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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.

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

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

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.

 

For this Vancouver Island community, tight deadlines, plug valves, and a rising tide were among the challenges faced during this condition assessment project.

Sometimes the catalyst for a pipeline inspection can come from an unexpected source. In this instance, the story began when it was noticed that a sewer pipe was exposed from erosion during low tide along the beach. That observation set the wheels in motion for an eventual inspection of a critical force main that services approximately 41,000 residents in both the Town of Comox and the City of Courtenay on the eastern coast of Vancouver Island.

The pipeline was installed in the early 1980s, and consists of an 8.75 km large-diameter force main that connects the City of Courtenay, Town of Comox and K’ómoks First Nation Community to the Comox Valley Water Pollution Control Centre (CVWPCC). This includes a five-kilometer portion buried in an “intertidal” foreshore section (area between high and low tide).

Over time, a section of beach eroded and exposed the line to coastal wave action (high tide hides the pipe). The Comox Valley Regional District (CVRD) took steps to restore the beach section where pipeline had been exposed, and began developing plans to relocate the exposed force main off the foreshore.

Island community concerned about pipeline risk of failure.

Sensitive location and potential environmental consequences strike nerve with community.

A new concept was developed that would utilize a portion of the existing force main within the foreshore but remove from service the exposed force main. Due to its sensitive location and the environmental consequences of a potential failure, the CVRD elected to complete a highly specialized pipe condition assessment on the entire length of the line to better understand the remaining service life and condition of the force main. As a result, the project timeline was tight, as CVRD needed imminent results to proceed with corrective action immediately should it be required.

The assessment challenges began from the get-go.

The inspected portion of the pipeline was built of two different pipe materials (PCCP and BWP) and three different pipe diameters (450-, 750- and 820-mm). As well, the critical line could not be taken out of service. The CVRD consultant, Associated Engineering, assisted in developing the request for proposal (RFP) process used to select Pure Technologies (Pure) to conduct the condition assessment, which included an electromagnetic inspection, structural curves, leak and gas pocket detection, and transient pressure monitoring.

Pure proposed the acoustic-based SmartBall® tool for the leak and gas pocket detection, and its free-swimming PipeDiver® inspection platform for the electromagnetic inspection of the line.

“This project had a lot of challenges, especially since the asset was so critical to the region. However Pure was able to help us understand the true condition of the line without requiring a shutdown of the critical force main, and has given us defensible information to make informed decisions in the future.”

Kris La Rose, Senior Manager Water/ Wastewater Services, Comox Valley Regional District

Pipeline alignment follows along the Vancouver Island coast.

Transient pressure monitoring used to understand surge pressures within the line.

First, transient pressure monitors were installed at the Courtney Pump Station (CPS). For more than 4 weeks, the recorded pressure data was used to understand the operational and surge pressures within the force main and their impact on the structural integrity of the pipeline.

SmartBall® technology detects and locates acoustic signature related to leaks and gas pockets.

While transient pressure data was collecting, Pure deployed its proprietary SmartBall technology, a multi-sensor tool used to detect and locate the acoustic signature related to leaks and gas pockets in pressurized pipelines.

The tool has the ability to inspect long distances in a single run, and while the SmartBall is deployed, the pipeline remains in service, limiting disruption to customers.

PipeDiver tool collects electromagnetic data regarding the pipe wall.

PipeDiver® electromagnetic technology designed to assess PCCP, BWP and metallic pipes.

In addition to utilizing the SmartBall tool, Pure chose to deploy the PipeDiver platform, a free-swimming condition assessment tool that collects electromagnetic data regarding the pipe wall, and operates while the pipeline remains in service, an important factor for the force main inspection. The tool travels with the product flow and utilizes flexible petals to navigate plug valves, tees and bends in the pipeline.

Crews had to retrieve the PipeDiver tool within a short 20-minute time window.

Tight time-frame for tool insertion and retrieval of sensor data.

Due to the criticality of the line, and a small capacity wet well at the CPS, the inspection teams had a very short time window (20 minutes) to insert the inspection tools. The small capacity wet well also meant that boosting flows was limited – if pumped too hard, the wet well would draw down and empty, and if pumped too slow, the PipeDiver tool could get lodged at the inline plug valves. (Low flow rate is not a significant problem for the SmartBall tool.) The solution was to first use the SmartBall inspection tool to test the flows in order to optimize the inspection approach for the PipeDiver run.

While the low flow rate slowed the SmartBall inspection, a forecast of rain moved up the PipeDiver run a day ahead in order to take advantage of extra flows that could be provided by the wet weather. The tool also had to navigate a series of 90-degree bends and a plug valve with a small port width in the pump station pipe.

Tracking the tools along the beach was fraught with potential for problems. Inspection crews needed to monitor the tidal forecasts in order to access the tracking sensors during the tide ebb, which meant a short window to retrieve the sensor data.

In spite of the challenges and risk, the dynamic four-day inspection proved successful, and went off without a hitch. The Pure Technologies crew and CVRD operators worked very well together, and their collaborative efforts ensured that this important project was successfully completed.

Damp weather didn’t dampen the inspection ingenuity of the team.

Data analysis indicated no electromagnetic distress on inspected pipes.

Based on the inspection data, Pure analysts identified zero (0) leaks, one (1) acoustic anomaly associated with trapped gas, five (5) acoustic anomalies characteristic of transient gas and two (2) acoustic anomalies associated with entrained gas. In particular, gas pockets are of significant concern in force mains, 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.

The results also showed no indication of electromagnetic distress on the inspected pipes, which was good news, in spite of the corrosive salt water environment.

Overall, the CVRD was pleased with the inspection results, as they were able to understand the condition of the pipeline and make an informed decision for capital improvements. The project demonstrates how the region uses actionable data to effectively manage their finances and risk, while continuing to provide the community with a safe and reliable delivery of wastewater.

 

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

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

Artis REIT is an unincorporated closed-end real estate investment trust primarily focused on creating value for unitholders through the investment in and ownership of quality commercial properties in select markets. Artis REIT’s portfolio is comprised of industrial, retail, and office properties in Canada and the United States.

Project Details

Services
SoundPrint® Acoustic Monitoring – Parking Garages

Monitoring system commissioned in February 1994

System has been maintained and upgraded as needed, operating continuously since commissioning

Structure Type
Two-way unbonded post-tensioned concrete ground level slab above parking garage
Monitored Area
5,967 m2
Number of Zones
3
Number of Sensors
60

Project Highlights

System has performed in excess of 97% of efficiency over its lifespan

Detected and located 181 wire failures to date, of which 81 have been confirmed by physical inspections

Annual post-tensioning investigations planned according to monitoring results with as needed tendon replacements

Predictable wire failure rate on 8.1/year has allowed for accuracte forecasting of tendon replacements, averaging 6.6/year since 1999

Identified critical area to allow for focused remediation efforts

Challenge
Prior to the installation of the monitoring system, a single post-tensioning strand erupted from the slab surface. Investigations of the state of the ground level slab revealed significant waterproofing issues on the slab edges and water ingress into the tendons. Selective, invasive, inspections on strands throughout the structure were undertaken and resulted in 164 strands replaced from a total of 850. The status of the remaining tendons was uncertain, and a comprehensive monitoring solution was desired to identify areas of active corrosion.

Solution
In order to gain further insight into the deterioration rates of the structure, a SoundPrint monitoring system was installed in February 1994. The system was the first of its kind, and the monitoring experience gained was used to refine monitoring protocols and equipment. Improvements in the technology led to significant upgrades in 2001 and 2008, without any significant interruption to the data acquisition. Overall, the system has been in continuous operation in excess of 22 years and operated at over 97% efficiency through its life.

Results
Physical investigation of detected events have been regularly undertaken by qualified consulting engineers.  The process has resulted in the following:

  1. Wire events identified and located by Pure Technologies, and reported to client and consulting engineer.
  2. Consulting engineer schedules annual investigation of existing recesses and/or creates new recesses to check condition of the strands on which the wire events may have occurred.
  3. Based upon the condition of the strands inspection, the consultant recommends tendons for replacement.

Through these inspections, 81 wire failures have been confirmed by the finding of tension deficient cables in the reported areas. The monitoring results are displayed in the chart, which shows the linear nature of the post-tensioning deterioration in the three (3) ground level slabs. This consistent rate allows the client to accurately budget tendon replacements to maintain the structural integrity while minimalizing unexpected costs and interruptions to the garage operation.

SoundPrint®

Ensure the long-term integrity of bridges and structures with precise failure detection.

Structural Monitoring for Bridges & Structures

SoundPrint can detect and locate failures in high-strength steel wire, strand or cable through continuous, non-intrusive remote monitoring.

SoundPrint helps bridge or structure owners and engineers ensure the long-term integrity of materials like post-tensioned concrete building structures and pre-tensioned suspension and cable-stayed bridges. Because it continuously monitors for failure of tensioned steel elements, SoundPrint saves money on other bridge and structure inspection and NDE techniques.

Once SoundPrint has generated an understanding of the frequency and location of failures, other investigative techniques can be more cost-effectively applied to further evaluate the extent of deterioration.

How it works

SoundPrint Acoustic Monitoring system is installed on a Bridge or Structure.

Sensors measure the dynamic energy release when tensioned wires fail.

Onsite Data Acquisition Unit performs preliminary hardware filtering and real-time pre-processing rejecting superfluous acoustic event data.

Data from events that has passed preliminary filtering processes is transferred to our data-processing centre to be further examined.

Through a combination of applied proprietary software, and highly trained professional analysis, acoustic events are assigned a time, location, and specific classification.

If and when the event is classified as noteworthy, electronic alerts are sent, via email, to the client. The data is immediately accessible on the 3D GIS website, and reports can be custom generated.

Benefits

  • Saves money on bridge inspection
  • Complementary to other inspection techniques
  • Easily integrated into Bridge Management System
  • Access data from anywhere

Types of bridges

Suspension bridges
The main cables and suspender ropes of suspension bridges are often subject to aggressive environments where hidden corrosion of the wires leads to reduction in structural safety. SoundPrint provides complete, continuous surveillance of cable components on suspension bridges so that areas of active corrosion can be pinpointed.
Cable-stay bridges
The SoundPrint acoustic monitoring system provides a complete continuous remote health monitoring solution for stay-cables. Corrosion or fatigue-induced failures can be detected long before they compromise the integrity of the stay.
Post-tensioned bridges
Suspect grouting practices and poor detailing has led to concerns about the durability of post-tensioned bridges and their susceptibility to corrosion-induced tendon failure. SoundPrint has been used to provide assurance about the condition of post-tensioned bridges with sophisticated acquisition and event filtering capabilities that can reliably detect low energy wire breaks in fully-grouted tendons in noisy environments.

Featured Case Study

Fred Hartman Bridge

Texas Department of Transportation (TxDOT)

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

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

Highways England (formerly the Highways Agency) is a government-owned company with the responsibility of managing the core road network in England. It operates information services, liaises with other government agencies and provides staff to deal with incidents on the roads it manages. The company managed The Mossband Viaduct, which carried traffic over a roadway and railway until its demolition in 2008.

Project Details

Services
SoundPrint® Acoustic Monitoring – Bridges

Monitoring system commissioned in 2001

Operated continuously until bridge demolition in 2008

Bridge Type
Post-tensioned concrete
Monitored Length
836 ft (255 m)
Number of Spans
8
Number of Sensors
210

Project Highlights

System has performed in excess of 99% of efficiency over its life

SoundPrint identified and located 6 specific wire break events

Structure life extended over 7 years via structural health monitoring

Client estimated economic benefits $30 to $40 million

Challenge

The viaduct was comprised of twin decks – one deck was constructed of concrete girders butted up against each other, with a top cantilevered slab, while the second deck was a voided box-girder. Half of the spans were post-tensioned cast in-situ concrete table spans and four were suspended spans supported by the table spans on half-joints.

Conventional visual investigations were performed in 1990, 1995, and 1999.

The first investigation discovered water ingress at all the deck joints and next to the drainage pipes. This was believed to have been occurring over many years. General corrosion of the surface reinforcement in these areas resulted in surface spalling.

The second inspection revealed the presence of several corroded and broken tendons in the in-situ table spans. The damaged tendons were located in the deck over the pier supports, where the cable profiles approached the top surface of the deck. A deck construction joint within a meter of the pier support provided a direct water path to the tendon ducts. The cable profiles descended from this location into the mid-span of the table span and to the half-joint anchorage area.

As is often the case with selective visual investigations, one location often showed severe corrosion while an adjacent location appeared undamaged. In this case, the third inspection showed that some of the longitudinal tendons had all the strands completely corroded whereas only two meters away, they appeared in good condition. Clearly, the tendons at the half-joint locations were at risk at all 14 locations, but the extent of deterioration at every location was unknown.

Solution

The Highways agency implemented a comprehensive bridge management plan starting in 1999 to assess the rate of deterioration of the post-tensioning, and if necessary, to intervene and strengthen the structure. ­The plan consisted of:

  • Monthly visual inspections of critical sections
  • Installation of vibrating wire stain gauges to monitor cracks on the sides of the sections and soffit of construction joints
  • Load testing to compare stain changes
  • Installation of a SoundPrint acoustic monitoring system to monitor the rate of deterioration of the post-tensioning system

In late 2000, 210 acoustic sensors were installed along the 836 foot (255 m) length of the viaduct in three rows to fully monitor all post-tensioning tendons. ­The sensors were multiplexed at local junction boxes to minimize cabling and data acquisition requirements. Data was acquired via a single acquisition unit calibrated to reject the majority of non-wire events, with events of interest transferred to servers in Calgary, AB for analysis.

Results

The wire break rate found was lower than expected. Six wire breaks were detected during the extended life of the structure, giving engineers/owners confidence that the bridge management program was effective. Further, strain readings during the AIL annual load tests showed that the structure was not experiencing severe changes in deflections, and that the serviceability requirements were being met. ­ The crack growth was also monitored, and thought to be consistent with the rate of deterioration observed with the acoustic system.

 

In this case, the acoustic monitoring system was used to extend the life of the structure by seven years and 10 months, until a new bridge could be built as part of the A74 Cumberland Gap. Approximately $1.4 million was spent on the two monitoring systems and the load tests over 8 years, including the system-related inspection and reporting functions by engineers.

 

Client estimated that the economic benefit in delaying the permanent bridge replacement and not fast tracking a temporary structure was between $30-$40 million dollars.

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.

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 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.

Calgary, Alberta and Rye Brook, N.Y., April 25, 2017 – Pure Technologies Ltd. (TSX: PUR) and Xylem (NYSE: XYL) announced today that they have entered into a commercial collaboration whereby Xylem will represent Pure’s products and services to the water sector in the Gulf Cooperation Council countries (UAE, KSA, Qatar, Bahrain, Kuwait and Oman), and in India, Singapore and Malaysia.

Pure provides a wide range of patented technologies for managing critical infrastructure across the water, wastewater and key transportation sectors. Xylem is a global water technology leader that offers solutions for managing water across the water cycle. Both companies are actively engaged in addressing customer challenges in water infrastructure, including non-revenue water, extending asset life, and reducing the risk of water main breaks.

Water faucets leaking

“We are delighted to partner with Xylem in promoting our shared vision of applying innovative technologies and strategies to reduce water loss and for pro-active management of water and wastewater pipeline infrastructure,” said Jack Elliott, President and CEO of Pure Technologies Ltd. “Pure has been active in these countries for several years and has established a reputation for technical excellence, value and integrity.  Xylem’s strong presence in these countries will help to grow the market for Pure’s solutions.”

“We are excited to be working with Pure in this new collaboration, which will help us reach even more customers with critical solutions,” said Patrick Decker, President and CEO of Xylem. “It is a natural extension of Xylem’s strategic focus on driving growth in the emerging markets and offering smart water technologies to better meet our customers’ immediate and emerging needs.  This collaboration expands our growing partner ecosystem and helps us create value for our customers and other stakeholders by leveraging our global distribution network.”

Pure and Xylem will be hosting joint workshops in the regions over the next few months to introduce the collaboration to water agencies, industrial water users and regulators.

About Xylem

Xylem (NYSE: XYL) is a leading global water technology company committed to developing innovative technology solutions to the world’s water challenges. The Company’s products and services move, treat, analyze, monitor and return water to the environment in public utility, industrial, residential and commercial building services, and agricultural settings. With its October 2016 acquisition of Sensus, Xylem added smart metering, network technologies and advanced data analytics for water, gas and electric utilities to its portfolio of solutions. The combined Company’s nearly 16,000 employees bring broad applications expertise with a strong focus on identifying comprehensive, sustainable solutions. Headquartered in Rye Brook, New York with 2016 revenue of $3.8 billion, Xylem does business in more than 150 countries through a number of market-leading product brands.

About Pure Technologies Ltd.

Pure Technologies Ltd. is an international asset management, technology and services company which has developed patented technologies for inspection, monitoring and management of critical infrastructure around the world.

Gateway of The North City of North Bay

On one hand, it may seem like a waste of capital dollars if you perform a pipeline condition assessment and the final analysis turns up no leaks. Alternatively, you can also look at the no-leak report as a good news validation story, especially when using the information to help establish an asset management plan.

Such was the case for a city of 51,000 situated between the shores of lovely Lake Nipissing and Trout Lake in Northern Ontario.

In September 2016, the  City of North Bay (City) retained the services of Pure Technologies (Pure) to perform a two-phase condition assessment on the Marshall Avenue Force Main (MAFM). The MAFM is a critical 508mm (20-inch) asbestos cement pipeline that services approximately half the city, and transfers wastewater from the Marshal Avenue Pump Station to the North Bay Sewage Treatment Plant.

Aerial picture with sewer map

The City was interested in exploring technologies to help them better understand the actual condition of their force main in order to implement a comprehensive asset management program using the inspection data.

To assist in the assessment, Pure Technologies elected to first conduct transient pressure monitoring, followed by a SmartBall® inspection to acoustically identify and locate leaks and pockets of trapped gas along the pipeline.

Transient pressure monitoring helps understand structural integrity of the pipeline

First, transient pressure monitors were installed at the pump station discharge header. For approximately six weeks, the recorded pressure data was used to understand the operational and surge pressures within the force main and their impact on the structural integrity of the pipeline.

When pipe wall degradation is combined with surge pressures, the likelihood of pipe failure can be significantly increased.  Evaluation of the pump station operation, such as pump start-up mode, typical and peak flows, operating and surge pressures, and surge protection, can provide important information on the stress.

SmartBall with its controls and tools

SmartBall tool provides acoustic signature related leaks and gas pockets

While transient pressure data was collecting, Pure deployed its proprietary SmartBall technology, a multi-sensor tool used to detect and locate the acoustic signature related to leaks and gas pockets in pressurized pipelines. The tool has the ability to inspect long distances in a single run, and while the SmartBall is deployed, the pipeline remains in service, limiting disruption to customers.

Unlike traditional listening tools like correlators, which have limited success on large diameter pipes, the free-flowing SmartBall technology provides a high degree of accuracy, since as the ball rolls inside the pipe, it can inspect every inch of the main to detect leaks and gas pockets.

From insertion to extraction, the SmartBall inspection took a little over four hours, with no unexpected events as anticipated during the planning stage.

SmartBall functionality chart

Results lead to effective management of finances and risk

Based on the inspection data, Pure analysts reported zero (0) anomalies characteristic of leaks, and 13 acoustic anomalies characteristic of pockets of trapped gas, mostly around air valves.  In particular, gas pockets are of significant concern in force mains, 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.

Gas pockets combined with pressure transients can have significant impact on the pipeline, as vacuum conditions may be created. This can cause cavitation at the gas pocket as the transient gas passes, increasing stress on the pipe wall and therefore increasing the risk of failure if the structural capacity has been compromised.

City considering adding more air valves to help expel collecting gas

Based on a hydraulic evaluation of the pipeline, structural fatigue was not a concern, although test pits were recommended to determine asbestos cement thickness and gas pocket mitigation using swabs also recommended. In the near term, the City is considering adding more air valves to the pipeline to help expel collecting gas.

Overall, the City of North Bay was pleased with the project results, as they were able to understand the overall condition of the pipeline and make an informed decision for capital improvements of the Marshall Avenue Force Main. The project demonstrates how the City uses actionable data to effectively manage their finances and risk, while continuing to provide the community with a safe and reliable delivery of wastewater.

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.

 commissioning of a 50 km AFO system on the Lake Huron Water System’s water main transmission pipeline

Last week, government officials, special guests and educators gathered in London, Ontario to celebrate the successful funding, installation and commissioning of a 50 km AFO system on the Lake Huron Water System’s water main transmission pipeline – a 1200mm diameter PCCP supplying more than 500,000 people in southwestern Ontario.

Optic Fiber inside a pipe and Press Conference

“The project was special,” said Mike Wrigglesworth senior vice-president at Pure. “We love partnering with forward thinking utilities like London Region to save money by using innovative technologies like the AFO system. Instead of budgeting for an expensive replacement program or dealing with disruptive bursts, London Region have saved millions of dollars by actually managing the pipeline.”

The event was covered by the London Free Press, which wrote the following story.

Water supply safeguard comes down the pipe

Now, we can keep an ear out for problems with a pipeline that brings fresh water to London. The city and region took the wraps off a new, fibre-optic cable installed in the water pipeline from Lake Huron to London with an announcement Friday at London Convention Centre.

If that pipe is about to break or leak, new monitoring technology will warn water watchers, preventing a ­rupture.

“We have an acoustic fibre-optic system that allows pipelines to be managed, identifying problems before they become bigger. When a pipeline fails, it is a big mess,” said Mike Wrigglesworth, senior vice-president of Pure Technologies, the Alberta firm supplying the cable.

Staff members behind an open pipe

The $7.5-million project has installed the acoustic cable on a 50-kilometre stretch between the Grand Bend water treatment plant and an Arva reservoir, covering seven municipalities, which are sharing the cost with Ottawa and the province.

The acoustic cable lets staff “listen” to the pipeline for steel wires snapping as the pipe breaks down. There are hundreds of such wires in each section of pipeline.

“One wire breaking in a pipe is no big deal, but 30 or 40 is a weak section of a pipeline,” Wrigglesworth said.

“It can inform which sections of pipe are deteriorating, in real time, and we can be pro-active,” said Wrigglesworth. “We can identify which sections of pipe have a problem and make a plan to repair.”

A repair might cost $75,000, a “huge savings” over the cost of fixing a rupture, which could run to as much as $1.5 million, he said.

The Lake Huron-to-London pipeline has broken twice, in 2010 and 2012.

Under the new system, “We will get an email to say a section of pipe has a break, they even give us the map location of where it happens,” said John Walker, operations manager for the Lake Huron and Elgin area primary water supply, which oversees the regional and city water system.

“At some point, we will have to extend this (acoustic cabling) to Lake Erie,” Coun. Harold Usher said of the city’s other water supply pipeline. “Everything we do in one, we will do in the other. We cannot have farmer fields flooded.”

The $7.5-million upgrade to the Lake Huron-to-London water line is part of $179.1-million in water safety infrastructure investments across Southwestern Ontario. The federal and provincial governments are paying about $50 million each, with municipalities picking up the balance. In all, eight projects will be completed by 2017.

Celebration Cake

In preparing for its water future, the Region of Peel (Peel) adopts a unique assessment strategy for a newly constructed potable water transmission main that extends deep underground through the heart of Peel Region. The effort is paying off, with Peel decision makers gaining a better understanding of this pipeline as it comes into service.

Working on a new potable water transmission main

Peel Water & Wastewater services approximately 1.3 million residents and 88,000 businesses in Brampton, Caledon and Mississauga. The Hanlan Water Project is the largest water pipeline capital initiative ever undertaken by Peel, with a cost of approximately $500 million. The completed transmission and sub-transmission mains included in the Hanlan Water Project will serve Peel’s growth projections for the next two decades.

The project includes 15 km of 2400mm (96-inch) PCCP water transmission main. Construction began in 2011 and is scheduled for completion by 2017. The project is split into three contracts and construction includes both tunnelling and open-cut methods.

Outside and inside a tunnel

Some pipeline sections tunneled in excavated depths of 50 meters

The project is unique from the point of view that the majority of the pipeline will be built under existing infrastructure, with some sections of pipeline tunnelled in excavated depths up to 50 meters (150 feet).

Peel has encouraged the use of technology and innovation throughout this project and has included innovative assessment strategies by Pure Technologies prior to pipeline commissioning. Baseline condition assessment and real-time monitoring technologies have offered value, and peace of mind to Peel managers and decision makers involved with this project.

SoundPrint® acoustic fiber optic (AFO) inside a pipe

Acoustic monitoring versus electromagnetic inspection technology

Pure’s baseline condition assessment includes visual inspection, 3D inertial mapping, electromagnetic (EM) inspection where applicable and SoundPrint® acoustic fiber optic (AFO) monitoring the pipeline during hydrostatic pressure testing of the pipeline. The project includes a continuous monitoring solution once the pipeline is commissioned into service, expected in 2017.

AFO monitoring is an innovative monitoring technology for identifying wire breaks in PCCP pipes. Unlike EM, 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.

By ‘listening’ for wire breaks, pipes that are approaching failure can be identified and rehabilitated. With the installation of AFO technology at the time of construction, Peel ensures active management of their most valuable buried assets, for the life of the asset.

“A snapping wire or two won’t sound an alarm bell,” says Adam Koebel on behalf of the Data Analysis Group at Pure. “But when our monitoring team notices a large number of pings from the wires breaking in a concentrated location, that’s when we focus attention on the acoustic anomalies to determine whether remedial action needs to take place.”

The project was split into 3 contracts with varying scope per contract

The 15 km of 2400mm PCCP project was split into 3 contracts with different general contractors, and complimentary scope per contract.

Pipeline construction along a road

The acoustic monitoring covered a distance of 1,138 meters and spanned a total of 132 pipe sticks. Analysis of the data recorded during the pipeline monitoring found two (2) acoustic anomalies consistent with wire wrap breaks, which amounts to a negligible amount of change or distress. Pure conducted a second (post pressure test) EM scan to confirm the AFO testing and determine the presence of pipe wall distress.

Contract 1 (underway) includes visual inspection and mapping

Pure’s involvement in Contract 1 began in 2016, with a visual and sounding inspection of 5.87 km of the 2400m PCCP pipeline and included identifying potential joint defects and other signs of distress, as well as verifying lay schedule from within the pipe. AFO monitoring will let Peel and their contractor know if any distress occurred during hydrostatic testing.

Contract 3 is on schedule to wrap-up in 2017, while Contract 4 scope of work will include final disinfection and commissioning of the new feedermain.

Once a baseline condition has been established, the AFO system will allow Peel to track the deterioration rate and identify at-risk pipes before they fail.

For Peel, acoustic fiber optic monitoring is like preventative medicine, and as a safeguard, it’s proven to work.

Fiber optic
City of Vancouver from the air

With its Pacific Ocean entranceway and towering backdrop of snow-dusted mountains, it’s no wonder the City of Vancouver ranks among the most laid-back, beautiful cities in Canada, and indeed, the world. Water is in its blood.

This spring the coastal seaport city retained the services of Pure Technologies (Pure) to perform a condition assessment and risk analysis of the Powell-Clark Feeder Main, part of the city’s water system that daily delivers 360-million liters of high-quality water throughout the city. During the course of the assessment, the inspection team had to deal with unexpected challenges, but in true West Coast spirit, collaboration between the inspection teams led to success.

Over five days in March 2016, Pure performed an electromagnetic inspection of the subject pipeline utilizing its free-swimming PipeDiver® platform, and an acoustic inspection using its free-flowing SmartBall® inspection tool. Pure also monitored this feeder main using a Transient Pressure Monitor for three months prior to the previous two inspections.

PipeDiver device

PipeDiver inspection identifies electromagnetic anomalies

The Powell Street Feeder Main is comprised of prestressed concrete cylinder pipe (PCCP), ranging from 750 to 900-mm in diameter. The Clark Drive Feeder Main consists of 750-mm of bar wrapped pipe (BWP).

The PipeDiver electromagnetic inspection covered a cumulative distance of 4.57 kilometers and spanned 676 pipes. 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.

Analysis of the data obtained during the inspection determined that one (1) pipe (less than one percent of the pipeline) in the 750 mm Powell-Clark Feeder Main displayed electromagnetic anomalies consistent with 30 broken prestressing wire wraps. This is well below the average distress rate observed by Pure Technologies in PCCP pipelines, which is 3.8 percent of pipes in structural distress.
SmartBall with case and insertion tools

SmartBall inspection tool used to locate leaks and gas pockets

In addition to the EM inspection, Pure also performed a SmartBall inspection to identify and locate leaks and pockets of trapped gas along the pipeline.

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 a water main to detect leaks and gas pockets.

The SmartBall tool was inserted into the pipeline through a flange access and acoustic and sensor data was collected and recorded as the tool traversed the pipeline. At a distance of 5.8 kilometers, (only 470 meters from the end of the inspection run), the tool stopped tracking.

Crews from the City and Pure put their heads together to solve the problem.

ROV camera shows a tool cart inside the pipe

Collective thinking clears the debris and all is well

By analyzing data from the earlier PipeDiver 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 forgotten tool cart. The cart and SmartBall tool were extracted, the data was evaluated and considered valid, and all was good.

From the SmartBall data, Pure Technologies detected three (3) anomalies characteristic of leaks and zero (0) acoustic anomalies characteristic of pockets of trapped gas.

While no gas pockets were identified during this inspection, 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 gas.

Validated results help the City manage its infrastructure

In spite of the cart debris blocking the SmartBall tool during the last few meters of its long inspection journey, the data collected during the pipeline assessment was analyzed as valid.

When combined with the results from the PipeDiver 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 assessment and management of their infrastructure.

With the deteriorating state of many aging water mains found in cities across North America, urbanites are frequently witnessing unexpected plumes of water erupt as man-made geysers in their own metropolitan backyards.

While natural geysers are awe inspiring, urban geysers are much less so, due to their destruction to property, roads and the environment. Because an uninterrupted water flow is the lifeblood of every well-managed city, getting an early warning on the weak spots within the water network translates into smart municipal business, and can help prevent catastrophic blowouts down the road.

No company understands this reality better than Pure Technologies (Pure), developers behind Acoustic Fiber Optic (AFO) technology that monitors the structural health of PCCP transmission mains. Pure’s near real time AFO technology is now embraced by a growing number of pipeline operators across North America and Asia.

Map of pipeline operators across North America and Asia using AFO technology.

Reasons why water mains crack, leak and burst

Many utilties operate water mains made from prestressed concrete cylinder pipe (PCCP). This pipe consists of a concrete core, a thin steel cylinder, high tensile prestressing wire and a mortar coating. When the mortar cracks, water seeps in and corrodes the reinforcing wire.  As the wire breaks, it creates a weak spot, and as internal water overwhelms the core, the wire gives way and the pipe can burst, often with a geyser-like force.

Pure’s AFO technology monitors in near real time, the structural integrity of prestressed pipe by recording the “pings” or number of wire breaks in each main section.

“A snapping wire or two won’t break the camel’s back enough to sound an alarm bell,” says Adam Koebel on behalf of the Data Analysis Group at Pure. “But when our monitoring teamnotices a large number of pings from the wires breaking in a concentrated location, that’s when we focus attention on the acoustic anomalies to determine whether remedial action needs to take place.”

Koebel stresses that while it may take weeks, months or even years, eventually one extra straw will break the camel’s back and for a pipeline, that last additional cracking wire has the potential to turn a small leak into a large problem.

“Once a baseline condition has been established through electromagnetic inspection, the AFO system allows us to track the deterioration rate and identify at-risk pipes before these fail. It’s preventative medicine, and as a safeguard, it’s proven to work. The fiber never lies,” adds Koebel.

Pure AFO developed to replace limitations of hydrophone array technology

Prior to Pure’s deployment of its first acoustic fiber optic system in 2007, transmission mains were chiefly monitored using cumbersome hydrophone array technology.

This older sonic technology has limitations, especially since the system’s success depends on an array of submerged microphones embedded in the cable, all in functioning order, spaced from 100 to 200 feet apart. That’s the downside – the equipment failure rate is high in a permanent immersion environment, and each hydrophone array has a monitoring distance limited to less than eight kilometers (five miles) of pipeline.

Comparatively, AFO technology is reliable at recording breaking (pinging) wire wraps, since the entire cable is acoustically sensitive from the start of the data acquisition unit to the end of the fiber. An AFO system can monitor 20 kilometers (12 miles) with a single system and 40 kilometers (24 miles) with a dual system. Moreover, Pure’s AFO system can be installed and function whether the mains are dewatered or in service.

Tech working inside a pipe

 

Big boom theory helps promote AFO technology and PCCP management

To address the limitations of hydrophone array technology, Pure’s research and development team set out to develop a better way to improve the accuracy and reliability of pipeline monitoring.  The elusive research effort took seven years, and after consulting with leaders in the field of digital signal processing and acoustic sensing, Pure developed its own proprietary acoustic technology for PCCP environments.

“Based on the operating expense and limitations of hydrophone arrays, selling our new AFO solution was relatively easy,” says Peter Paulson, co-founder of Pure and one of the researchers behind the development of the innovative AFO technology.

According to Paulson, Pure proved the efficacy of their monitoring system during an early test run for pipeline clients.

“At the time, we had set up a demo pipeline operation on our grounds, and in a distant tent we gathered clients around to listen in around a computer screen. One of our test engineers then cut a single prestressed wire from the pipeline located a block away. Because we had amplified the sound print, the immediate resounding “boom” startled the attendees into recognizing that our AFO technology really does work. We built our reputation from there.”

The rest is acoustic fiber optic history. AFO technology is now regarded as the leading standard of PCCP monitoring.

Pure surpasses 1,120 km AFO monitoring milestone

Pure has surpassed 1,120 kilometers (700 miles) globally of active AFO monitoring. Currently within North America and China, Pure is monitoring 56 mains from a combined total of 17 clients. Pure’s active AFO system has recorded more than 43,600 wire breaks from its managed roster of pipelines located in North America and China alone.

For every AFO system, the pipeline data is streamed to a Pure data analyis team who analyze the acoustic information. Any and all wire breaks captured by the AFO system are reported within one business day to the client. If any problem is detected and confirmed, the client is notified and they can then proactively manage their pipeline by choosing how to intervene before serious damage occurs.

Koebel likens AFO data management to road repairs. “Better to repair a pothole than tear up the entire street to find the problem,” he says. “In essence, that’s the value we bring to the table. If clients don’t hear from us that means they’ve got good pipes.”

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.

This notion came to life in a North American survey conducted in 2014 and published online this year in The American Water Works Association Journal on current sustainable infrastructure practices among water and wastewater utilities.

Authored by associate professor Amy Landis, the survey found that of the 125 American utilities that responded, less than half “failed to implement some form of sustainability practice, which ranged from renewable energy to infrastructure repair to demand management. Of the respondents, only 18 percent of utilities reported publishing a sustainability policy or vision.”

Surprising results in spite of critical importance

The results are rather surprising, considering that sustainable water infrastructure is critical to providing the American public with clean and safe water. The American Society of Civil Engineers (ASCE) gives drinking water and wastewater infrastructure a “D” grade, which puts the infrastructure in “poor and at risk” with most of the assets approaching end of service life, some reaching the age of 100 years old or more.

For combined water and wastewater utilities, the most common selected metric to evaluate sustainability practice was “water consumption and/or water delivery efficiency” at 63 percent. Coming in second for sustainable infrastructure practice was “employ trenchless pipe repair and/or rehabilitation.”

Old main

Buried assets are approaching end of service life, some reaching the age of 100 years old or more.

Helping water utilities embrace sustainability

The good news is that it is easier today for public water utilities to move forward on the path to social, environmental, and economic sustainability. Modern inline technologies and precise data analysis tools certainly help the effort.

For more than a decade, Pure Technologies has played a key role in helping progressive utilities follow through with actions to promote sustainable practices for their water and wastewater infrastructure.

Sustainable practices include helping pipeline owners optimize capital and remaining useful life as they seek to more efficiently manage their assets.

As a trusted global leader specializing in the assessment, monitoring and management of pressurized pipelines, Pure has completed structural condition assessment on more than 8,000 miles of critical water mains. This has helped utilities avoid critical pipeline failures that can be expensive to remediate and damaging to their reputation. In addition, Pure has located more than 4,000 leaks on mains using inline leak detection. Through these activities, billions of gallons have water have been saved through repaired leaks and avoided pipe failures.

Pipe Surface Inspection

By understanding the operational conditions in their system, utilities can develop a defensible plan for managing their infrastructure.

Capital savings can be invested back into the system

The numbers continue to impress. Based on Pure’s condition assessment data, we have 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. This is comforting information to utilities with aging pipelines still in operation, as is the case with the remarkable cast iron water main buried in 1831 beneath what is now Greenwich Village.

By identifying and repairing isolated sections that require intervention followed by a long-term management strategy, a utility can realize major capital program savings over replacement or large-scale rehabilitation. On average, a utility owner can proactively manage a pipeline for 5 to 15 percent of the capital replacement cost. The money saved can be invested to fix and sustain other parts of the system.

The U.S. EPA and ASCE estimate the funding costs associated with buried infrastructure ranges from more than $200 billion to 1 trillion over the next 25 years. The numbers are staggering. Pure Technologies is helping utilities manage their buried infrastructure through its Assess and Address™ approach to pipeline management, and as result, has saved clients hundreds of millions of dollars in replacement costs.

Public pressure to do the right thing

With drought, climate change and water conservation now part of the daily conversation, the pressure is on for public utilities to incorporate sustainable practices into their planning. It’s the right thing to do, from an economic, environment and social standpoint.

By having a strong understanding of the risk and operational conditions of different areas in their system, an appropriate and defensible inspection plan can be developed. This process allows utilities to develop a sustainable long-term strategy for managing their infrastructure well into the next century.

Water and sewer utilities across North America are facing a major funding gap related to their buried pipeline infrastructure. Based on current estimates, utilities do not have enough capital available to fix or replace their aging assets. In addition to the funding gap, utilities are under scrutiny because of increased incidences of pipeline failures that are disruptive to communities and expensive to mitigate.

This new reality has forced utilities to squeeze more remaining life out of existing assets, creating more demand for condition assessment programs that allow utilities to identify specific areas of damage and selectively repair pipelines in favor of full replacement.

Historically, condition assessment has been in the realm of a few specialized firms that respond to high profile pipeline failures; however, the industry has changed and condition assessment is becoming widely used and trusted. This approach has been adopted by many utilities that have successfully managed risk and extended the life of assets for a fraction of the cost of a replacement program.

According to a study by Pure Technologies, the majority of pipelines 16 inches and above can be cost-effectively managed for between 5 and 15 percent of the replacement cost. The study found that pipeline damage is typically not systematic across an entire pipeline, but is usually localized due to factors such as design, manufacturing, installation, environmental, operational or maintenance factors.

Equipped with this information, utilities can be assured that assessing the majority of their mains before replacement can reduce their infrastructure gap and extend the useful life of assets.

However, one question that often gets asked about condition assessment programs is how a utility should choose the right condition assessment solution.

The easiest way to solve this challenge is to employ a risk-based approach to condition assessment using a variety of tools that offer different resolutions.

Staff inserting tools

Defining Risk and Pipeline Priorities

Risk is a measure of the probability and consequence of uncertain future events, in this case, potential pipeline failure. A basic approach can be used to define risk even in complex systems; simply, risk is a product of Consequence of Failure and Likelihood of Failure (CoF x LoF).

Consequence of Failure (COF) refers to the damage a failure would cause based on factors like its location, the amount of users it supplies, and its size and operating pressure. Likelihood of Failure (LOF) refers to the probability of a failure occurring based on factors such as age, pipe material, soil conditions, operating pressure, failure history, among others.

Generally, the Consequence of Failure is well defined by the potential damage a pipeline failure would impose on the surrounding environment and is generally fairly static – or – once defined, it is unlikely going to change rapidly.

With this in mind the key to managing risk, or the possibility that a pipeline could fail, is in understanding the Likelihood of Failure. This can be achieved by quantifying the physical condition of the pipeline and understanding and quantifying the factors that affect the potential for deterioration of the assets.

Once risk is defined, the pipeline inventory can be prioritized which helps in the selection of condition assessment approaches and the application of the appropriate technologies. In general, high-risk pipelines warrant a detailed assessment while low risk pipelines can use lower resolution alternatives.

Using Risk to Select Condition Assessment Techniques

When selecting condition assessment techniques, qualifications and technical judgment should be used in lieu of price. High resolution tools come with a higher cost, but saving money on a low resolution condition assessment is not a responsible alternative for a high-risk main.

For example, the savings gained by selecting a low resolution technology for a large-diameter pipeline with a high CoF are often miniscule in comparison to the repair and capital programming decisions that result from the low resolution condition assessment data. If the data is inconclusive or inaccurate, a utility may unnecessarily invest millions in a capital replacement program that was not required, easily eliminating the savings achieved by selecting the less expensive condition assessment option.

Tech monitoring results

Additionally, the cost of a failure should be considered when selecting a lower-cost assessment for a critical pipeline. The average cost of a large-diameter pipe failure is between US $500,000 and $1.5 million; money saved on lower-resolution assessments can easily be negated by the cost of mitigating a single failure and the resulting reputational damage.

One method of selecting a technology is to compare uncertainty to risk. As mentioned earlier, risk is a measure of the probability and consequence of uncertain future events. When dealing with a high-risk asset, it is important that the solution allows the utility manager to minimize the uncertainty of the condition assessment. More importantly, it is crucial that the utility manager knows the condition of the asset to the best extent possible, particularly in areas where there is a high Consequence of Failure.

Pure Technologies has a suite of condition assessment tools with different resolutions. Our low resolution solutions can provide basic condition data on leaks, air pockets and areas of pipe wall stress that could represent damage. This is a valuable prescreening option for high-risk mains, or alternatively for lower risk mains, can be enough detail for a utility to manage the asset.

Pure’s medium and high resolution tools provide more comprehensive data for higher risk pipe. Our high resolution tools can provide detailed accuracy, for example, locating small pits on metallic pipe. The data collected from both medium and high resolution tools is often used by utilities to create rehabilitation plans for critical mains.

Regardless of the solution provider, it is important that utilities employ a balanced, risk-based approach to condition assessment that uses appropriate tools. The most important factor a utility owner can remember is that there is no silver bullet to assess an entire system.

Sewer pipes below a road

A critical component of Queensland Urban Utilities’ sewerage network is a series of large-diameter sewer rising mains – also known as force mains – which are responsible for transporting 50 per cent of raw sewage in the Brisbane area for treatment. The mains are made of mild steel cement-lined (MSCL) pipe and prestressed concrete pipe (PCP), of diameters ranging from 1295 to 1840 millimetres (52 to 74 inches). The reliability of these sewer rising mains are important from both a customer and environmental perspective.

Building upon previous assessments conducted by Pure Technologies’ Engineering Services, Queensland Urban Utilities sought to identify industry best practices for assessing these critical large-diameter rising mains. The goal of the assessment was to understand the current condition of the mains and identify what remedial works or condition monitoring approaches would help maintain the safe operation of the mains, while extending the life of the assets in accordance with management plans.

In consultation with Pure Technologies, a comprehensive assessment methodology was developed which included: SmartBall® leak and gas pocket detection; ground surveys to determine residual ground cover; isolation, dewatering and cleaning of the mains; CCTV and laser profiling to determine internal deterioration; valve inspections; PureEM™ inspection to determine structural deterioration of the pipe walls; internal visual inspection to confirm and further document findings; transient pressure monitoring to identify loading conditions; and an engineering assessment with rehabilitation recommendations.

PureNET Overhead

A customised EM tool was designed to assess the condition of QUU’s
steel pipe.

Field Data Collection

The inspection provided QUU with actionable information about their assets.

 

Related Topics

“Queensland Urban Utilities is keen to embrace new technologies to improve our customer service and the reliability of our water and sewerage network,” says Jonathan Farrell, Design Manager at QUU. “The technical expertise provided by Pure has allowed us to undertake an accurate condition assessment and have the appropriate data to make an informed decision on the current condition of the mains. This will allow us to plan cost-effective, timely upgrades to ensure the asset reaches its design life.”

This was a first-of-its-kind assessment in Australia applying new inspection technologies, including the customisation of a 48-detector PureEM tool, as well as a new risk assessment technique for metallic pipes. Detections from the PureEM inspection (i.e. discrete areas of structural deterioration) were validated utilising alternate electromagnetic and ultrasonic techniques, which provided supplemental condition information for the structural assessment.

Inspection and assessment work on two of these critical mains has been completed at this point. The inspection identified specific pipes along the mains with deterioration; but more importantly, the engineering assessment with structural modeling determined that less than 1 per cent of pipes are at a higher risk of failure, meaning the main is in primarily good shape. This data coupled with engineering recommendations is enabling Queensland Urban Utilities to make informed decisions on the mains, including: selective repair or replacement, condition monitoring, and operational changes (i.e. safe working pressure), all for a fraction of the capital replacement costs.

In addition, the work associated with the assessment has provided Queensland Urban Utilities with some valuable lessons learned on the safe management and operation of the mains.

 

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Cast Iron Pipes

Managing Metallic Pipelines

Pure offers a number of leading edge technology options for assessing the condition of ferrous water and wastewater mains.

Padre Dam Municipal Water District Assesses Steel Pipeline with Advanced Inline Technology

In November 2012, PDMWD wanted to assess the condition of a 1.2-mile (2-kilometer) stretch of 20-inch (500-mm) mortar-lined steel pipeline that was thought to be in poor condition and may need replacement. Before committing to the large capital project, PDMWD completed a non-destructive inline assessment.

Steel Pipes

Steel Pipe

In an article from the August 2013 Issue of Municipal Sewer and Water, the author explores how Baltimore City Public Works (BPW) is managing its again water system using Acoustic Fiber Optic Monitoring and free-flowing electromagnetic (EM) technology.

Abstract

Since the late 1990s there have been numerous inspection and monitoring projects focused on identifying and quantifying wire break damage in PCCP water and wastewater pressure mains. The pressing need to identify and manage deterioration of PCCP has resulted in the rapid development of a small but highly focused niche industry of condition assessment of PCCP mains. During this time, there have been various theories and postulations regarding the performance and deterioration of PCCP mains. This paper statistically reviews data from more than 500 miles of electromagnetic inspection and acoustic monitoring that have been performed since 2001 to develop scientifically based conclusions on a variety of topic areas regarding the performance and deterioration of PCCP mains. Topic areas include:

  • The mean for percent of damaged pipe sections (percent of damage) are reported. The industry has many views on the performance of PCCP. This paper reports the percent of damage by reviewing the total number of PCCP sections inspected and those that were reported as having wire break damage.
  • The percent of damage is further evaluated by the year of manufacture binned according to the various AWWA C301 and C304 versions. This includes an analysis of what is the mean percent of damage for pipe manufactured with Class IV prestressing wire.
  • Percent of damage is also compared between embedded cylinder or lined cylinder pipe to determine if one type of design has an improved performance.
  • Percent of damage is also compared for water (including raw water) vs. wastewater mains

Authors

  • Michael S. Higgins, P.E., Pure Technologies, Columbia, MD, USA.
  • Allison Stroebele, P.Eng., Pure Technologies, Columbia, MD, USA.
  • Sana Zahidi, Pure Technologies, Columbia, MD, USA.

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.

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 the latest issue of Water and Wastewater International ( WWi), Pure’s director of research and development, Xiangjie Kong, participated in the monthly executive technology comparison which features commentary from different industry experts on a specific issue. In this issue, executives provided insight about how utilities can identify and locate leaks in difficult operational conditions.

The most challenging conditions that operators encounter are:

  • Locating leaks on large-diameter transmission mains
  • Inspecting non-metallic mains
  • Leak detection in low pressure mains
  • Challenging operating conditions such as urban areas
AWWA ACE12
Mark Holley

Check out the full article in WWi to find out how operators can overcome challenging conditions using inline leak detection technologies.

Read the full article in Water and Wastewater International »

Kong has led the development of some of the most advanced water pipeline inspection techniques and tools. In addition to publishing over 30 papers in academic and industry journals, he was the co-principal investigator of a research project sponsored by American Water Works Association Research Foundation.

 

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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.

North American utilities are beginning to take notice of aging water and wastewater infrastructure as leaks, consent decrees and critical pipeline failures become more frequent. Coupled with increased service disruptions is an economic climate where large-scale capital projects aren’t possible; utilities are being forced to rehabilitate aging systems within tight capital budgets.

One solution utilities have to address their infrastructure is to manage risk through selective rehabilitation of critical pipeline assets. Through more than 8,000 miles of large-diameter pressure pipe assessment, Pure Technologies has found that roughly 4 percent of pipelines have some level of deterioration, while even less requires immediate attention.

While the logistics – and cost – of full-scale capital replacement is very daunting, pipelines can typically be safely managed for a fraction of this cost, in most cases between 5 and 15 percent. Through the use of condition assessment, many utilities across the United States have been successful in renewing their assets by prioritizing their assets and making the most critical repairs.

In the second of two parts of an interview conducted by Water Online Radio, Pure Technologies Vice President of Business Development Muthu Chandrasekaran discusses how utilities can address their aging infrastructure.

AWWA ACE12
Mark Holley

On the Pure’s Inspection Data:

“We’ve shown many utilities that the majority of their pipelines are in good shape and that they need to address only a few critical pipes,” says Chandrasekaran. “From a risk perspective, it gives them a way to proactively manage that infrastructure, because the cost to replace it is often in the hundreds of millions.”

On how Pure’s solutions work:

“A challenge for many utilities is how they are going to inspect pipelines that are non-redundant,” says Chandrasekaran. “One of the things that Pure Technologies has been good at with our R&D group is finding innovative ways to get tools that can find and get the data the utility needs into a live pipeline and then out of a live pipeline.”

On Pure’s work with utilities:

“We are there to be a trusted advisor to our utility partners, to help them manage their large-diameter pipeline assets. We’ve actually started getting more into the small diameter sector as well, to help them on all of their buried infrastructure,” says Chandrasekaran. “It’s very challenging for utilities with very tight budgets to manage many miles of buried infrastructure. We’ve developed a suite of technologies to help them understand where their problems are occurring and how to mange these assets.”

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.

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.

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 is currently installing Acoustic Fiber Optic (AFO) monitoring on the Cutzamala pipeline in Mexico in an ongoing four phase project that started in 2010.

The initial phase of the project began in 2010 with the installation of about 25 kilometers of AFO, as well as a data acquisition and management system (DAQ) in the Pericos Tank. The second phase, which is currently being completed by the Pure Technologies team, will complete the remainder of the middle portion of the line with 47 kilometers of fiber and a DAQ in the St. Isabel Tank.

AFO technology monitors the condition of prestressed pipe by tracking the amount of wire breaks in each pipe section. The system allows a utility to monitor pipeline deterioration and see at-risk pipes before they fail. The four phase project was organized by priority, with the highest-risk areas of the system receiving AFO first.

Because of a number of failures before the AFO system was installed, the utility became more conscious of their pipeline condition, but realized it was unrealistic and too costly to replace the entire line, leading to the decision to adopt AFO. Since the completion of phase one, the results have been very successful; there has been a lot of acoustic activity on the pipelines, which has allowed the utility to detect and identify distressed pipes and prevent failures.

AFO Installation
AFO Up Close

Phases three and four will be completed in 2013 and 2014. Phase three will install about 30 kilometers fiber from the Torre TO-5 to the St. Isabel Tank with a DAQ in each tank. The final phase will install about 48 kilometers of fiber from the Pericos Tank to the Analco Tunnel, with an additional two DAQ’s.

The Cutzamala pipeline runs from the State of Mexico to the border of Mexico City and is one of the most important transmission mains in the country, supplying water to about 5 million people living in Mexico City. There are two parallel pipelines in the Cutzamala system each about 75 kilometers long.

 

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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.

Pipeline Inspection Services

Pipeline Inspection Services

Our suite of pipeline services give operators information which enables them to implement cost-effective and proactive risk management systems and timely and targeted rehabilitation or replacement programs.

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.

Introduction

Underground pipelines are among the most valuable, yet neglected, assets in the public arena. They provide essential services such as supply of energy and drinking water and collection of wastewater. But we install the cheapest we can, bury it and forget about it – at least until something goes wrong. Then we are faced with having to fix the problem under emergency conditions, often considering only immediate needs and not the future operation of the pipeline in question.

This infrastructure must be seen as an asset, and managed as such. Properly maintained the pipe networks are valuable assets that are critical to delivering services to customers, and in any business the means of connecting product or service to customers is a major link in the business value chain. Not to maintain this network is negligent bordering on criminal.

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

Pipeline operators from around the world are discovering that simply replacing their aging pipeline assets is cost prohibitive and that advanced condition assessment services from Pure can help them confidently make informed decisions that drastically reduce capital and operating costs.

There are many ways in which a pipeline can deteriorate to a state of failure; countless sources of stress both inside and outside the pipe can take their toll.

Single-step blowouts of pipe walls are quite rare; pinhole leaks, hairline cracks, corrosion and leaking gaskets 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.

Pipes at highest risk are typically constructed using dated materials or methods, running through an area with heavily 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.

Older pipes that face stresses such as heavy traffic, construction activity, pressure transients or advanced age are more likely to fail. However there are other factors at work such as installation or material defects that may surface over a shorter period of time. The net result is that age alone can not be relied on as an indicator of a high risk pipe.

Types of pipe material and typical causes 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. Regions 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.

Corroded Wires, Embrittled Wires, Cylinder Perforation

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 not 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.

Tuberculation, Bell Cracking, Longitudinal Cracking, Corrosion

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.

Leadite is a sulphur-based joint-sealing compound commonly used in the 1940s and 1950s that appears to produce pipe failures due to the difference between its coefficient of thermal expansion and that of the metal in the pipes it seals. Leadite in pipe joints expands at a different rate than the pipe itself, causing added stress near the joints. This undesirable behaviour has resulted in particularly destructive joint ruptures on otherwise strong iron pipes.

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.

Abstract

Acoustic monitoring has played a major role in the management of one of the world s largest civil engineering projects. After experiencing failures on their pipeline between 1999 and 2001, the Man-Made River Authority (MRA) undertook an aggressive condition assessment program. This program led to the development of a comprehensive Pipeline Risk Management System (PRMS), making the Great Man-Made River Project one of the best managed pipelines in the world. The planned expansion of the existing acoustic monitoring system, a key component of the PRMS, will allow for monitoring of over 700km of pipeline.

This paper will discuss steps taken to-date, the acoustic monitoring technology and the expansion of this key component to the management strategy for the pipeline.

Authors

  • A. Lenghi. Man-Made River Authority. Benghazi, Libya.
  • N. Amaitik. Man-Made River Authority. Benghazi, Libya.
  • M. Wrigglesworth. Pure Technologies Ltd. Calgary, AB., Canada.

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.