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Case Study

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

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

THE CHALLENGE

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

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

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

Project Highlights

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

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

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

Services Provided

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

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.

Today, new advancements in technologies and data analytics are helping utilities build asset management programs using a risk-based approach to pipeline condition assessment with the lowest financial impact.

There is no one-size-fits-all approach to assessing metallic pipelines. An approach should be tailored within the context of your risk tolerance while taking into consideration the material, diameter, and past failure history. Many different methods and technologies can be combined to provide data and information to make decisions and prioritize pipelines. The approach can range from do-nothing to a full in-line inspection making targeted repairs and be progressive in nature.

This white paper will highlight:

  • how to develop a risk-based program
  • how to define which of the three approaches to assessing metallic pipe best fits your goals and risk-tolerance
  • how other utilities are finding success using these approaches to: extend remaining useful life, optimize capital expenditures, prevent failures, and increase confidence and level of service.

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.

 

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.

 

 

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

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

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

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

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

Gas pockets are of significant concern in force mains.

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

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

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

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

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

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

Preliminary Risk Analysis

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

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

Acoutic-based SmartBall® tool locates leaks and gas pockets

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

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

Internal Corrosion Potential Survey.

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

Pipe Wall Assessment.

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

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

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

Condition Assessment Analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

 

Case Study

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.

For utilities with large-diameter networks, waiting for failures to occur before repairing or replacing highly critical mains is not an option.

Massive pressured water lleak on a street

With a large amount of buried water infrastructure reaching the end of its service life, operators have every incentive to take a proactive approach to asset management.

Nowhere is this more critical than in busy urban centres. The fallout from an unexpected failure can have major societal costs, and greatly diminish public confidence in the utility.

Asset management begins with condition assessment

Successful asset management begins with condition assessment, the point at which problems and challenges are understood and shaped into definitive plans from both an operational and financial perspective.

To proactively address their pipeline conditions, operators today have access to variety of tools, technologies and engineering analysis that allow for a comprehensive condition assessment of large-diameter pressure pipes, for both water and wastewater systems.

“Unfortunately there is no ‘silver bullet’ with regard to condition assessment technologies,” said Mike Wrigglesworth, Senior Vice President of Pure Technologies. “Each pipeline is unique, and no single technology is the fix for all situations. A combination of factors, from pipe material to soil conditions, operational challenges, age, installation and third party factors will all play a role in the likelihood of failure. Combined with the consequence of failure, a risk-based approach can then be used to select the best condition assessment tool or technologies.”

Matching assessment technology with the pipeline conditions and project goals

While operators can now deploy a number of data-based tools and techniques to assess pipeline conditions, each technology also comes with varying degrees of limitation. For instance, while magnetic flux leakage (MFL) tools provide the highest resolution data for steel pipe, MFL is of limited value for concrete pipe.

Medium resolution techniques such as electromagnetics can identify localized areas of wall loss on metallic pipes such as ductile iron and steel, but not on cast iron pipe as cylinder thickness is often too thick and material properties vary considerably, negatively affecting results. In both cases, it is often prudent to deploy leak detection technologies, as studies show joint defects lead to leaks, and leaks are precursors to failure.

“Often the best solution is to use different but complementary technologies to collect robust condition data that is then evaluated using engineering analysis against a comprehensive risk of failure versus a consequence of failure analysis.”

Sahara® Leak and Gas Pocket Detection

Pure’s proprietary Sahara® inspection platform is a tethered, multi-sensor tool that can identify acoustic-based leaks, gas pockets and visual anomalies in real time, with no disruption to service.

The Sahara tool features a small parachute that uses the product flow to draw the sensor through the pipeline while being controlled from the surface.

SmartBall® Leak and Gas Pocket Detection

SmartBall® is a multi-sensor tool used to identify a variety of conditions in pressurized pipelines. The tool is easy to deploy through existing pipeline features, and travels untethered with the product flow, collecting information.

The tool’s highly sensitive acoustic sensor can locate small leaks and gas pockets, with typical location accuracy within 6 feet (1.8 m).

PipeDiver® Condition Assessment

PipeDiver® is a free-swimming condition assessment tool that operates while the pipeline remains in service.

Originally designed for use in PCCP, the tool has electromagnetic sensors to identify and locate broken prestressing wire wraps. For metallic pipelines, the optimized PipeDiver has the ability to pinpoint localized areas of wall loss.

The tool is also able to deliver video images from inside the pipe.

PipeWalker™ Condition Assessment

The PipeWalker tool provides a viable option for pipeline condition assessment in situations where the pipe is dewatered or where the option to dewater is available.

The tool is equipped with electromagnetic sensors for detecting wire wrap breaks on PCCP pipes and for detecting corrosion on metallic pipes.

PureRobotics® Pipeline Inspection

PureRobotics® is a depth-rated robotic pipeline inspection system that can be configured to inspect pipe applications 24-inches and larger.

Tethered by a high-strength fiber optic cable, the crawler is capable of performing multi-sensor inspections in dewatered pipes or while submerged in depressurized pipes.

The crawler features HD digital CCTV, and can be equipped with electromagnetic sensors, Inertial Mapping, 3-D LIDAR, LASER, SONAR and other tools upon request.

Matching the level of resolution to the risk of the line

While there are a variety of approaches available for assessing a pipeline’s condition, much of an operator’s effort must go into matching the level of resolution of the approach to the overall risk of the line.

The idea is to put the highest resolution technologies on the most critical lines. In the end, the goal of deploying a particular technology (or complementary technologies) is to identify and locate the areas that need rehabilitation or repair as opposed to wholesale replacement of those lines.

Armed with the right information, operators can determine remaining useful life, and confidently move forward to prioritize and target capital spending, while avoiding failures.

Worker joining two pieces of pipe

Using risk-based data analysis and innovative renewal strategies, two US water systems show how utilities can avoid full pipeline replacement, reduce service interruptions, and save money.

As this informative Opflow article discusses, by more precisely understanding the condition of buried infrastructure, water utilities can more effectively focus resources to prolong safety and increase reliability.

Authors: Randy Moore, Travis Wagner, Nathan Faber, Robert Stanley, Buzz Pishkur, Jessie Allen

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.

Massive pressured water leak

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

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

Worker inspecting pipe

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

Single-episode blowouts garner all the attention

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

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

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

Broken water pipe on a street

Age alone does not indicate high-risk pipes

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

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

Broken pipe

Types of pipe material and typical cause of failure

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

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

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

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

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

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

Workers digging with mechanical shovel

Making ongoing condition assessment part of proactive asset management

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

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

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

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

Pipeline owners leverage data to make better decisions

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

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

Targeted testing results chart

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

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

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

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

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

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

Colored candies and broken pipe

Using coloured candies to understand distribution principle

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

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

Coloured candies distribution chart

The more samples, the more certainty in the distribution data

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

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

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

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

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 Baltimore

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

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

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

Broken water mains propel utility to investigate distribution system

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

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

WachsWater Workers

Valve management delivers operational intelligence to mitigate risk

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

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

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

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

Damaged valve

Valve training pays dividends sooner than expected

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

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

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

Baltimore proves its commitment to municipal water stewardship

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

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

Tech analysing data

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

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

Inspection Prototype

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

Electromagnetic Inspector

Electromagnetic technology platforms recognized around the world

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

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

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

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

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

Tech inspecting a pipe with a tool

At Singapore International Water Week 2016, one of Pure`s licencees presented a poster on two acoustic-based technologies (tethered Sahara® and free-swimming SmartBall®) used to locate 674 leaks on large-diameter trunk mains operated by this Malaysia water operator.

Conducted over four months, the in-line inspection and resulting repairs has saved total of 46.7 million liters of water daily. The pipe diameters ranged from 300mm to 2,200mm.

 

SmartBall in-line leak inspection platform

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

Sahara in-line leak detection platform

The tethered Sahara tool includes an acoustic sensor to perform leak and gas pocket detection, a high-resolution video camera to assess internal pipe conditions, and an electromagnetic sensor to identify stress in the pipe wall. Because the parachute-like tool is drawn by product flow and is tethered to a data acquisition unit on the surface, it gives the operator close control to confirm suspected leaks, gas pockets and other pipeline anomalies.

 

Utilities have limited asset management funding at their disposal and yet waiting for failures to happen before repairing or replacing critical water mains is simply not a cost-effective option.

Cities need a working water infrastructure. It’s that simple. The solution, though, has tended to be a lot more complicated. The majority of urban water infrastructures are old and reaching the end of their usage expectancy. In addition, most are buried deep beneath the very cities they service and system-wide pipeline replacement is far too costly. Yet, if those large-diameter pressurized pipelines unexpectedly fail, the consequences can be catastrophic, to the city and the people living there. It can also shake the public’s confidence in the utility, harming its reputation in the process.

The fact is, not all old pipe is bad pipe. The Water Research Foundation Report found that age is not a primary factor for pipe failure. Many buried pipes, well over 100 years old, can still be considered in “like new” condition. Through extensive research and data from more than 14,000 milesof pressure pipeline inspection, we have found that less than 1% of pipes are damaged enough to need immediate repair. And that’s good news for cash-strapped, resource-short pipeline operators.

Unfortunately, there is no “one technology fits all” solution to this problem, which is why the choice of assessment tools is critical. The smartest choice is to deploy different but complimentary technologies that can collect the robust condition data required to evaluate which pipes need repair or replacement and which should be left alone. This pipe-by-pipe approach helps utilities make informed decisions based on assessment results, which in turn can reduce capital costs by as much as 90 percent.

Pure Technologies’ Assess and Address® approach is not only logical, scalable and cost effective, it also provides the highest return on investment.

Beginning with Pure’s risk-based assessment method followed by the deployment of complimentary technologies – like SoundPrint® – we work together with utilities to help facilitate pro-active, cost effective renewal and enduring pipeline management strategies that help keep our cities up and running for years to come.

Hanging rock with a sheep above

Don’t Get Stuck Between a Rock and a Hard Place

City of Belmont Skyline

To help budget over the next 20 years, the City of Belmont (City) wanted to proactively understand and assess their force mains through a comprehensive condition assessment. Located in the San Francisco Bay area, Belmont serves 26,000 residents and maintains more than 90 miles of sewer mains comprising of 85 miles of gravity mains and 5 miles of force mains, of varying size and material.

To address its goal, the City contracted Pure Technologies (Pure) to deploy a wide range of both proprietary and third-party technologies and techniques to achieve a holistic assessment. The risk associated with a failure was significant, owing to a lack of redundancy, difficulty and cost of bypassing flow and potential for severe consequences to public health and the environment.

Pure provided inspection and condition assessment services on eight of the City’s force mains. The project scope included GAP analysis, condition assessmentengineering analysis, and necessary repair or replacement recommendations to establish a long-term management plan for Belmont’s force main inventory.

Variety of solutions and technologies used to assess inventory

A number of solutions and technologies were used to assess Belmont’s force mains. Phase one involved a GAP analysis, performed by interviewing operations staff and reviewing historic information, GIS maps, and drawings.

Phase two included an assessment of the eight force mains through the use of various technologies, including SmartBall® leak and gas pocket detection, SmartBall Pipe Wall Assessment (PWA), soil corrosion survey, hydrogen sulfide monitoring, transient pressure monitoring, and hydraulic evaluation.

SmartBall with extraction tool and controls

SmartBall leak detection is a free-flowing tool used to locate leaks and gas pockets in pressurized pipelines. The tool is equipped with a highly sensitive acoustic sensor that is able to locate “pinhole” sized leaks. Pipeline leaks are of concern for force mains as these emit illegal discharges to the environment and are often found to be a precursor of major failures. In metallic pipes, gas pockets are of significant concern, as hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall.  This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Pipe wall assessment (PWA) is a screening technology for assessing the condition of metallic pipelines by identifying pipe sections with increased levels of stress. SmartBall gas pocket and leak detection services were used for the 8-12-inch diameter mains.

Transient pressure monitoring and hydraulic evaluation used on the smaller mains

Transient pressure monitoring and hydraulic evaluation was used to evaluate the smaller 6-inch force mains. Hydraulic pressure transients occur in pipelines when steady-state-conditions of the system change due to pressure or flow disturbances. It is important to conduct transient pressure monitoring and hydraulic evaluation because damage from pressure transients can include cracking of mortar coating or lining, crack propagation, movement at joints, and structural fatigue.

During the condition assessment, Pure evaluated the likelihood and consequence of failure criteria and developed a scoring system, placing each force main in one of three categories: low risk, moderate risk, or high risk.

Satellite image with location map

For phase three, Pure conducted a life cycle and financial analysis, outlining the potential life and replacement/repair costs for each force main. By comparing results identified in each assessment phase, the City of Belmont can now move forward and create both a short-term and long-term rehabilitation plan.

“Through innovative technology, comprehensive data gathering and analysis, Pure Technologies helped us to assess condition of our large force mains within budget constraints, to help us plan our future capital improvement program…”

Each main evaluated with an overall risk rating

The GAP analysis included a review of all the information given to Pure at the beginning of the project and included historic information, GIS, and some drawings. During this phase, many of the parameters such as pipe length and material were found to differ from what was originally thought through the process of internal inspections and external excavations.

Pure conducted the SmartBall leak and gas pocket detection survey on four force mains and found 21 unique anomalies. The SmartBall PWA discovered seven indications of stress on the two metallic pipelines.  Hydraulic analysis of all eight force mains revealed that several force mains have a nominal increased potential for failure due to significant pressure swings and a large quantity of pumping cycles. Hydrogen sulfide monitoring was performed on six force mains to quantify the potential for internal corrosion caused by hydrogen gas.

Once all tests were completed, each force main was evaluated by its likelihood of failure and consequence of failure, and then given an overall risk rating.

Assessment includes life cycle and financial analysis

By determining overall risk for each force main, Pure was able to complete a life cycle and financial analysis and provide Belmont with the best data available to make long-term decisions on managing their assets. Each force main was given an estimate of its remaining life as well as a financial comparison of different management option costs. The financial comparison took capital replacement costs into account with Pure’s Assess & Address™ approach in both the best case and worst case scenarios. In both instances, the management options showed costs significantly lower than a full capital replacement option.

Using both the data and short and long-term recommendations provided by Pure, Belmont is now fully equipped to make the best possible decision and budget accordingly over the next 20 years, while continuing to address and mitigate risk.

The most common form of pipeline integrity used by oil and gas pipeline owners is inline inspection (ILI). Inspection pigs are widely used to clean pipelines, as well as identify areas of damage along the pipe wall to ensure the safe delivery of energy products.

Historically, once a pig is deployed in a pipeline, a technician confirms the tool’s arrival time at various tracking locations throughout the planned inspection distance. Once the tool has passed each location, it is out of sight until it reaches the next tracking point. However, recent technological advancements in tracking technology now allow for pigs to be tracked remotely throughout an entire ILI run.

Remote tracking combines the use of above ground markers (AGMs) and Remote Tracking Units (RTUs) that are deployed before an ILI run is scheduled to take place and are used to track the pig from a central location. When a pig approaches a tracking site, the RTU and AGM are activated to track the tool, which eliminates the need to have a field technician to be on site.

Consistent Live Tracking

PureHM has developed a web-based software called LiveMap that tracks a pig throughout the entire ILI run. LiveMap provides real-time updates via email or SMS with the pig’s location, speed, and estimated time of arrival to ensure that there is better visibility for stakeholders during a project. This advanced technology mitigates the risk of unexpected challenges in an ILI run, such as a stuck pig or speed excursion.

Live tracking offers more control throughout an inspection, and can help prevent costly incidents such as lost pigs by providing accurate information on a pig’s location. A lost pig can interrupt or stop product flow in a pipeline, and can lead to pipeline damage and unforeseen service disruptions.

LiveMap drawing

During an ILI run, the time and speed information collected each time the pig passes the AGM is updated and presented in LiveMap. In traditional legacy tracking runs, this is completed and reported by the field tracker, while in remote tracking runs this is completed automatically with a defensible record of the passage.

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

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Traditional methods of wastewater condition assessment focuses almost exclusively on the gravity system and valve
actuation, using tools such as smoke testing, CCTV, and zoom cameras. While effective on gravity mains and valves,
these methods are not applicable in force mains.

Inspecting force mains is more challenging due to lack of redundancy, lack of access points, cost, technology limitations, while the consequence of force main failures can be significant financially, environmentally and socially.

A successful wastewater asset management program uses a holistic approach which prioritizes the entire system, collects data through condition assessment and provides analyzed reports in order to develop a targeted, informed action plan for long-term sustainability of a collection sewer system.

City of Saskatoon

While pipeline management may seem unaffordable, understanding the condition and targeting repair provides an alternate approach to wholesale replacement and allows operators to accomplish the same de-risking effort with less money.

The City of Saskatoon operates more than 100 kilometers of water mains (400 mm diameter and larger) within the Water and Sewer Preservation Group.  The City has an extensive water main break database dating back to 1959, which assigns a condition rating to water main segments. These ratings are useful for evaluating small diameter local lines where the consequence of water outages are low, and a “run to failure” strategy is acceptable.

For large diameter transmission water mains, waiting for failures to occur before repairing or replacing highly critical mains is not an option. A proactive approach to condition assessment is needed.

“The benefits of accurate condition data can be significant,” says Stephen Wood, P. Eng. Water and Sewer Preservation Manager for the City.  “Allocating limited maintenance and replacement funds on the correct locations is crucial and this is impossible without good condition data. However, obtaining condition data on highly critical, non-redundant, pressurized water mains can also be costly. For this reason the City set out to determine where to focus its condition assessment efforts.”

First priority: where to start?

To help Saskatoon better understand its network and overcome its particular challenges, the City partnered with Pure Technologies to help answer the questions: where do we start in prioritizing our pipelines based on Risk, and what strategy should we implement moving forward?

Straight capital replacement is unaffordable. The City recognized the need to set up a risk framework in order to evaluate its highest priority pipelines first, rather than looking at a pipe based on when it was installed.

Pure proposed a data driven, risk-prioritized approach to managing the critical buried infrastructure. The City and Pure worked closely to develop a systematic approach with specific tasks to implement a pipeline risk prioritization plan.

1. Collect existing data and provide a “gap analysis”

Prior to the project, existing information was collected and reviewed as it related to the pipeline assets. Pure looked at maintenance records and compared existing information with what is necessary to develop the preliminary risk assessment and ultimately the condition assessment of each asset. This “gap analysis” provided a summary of the available information related to the pipelines as well as what is not currently available.

At the same time, additional pipeline attributes were gathered, including existing information on material, diameter, failure history, previous rehabilitation, hydraulics, soil sampling, etc.

Risk graphic and aerial map of water main conditions

(Left) Circle size represents the total pipe length under each risk category.
(Right) Aerial map of water main conditions by neighbourhood.

2. Define risk category and establish relevant risk factors

Pure adopted a logical approach to quantify risk as the product of likelihood of failure (LoF) index and consequence of failure (CoF) index. Relevant risk factors were selected after learning the historical pipeline behavior and data availability. Each factor was assessed by a score value between high (5) to low (1).

3. Compute the risk analysis

Based on the metrics of consequence of failure, likelihood of failure scoring and layered with risk mitigation factors, Pure performed a risk computation using PureNet in-house software to determine the highest risk pipes and recommend the inspection technology.

4. Calculate pipeline and neighbourhood risk

Pure had the ability to look at a single line and plot it into risk zones node to node, feature to feature, and within set neighbourhood parameters. The risk zones recognize that pipelines do not deteriorate on a uniform basis. By aggregating the data by neighbourhood, the risk prioritization can help decision makers plan and target regions, facilitate scheduling, maintenance and repairs, and better communicate with stakeholders.

5. Model budgetary needs for different management scenarios

Through the exercise, Pure gave the City a static risk picture to provide a baseline look at the system, as well as a plan to forecast risk and establish appropriate budgets for multiple management strategies.

Pure developed a 50-year pipe replacement plan that systematically replaces pipe based on risk priority up to the available budget in a given year.

“Allocating limited maintenance and replacement funds on the correct locations is crucial and this is impossible without good condition data.”

Replacement model versus condition assessment model

The replacement model offers limited coverage due to the high replacement costs from replacing entire pipe segments at a time. In comparison, the condition assessment model can achieve greater coverage for lower cost due to its unique methodology.

The condition assessment strategy is an approach where a program is developed that systematically inspects pipe based on risk priority and only addresses damage where needed. Under this program, pipelines are screened for repair or replacement depending on current condition of individual pipes. The provision of additional knowledge allows only the worst of the pipes to be addressed and avoids the premature repair or replacement of those pipes still in good condition.

What’s next?

“The results of the report give us a clear indication of the benefits of condition assessment along with a priority list for addressing our highest risk locations,” says Stephen Wood.  “The next step is to put the plan into action. We are currently working on developing a project for 2016 that will provide a condition assessment of approximately 2.5 kilometers of our highest risk water mains.”

Utilities Complete Condition Assessment Of Bar-Wrapped Pipe With Smartball®, Pipediver®, And Robotic Platform Tools

By the early 1940s, cast iron pipe was losing its historic cachet as the go-to material for new buried infrastructure. Cast iron’s replacement was bar-wrapped pipe (BWP), and it quickly gained acceptance as a reliable, durable and cost-effective pipe material for use in large-diameter transmission and sewer force mains.

Typically, BWP consists of a welded steel cylinder with reinforcing bars wrapped around the cylinder to provide strength. An internal concrete lining and external mortar coating provide corrosion protection to the steel components. The watertight membrane enables the composite pipe to withstand high internal pressures and the effects of external earth and traffic loads.

Until recently, BWP condition assessment proved difficult

Despite early adoption from many pipeline operators, the downside to BWP has been the difficulty to assess the pipe’s condition, where failures are often precipitated by deterioration of the reinforcing bars and long periods of leakage that often go undetected.

It’s now 70 years later, and the methods to assess the condition of bar wrapped pipe have only been recently developed and commercialized. On this forefront, Pure Technologies is recognized for its toolbox of condition assessment technologies that can identify broad areas of cylinder corrosion and bar breaks.

Two Texas cities join forces to assess shared BWP water supply line

In one specific case, the city of Irving and a partnering agency in North Texas joined together to initiate a condition assessment project of their shared water supply line, made up primarily of bar-wrapped pipe. Constructed in 1955, the 48-inch Jamison Water Transmission Main is a critical non-redundant pipeline that conveys potable water to a combined population of 400,000 residences within the Dallas Fort-Worth Metroplex.

The two agencies worked side by side to implement an Assess and Address™ pipeline inspection protocol to determine the condition of the pipeline and to increase the utilities’ reliability of water delivery.

The condition assessment utilized inline acoustic leak and air pocket detection, robotics with high definition CCTV and enhanced electromagnetic detection, transient pressure monitoring and non-linear Finite Element Analysis (FEA) of the steel cylinder corrosion and broken bar wraps.

The results concluded that 97 percent of the 583 pipes inspected had no detectable damage. Less than 3 percent of the total pipes inspected exhibited minor distress, of which 15 (2.5 percent) pipes exhibited thinner steel cylinder.

Through close collaboration, the two agencies were able to effectively manage a shared asset with the goal of preventing disruptive and expensive pipe failures. The information gained from the assessment will allow for the implementation of a cost-effective, long-term management plan to extend the life of the pipeline.

Trinity River Authority of Texas (TRA) evaluates 8.8 miles of critical BWP transmission main

In a second case involving BWP, Pure collaborated with Trinity River Authority on assessing the condition of a pipeline that is a critical link in the reliable delivery of drinking water to five cities within the Dallas-Fort-Worth Metroplex. The aging pipeline was scheduled for replacement due to previous failures and inability to be removed from service for repairs.

To understand the overall pipeline condition, TRA contracted Pure to inspect and evaluate the pipeline by conducting comprehensive hydraulic, leak detection and condition assessment on 8.8 miles of the 30-inch bar-wrapped pipe.

For the leak and air pocket assessment, TRA used the SmartBall® inspection tool, a non-destructive, free-swimming technology that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. Regular leak detection inspections can help utilities identify leaks that may not be visible at the surface.

Increased reliability, reduced capital costs

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

The inspection of the BWP identified 14 pipes with bar break damage and 72 pipes with electromagnetic anomalies resembling cylinder defects out of 1284 inspected pipes. By repairing specific pipe sections with deterioration, TRA was able to avoid replacing the entire pipeline at a high capital cost and continue providing reliable service to customers in the region.

The Usutu Water Scheme supplies raw water to a number of coal-fired power stations and towns in the Mpumalanga province of South Africa. The bulk water pipeline, completed in the late 1970s, consists of large diameter (DN1300 mm) pre-stressed concrete non-cylinder pipe (PCP) that links two mains for a total of 90 kilometers between the Rietspruit, Davel and Kriel Reservoirs.

Recognizing that the infrastructure might be reaching the end of its lifespan, the Department of Water and Sanitation (DWS) called on SSIS Pipeline Services, which represents Pure Technologies in South Africa, to conduct a comprehensive condition assessment of the pipelines.

Destructing the old to help evaluate the current pipe state

Due to a lack of records, DWS provided Pure with old removed pipes, as well as spare pipes that were destructively evaluated to determine the design specs and calibrate the electromagnetic signal to accurately detect wire breaks.

Every pipeline is unique, and if a utility has a strong understanding of the operational conditions of different areas in their system, an appropriate and defensible inspection plan can be developed, pipe by pipe. Pure came onboard bringing its inspection, risk assessment and engineering analysis services, along with its comprehensive suite of technologies to survey the pipeline for leaks, gas pockets and wire breaks.

Civil Engineering Cover June 2015

Pipediver Field crew operators insert the PipeDiver inspection tool into the pipeline.

Field crew operators insert the PipeDiver inspection tool

Pipediver Field crew operators insert the PipeDiver inspection tool into the pipeline.

Ostrich

Project begins with leak detection surveys

For DWS, Pure and SSIS began with leak and air pocket detection surveys, employing Pure’s proprietary SmartBall™ technology. As the free-swimming SmartBall tool rolls through the pipeline, it collects acoustic data. The acoustic sensor identifies the sound of water leaving the pipeline, or the sound of trapped air at the top of the pipeline, which can reduce the water flow and increase strain on the pumps.

Easy to deploy, the SmartBall tool is an excellent screening tool for PCP inspection programs by identifying leaks and air pockets in the main. These areas provide a preliminary look at the condition of the pipeline.

As a follow-up to the SmartBall survey, SSIS employed its Sahara® platform, a tethered tool with attached audio-video surveys to gain a better understanding of the leak locations along the pipeline. A total of ten leaks were detected and accurately located using SmartBall and Sahara.

PipeDiver™ electromagnetic survey evaluates the pre-stressing wires

Because the Usutu pipelines could not be taken out of service, crews inserted Pure’s revolutionary PipeDiver™ tool, which features collapsible fins that allows it to pass through sharp bends, diameter reductions and butterfly valves as it is carried by the flow of water.

The free-swimming PipeDiver inspection platform uses electromagnetic (EM) sensors to evaluate the existing condition of the pre-stressing wires. EM inspections collect a magnetic signature for each pipe section to identify anomalies that indicate zones of wire break damage. The presence of wire breaks in concrete pressure pipe is often a sign of impending failure. This inspection method is the best available technology to determine the baseline condition of the PCP mains.

While the PipeDiver survey was performed, the critical pipeline remained in operation. The entire 90 kilometers of pipeline was inspected in three runs, and the inspections found the majority of pipes to be in good condition.

Investigation replaces uncertainty with peace-of-mind risk assessment

In addition to using to the monitoring technologies described above, Pure also conducted a variety of other risk assessment and engineering analysis services for the project.

This included field verification data to compile a calibrated hydraulic model to mime the steady state and transient behaviour of the pipelines. The results showed that DWS’s current operating procedures worked well to control the flow and prevent pressure surges.

Pure Technologies also completed a finite element analysis (FEA) to quantify the structural ramifications of the broken pre-stressing wires detected by electromagnetic inspection. This analysis was used in tandem with the electromagnetic inspection results in the risk assessment.

DWS sets a good example for managing its transmission main assets

The project highlights the value of embracing a proactive pipeline condition assessment programme using best practices, expertise, and cutting-edge technology.

The investigation confirmed the asset life can be extended, while managing DWS’s exposure to risk and sets a good example for other South African utilities to follow in developing a sustainable long-term strategy for managing their asset

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A ruptured sewer pipe can attract a lot of unwanted attention, even when it happens on private property. Last year, hours before celebrities were to arrive at the Golden Globes Awards show at the Beverley Hills Hotel, a reputed sewer pipe burst, spewing a mess of wastewater on the red carpet, according to media reports. When large pipes fail, it’s usually breaking news. And when the failed pipeline is part of a pressurized wastewater force main network, repercussions to the environment and the public have the potential to be catastrophic, with fallout to a utility’s reputation. In Canada, pressurized force mains that carry sewage make up only about 7.5 percent of the typical wastewater system compared to gravity mains. Because sewer force mains tend to run constantly, and often operate without redundancy, there is little opportunity to assess the pipes. When problems arise, and a critical force main is out of commission, the entire wastewater system can stop, causing overflows or the need to implement costly bypass pumping. Worse still, pollution generated by a raw sewage leak can flood to the surface and into a watercourse. Clean-up costs can be staggering and environmental impacts can be devastating.

PureRobotics device

The PureRobotics platform can assess the structural integrity of force mains and provide inline video to observe internal pipe conditions.

Force mains have unique signs of impending failure

Internally, force mains have unique warning signs of failure. Because of the sewage flow, trapped gas pockets can allow concentrations of hydrogen sulfide gas to be released from solution and subsequently convert to sulfuric acid by bacteria on the pipe wall, leading to corrosion of the pipe wall. As the pipe wall corrodes internally, it becomes weaker and more likely to fail unexpectedly. While corrosion and defect failures on sewer pipelines are a fact of life for wastewater utilities, these failures do not occur systemically. As a result, knowing when to replace and when to preserve assets through close inspection is more critical than ever.

SmartBall with extraction tool and controls

Managing force mains proactively can help utilities prevent environmental regulation violations that are expensive to mitigate.

Addressing the high consequence of failure in wastewater pipes

Aging pipes, increasing costs of failures and high replacement costs represent significant challenges facing force main owners. As a result, utilities have come to rely on Pure Technologies for its suite of technologies that can identify the weak links. Selective rehabilitation of force mains maximizes the life of the asset, typically at 10-15 percent of replacement costs. Pure’s strategy employs a risk-management approach that looks at likelihood of failure (LOF) and consequence of failure (COF). LOF variables are related to the chance that a pipe could fail, and include: pipe age, material, operating conditions and soil conditions, among other things. COF variables may include the pipe size, its location, environmental and social consequences of a rupture, interruption to service and tarnished public reputations.

Low risk assessment

For low risk force mains, screening and desktop evaluations such as hydraulic analysis and pressure management within the system are often enough to manage the assets. As risk goes up, however, utilities should look at higher resolution technologies that offer more confidence for higher predictability.

Medium resolution assessment

The SmartBall® Pipe Wall Assessment (PWA) tool is Pure’s best technology for identifying leaks, gas pockets and wall stress locations in metallic sewer force mains. PWA technology looks at pipeline walls affected by loading and bedding conditions, as well as other factors that cause stress on the pipe, including structural damage caused by internal or external corrosion. As the free-swimming SmartBall tool rolls through the pipeline, it collects both acoustic and electromagnetic (EM) data. The acoustic sensor is used to identify the sound of wastewater leaving the pipeline, or more often, the sound of trapped gas at the top of the pipeline. Trapped gas within a force main may lead to internal corrosion and eventual breakdown of the pipe wall which is the primary cause of force main failures. In addition to the acoustic data, the SmartBall platform also collects EM data to identify areas of the pipe wall that are under stress. Areas of the pipe wall with damage will be under more stress than areas with limited or no damage. Stress on the pipe wall can also be caused by other factors such as excessive loading and hard bedding surrounding the pipe. Recent developments in SmartBall technology now allow for the combination of leak and gas pocket surveys with PWA surveys in a single deployment, providing a complete screening tool for force mains. Based on initial surveys using the SmartBall PWA tool, areas where gas pockets overlap with stress anomalies represent the largest area of concern of force main owners, as it indicates a high likelihood of corrosion.

High resolution assessment

In force mains with a higher risk, utilities should also consider assessment with a higher resolution tool in addition to a pre-screening survey that detects anomalous changes. For lines that cannot be taken out of service, Pure can deploy the PipeDiver tool, which uses electromagnetic sensors to detect areas of damage along the pipeline. The inline inspection system is an innovative, free-swimming condition assessment platform specially designed for in-service inspection of pressure pipelines. Configured with PureEM™ sensor arrays, the tool can be used with precision to identify wire breaks in PCCP and broad areas of cylinder corrosion in metallic pipe.

No one solution for every pipe or pipeline

While there is no silver bullet for assessing every pipeline, if a utility has 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 force main owners to develop a sustainable long-term strategy for managing their critical force main assets.

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

Comprehensive condition assessment of wastewater force mains provides significant challenges to owners/operators of collection systems as the ability to shut down or expose the pipeline for a thorough inspection is often impractical due to operational and/or financial considerations. Traditional gravity sewer inspection techniques (i.e. visual-based technologies) do not always transfer easily to their wastewater pressure pipe counterparts and visual assessments do not provide the structural condition of force mains – something that is critical in determining the true pipe condition. Therefore, a different set of inspection tools and assessment techniques is required for force mains.

The most effective strategy to safely manage a force main inventory is to implement a risk-based approach for any data collection, inspection, condition assessment, and management techniques. Using asset risk to guide the management strategies, an owner/operator can ensure they are implementing the right approach, at the right time, with the lowest financial impact. While recent advances in force main inspection technologies, assessment techniques, and repair/rehabilitation methods now allow for substantial extension of existing asset service life, a risk-based approach to their implementation will ensure resources are focused on the correct pipelines. The goal should always be to focus the proper resources in managing the asset while safely getting the most service life out of the force main.

Authors

  • Travis B. Wagner, Pure Technologies Ltd., Columbia, MD, USA
  • Jennifer Steffens, Pure Technologies Ltd., Atlanta, GA, USA

Abstract

The topics of liability and negligence as they relate to water main failures are discussed from both a historical and current viewpoint. The historical perspective is provided in a 1948 Journal AWWA article, and we consider changes in liability issues from that time to the present. Case studies from various states are also presented that will provide water utilities insights into sovereign immunity and what constitutes discretionary function.

Some of the key findings for water utilities were: that they should understand the laws and relevant legal decisions in their state because each state has its own laws related to how immunity is determined; that even immunity, in some states and or cases may not be the final determining factor that can relieve them from liability for breaks and leaks; that they should implement a written policy or plan to address deteriorating infrastructure; and that they should keep accurate and comprehensive records.

Authors

  • Frank J. Blaha, P.E., Senior Account Manager, Water Research Foundation
  • Peter E. Gaewski, P.E., Retired
  • Paul R. McCary, J.D., Partner, Murtha Cullina LLP
  • Graham T. Coates, J.D., Associate, Murtha Cullina LLP

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.

The most pressing issue surrounding water and wastewater assets is with aging pipelines. While there are many of miles of pipes beneath the ground, the most critical are large-diameter water and wastewater mains, which are often the most valuable asset a municipality owns. These pipelines provide critical services for communities and are beginning to leak and rupture more frequently; not only does this disrupt these vital services but also costs municipalities billions of dollars annually.

While the cost of replacement is high, it is less expensive than allowing these assets to operate until failure. However, for many utilities, it doesn’t need to be all or nothing – the majority of water and wastewater systems can be safely and efficiently managed using a risk-based condition assessment approach.

The primary misconception that many operators have is that the majority of aging pipelines need replacement. This thought process often comes after a critical large-diameter failure, which can cause a negative public perception that the majority of pipe in a system is in near-failing or poor condition. Replacing large sections of pipe is not only extremely expensive – the average cost to replace one mile of pipe is US$1.8 million – but is also extremely difficult logistically, especially as urbanization continues.

Fortunately for utilities, the vast majority of pipelines can remain operational well beyond their intended design life, provided they are managed properly.

Pipe distress is a localized problem, meaning that one pipe section that is badly deteriorated or has failed could be neighbored by pipes that have virtually no damage at all. This is because local factors – such as load, soil conditions, operating conditions and installation – affect how quickly a pipe deteriorates. Through more than 8,000 miles of pressure pipe assessment, Pure Technologies has found that only 4 percent of pipe has some level of distress while less than 1 percent requires immediate renewal.

By managing assets, operators can combine the best of each approach – renewing large-diameter pipe with isolated damage and replacing lower cost assets – to achieve the highest return on investment. Proactive utilities have realized that when implementing condition assessment for a system of pipelines, a risk-based approach is an effective way to ensure resources are invested in an intelligent, defensible and repeatable manner that maximizes the benefit of a program.

Engineers analysing data

Risk-based condition assessment combines state-of-the-art technologies with expert engineering analysis.

Worker performing assessment

Condition assessment can help operators identify specific pipe sections that require renewal.

Defining Risk

To determine risk, operators must measure the probability and consequence of uncertain future events – in this case, pipe failure. This can be determined by multiplying two factors, consequence and likelihood of failure. Consequence of Failure (COF) refers to the damage a failure would cause based on factors such as 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 uncertainty 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.

To determine the physical condition of an asset, there are a number of technologies that can identify both the presence and level of distress. When determining which to use for each asset, risk is the most important factor. For high-risk assets, a detailed assessment is needed, while lower risk assets may warrant a lower-resolution screening or no assessment at all, as the cost of assessment would outweigh the benefit of replacing the asset entirely.

Naturally, as the resolution increases on an inspection technology, so does the certainty it provides to the operator, as well as the cost of the project. However, when deciding how to best assess critical pipeline assets, a simple comparison to how people should handle a significant health concern draws an important parallel for operators of large-diameter pipelines.

For example, if a person gets chest pain when they exercise – a serious problem – there are different levels of medical certainty they can attain. Going online to search medical journals or websites and completing a self-diagnosis is a free option, but it provides little certainty of long term health. A second option is visiting a general practitioner. He will be able to decide whether or not something is wrong, but won’t be able to diagnose it specifically and will recommend further investigation. To be confident in the results, the person would need to visit a heart specialist and complete specific tests.

While each of these options gets more detailed and expensive, the risk of leaving a heart problem untreated outweighs the cost of a detailed evaluation from a specialist. Utility managers should treat their critical large-diameter pipeline assets the same way a significant health problem, as the risk of uncertainty far outweighs the cost of being sure.

As municipal operators continue to grapple with aging water and wastewater infrastructure, identifying and managing risk should be an important consideration in the development of pipeline management, renewal and replacement programs.

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Pipeline Inspection and Condition Assessment Services

Pipeline Inspection and Condition Assessment Services

We provide water and wastewater organizations a comprehensive suite of technologies that provide actionable pipeline information to better understand the condition of their pipe.

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.

TRA Verification
To supply roughly 500,000 people from eight different municipalities with treated water, the Lake Huron Primary Water Supply System (LHPWSS) operates a major 1200-mm (48-inch) Prestressed Concrete Cylinder Pipe (PCCP) transmission main that spans 47 kilometers (29 miles).

After four failures on ‘Pipeline A’ in 2012, 2010, 1988 and 1983, LHPWSS began taking a proactive approach in managing its most critical pipeline through a technology-driven management program. This includes regular inspection of the transmission main to identify specific pipe sections that have distress and are at risk of failure.
In addition to proactively managing its infrastructure, LHPWSS is also twinning the transmission main to provide redundancy in the event that Pipeline A needs to be shut down.

After a full inspection of Pipeline A in November 2012, LHPWSS assessed 6.5 kilometers (4 miles) of PCCP along the twinned ‘Pipeline B’ in December 2013 using the PipeDiver® platform. Pipeline B currently spans 28.5 kilometers (17.7 miles) and features both PCCP and Steel pipe.

The PipeDiver tool is an electromagnetic (EM) platform that operates while a pipeline remains in service. EM inspections of PCCP pipelines identify the quantity and location of broken wire wraps, which are the main structural component in PCCP. As these wraps begin to deteriorate and break, the pipe section becomes weaker and more likely to fail catastrophically.

Worker inside a pipe
Staff extracting the PipeDiver® tool

Pure’s staff extract the PipeDiver® tool from LHPWSS’s Pipeline B.

LHPWSS’s inspection of Pipeline B was also the first use of video on the PipeDiver platform. Through the video application, LHPWSS was able to see inside the pipe under live operating conditions. The use of video during inspection provides additional information to use in conjunction with the electromagnetic data.

While the full results of the Pipeline B inspection are not finalized, the inspection demonstrates LHPWSS’s commitment to preventing transmission main failures and providing reliable water service.

This approach has been effective for LHPWSS in the past, as the 2012 inspection of Pipeline A identified only 58 pipe sections with EM anomalies out of a possible 10,000 pipe sections. This represents a distress rate of only 0.6 percent – well below industry average. Of the identified anomalies, only seven pipe sections had a relatively high level of distress.

Of the pipes with relatively high distress, two were located within a twinned section and therefore had a lower consequence of failure. The remaining five pipes were located within 3.5 kilometers (2 miles) of each other and are in the same vicinity of failures that occurred in 2010 and 2012.

LHPWSS has since verified and replaced the three most distressed pipes from the five that didn’t have redundancy to mitigate the risk of another failure. Plans to replace the remaining two pipes are scheduled for 2014.

By identifying isolated problems on its major transmission main, LHPWSS is able to avoid completing expensive and challenging replacement projects while maintaining safe pipeline operation. This approach allows capital to be deferred to other projects and prevents the replacement of pipe sections with remaining useful life.

 

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Case Study

Case Study: Lake Huron Primary Water Supply System

In October 2013, LHPWSS and Pure Technologies used advanced non-destructive free-flowing technologies to inspect a critical transmission main for leaks, gas pockets and structural deterioration while the pipeline remained in service. The results were successfully validated in spring 2013.

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.

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.”

Asset management strategies provide utilities with information on their buried assets; knowing what assets they have and when they will need rehabilitation is crucial for planning and fiscally responsible decision making.

A number of recent reports have highlighted the need for better asset management practices in the water and wastewater industry.

Black & Veatch’s Strategic Directions in the U.S. Water Utility Industry Report, released in 2012, highlights the need for asset management programs that streamline all the information and planning in a system.

Field Data Collection

The Canadian Infrastructure Report Card 2012 also highlighted the need for better asset management among Canadian utilities. The report found that many municipalities lack the internal capacity and resources to accurately assess the state of their infrastructure; many respondents had limited data on water treatment and pumping facilities and the condition of buried pipeline assets.

In order to help utilities with asset management master planning, Pure Technologies is now offering the PureNET™ asset management software which allows water utilities to manage water infrastructure data more effectively. PureNET links data from existing utility databases such as billing systems, hydraulic models, workload programs and maintenance management systems.

PureNET also has the ability to merge data from Pure’s pipeline inspection and monitoring technologies, it is fully integrated and extracts the most relevant information from each database, making asset management less complex and time consuming.

Initial case studies of utilities using PureNET show that the implementation of the system within a utility’s pipeline network can increase financial earnings by 3.5 percent.

PureNET helps streamline planning and decision making by establishing maintenance priorities, budgets, and planning of future projects, as well as providing information on the condition and useful life of a utility’s infrastructure. The software moves utilities from reactive to proactive asset management and bridges the gap between engineering and finance.

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Pipeline Asset Management Software

PureNET™ – Integrated Non Revenue Water and Asset Management Software

In order to help utilities manage all aspects of their complex water and wastewater systems, PureNET™ allows utilities to manage their infrastructure data more effectively.

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 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.

After prestressed wire break activity on the Cutzamala Pipeline, The Mexican National Water Commission (CONAGUA) intervened on two pipe sections that were near failure.

The wire breaks were identified by an Acoustic Fiber Optic (AFO) monitoring system that detects wire breaks on pipelines that utilize prestressing wires for structural stability; however, CONAGUA took quick and decisive action to prevent a failure.

After shutting down the pipeline, it took only 24 hours to assemble a crew that included almost 100 people to verify and replace the damaged sections and return the critical pipeline to operation. One of the distressed sections had visible corrosion while the section directly next to it had wire break activity but no visible damage.

The prevention of a major failure was crucial, as the Cutzamala system supplies water to about 5 million people living in Mexico City. The system features two parallel pipelines that stretch about 75 kilometers and are made 99-inch Prestressed Concrete Pipe (PCP) and Prestressed Concrete Cylinder Pipe (PCCP). Both pipe designs utilize high strength steel prestressing wire as the primary strength member. PCP differs from PCCP slightly in that it does not have the steel cylinder core, but instead is made of stronger concrete.

CONAGUA currently has AFO technology installed on about 70 kilometers (43 miles) of the two pipelines combined. The technology monitors the condition of prestressed pipe by recording the amount of wire breaks in each pipe section. The system allows CONAGUA to track pipeline deterioration and identify at-risk pipes before they fail.

Pipe Excavation
Pipe Scanner

Pipeline monitoring was initially adopted for the Cutzamala system due to a number of failures that disrupted service. After realizing that complete replacement was too expensive and unrealistic, CONAGUA decided to install AFO. The results have been positive so far, with the system identifying wire breaks along the monitored sections, allowing for the successful preventative repair of pipe sections.

In July 2012, CONAGUA also completed an electromagnetic (EM) condition assessment of the Cutzamala pipelines using PipeDiver® technology, a free-swimming tool that allows for non-destructive condition assessment of pipelines while they remain in service. The tool travels through the pipeline with the flow of water, collecting electromagnetic (EM) data that is analyzed to understand the baseline condition of the pipe.

The EM assessment provided CONAGUA with a baseline condition for each pipe section, while the monitoring system alerts operators about wire breaks on specific sections as they happen.

 

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Pipeline Monitoring

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.

Abstract

Recently the industry has been emphasizing broken prestressing wires as a basis for the management of Prestressed Concrete Cylinder Pipe (PCCP). The approach includes: evaluating broken wires, establishing a threshold level of broken wires for repair, and repairing only sections that exceed the threshold.

While evaluating wire breaks are an important part of PCCP management, it is important to acknowledge additional factors beyond wire breaks. By acknowledging additional condition factors, limitations of wire break assessment, and considering other rehabilitation approaches, there may be a more sustainable PCCP management approach (or combination of approaches). The approach may reduce risk and be more sustainable in terms of costs (current and future).

For some areas, the San Diego County Water Authority found the comprehensive rehabilitation approach, steel relining of PCCP, to be more sustainable in terms of costs. In addition, the approach significantly reduced the risk of a pipeline failure. However, in other areas, a localized, as-needed repair approach, such as Carbon Fiber, was more sustainable in terms of costs.

Authors

  • Nathan D. Faber, P.E., San Diego County Water Authority, Escondido, CA, USA.
  • Martin R. Coghill CEng MICE, Jacobs Engineering Group Inc., San Diego, CA, USA.
  • John J. Galleher, P.E., Pure Technologies, San Diego, CA, USA.

Non-Revenue Water (NRW) has been one of the biggest challenges for water utilities, with some seeing levels upwards of 50% across Asia. According to the Asian Development Bank this equates to around 29 million cubic meters of water lost in Asia each year at a value of $9 billion in revenue.

Another obstacle is the effective management of water services infrastructure and maximizing capital budgets. With pipelines reaching the end of their useful life, utilities must make difficult fiscal decisions regarding replacement and rehabilitation of their infrastructure.

K-water, the national bulk water utility in South Korea, controls everything from collection, treatment and pumping to maintenance, inspection and rehabilitation of the nation-wide pipeline system. The pipes in these critical bulk trunk mains are primarily large-diameter (greater than 2000 mm), and supply water to many of the smaller cities across Korea. Large cities, such as Incheon or Jeonju, are responsible for their own collection, treatment and distribution. In addition to supplying treated water to these small cities, many have contracted K-water to manage and maintain their distribution systems as they battle the challenges of ageing infrastructure.

K-water has done an exemplary job of maintaining its nation-wide pipeline system, which totals about 5000 kilometres, as well as helping smaller cities with their critical infrastructure management through individual contracts. While K-water’s critical trunk mains have a very low NRW, usually around 2%, many of its clients suffer from high levels of NRW as their pipeline infrastructure ages and begins to leak.

To address large-diameter leaks and ageing systems, K-water adopted a tethered system with acoustic leak detection and inline video – called Sahara® Leak Detection from Pure Technologies. While many utilities around the world use this tool for large-diameter leak detection, K-water instead chose to use it as a complete condition assessment tool to provide information on its pipelines and accurate location of leaks.

 

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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.

Sahara® - Leak & Gas Pocket Detection

Sahara® – Leak Detection for Water Trunk Mains

Leak and gas pocket detection using a tethered acoustic sensor allows for real-time results, and maximum control and sensitivity.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming inline leak detection technology designed to operate in a live water mains.

Baltimore County Department of Public Works (DPW) wrapped up a busy two-month inspection schedule in November 2012 after completing ten force main inspections using the SmartBall®, PipeDiver® and PureRobotics® technology platforms.

Twenty-three total inspections took place on ten different Prestressed Concrete Cylinder Pipe (PCCP) force mains over the inspection period, requiring extensive planning and organization between DPW and Pure.

SmartBall leak detection inspections were completed on nine force mains as part of the overall condition assessment of PCCP force mains. Initial leak and gas pocket detection is crucial in condition assessment, since the presence of leaks or gas pockets is often a preliminary indicator of a potential failure location.

Gas pockets in force mains are of significant concern as hydrogen sulfide gas within the wastewater may be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

For structural condition assessment of the force mains, Pure Technologies used PipeDiver technology for six inspections and the PureRobotics platform for three inspections.Two electromagnetic platforms were used for the inspections to meet the different operational challenges at each force main.

Both tools identify areas of distress and quantify the amount of estimated wire breaks on PCCP force mains while allowing them to remain in service. Having the line remain in service is often important for force main condition assessments since most lack redundancy and the ability to be shut down for inspection.

In total, DPW and Pure Technologies completed just over 15 miles of SmartBall leak detection, almost 11 miles of PipeDiver condition assessment, and about 3 miles of robotics inspection. The pipe diameters varied for each force main, ranging from 16-inch to 42-inch PCCP.

Baltimore County is inspecting their force mains after entering into a Consent Decree brought forth by the U.S. Department of Justice, the Maryland Department of the Environment (MDE) and the Environmental Protection Agency (EPA) in September 2005. The consent decree stipulated that Baltimore County inspect all force mains in its collection system with one or more methodologies appropriate to the specific characteristics of each force main.

Although the Consent Decree stipulates that the force mains be inspected, it allowed Baltimore County the flexibility to specify the method or technology at the time the inspections are performed.

The Baltimore County DPW has taken this opportunity to go beyond a minimalist approach, choosing to inspect its force main inventory with advanced non-destructive condition assessment technologies, reaffirming their ongoing commitment to providing reliable service and preventing pipeline failures.

DPW’s sewer force main inspection program was featured in the November issue of Trenchless Technology. Click here to see the article.

 

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Sewer inspection hole

Sewer Force Main Inspection

Pure Technologies has the complete portfolio for sewer force main and large diameter gravity main inspection. As the trusted global leader, we have successfully inspected thousands of miles of pipeline.

As part of a comprehensive pipeline management program, Washington Suburban Sanitary Commission (WSSC) and Pure Technologies have been monitoring sections of Prestressed Concrete Cylinder Pipe (PCCP) using Pure’s Acoustic Fiber Optic monitoring since 2007.

In October 2012, WSSC took the opportunity to proactively verify a 0.5 mile section of the River Road transmission main that had experienced elevated wire break activity. The individual pipes to be rehabilitated were selected from a comprehensive list of all monitored pipelines that contains all pipe sections that have an elevated risk of failure according to Finite Element Analysis and a combination of data sets, primarily collected from electromagnetic (EM) inspections and AFO monitoring.

AFO Install

This is part of a new drive from WSSC to initiate repairs on pipelines experiencing a high number of wire breaks before the situation becomes critical and prior to the normal 5 to 6-year inspection cycle.

Using an EM verification tool and internal visual and sounding, Pure verified all the wire breaks recorded with AFO and determined that all of the pipes were significantly more distressed than they were two years ago after the initial EM inspection.

In addition to the wire breaks, a hollow section was found on one of the pipes that signals a broad loss of prestressed wires. This hollow section was not found during the initial EM inspection and shows that the pipe section was beyond its allowable amount of wire break damage.

The verification of the four damaged pipe sections on River Road shows WSSC’s commitment to preventing pipeline failures through ongoing proactive pipeline management.

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Pipeline Monitoring

Pipeline Monitoring

Providing real-time critical data of a prestressed pipeline allows the asset owner to effectively moniture changes in structural integrity and address necessary improvements.

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.

Introduction

A significant percentage of the United States force mains have been in use for several decades and never been assessed or proactively managed. To safely rely on these pipelines, their condition should be periodically checked to ensure there are no locations susceptible to failure.

In addition, many wastewater agencies are faced with EPA consent decrees that require condition assessment of force mains. As a result, many agencies are now faced with the daunting task of assessing their sewer force mains—a task that until recently was often not feasible due to operational constraints. However, Pure Technologies continues to improve technology and can now obtain a realistic assessment of a force main within the common constraints of most wastewater agencies.

Authors

  • Michael S. Higgins, P.E.; Pure Technologies, Columbia, MD, USA.

Introduction

In 1996, Providence Water experienced a catastrophic failure of its 102″ PCCP aqueduct pipeline. Subsequently, the main underwent an extensive assessment and repair and was returned to service with plans that the main would be re-inspected in approximately 5 years.

In 2005, Providence Water re-inspected the aqueduct. Since the previous inspection, the state-of-the-art for assessing PCCP mains has progressed significantly. Non-destructive technologies available for assessing and monitoring PCCP pipe have made significant strides. Providence Water implemented state-of-the-art inspection procedures to obtain the best possible assessment of the aqueduct. Following the assessment of 4.5 miles of the aqueduct, Providence Water opted to install a fiber optic acoustic monitoring sensor to continuously monitor the condition of the aqueduct and identify pipe sections experiencing ongoing wire break activity.

Providence Water utilized the following technologies during the most recent 2005/2006 inspection/monitoring program:

  • Electromagnetic Inspection – to detect wire breaks in the prestressing wire
  • Visual and Sounding Inspection – to inspect for cracks or delaminations
  • Resistivity Testing – to determine the actual number of wire breaks on excavated pipe sections (vs. the estimated number based on the electromagnetic inspection)
  • Acoustic Monitoring – to detect future wire breaks as they occur in the operational aqueduct

Following the initial inspection, one pipe section was found to be in a state of incipient failure. As a result, several nearby pipe sections were strengthened and a decision was made to install the acoustic monitoring system. This paper focuses on the assessment and monitoring technologies used during this project and describes the capabilities and limitations of these technologies.

Authors

  • Michael S. Higgins, P.E.; Pure Technologies, Columbia, MD, USA.
  • Paul J. Gadoury, P.E., Peter LePage, Rich Razza; Providence Water Supply Board, Cranston, RI, USA.
  • Jack Keaney, P.E., Ian Mead, P.E., CDM, Providence, RI, USA.

Introduction

The City of Phoenix is currently in a multi-year program to investigate 150 miles of prestressed concrete cylinder pipelines (PCCP). The failure of a 60-inch pipeline focused the efforts of the investigation to a pipeline known as the Superior pipeline.

The Superior pipeline is a 2.2-mile long, 29-year old pipeline that ruptured on October 3, 2006, resulting in extensive damage to the surrounding community. The pipeline was immediately shutdown and the failed section of pipeline was repaired. However, the condition of the remaining pipe and the potential for additional failures was a concern.

To identify wire breaks, Pressure Pipe Inspection Company (PPIC) conducted Remote Field Transformer Coupling investigations. In addition, visual and sounding investigations were conducted by Openaka of Branchburg, New Jersey to identify internal defects. These investigations identified pipe segments that were in need of immediate repair prior to putting the pipeline back in service. This information provided baseline wire break information for the subsequent investigations.

Prior to putting the pipeline back into service, 11,700 linear feet of fiber optic was installed by Pure Technologies allowing the City to acoustically monitor wire breaks in real time. This information was critical as the pipeline needed to be back in service to meet the high demand for water during the hot Phoenix summer. Real time wire break monitoring allowed the City and Brown and Caldwell to slowly resume the operation of the pipeline to prevent another failure. Monitoring of the pipeline was conducted from February 2007 through January 2008 and the pipeline was found to be extremely active with an initial average of three wire breaks occurring each day.

This paper focuses on the investigations conducted and conclusive results relative to:

  • Benefits of multiple technologies for PCCP investigations
  • Calibrated vs. non-calibrated curves for electromagnetic analysis
  • Real time data collection through fiber optics to monitor pipeline conditions
  • Verification of fiber optic results using electromagnetic analysis
  • Pressure and surge monitoring

Authors

  • Ronald Ablin, P.E., Brown and Caldwell, Phoenix, AZ, USA.
  • Brandy Kelso, P.E., City of Phoenix Water Services Department, Phoenix, AZ, USA.
  • Bethany Williams, P.E., The Pressure Pipe Inspection Company, Phoenix, AZ, USA.
  • Myron Shenkiryk, Pure Technologies, Phoenix, AZ, USA.