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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

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

From Manure To Modern

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

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

100 Years of Continuous Improvement

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

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

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

With Challenge, Comes Major Opportunity

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

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

Extreme Preparation for Extreme Weather

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

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

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

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

Be Best-In-Class

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

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

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

 

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

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

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

The 4th Industrial Revolution

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

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

Smart Water

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

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

Our Newest Solution

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

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

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

 

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

You’re Not Going to Start with Perfection

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

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

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

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

Utilities need to start asking themselves the following questions:

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

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

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

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

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

 

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

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

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

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

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

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

Project background

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

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

Prepping the PipeDiver tool for the electromagnetic inspection.

Understanding the pipe material determines inspection methods

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

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

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

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

As a precaution, two models of PipeDiver tool assembled

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

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

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

That was good call.

Getting the PipeDiver tool ready for the first insertion.

Sections of pipeline 3 inches smaller than anticipated

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

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

From here, the inspections went off without a hitch.

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

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

A beautiful way to end a successful inspection.

TOSA has a better understanding of their linear assets

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

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

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

Nothing grabs headline news like the failure of a rising main, which can be extremely damaging to the environment and harmful to a utility’s reputation.

Historically, wastewater rising mains have been difficult to manage, especially those made with ferrous materials, where the failure method is slow when compared to concrete pressure pipe. As well, sewer rising mains have special operational challenges that don’t apply to gravity sewer mains as they typically cannot be taken out of service for inspection, and due to the presence of solids in the fluid, rising mains represent a far more abrasive environment than potable systems such that assessment methods for water mains may not be applicable.

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

Gas pockets are of significant concern in rising mains.

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

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

Value of a risk-based approach to manage rising mains.

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

Four steps to a risk-based approach.

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

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

Most common reasons for pipeline failure.

Preliminary analysis.

Preliminary analysis includes collecting the right data to develop a prioritized plan for assessment, including the selection of appropriate technologies. To help make preliminary decisions, Pure collects all available information to understand the history of the pipeline and the likely failure modes. The data analysis will provide an understanding of the construction and context of the pipeline. Data of interest typically includes pipe characteristics, installation factors, environmental and performance-related data, operational data, and failure data.

Acoustic-based SmartBall® tool locates leaks and gas pockets

Acoustic-based SmartBall® tool used to locate leaks and gas pockets.

Sahara is an inline tethered tool that can locate leaks and gas pockets.

Internal corrosion potential survey.

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

Pipe wall assessment.

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

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

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

Condition assessment analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

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

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

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

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

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

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

The mains assessed were constructed of steel in the 1960s

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

First step: gathering condition assessment data.

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

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

24-Detector PipeDiver tool

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

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

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

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

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

Challenges included nighttime work with traffic control and rain.

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

Project challenges included non-existent lay sheets. 

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

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

Testing the PipeDiver through a butterfly valve

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

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

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

Damaged pipe

Pipe damaged from suspected backhoe bucket teeth during previous excavation.

Two pipes excavated to validate inspection results.

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

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

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

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

Excavated pipe

Two pipes were excavated to validate results.

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

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

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

 

 

Tethered inline inspection tool helps European city determine condition of steel pipeline unused for more than 4 decades.

Bilbao is an industrial port city in northern Spain, surrounded by famous green mountains. The metropolis, where more than a million people live, is also famous for the Guggenheim Museum Bilbao, the curvy, titanium-clad building that sparked a downtown revitalization when it opened in 1997.

Recently the city’s utility, Bilbao Bizkaia Water Consortium (BBWC), sparked interest in a possible revitalization program for a segment of its pipeline infrastructure that it had inherited. This involved the inspection of an older steel pipeline that had remained non-operational for more than 40 years.

In July 2017, Pipeline Infrastructure, consultant to Bilbao Bizkaia Water Consortium, decided to conduct a non-destructive evaluation of the utility’s Venta-Alta-Ollargan-Etxebarri Pipeline that had been unused since the 1970s. The utility wanted to use Pure Technologies’ tethered Sahara® acoustic platform for a leak and air pocket inspection to determine the current condition of the pipe wall.

Although not planned initially, owing to the effortless inspection of the Venta-Alta-Ollargan-Etxebarri Pipeline, the crews mobilized for an additional Sahara inspection at the Venta Alta Treatment plant, and the following day, a survey on 600 meters of a 500mm diameter reinforced concrete pipeline located in Portugalete. This pipeline traverses under the Bilbao River near the famous Vizcaya suspension bridge.

“We were pleased with the overall Sahara inspections, and all teams collaborated closely to inform us of the tool’s progress. Now that we know the current state of the pipelines, we can optimize our budgets to make better asset management decisions.”

Ángela Ríos Somavilla, Consorcio Aguas de Bilbao Bizkaia

Sahara inspection

Crews setting up to install the Sahara tool and then track its progress.

About the Venta-Alta-Ollargan-Etxebarri pipeline.

Once a critical main within the city’s linear network, the Venta-Alta-Ollargan-Etxebarri pipeline had been decommissioned for more than four decades. Constructed of steel, with an interior epoxy coating, the 1200mm diameter pipeline is more 3,000 meters in length.

The Bilbao Bizkaia Water Consortium sought assistance to assess the condition of the pipeline to determine the possibility of its operation again to deliver surplus water during the storm season for use in the generation of electric power at a nearby Hydro plant.

Due to the age of pipeline, and the fact that it was non-operational for over 40 years, BBWC was interested in locating any possible leaks in order to plan a defensible course of action.

Based on the inspection results, BBWC would then determine if it was necessary to design a new pipeline or opt for continuous rehabilitation. The other option, if feasible, would be to repair any defects in a timely manner to ensure the proper operation and safety of the pipeline, all the while making informed capital decisions.

A lot was at stake, which was why the inspection was so critical to BBWC.

Sahara is an inline tethered tool used to locate leaks and gas pockets without disruption to service.

Tethered Sahara technology accurately locates leaks with sub-meter accuracy.

To ascertain the condition of the line, BBWC selected the Sahara leak detection platform  for the inspection, conducted over three days with seven insertion points along the affected pipeline. Sahara is an inline tethered tool that can assess pipelines 152mm and larger, without any disruption to service.

Propelled by a small parachute inflated by the product flow, the tool requires a flow velocity as little as 0.3 m per second to progress through a water main. From a single insertion, the tool can travel more than one kilometer if flow, pressure and pipeline layout allow it.

Because the sensor tool is tethered, an operator can stop and reverse the tool to investigate acoustic events such as leaks, gas pockets and visual anomalies. At the same time, an above-ground operator locates the sensor above ground.

Much of the pipeline traverses an urban environment.

Pipeline commissioned exclusively for inspection.

The mothballed Venta-Alta-Ollargan-Etxebarri pipeline was commissioned exclusively for the inspection, which took 3-4 hours to fill and bring up to pressurize again. BBWC initiated a flow rate of 650 l/s and 700 l/s in order to obtain a flow velocity of approximately 0.6 m/s. enough to propel the Sahara sensor. Pressure varied between 1.2 and 2 bars.

As mentioned, owing to the early completion of the Venta-Alta-Ollargan-Etxebarri inspection, crews then mobilized to perform two additional surveys, one day at the Venta Alta treatment plant and the following day on the reinforced concrete pipeline than runs under the Bilbao River.

During the entire five-day survey, the Sahara mobilization crews kept in constant contact with BBWC, accurately communicating the inspection time, depending on the length of each of the pipe sections, number of fittings, access difficulty, etc. in order to the limit the supply and avoid the unnecessary waste of water.

While the crews faced some challenges, overall all three inspections were successful, and went off without a major hitch.

Inspection results prove that for most pipelines, age does not matter.

Analysis of the acoustic data identified no new leaks along the 2800 meters of inspected Venta-Alta-Ollargan-Etxebarri pipeline. For a pipeline decommissioned for over 40 years, the line is in surprisingly remarkable condition.

Three leaks were identified on the reinforced concrete pipeline, all located under the river. Knowing the current state of the pipelines, Bilbao Bizkaia Water Consortium can now make informed capital decisions on whether to repair or rehabilitate the lines. Knowledge is power.

 

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

This preeminent steel producer is a North American leader in advanced steel manufacturing technology. Typical to most steel processing plants, this mill uses recirculated water for a broad variety of purposes, including cooling the blast furnaces, quenching slag, and drawing heat from the overall hot plant environment.

Project Details

Services
PureRobotics® electromagnetic condition assessment
PureRobotics® HD-CCTV inspection
Risk assessment and prioritization
Single day mobilization and inspection
Timing
2015
Pipe Material
Lined Cylinder and Embedded Cylinder Pipe (Types of PCCP)
Inspection Length
0.68 miles
Diameter
48-inch & 54-inch
Transmission Type
Recirculating Water

Project Highlights

0.68 miles (1.09kms) total distance inspected

117 pipes inspected

31 pipes with broken wire wraps

25 repaired and replaced pipes

Challenge

The lines used for recirculating water play a critical role in the operation of a steel plant. When the mill scheduled a brief operational shutdown, they wanted to quickly understand the true condition on a section of their return and supply lines in order assess and prioritize risk and rehabilitate any problem pipes.

On June 2015, the steel mill engaged Pure Technologies Ltd. (Pure) to conduct a non-destructive evaluation of the prestressed concrete cylinder pipe (PCCP) sections in the 48 inch Recirculating Water Return (RWR) and the 54-inch Recirculating Water Supply (RWS) Lines.

The inspected portion of RWR Line is composed of single wrap lined cylinder pipe (LCP). The inspected portion of RWS Line is composed mainly of single wrap embedded cylinder pipe (ECP) without shorting and a short section of single wrap LCP. The pipes were manufactured in 1981.

Pure Technologies previously inspected the 48-inch RWR Line in July 2009 and January 2010 and the 54- inch RWS Line in January 2010. To facilitate a direct comparison between past and current inspection results, the data from the 2010 inspection was reviewed to ensure data analysis continuity.

Solution

The purpose of the single day inspection was to locate and identify pipes that have broken prestressing wire wraps, using Pure’s electromagnetic inspection technology. An electromagnetic inspection provides a non-destructive method of evaluating the baseline condition of the prestressing wire, the structural component that provides the pipe’s strength.

Since the line was dewatered, the survey requirements would also include a visual inspection, which led Pure to recommend the tethered PureRobotics platform, as it is equipped with a high definition CCTV camera to deliver a live video stream from inside the pipe.

The robotic transporter is designed to carry a variety of sensors and tools and can travel a total of 2.9 kilometers from a single point of access. With the new generation of robot, the speed is doubled to 85 feet per minute, which greatly improves efficiency in the field, a huge benefit during time-critical shutdowns.

The inspection went off without a hitch, as crews from the plant had earlier prepped all access points. Pure simply set up a tripod with a chain fall, and lowered the tethered robot through a manhole into the pipe to begin the inspection journey.

Results

Overall, the survey was a low effort, little disruption inspection, conducted in less than a day.

The inspection covered a cumulative distance of 0.68 miles and spanned a total of 177 pipes.

Of these pipes, 25 are replacement pipes or have been previously repaired using carbon fibre.

Analysis of the data obtained during the inspection determined that out of the remaining 152 pipes, 8 pipes in the 48- inch RWR Line and 23 pipes in the 54-inch RWS Line displayed electromagnetic anomalies consistent with prestressing wire damage, ranging from 5 to 40 broken wire wraps.

With the actionable information delivered by Pure, the mill was able to learn about the current condition of their critical assets, and strategize rehabilitation and repair initiatives that meet the goals of their production. In the end, effective asset management using the latest tools and strategies helps reduce costs through targeted spending.

Case Study

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

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

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

Project Details

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

Project Highlights

Inspection identified 13 pipe sections with electromagnetic anomalies

Defects ranged from 20-55% wall loss

Transient pressure monitoring indicated pipeline operating within design capacity

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

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

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

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

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

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

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

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

Case Study

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

Project Details

Services
PureRobotics® electromagnetics (EM) condition assessment

PureRobotics HD-CCTV inspection

Inertial measurement unit for GIS component

Risk prioritization

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

Project Highlights

EM data identified 17 anomalies warranting further investigation

HD-CCTV identified longitudinal cracks consistent with overloading

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

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

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

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

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

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

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

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

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

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

Case Study

The City of Calgary provides water and wastewater services for more than 1 million people in the Greater Calgary area. For many municipalities, accurate and regular condition assessment of large-diameter pressure pipelines has become more important in recent years as these assets continue to age and risk of failure increases.

In Calgary, three critical feedermains (14th Street/North Hillhurst, John Laurie and Top Hill) are each constructed of different materials: lined cylinder pipe (LCP), prestressed concrete cylinder pipe (PCCP) and bar wrapped pipe (BWP). The pipes range from 750mm (30-inch) to 900mm (35- inch) in diameter.

Project Details

Services
PureRobotics® electromagnetic condition assessment

PureRobotics® HD-CCTV inspection

Risk Prioritization

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

Project Highlights

Condition assessment on 2.92 miles (4.7 kms) 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
In an annual condition assessment program, The City inspects its PCCP, BWP and LCP for deterioration. By identifying isolated pipe sections with deterioration, the City is able to make selective repairs in favor of full-scale replacement, which comes at a high cost and may replace sections with significant remaining useful life.

In data collected from more than 14,000 miles of pressure pipe condition assessment, Pure Technologies has found that only a small percentage of pipes (less than 5 percent) are in need of repair and therefore have years of service left. Condition assessment data also suggests that pipe distress is localized, and significant ROI can be achieved by locating and addressing isolated problems through structural inspection.

Solution
To inspect the three feedermains, the City deployed PureRobotics®, a tethered robotic system that delivers live video, and is equipped with electromagnetic technology that can be configured to inspect a variety of pipelines and materials with different operational conditions.

In BWP, the technology identifies and locates broken bars and areas of corrosion on the steel cylinder, which are the main indication this type of pipe will eventually fail. Although BWP looks similar to PCCP in cross section, the 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. PCCP utilizes mild steel for the cylinder, but high strength steel is utilized for the wire, which is wrapped under high tension. 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 type of failure is also much different; PCCP tends to fail suddenly with a large dispersion of energy. This type of failure is less likely in BWP where failures are similar to steel pipe with long periods of leakage occurring prior to rupture. Because of the differences in make-up, BWP and PCCP are inspected using unique methods to determine their structural condition.

Results
Of the 694 pipes cumulatively inspected over the 4.74 kilometers, eight (8) pipes were identified with electromagnetic anomalies consistent with broken prestressing wraps. Additionally, two (2) pipes were found with an anomalous signal not characteristic of broken bar wraps that can be attributed to a change in the pipe cylinder.

Evaluation of the John Laurie Boulevard Feedermain concluded that one (1) pipe was identified to have an anomalous signal likely caused by a non-uniform cylinder. Images obtained from the robot indicated this pipe has damaged internal mortar and exposed cylinder. Additionally, two (2) pipes on this feedermain were identified to have damaged internal mortar and exposed cylinder, but did not contain anomalous signals.

The City of Calgary was pleased with the results, and through condition assessment, has been able to identify and address individual distressed pipe sections on otherwise serviceable feedermains. This has allowed the City to avoid potential ruptures, while increasing service reliability and useful life of the feedermains.

Case Study

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

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

Project Details

Services
PureEM™ manned electromagnetic inspection

Handheld ultrasonic thickness testing

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

Remaining useful life projections using Monte Carlo simulation

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

Project Highlights

Survey covered 917 feet and spanned 125 pipes

12 pipes identified with electromagnetic anomalies

Defects identified ranged from 15 to 35 percent wall loss

Inspection deployed 48-detector electromagnetic tool

Challenge

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

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

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

Solution

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

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

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

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

Results

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

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

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

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

Quote

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

Case Study

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

Project Details

Services
PureRobotics™ electromagnetic condition assessment inspection

PureRobotics HD-CCTV inspection

Structural assessment

Engineering services

Risk prioritization

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

Project Highlights

EM data identified 17 anomalies warranting further investigation

FMWD selected 2 locations to perform test pitting

Results revealed minimal wall loss and continued operation of water main

Challenge

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

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

Solution

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

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

Results

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

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

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

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

Case Study

Evides Watercompany was open to exploring new ways to reduce risks and extend the service life of their buried infrastructure. In particular, Evides wanted to assess the condition of its TL2.60 pipeline, a cement-lined 800mm (31.5 inch) steel pipe, with 2.8 kilometers (1.7 miles) of the inspected pipeline running along an important highway connecting Rotterdam to The Hague.

To assist in the condition assessment, Evides elected to deploy the 24-sensor PipeDiver®, an innovative tool from Pure Technologies designed to assess and address large-diameter metallic pipelines.

Project Details

Services
SmartBall® leak detection

PipeDiver® condition assessment

Timing
2016
Pipe Material
Steel
Inspection Length
2.84 km (1.7 miles)
Diameter
800mm (31.5-inch)
Transmission Type
Water

Project Highlights

 

Four (4)
pipes identified with anomalies

60% wall loss
on one pipe section identified by EM data

Zero (0)
leaks detected

 

HD-CTTV identified
estimated savings due to inspection: 1.1M Euros

 

Challenge
Prior to inspection, Evides created a series of predetermined defects made on a specific pipe segment in a research environment. The objective was to validate the tool against a range of known defects in a pipe with the same characteristics as the pipe inspected. During this process, all defects within the stated sensitivity were detected by the 24D PipeDiver tool at the precise location, providing confidence for the upcoming live inspection.

PipeDiver is a flexible, free-swimming condition assessment tool for pressurized water and wastewater pipelines. The video-equipped tool is ideal for critical pipelines that cannot be removed from service due to a lack of redundancy or operational constraints.

Solution
While PipeDiver has traditionally been deployed on prestressed concrete pipe to identify and locate broken prestressing wire wraps, the 24-detector PipeDiver has been specifically developed for metallic pipelines. For the Evides inspection, the PipeDiver tool with 24 electromagnetic sensors was used to locate and identify steel pipes with anomalies associated with corrosion or reduced wall thickness.

This Evides inspection marked the first condition assessment of metallic pipe using the 24D PipeDiver in Europe, an exercise that confirmed the validity of the tool’s sensor technology and validate once more the effectiveness of the platform to inspect pipelines.

The insertions went off without a hitch, and the PipeDiver sailed through the pipeline obstacle course with ease, gathering EM data along the route.

Results
Of the approximately 237 pipe sections inspected during the real inspection, four pipes were identified with anomalies indicative of cylinder wall loss, ranging between 30 percent and 60 percent. The wall loss defects ranged from 10.8 to 37.7 cubic centimeters (0.64 to 2.30 cubic inches).

After the inspection, three out of the four locations were dug-up to verify the reported defects, using non-destructive ultrasonic techniques. On each of the locations, the defects were found, and the actual material loss was in the range of the reported material loss.

Overall, the results proved the worth of PipeDiver as an advanced condition assessment tool able to deliver precise, actionable data on metallic pipes. The exercise showed the PipeDiver tool as a cost-effective solution versus methods that have operational constraints or require a shutdown or dewatering, or in this case, taken out of service. Evides estimated capital savings of 1.1M Euros as a result of the inspection and repairs.

Quote

“PipeDiver proved to be a suitable tool for one of our most important inspection needs: Corrosion of cement-lined steel pipes. We are especially glad the tool was able to pass a butterfly valve, and to be inserted and extracted through 600mm manholes, as this greatly improves operability and cost effectiveness.”

–Bart Bergmans, Project Manager, Infrastructure Asset Management, Evides Watercompany

Case Study

In 2015, Utilities Kingston retained the services of Pure Technologies to perform a condition assessment on the Dalton Avenue (North End) Pump Station Force Mains.

At approximately 35 years, each asset was entering a critical stage of its life-cycle. The purpose of the assessment was to identify the structural condition of the 450mm and 600mm force mains, both of which are approximately 1,550 meters long and follow a parallel route.

The assessment included transient pressure monitoring, a SmartBall® leak and gas pocket detection survey, and a PipeDiver® electromagnetic inspection of the pipeline.

Project Details

Services
SmartBall® leak and gas pocket detection
PipeDiver® electromagnetic inspection
Transient pressure monitoring
Risk of failure evaluation
Timing
2015
Pipe Material
Ductile Iron, Steel, Reinforced Concrete
Inspection Length
3.05 kilometers (1.9 miles)
Diameter
450mm to 600mm (18 inch to 24 inch)
Transmission Type
Wastewater

Project Highlights

 

3.05 kms cumulative distance of survey

 

1 acoustic anomaly associated with transient gas (SmartBall inspection)

55 pipes with EM anomalies characteristic of localized wall loss (PipeDiver inspection)

 

Zero leaks detected

 

Challenge

The older of the two force mains is 450mm (18-inch) in diameter, constructed of ductile iron built in the late 1950s, and had failed several times over its lifetime. The newer of the two force mains is 600mm (24-inch) in diameter, built from reinforced concrete (RCP) and steel, with two sections of suspected metallic pipe, which was not confirmed in the profile drawings.

As the pipe material specifics were still unknown at the time of the inspection, Pure Technologies elected to conduct a PipeDiver run to accommodate both possible types of pipe material – assumed by all to be bar wrapped pipe (BWP) and prestressed concrete cylinder pipe (PCCP).

Historically, it has proven challenging to assess the condition of pressurized mains that carry sewage, especially those made with ferrous material. Metallic force mains have special operational challenges that don’t apply to gravity sewer systems, and due to the presence of solids in the flow, force mains represent a far more abrasive environment than potable water systems.

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.

Solution

Transient pressure monitors were installed on the header of each force main and for nearly five weeks the recorded pressure data was used to understand the operational and surge pressures within the force mains and their impact on the structural integrity of the pipelines.

Utilities Kingston began the initial force main condition assessment by deploying SmartBall technology, a free-flowing multi-sensor tool used to detect and locate the acoustic sounds related to leaks and gas pockets in pressurized pipelines. The tool has the ability to inspect long distances in one run, and requires only two access points, one for insertion and one for extraction. SmartBall is an effective condition assessment tool for force mains, which don’t typically feature butterfly valves, allowing the SmartBall to roll through the line quite easily, collecting acoustical data.

Following the SmartBall run, UK deployed the free-swimming PipeDiver assessment tool, which travels with the product flow, and utilizes flexible petals to navigate butterfly valves, tees and bends in the pipeline. Originally designed for use in pressurized concrete cylinder pipes (PCCP), the tool has specialized electromagnetic sensors (PureEM) to identify and locate broken prestressing wire wraps, (one of the main structural components and failure modes of a prestressed concrete pipe).

Historically, technologies available to assess the condition of metallic pipe have been limited. This led Pure TEchnologies to develop the specialized PipeDiver for metallic pipes, equipped with advanced electromagnetic technology to identify broken bars in bar wrapped pipe, and localized areas of wall loss in BWP, steel and ductile iron.

Results

In the end, one (1) acoustic anomaly characteristic of transient gas on the 450mm force main was identified with data collected during the SmartBall inspection. No acoustic anomalies were identified within the 600mm force main during the SmartBall inspection.

Of the 650 pipes inspected with the PipeDiver tool, a total of 55 pipes in the 450mm Dalton Avenue Pump Station force main had electromagnetic anomalies characteristic of localized wall loss. These results represent a high percentage of distress along the length of the pipeline and indicate a high risk of failure.

Recommendations included an extended period of transient pressure monitoring as the maximum pressures recorded exceed the 600mm RCP design limitations. Utilities Kingston should also review the pressure reducing valves at the pump station and investigate the operating procedures to determine the cause of the transient pressures.

The fact-finding data collected from both the inspections and transient pressure monitoring gave Utilities Kingston a better understanding of their real, not assumed assets. The results, which included a DIP risk of failure analysis, were used to complete a structural evaluation of the force mains, and have provided Utilities Kingston with actionable information regarding any necessary repairs or rehabilitation.