetic condition assessment equipped with PureEM™ technology and high-definition closed circuit television (HD-CCTV). The platform is a non-destructive, inline assessment tool that provides screening level wall data in the circumferential and axial directions of metallic pipelines.

By opting for an inline assessment in favor of traditional metallic inspection methods, FMWD has a baseline condition of the entire 2.2-mile main. After reviewing the EM data, FMWD was able to identify 17 EM anomalies that warrant additional investigation. The top 10 anomalies have been ranked based on the strength, area and repeatability of signal loss and visually using HD-CCTV. FMWD can now select the most appropriate locations to perform test pitting to obtain higher resolution data needed to evaluate rehabilitation or repair needs and determine the remaining useful life of the water main.

PureNET Overhead

FMWD inserts the PureRobotics tool for inspection.

Field Data Collection

During inspection, the tool remains tethered to the service and is controlled by an operator.

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PureRobotics™ – Pipeline Inspection

Robotic Pipeline Inspection

PureRobotics uses powerful modular robotic pipeline inspection systems that can be configured to inspect virtually any pipe application 12-inches (30.5 centimeters) and larger.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Sewer access

Sewer Force Main Inspection

Pure Technologies has the complete portfolio for sewer force main and large diameter gravity main inspection. As the trusted global leader, we have successfully inspected thousands of miles of pipeline.

Critical to its economic success is a reliable supply of water, which is supplied by Miami-Dade Water and Sewer Department through four major transmission mains operated by the City of Miami Beach’s Public Works Department that range in diameter from 20- to 36-inches.

A failure or disruption on one of these transmission mains would significantly reduce Miami Beach’s treated water capacity, and therefore its ability to act as a major tourism destination.

With infrastructure across the United States aging and reaching the end of its design life, utilities are experiencing more pipe failures that are both costly to repair and disruptive to local economies.

Although Miami Beach has never experienced a large-diameter water transmission main failure, it is proactively addressing deterioration on its critical pipelines using condition assessment.

In September 2013, Miami Beach completed an electromagnetic (EM) structural evaluation on 3.4 miles of its largest transmission main – the Julia Tuttle Causeway – which is made up of 36-inch Prestressed Concrete Cylinder Pipe (PCCP), Cast Iron (CI) and High Density Polyethylene (HDPE) pipe.

After completing a prescreening survey, Miami Beach completed an EM condition assessment survey using PipeDiver®, a free-swimming EM tool used to identify and quantify wire breaks in PCCP.

During an inspection, the tool collects a magnetic signature reading as it traverses the pipeline and identifies anomalies produced by wire breaks in PCCP. The tool is ideal for performing a baseline inspection of a PCCP pipeline that cannot be removed from service. The 3.4 mile inspection was completed successfully, with the tool tracked throughout the planned distance.

Staff with PipeDiver tool

The PipeDiver tool identifies and locates wire breaks in PCCP.

Tool insertion

The tool is inserted into a live pipeline in Miami Beach.

In PCCP, the prestressing wires are the main structural component; when wire breaks are found on a specific pipe section, it represents deterioration of its structural integrity. The ability to locate and quantify the amount of wire breaks in each pipe section allows a utility to make rehabilitation decisions and provides a baseline structural condition.

The data collected identified areas of prestressed wire breakage of varying degrees of criticality. The City is currently considering recommendations for rehabilitation, replacement and inspection of the remaining three transmission mains.

By managing its critical pipelines using a risk-based condition assessment approach, Miami Beach is proactively addressing deterioration in order to continue providing reliable service to a major economic hub.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Roughly US$14 billion in clean, non-revenue water is lost every year due to leaks and water main failures that could have been prevented.

If the loss of non-revenue water could be cut by half, an estimated US$2.9 billion could be generated and an additional 90 million people could have access to water.

Locating leaks on transmission mains represents the best opportunity for improvement.

Non-revenue water is defined as water that is produced for consumption but is lost before it reaches the customer. These losses are divided into three categories:

  • Physical (or real) losses due to poor operation and maintenance, lack of an active leak control system or the poor quality of underground assets.
  • Commercial (or apparent losses) include customer meter under-registration, data handling error or the theft of water in various forms such as illegal connections.
  • Unbilled authorized consumption includes water used for operational purposes, for fighting fires and water that is provided for free to certain consumer groups.

The best opportunity for improving this situation is by taking the first step in a NRW-reduction strategy and start focusing on leak and theft detection within transmission mains.

That’s where Pure comes in.

With over 2,000 miles of large-diameter pipelines inspected, Pure Technologies has located more than 4,000 leaks for an average of 2.2 leaks per mile using our advanced inline leak detection technologies significantly reducing NRW while saving millions of gallons of water and helping prevent failures for utilities around the world.

Fast forward to 2012, and the Birmingham Water Works Board (BWWB) had the challenge of maintaining a critical pipeline that was constructed well before the board was even established in 1950.

In order to determine the baseline condition of nearly 8 miles of the RCP transmission main and proactively address Non-Revenue Water (NRW) loss, BWWB completed four inspections using SmartBall® technology, a free-flowing leak detection platform that operates while the pipeline remains in service.

The inspections using inline leak detection were very successful, locating 26 leaks of varying size with close location accuracy. Twenty of the leaks have since been verified and repaired by BWWB, while the remaining six leaks have been deferred due to their size or matched up with existing features.

In the August 2013 issue of Trenchless Technology, BWWB’s project was featured as an example of how utilities can manage their aging pipeline infrastructure through the use of advanced leak detection technology.

Read Full Article»

 

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Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming inline leak detection technology designed to operate in a live water mains.

Case Study: Birmingham Water Works Board

In early 2012, the Birmingham Water Works Board (BWWB) ran a successful leak detection program on 7.7 miles (12 km) of 42-inch (1050-mm) Reinforced Concrete Pipe (RCP). The inspected pipelines are part of BWW’s system that transports water from the Shades Mountain Filter Plant to different areas of the city.

Bloomberg TV Story

Initially, owners and operators perceived that once a pipe was constructed and buried, inspecting pipelines was not necessary as long as they were in proper working order. But with the trend of urbanization and development, the risk of operating these pipelines became greater, as leaks or failures can significantly threaten communities and the environment.

The challenge of managing aging pipelines that were not built with the thought of inline inspection is daunting. To best mitigate risk, oil and gas operators should use a multi tool approach that incorporates both real-time and survey-based condition assessment technologies.

SmartBall® leak detection for oil and gas pipelines is an innovative tool that can effectively compliment integrity programs. The tool identifies acoustic anomalies associated with leaks which differ from anomalies created by other sounds and pipeline features. SmartBall technology is highly sensitive and can identify leaks that aren’t typically found using other systems.

 

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Pipeline Leak Detection Systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Technical Paper

Development of a Long Duration, Free Swimming, Inline Acoustic Leak Detection Inspection Tool

Acoustic leak detection inspection tools have become a common technique to identify minute pipeline leakage before the leak and the defect producing it can become a larger problem or even a rupture level event. While these inspection tools only identify small defects once they reach the through wall stage and result in leakage, they can be an effective means of demonstrating the pressure tightness of a pipeline and ruling out the presence of through wall defects that are below the detection threshold of other ILI inspection tools; in so doing finding a way into both the leak detection and pipeline integrity toolboxes.

hese distinctions can make assessing BWP challenging for pipeline operators attempting to renew their large-diameter water transmission mains, since the methods for determining baseline condition in the similar-looking pipe types are different.

PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water membrane. With BWP, the cylinder plays a much larger role in the structural integrity of the pipe. BWP is essentially designed as a steel pipe with mild steel used to manufacture the steel cylinder and steel bars.

The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage. The mild steel bars in BWP are thicker in diameter and wrapped under less tension, therefore corrosion takes significantly longer to lead to breakage.

This was the case for Trinity River Authority of Texas (TRA), who owns and operates 8.5 miles of 30-inch BWP and PCCP that supplies raw water from Lake Arlington to the Tarrant County Water Supply Project Water Treatment Plant in Euless, Texas.

The 30-inch pipeline, in conjunction with a parallel 54-inch pipeline, conveys raw water to TRA’s 87 mgd Water Treatment Plant (WTP). Treated water produced at the WTP is then supplied to five cities in the mid-cities region between Dallas and Fort Worth including Bedford, Colleyville, Euless, Grapevine and North Richland Hills.

TRA had originally planned to replace this pipeline, but chose to assess and selectively rehabilitate the pipeline by finding solutions that could identify the most distressed areas. The pipeline, constructed in 1973, is made up primarily of BWP, although there are some sections of PCCP.

In November 2012, TRA began a condition assessment program with Pure Technologies that included transient pressure monitoring, acoustic leak and gas pocket detection, internal electromagnetic inspection, and structural condition assessment including finite element analysis.

Pure Technologies staff verify the pipe condition

Pure Technologies staff verify the pipe condition

Crew verify and reveal corrosion on three pipe sections

Verification revealed corrosion on three pipe sections

After completing the inspections, TRA has verified and repaired three sections of BWP that were beyond the yield limit determined by BWP structural performance curves. During the verification, TRA and Pure determined that the distress areas identified in the structural assessment were accurate and the excavated pipe sections had bar breaks and corrosion.

The condition assessment project also identified four leaks and three gas pockets and although the four identified leaks were small (less than 2 gallons per minute), one was located in the front yard of a brand new church building and could have caused significant water damage had it not been repaired immediately by TRA. Water from this leak was visible at the surface 325 feet away from the actual leak location.

Through the use of condition assessment, TRA was able to selectively rehabilitate its assets for roughly 4 percent of the estimated $25 million replacement cost. The project has also allowed TRA to increase service reliability for customers in the region.

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

Case Study

Case Study: Trinity River Authority of Texas

After completing leak detection and structural condition assessment on 8.5 miles of PCCP and Bar-Wrapped Pipe, Trinity River Authority verified the results of inspection, finding three distressed pipe sections.

Technical Paper

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

Baltimore City features 130 miles of Prestressed Concrete Cylinder Pipe (PCCP), 15 percent of which is Class IV PCCP installed in the 1970s. This particular class of pipe has been prone to early failures across the United States, making it a major priority for BPW as it renews its water and wastewater infrastructure.
PCCP Diagram

The steel used in Class IV PCCP was the strongest used in the manufacturing of PCCP lines, but the same factors that gave the steel wires high strength have also made them vulnerable to brittleness when exposed to corrosive conditions, and therefore more likely to break.

Broken wires in PCCP are the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstates how PCCP typically fails.

How PCCP Fails

To prevent failures, BPW began installing monitoring equipment in its PCCP to alert staff when the prestressing wires break, BPW also regularly inspects its transmission mains for deterioration using EM technology that locates wires that are already broken.

Read “Ears Peeled for Trouble” in Municipal Sewer and Water »

 

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Assess & Address Pipeline Management Program

Pipeline Monitoring

Providing real-time critical data of a prestressed pipeline allows the asset owner to effectively monitor changes in structural integrity and address necessary improvements.

Case Study

Case Study: Baltimore City

In summer 2012, Baltimore City Public Works (BPW) intervened on a critical 54-inch PCCP pipe that was showing signs of distress. The pipe section was replaced and service resumed after avoiding a major pipe failure.

Each of the various pipe designs used in water networks across the United States has a specific life expectancy and operational requirements. Although some pipeline materials have well-developed, effective inspection technologies, assessing metallic water pipelines with mortar lining has historically posed a challenge for utilities, including the San Francisco Public Utilities Commission (SFPUC).

Without a reliable way to assess the condition of cement-mortar-lined pipelines, the San Francisco Public Utilities Commission set out to develop its own technology.

The third-largest municipal utility in California, SFPUC operates and maintains a large, complex water-delivery system for 2.6 million people and businesses in San Francisco, Alameda, Santa Clara, and San Mateo counties. The gravity-fed system reliably delivers water across the state without using energy-intensive pumping. Eighty-five percent of this water comes from the Upper Tuolumne River Watershed in the Sierra Nevada Mountains, where it’s stored in the Hetch Hetchy Reservoir and then transported 47.5 miles via the San Joaquin Pipeline (SJPL) across California’s Central Valley to the Bay Area. The SJPL system includes three large-diameter pipelines (56–78 in.), generally consisting of cement–mortar-lined steel that have been operating for more than 80 years. The pipelines can deliver 300 mgd.

To minimize the number of unplanned outages and determine the remaining pipeline life, SFPUC sought a technology that could assess the wall thickness of steel pipelines. Unfortunately, no technology was available, so SFPUC funded research to develop such technology. The project focused on SJPL. Because capital improvement funds were limited, however, SFPUC officials knew they needed a technology that would do the job and allow the utility to efficiently administer SJPL rehabilitation funds, according to Margaret Hannaford with the Hetch Hetchy Water and Power Project (HHWP), SFPUC.

In the August issue of AWWA Opflow, read about how SFPUC developed Magnetic Flux Leakage technology for reliable assessment of mortar-lined steel water pipelines.

Read Full Article»

Magnetic Flux Leakage (MFL)

Magnetic Flux Leakage (MFL)

Magnetic flux leakage (MFL) is an electromagnetic method of nondestructive testing that is used to detect corrosion, pitting and wall loss in lined and unlined metallic pipelines.

Case Study

Case Study: San Francisco Public Utilities Commission (SFPUC)

Without a reliable way to assess the condition of cement-mortar-lined pipelines, the San Francisco Public Utilities Commission set out to develop its own technology. In a project from 2007 to 2010, SFPUC developed and used MFL technology to inspect its critical San Joaquin Pipeline.

The inspections are part of AWU’s proactive condition assessment program that focuses on leak detection and structural condition assessment through the use of advanced non-destructive technologies.

Focusing leak detection efforts on large-diameter pipelines is an excellent method to reduce Non-Revenue Water (NRW) and gather baseline condition information. While leaks on small-diameter distribution mains are the most common, leaks on large-diameter transmission mains account for a significantly higher percentage of the total water lost; repairing even one leak on a transmission main can achieve a significant reduction in NRW.

Identifying air pockets reduces pressure on pumps that are attempting to pump water past an air pocket. As pockets grow in size, they can adversely affect the flow and capacity of a pipeline.

In addition a reducing water loss, early identification of leaks helps reduce pipeline ruptures, as leaks are often a preliminary sign that a pipeline may eventually fail due to pipeline corrosion or loss of bedding support due to soil erosion. By identifying leaks early on, AWU is effectively reducing NRW, reducing their risk of failure, and gathering valuable baseline condition information on its pipelines.

SmartBall Tracking
SmartBall Tool

The inspections completed in June 2013 were completed on two separate pipelines, the Ulrich 72-inch Prestressed Concrete Cylinder Pipe (PCCP) potable water transmission main and the Airport Road 24-inch C-303 Bar Wrapped Pipe (BWP) and Cast Iron potable water transmission main.

AWU used SmartBall® technology for both inspections. The SmartBall tool is a free-swimming inline leak detection platform that identifies the acoustic anomalies associated with leaks and air pockets that operates while the pipeline remains in service. The tool is tracked via fixed or portable receivers that are positioned strategically throughout the planned inspection distance. Following an inspection, the collected data is analyzed to determine if the acoustic anomalies represent leaks or air pockets and verified by AWU staff.

The Ulrich inspection covered a total of 6.6 miles in 6 hours and located no leaks or gas pockets. In order to successfully complete the inspection, AWU staff had to overcome one major operational constraint to ensure the tool could complete the inspection distance. Shortly after the insertion near the Ulrich WTP, the pipeline travelled beneath the Colorado River before making a 200-foot vertical climb, which can be difficult for free-flowing technologies without proper preparation. To overcome the challenge, AWU and Pure Technologies completed comprehensive flow simulations during the project planning phase to ensure the tool could traverse the vertical incline; this allowed the SmartBall tool to successfully travel up the steep hill.

In the Airport Road inspection, 2.4 miles of inspection was completed, successfully locating three leaks and giving AWU confidence that there are no air pockets restricting flow capacity in this line.

During both inspections, AWU and Pure Technologies worked closely to overcome operational challenges that allowed for successful leak detection surveys.

AWU supplies water to nearly 890,000 customers within and outside the corporate city limits of Austin, as well as the communities of Rollingwood, Sunset Valley, one water control and improvement district, five water supply corporations, seven municipal utility districts, and three private utilities. To ensure reliable service to its customers, AWU proactively addresses its infrastructure needs through regular inspection and rehabilitation to prevent service disruption and costly emergency repairs.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming in-line leak detection technology designed to operate in a live water mains.

WSSC needed to repair a 54-inch Prestressed Concrete Cylinder Pipe (PCCP) that was near failure. The decision was made after WSSC’s Acoustic Fiber Optic (AFO) Monitoring system, which is installed on about 75 miles of WSSC’s PCCP, identified several wire breaks in a short period of time.

The alternative, however, would have been much worse.

Had the pipeline failed, residents in Prince George’s County would have been without water for much longer than a few days. A failure would have also been more expensive than proactively replacing a pipe section, since more excavation and restoration is required to remediate a failed pipe. Luckily, four WSSC workers were able to fix an old valve, which allowed water to be diverted to residents and prevented complete water shut off.

WSSC explains the seriousness of the situation

“We wouldn’t be doing this if there wasn’t an imminent problem with this pipe.”

WSSC spokesman Jim Neustadt on WTOP Radio.

“[The acoustic system] tells us this pipe is headed out… We can’t just sit back and wait.”
– WSSC spokesman I.J. Hudson in the Washington Post.

Another WSSC official suggested a failure to the 54-inch pipe would have similar effects to previous failures WSSC has seen.

“Think about River Road when that water main exploded in 2008, and there was a pouring of water going down River Road. We don’t want this situation to end up like that.”

– WSSC spokeswoman Lyn Riggins on WTOP radio.

PCCP is concrete pipe that’s reinforced by high-strength steel wires; as wires in a pipe section snap, the pipe becomes more likely to fail. The AFO system used by WSSC identifies these wire breaks as they occur, and when the number reaches a certain limit, WSSC is advised to intervene on specific pipe sections to prevent failures.

After WSSC began experiencing major PCCP failures in the 1970s, it developed a strong commitment to infrastructure management technology in favor of large capital replacements. Beginning in 2007, WSSC and Pure Technologies began a partnership to create and Assess and Address™ PCCP management program. The program combines the early-warning system with regular condition assessment of its large-diameter pipes using inline leak detection and electromagnetic technologies.

WSSC in the news

Several stories surrounding the pipe intervention focused on how WSSC is managing its PCCP pipelines to prevent costly pipeline failures.

WSSC early warning system
Watch how WSSC is addressing its aging infrastructure by identifying the most critical problems using state-of-the-art inspection and monitoring technology. [ Source: WUSA9 ]
WUSA9 Story
See how WSSC’s monitoring system identified the problem in Prince George’s County to avoid a major pipeline failure. [ Source: WUSA9 ]
Gary Gumm Interview at WYSA9
WSSC’s Chief Engineer Gary Gumm outlines how challenging managing critical infrastructure is and what WSSC is doing to ensure that its customers have reliable service. [ Source: WUSA9 ]

WSSC is the 8th largest water and wastewater utility in the United States, serving over 460,000 customer accounts and 1.8 million residents in Montgomery and Prince George’s County, Maryland (suburban Washington D.C.). WSSC operates nearly 5,500 miles of water mains, with approximately 145 miles comprised of large-diameter Prestressed Concrete Cylinder Pipe (PCCP) equal to or greater than 36-inches in diameter.

The Washington Post Covers the Pipe Intervention

The Washington Post produced two notable stories providing information for Prince George’s residents, as well as discussion on why the intervention happened.

Four WSSC workers helped avert disaster by fixing defective valve

For almost 12 hours on July 16, WSSC mechanics chiseled years of thick rust off gears that corrosion had frozen in place and then fashioned new gears out of the gunked-up pieces of metal. By doing this, WSSC was able to isolate a shorter section pipeline to make repairs on the damaged 54-inch pipe section and avoid shutting down water service completely to Prince George’s residents.

To see the full story in the Washington Postclick here.

To see a video from WUSA9 on how workers closed the valve, click here.

Through management of its critical PCCP transmission mains, WSSC continues to show strong commitment to renewing its aging infrastructure and providing quality service to residents in its area.

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemnented for only a fraction of the capital replacement cost.

Case Study

Case Study Download: Washington Suburban Sanitary Commission

Beginning in 2007, WSSC and Pure Technologies began a partnership to create a comprehensive PCCP management program for WSSC’s large-diameter transmission mains. The Washington Suburban Sanitary Commission (WSSC) is the 8th largest water and wastewater utility in the United States, serving over 460,000 customer accounts and 1.8 million residents in Montgomery and Prince George’s County, Maryland (suburban Washington D.C.)

In April 2012, the District signed a Federal Consent Decree requiring improvements to the collections system aimed to eliminate illegal discharges of untreated raw sewage. As part of the requirements outlined within Consent Decree, a force main non-destructive testing and condition assessment program must be developed and implemented. The force main condition assessment program incorporates an asset management approach and risk categorization scale that classifies each of its force mains as high, medium, or low risk based on a previously conducted prioritization. The District and Jason Consultants (a wholly owned subsidiary of Pure Technologies) have developed individualized assessment strategy for each high and medium risk force main including the implementation of various inspection techniques and technologies.

Condition assessment and management of wastewater force mains has historically proven difficult for pipeline owners and operators. Conventional gravity sewer inspection methods (e.g. visual inspection, sonar and laser profiling) do not provide a full condition assessment of most pressure pipes since the loss of structural capacity cannot be quantified with these methods. As part of the condition assessment of force mains, leak and gas pocket detection is crucial since their presence is often a preliminary indicator of a potential failure location. Gas pockets in force mains are of significant concern as they are the primary failure mode for these critical pipelines. Hydrogen sulfide gas within the wastewater may be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

SmartBall Insertion
Tool Tracking

Based on Pure Technologies’ assessment of over 8,000 miles of pressure pipe, including over 400 miles of wastewater force mains, our clients have found that pressure pipes typically do not deteriorate or fail systematically along their full length. Rather, pipe condition is usually related to localized problems due to design, manufacturing, installation, environmental, operational, or maintenance factors. By identifying the localized areas of deterioration and performing “surgical” repair techniques, utilities can manage their pressure pipelines for often less than 10% of the replacement cost.

After completion of the SmartBall inspection and other screening techniques such as pressure transient monitoring and external corrosion evaluations, the District and Jason Consultants have identified locations for external evaluation for several force mains to determine the condition of the pipe wall. These evaluations will be conducted using various techniques including visual, physical measurements, and ultrasonic testing with the goal of District staff providing most of these inspection services. Jason Consultants will then work with District staff to deliver force main specific management strategies including:

  • Repair, rehabilitation, or replacement recommendations;
  • Recommendations for modifications to the force main including future inspection needs and air release valves;
  • Re-evaluation of force main risk based on inspection results and condition assessment;
  • Remaining useful life estimations;
  • Emergency response planning for high and medium risk force mains.

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Sewer access

Sewer Force Main Inspection

Pure Technologies has the complete portfolio for sewer force main and large diameter gravity main inspection. As the trusted global leader, we have successfully inspected thousands of miles of pipeline.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemnented for only a fraction of the capital replacement cost

Case Study

Case Study: Baltimore County Department of Public Works

Baltimore County Department of Public Works (DPW)has been working with Pure Technologies to manage its force main inventory since 2011. Through proactive and regular assessment, DPW has been able to identify select areas of pipeline deterioration, thereby avoiding unnecessary pipe replacement.

Metropolitan Water District of Southern California (MWD) is a regional wholesaler providing drinking water to nearly 19 million people at a rate of 1.7 billion gallons of water per day. In March 2013, (MWD) completed approximately 8 miles of electromagnetic (EM) inspection on a 78-inch water transmission main.

EM inspections locate and quantify the amount of wire breaks in PCCP pipelines, which is one of the main indicators that a pipeline will eventually fail.

The project also included visual and sounding inspection, structural curves and Acoustic Fiber Optic (AFO) monitoring installation for 4.5 miles of the transmission main. The visual and sounding is used to get an immediate assessment on the pipeline and to determine if there are any sections of pipe that are in an eminent state of failure. AFO was installed to monitor deterioration as it happens. The technology monitors the condition of prestressed pipe by recording the amount of wire breaks in each pipe section in real time. The AFO system allows MWD to track pipeline deterioration and together with the structural curves identifies at-risk pipes before they fail.

Due to the size and importance of this pipeline, the shutdown window for inspection and installation was very short and required careful planning and execution by MWD. The entire process was successfully completed in less than four days, well ahead of the planned schedule.

AFO Spool
Robotics Set Up

By combining the data from the EM inspections and activity on the AFO monitoring system, MWD can identify the amount of wire breaks on each section of pipe and prevent costly failures and service disruptions.

In terms of reducing NRW, locating leaks on large-diameter transmission mains represents the best opportunity for improvement. Leaks on small-diameter distribution mains are the most common, but the volume of water lost from these leaks represents a much smaller percentage of NRW than leaks on large-diameter pipes. Focusing leak and theft detection on transmission mains is the first step in a NRW-reduction strategy.

With over 2,000 miles of large-diameter pipelines inspected, Pure Technologies has located more than 4,000 leaks for an average of 2.2 leaks per mile using advanced inline leak detection technologies. Locating these large-diameter leaks has significantly reduced NRW, saved millions of gallons of water and helped prevent failures for utilities around the world.

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Pipeline Monitoring

Pipeline Monitoring

Providing real-time critical data of a prestressed pipeline allows the asset owner to effectively moniture changes in structural integrity and address necessary improvements.

Free-Swimming Pipeline Inspection

Electromagnetic Pipeline Inspection

Electromagnetic testing provides the best condition assessment data for large diameter PCCP (AWWA C301) and BWP (AWWA C303) pressure pipelines.

To proactively address its large-diameter Prestressed Concrete Cylinder Pipe (PCCP) for deterioration, Tampa Bay Water (TBW) completed a leak and gas pocket survey and electromagnetic (EM) inspection of the South-Central Hillsborough Regional Wellfield Transmission Main in April 2013.

TBW maintains a large pipeline network that serves the Tampa Bay and St. Petersburg metropolitan area and includes approximately 80 miles of PCCP. The pipeline inspections were completed on 8 miles of 42, 48 and 54-inch PCCP that convey wellfield supply to the Lithia Water Treatment Facility.

A leak and gas pocket survey was completed using SmartBall® technology as a forerunner for the EM condition assessment and provided TBW with an initial condition of the pipeline. The inspection was very successful, with the tool travelling steadily throughout and reaching all the tracking points. Several members of Tampa Bay Water were on hand at the retrieval to see the tool in action.

Early identification and repair of leaks can reduce Non-Revenue Water, but also helps determine the baseline condition of a pipeline, since leaks can be an indication that a pipeline might fail. In addition, locating and eliminating gas pockets reduces pressure on the pumps that are attempting to push water past a pocket. As pockets grow in size, they can significantly affect the flow of water and capacity of the pipeline if not released.

PipeDiver Team
Tool Insertion

In the following days, TBW prepared for the EM inspection using PipeDiver®, a free-flowing EM tool that is able to accurately locate and quantify broken wire wraps in PCCP. The wire wraps in PCCP act as the main structural component; broken wraps are the main indication that this type of pipe will eventually fail.

After completing inspection and analysis, Tampa Bay Water will have a wire wrap break estimate for each section of PCCP on this pipeline, which will allow them to make a prioritized rehabilitation and re-inspection plan.

The PipeDiver inspection was completed on schedule with the tool tracked throughout and retrieved successfully at the Lithia Water Treatment Plant. Results from both inspections are currently being analyzed for Tampa Bay Water.

 

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Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming in-line leak detection technology designed to operate in a live water mains.

Free-Swimming Pipeline Inspection

Electromagnetic Pipeline Inspection

Electromagnetic testing provides the best condition assessment data for large diameter PCCP (AWWA C301) and BWP (AWWA C303) pressure pipelines.

In order to proactively address water loss on its water transmission mains, Sweetwater Authority completed a SmartBall® leak detection survey in January 2013 on over 5 miles of a 36-inch steel water transmission main to locate leaks and gas pockets. The tool located two acoustic anomalies indicating small and medium sized leaks on the pipeline. No pockets of trapped gas were located.

The two locations were reviewed by Sweetwater Authority staff and it was determined that one of the leaks was located at an existing valve to an adjacent pipeline. This valve is used for isolation between the two pipelines so there was no water coming from the pipe into the surrounding environment. However, the other leak, which was the small leak, was validated through excavation by Sweetwater. It was quickly repaired and this critical pipeline was placed back into service.

The SmartBall platform is a non-destructive, free-swimming tool that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. When acoustic anomalies are present, the data is analyzed to determine if it is a leak, gas pocket, or just an external sound. The tool is tracked using receivers that are mounted along the pipeline at strategic locations; Sweetwater and Pure tracked the tool successfully at all six receivers during this inspection.

Insertion Site
Extraction Site

Regular leak detection surveys can help utilities identify leaks that may not be visible at the surface. By repairing leaks utilities can reduce their Non-Revenue Water and prevent pipeline failures, as leaks are often a preliminary indication that a pipeline will eventually fail.

Location and elimination of gas pockets is also beneficial as it reduces pressure on pumps that are attempting to pump water past a gas pocket. As these pockets grow in size, they can significantly reduce the flow and capacity in a pipeline if they are not released.

In addition to reducing water loss in the pipeline, the leak detection survey will provide valuable condition data that could be used in future condition assessment projects.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming in-line leak detection technology designed to operate in a live water mains.

Abstract

Recently the industry has been emphasizing broken prestressing wires as a basis for the management of Prestressed Concrete Cylinder Pipe (PCCP). The approach includes: evaluating broken wires, establishing a threshold level of broken wires for repair, and repairing only sections that exceed the threshold.

While evaluating wire breaks are an important part of PCCP management, it is important to acknowledge additional factors beyond wire breaks. By acknowledging additional condition factors, limitations of wire break assessment, and considering other rehabilitation approaches, there may be a more sustainable PCCP management approach (or combination of approaches). The approach may reduce risk and be more sustainable in terms of costs (current and future).

For some areas, the San Diego County Water Authority found the comprehensive rehabilitation approach, steel relining of PCCP, to be more sustainable in terms of costs. In addition, the approach significantly reduced the risk of a pipeline failure. However, in other areas, a localized, as-needed repair approach, such as Carbon Fiber, was more sustainable in terms of costs.

Authors

  • Nathan D. Faber, P.E., San Diego County Water Authority, Escondido, CA, USA.
  • Martin R. Coghill CEng MICE, Jacobs Engineering Group Inc., San Diego, CA, USA.
  • John J. Galleher, P.E., Pure Technologies, San Diego, CA, USA.

Baltimore County Department of Public Works (DPW) wrapped up a busy two-month inspection schedule in November 2012 after completing ten force main inspections using the SmartBall®, PipeDiver® and PureRobotics® technology platforms.

Twenty-three total inspections took place on ten different Prestressed Concrete Cylinder Pipe (PCCP) force mains over the inspection period, requiring extensive planning and organization between DPW and Pure.

SmartBall leak detection inspections were completed on nine force mains as part of the overall condition assessment of PCCP force mains. Initial leak and gas pocket detection is crucial in condition assessment, since the presence of leaks or gas pockets is often a preliminary indicator of a potential failure location.

Gas pockets in force mains are of significant concern as hydrogen sulfide gas within the wastewater may be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

For structural condition assessment of the force mains, Pure Technologies used PipeDiver technology for six inspections and the PureRobotics platform for three inspections.Two electromagnetic platforms were used for the inspections to meet the different operational challenges at each force main.

Both tools identify areas of distress and quantify the amount of estimated wire breaks on PCCP force mains while allowing them to remain in service. Having the line remain in service is often important for force main condition assessments since most lack redundancy and the ability to be shut down for inspection.

In total, DPW and Pure Technologies completed just over 15 miles of SmartBall leak detection, almost 11 miles of PipeDiver condition assessment, and about 3 miles of robotics inspection. The pipe diameters varied for each force main, ranging from 16-inch to 42-inch PCCP.

Baltimore County is inspecting their force mains after entering into a Consent Decree brought forth by the U.S. Department of Justice, the Maryland Department of the Environment (MDE) and the Environmental Protection Agency (EPA) in September 2005. The consent decree stipulated that Baltimore County inspect all force mains in its collection system with one or more methodologies appropriate to the specific characteristics of each force main.

Although the Consent Decree stipulates that the force mains be inspected, it allowed Baltimore County the flexibility to specify the method or technology at the time the inspections are performed.

The Baltimore County DPW has taken this opportunity to go beyond a minimalist approach, choosing to inspect its force main inventory with advanced non-destructive condition assessment technologies, reaffirming their ongoing commitment to providing reliable service and preventing pipeline failures.

DPW’s sewer force main inspection program was featured in the November issue of Trenchless Technology. Click here to see the article.

 

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Sewer inspection hole

Sewer Force Main Inspection

Pure Technologies has the complete portfolio for sewer force main and large diameter gravity main inspection. As the trusted global leader, we have successfully inspected thousands of miles of pipeline.

As part of a comprehensive pipeline management program, Washington Suburban Sanitary Commission (WSSC) and Pure Technologies have been monitoring sections of Prestressed Concrete Cylinder Pipe (PCCP) using Pure’s Acoustic Fiber Optic monitoring since 2007.

In October 2012, WSSC took the opportunity to proactively verify a 0.5 mile section of the River Road transmission main that had experienced elevated wire break activity. The individual pipes to be rehabilitated were selected from a comprehensive list of all monitored pipelines that contains all pipe sections that have an elevated risk of failure according to Finite Element Analysis and a combination of data sets, primarily collected from electromagnetic (EM) inspections and AFO monitoring.

AFO Install

This is part of a new drive from WSSC to initiate repairs on pipelines experiencing a high number of wire breaks before the situation becomes critical and prior to the normal 5 to 6-year inspection cycle.

Using an EM verification tool and internal visual and sounding, Pure verified all the wire breaks recorded with AFO and determined that all of the pipes were significantly more distressed than they were two years ago after the initial EM inspection.

In addition to the wire breaks, a hollow section was found on one of the pipes that signals a broad loss of prestressed wires. This hollow section was not found during the initial EM inspection and shows that the pipe section was beyond its allowable amount of wire break damage.

The verification of the four damaged pipe sections on River Road shows WSSC’s commitment to preventing pipeline failures through ongoing proactive pipeline management.

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Pipeline Monitoring

Pipeline Monitoring

Providing real-time critical data of a prestressed pipeline allows the asset owner to effectively moniture changes in structural integrity and address necessary improvements.

Pure Technologies completed another successful year of its leak detection program with the City of Dallas and the Dallas Water Utilities (DWU) in July 2012.

This year, 16 leaks were found using Sahara® in just over 12 miles of inspection. The City and DWU are always efficient in repairing identified leaks, and since the conclusion of the 2012 inspection, have repaired about half of the leaks.

In 2004, DWU, which services 2.4 million customers in Dallas and nearby communities, began an ongoing proactive annual leak detection program using Sahara leak detection, though the DWU and Pure had been doing electromagnetic (EM) condition assessment since 2000. The leak detection program inspects pipes between 12-inches to 84-inches, and the transmission mains are made up mostly of Prestressed Concrete Cylinder Pipe (PCCP), but also feature Cast Iron Pipe and Ductile Iron Pipe. To date, approximately 86-miles have been inspected using Sahara.

The decision to implement an ongoing program with Pure stemmed from an internal study conducted by the City of Dallas of their large-diameter leak detection. The study found that it needed new technologies to improve efficiency.

Large-diameter water transmission mains in Dallas have a higher potential of developing leaks in the summer. Due to the high heat and lack of precipitation, the ground becomes extremely dry and hard, this shifts buried pipeline infrastructure slightly which can cause leaks to develop and ultimately water mains to break.

Sahara has been extremely effective in detecting leaks for DWU. Since the program began, 116 leaks have been found in DWU’s large-diameter transmission main network. The estimated water savings from all of the leaks detected by Sahara and repaired by DWU, is about 7.2 million gallons per day. DWU has also seen a 17 percent reduction in catastrophic water main failures since the start of the program; increasing service reliability.

 

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Sahara® - Leak & Gas Pocket Detection

Sahara® – Leak Detection for Water Trunk Mains

Leak and gas pocket detection using a tethered acoustic sensor allows for real-time results, and maximum control and sensitivity.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming in-line leak detection technology designed to operate in a live water mains.

Pure Technologies pinpointed wire breaks on a large-diameter water main in Tucson using Acoustic Fiber Optic monitoring, possibly preventing a major failure.

On August 13, Tucson Water went into emergency mode when several wire breaks occurred in a short period of time on one of its 96-inch Prestressed Concrete Cylinder Pipe (PCCP) water transmission mains, indicating there was a high risk of failure. Tucson Water was able to react quickly to the wire breaks by reducing the pressure in the pipe and diverting water from another main to serve its customers, subsequently preventing a failure.

In the following days, Pure and Tucson Water verified the pipe and found it to be more damaged than originally expected, requiring more repairs. The condition of the pipe made it clear that Tucson Water’s decision to shut down and repair the line immediately prevented a failure.

This same pipeline failed in 1999 about 700-feet upstream from this pipe, dumping 38 million gallons of water into neighborhoods and costing the city $2.5 million. Since that time, Pure has been working with Tucson to develop a pipeline management program including electromagnetic (EM) assessment and AFO monitoring. Tucson Water was the first utility in North America to install an AFO system throughout their entire PCCP inventory.

Below is an ABC News 4 Tucson story outlining how Tucson Water’s AFO system identified an at risk pipe before it failed.

Pure and Tucson Water will continue to monitor the large-diameter water mains in Tucson to identify areas of distress and proactively repair pipe sections.

 

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Assess & Address Pipeline Management Program

Pipeline Monitoring

Providing real-time critical data of a prestressed pipeline allows the asset owner to effectively moniture changes in structural integrity and address necessary improvements.

Pure Technologies worked with Baltimore City Public Works on July 16, 2012 to dig up a 54-inch pipe section that was ready to fail along the Gwynns Falls/Southwestern Transmission Main.

The excavated pipe section was severely damaged, and had it failed, would have caused significant damage, inconvenience and financial cost. The removal of the distressed pipe section shows Baltimore City’s commitment to preventing major failures in The City’s water system.

A feature story on WBAL-TV 11 from July 17 shows Pure working on verifying their results of the Gwynns Falls/Southwestern Transmission Main.

Pipeline Inspection in Baltimore
Water Main Repairs Get Expensive

Pure engineers inspected this line in March 2012 using PipeDiver® — a free-swimming tool that uses Electromagnetics (EM) to detect broken prestressing wires in Prestressed Concrete Cylinder Pipe (PCCP) – and found that the pipeline had wires broken in several sections.

In recent months, the situation became critical and removal of a severely damaged pipe section was strongly recommended when prestressing wires began breaking more frequently. The increase in wire break activity was detected early on through Pure’s Acoustic Fiber Optic (AFO) monitoring system that was installed during a 2007 project with Howard County. This system gives utilities an early warning alarm when pipelines begin to rapidly deteriorate, ultimately allowing the utility to resolve problems early on and prevent catastrophic failure.

After the city shut down and dewatered the transmission main, Pure’s team mobilized on site to inspect the distressed pipe section more closely. In the verification process, the wire break locations were confirmed through impact testing. Two large cracks were also found upon visual inspection, which created a hollow section in the pipe, confirming Pure’s suspicion that a failure could have occurred at any time.

Pure also inspected the distressed pipe section with an EM verification tool. After a combined analysis of data collected from the EM tool, PipeDiver®, and the AFO monitoring system, a good correlation was found between the distressed locations predicted by all three technologies. As a result, the damaged pipe was removed from the ground and the pipe was returned to operation on Saturday, July 21, 2012.

Through proactive measures, The City of Baltimore was able to avoid a major failure that would have caused significant disruptions to service and substantial financial cost. The City is committed to Pure’s proactive approach in pipeline management to continue preventing major failures.

 

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PipeDiver® Draws Media Attention for Baltimore

PipeDiver® Draws Media Attention for Baltimore

In early March, a group of reporters and video crews from local news stations gathered around the insertion site for a high profile PipeDiver® electromagnetic inspection in Baltimore, Maryland. It was necessary to perform the inspection without shutting down service to residents.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

PCCP Pipe

Managing Prestressed Concrete Cylinder Pipe (PCCP)

Large diameter prestressed concrete cylinder pipelines (PCCP) are a significant investment for many water and wastewater agencies. Assessing and monitoring the condition of these pipes is becoming an increasingly important and challenging task.

Louisville Water Company (LWC) needed an accurate condition assessment tool that didn’t require pipeline shutdown and lengthy cleanup. The utility turned to Pure to provide a solution. The PipeDiver® tool, moving with the flow of the water in the main, completed an 8.8-mile inspection of a 5-foot diameter PCCP main in eastern Jefferson County last month. Through a contract with LWC, Pure conducted the large-diameter PipeDiver electromagnetic inspection using the large launch and extraction stacks for the first time. View media coverage of the inspection.

In the past, inspections required such mains to be taken out of service, thus disrupting continuous service to customers. The pipeline may have been damaged during a pressure surge in 2009, prompting the utility to assess the main’s integrity.

The PipeDiver took five hours to travel from the B.E. Payne Water Treatment Plant through the main at an average velocity of 2.75 ft/s to a large water tank near North English Station, passing four 60″ butterfly valves in the 41-year-old PCCP pipe. This is the second phase in an 11-mile inspection project that started in May 2011 with a 2.5 miles robotic inspection, and will continue in October 2011. The PipeDiver tool is best suited for prestressed concrete lines as its electromagnetic sensors assess defects in the metal wires that give the prestressed concrete of the main its strength as it travels through the pipe.

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Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

PCCP Pipe

Managing Prestressed Concrete Cylinder Pipe (PCCP)

Large diameter prestressed concrete cylinder pipelines (PCCP) are a significant investment for many water and wastewater agencies. Assessing and monitoring the condition of these pipes is becoming an increasingly important and challenging task.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemnented for only a fraction of the capital replacement cost.

The first PipeDiver project was recently completed on a fully operational prestressed concrete cylinder pipe (PCCP) wastewater force main for Baltimore County Department of Public Works. The inspection was completed as part of a comprehensive assessment of a 54-inch force main that also included Pure’s SmartBall® technology.

September 2011

PipeDiver’s electromagnetic assessment sensors provide a non-destructive method of evaluating the baseline condition of the prestressing wire (the primary structural component of PCCP) by estimating the quantity and location of wire breaks for each pipe section.

PipeDiver Insertion
“This is a significant advancement in wastewater force main condition assessment,” said Travis Wagner, P.E., Pure’s wastewater assessment leader. “The comprehensive condition assessment of PCCP force mains has historically proven difficult for wastewater collection system owners/operators since unlike potable water transmission mains, force mains generally lack redundancy and therefore, the ability to shut down the pipeline for a traditional comprehensive PCCP assessment.”

Thorough force main inspections often require significant operational and/or financial expenditures in order to bypass the wastewater flow via temporary pumping or a piped diversion. Through the successful implementation of the SmartBall and PipeDiver tools, PCCP force main owners/operators now have the ability to conduct comprehensive condition assessments of their wastewater PCCP assets with a significantly lower operational impact.

 

Case Study

Case Study

Baltimore County – Sewer Force Main Assessment

As part of Baltimore County, Maryland’s Wastewater Force Main Asessment Program, Pure Technologies inspected the 54-inch Patapsco PCCP Force Main using the SmartBall® and PipeDiver® pipeline assessment tools.

Authors

  • Mike Wrigglesworth; Pure Technologies, 300-705 11th Ave SW, Calgary, AB, Canada, T2R 0E3; +1.403.266.6794
  • Michael S. Higgins, P.E.; Pure Technologies, 8920 State Route 108, Suite B; Columbia, MD 21042; 443-766-7873

Introduction

In 1996, Providence Water experienced a catastrophic failure of its 102″ PCCP aqueduct pipeline. Subsequently, the main underwent an extensive assessment and repair and was returned to service with plans that the main would be re-inspected in approximately 5 years.

In 2005, Providence Water re-inspected the aqueduct. Since the previous inspection, the state-of-the-art for assessing PCCP mains has progressed significantly. Non-destructive technologies available for assessing and monitoring PCCP pipe have made significant strides. Providence Water implemented state-of-the-art inspection procedures to obtain the best possible assessment of the aqueduct. Following the assessment of 4.5 miles of the aqueduct, Providence Water opted to install a fiber optic acoustic monitoring sensor to continuously monitor the condition of the aqueduct and identify pipe sections experiencing ongoing wire break activity.

Providence Water utilized the following technologies during the most recent 2005/2006 inspection/monitoring program:

  • Electromagnetic Inspection – to detect wire breaks in the prestressing wire
  • Visual and Sounding Inspection – to inspect for cracks or delaminations
  • Resistivity Testing – to determine the actual number of wire breaks on excavated pipe sections (vs. the estimated number based on the electromagnetic inspection)
  • Acoustic Monitoring – to detect future wire breaks as they occur in the operational aqueduct

Following the initial inspection, one pipe section was found to be in a state of incipient failure. As a result, several nearby pipe sections were strengthened and a decision was made to install the acoustic monitoring system. This paper focuses on the assessment and monitoring technologies used during this project and describes the capabilities and limitations of these technologies.

Authors

  • Michael S. Higgins, P.E.; Pure Technologies, Columbia, MD, USA.
  • Paul J. Gadoury, P.E., Peter LePage, Rich Razza; Providence Water Supply Board, Cranston, RI, USA.
  • Jack Keaney, P.E., Ian Mead, P.E., CDM, Providence, RI, USA.

Introduction

The City of Phoenix is currently in a multi-year program to investigate 150 miles of prestressed concrete cylinder pipelines (PCCP). The failure of a 60-inch pipeline focused the efforts of the investigation to a pipeline known as the Superior pipeline.

The Superior pipeline is a 2.2-mile long, 29-year old pipeline that ruptured on October 3, 2006, resulting in extensive damage to the surrounding community. The pipeline was immediately shutdown and the failed section of pipeline was repaired. However, the condition of the remaining pipe and the potential for additional failures was a concern.

To identify wire breaks, Pressure Pipe Inspection Company (PPIC) conducted Remote Field Transformer Coupling investigations. In addition, visual and sounding investigations were conducted by Openaka of Branchburg, New Jersey to identify internal defects. These investigations identified pipe segments that were in need of immediate repair prior to putting the pipeline back in service. This information provided baseline wire break information for the subsequent investigations.

Prior to putting the pipeline back into service, 11,700 linear feet of fiber optic was installed by Pure Technologies allowing the City to acoustically monitor wire breaks in real time. This information was critical as the pipeline needed to be back in service to meet the high demand for water during the hot Phoenix summer. Real time wire break monitoring allowed the City and Brown and Caldwell to slowly resume the operation of the pipeline to prevent another failure. Monitoring of the pipeline was conducted from February 2007 through January 2008 and the pipeline was found to be extremely active with an initial average of three wire breaks occurring each day.

This paper focuses on the investigations conducted and conclusive results relative to:

  • Benefits of multiple technologies for PCCP investigations
  • Calibrated vs. non-calibrated curves for electromagnetic analysis
  • Real time data collection through fiber optics to monitor pipeline conditions
  • Verification of fiber optic results using electromagnetic analysis
  • Pressure and surge monitoring

Authors

  • Ronald Ablin, P.E., Brown and Caldwell, Phoenix, AZ, USA.
  • Brandy Kelso, P.E., City of Phoenix Water Services Department, Phoenix, AZ, USA.
  • Bethany Williams, P.E., The Pressure Pipe Inspection Company, Phoenix, AZ, USA.
  • Myron Shenkiryk, Pure Technologies, Phoenix, AZ, USA.