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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.

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.

 

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.

Case Study

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

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

Project Details

Services
PureEM™ manned electromagnetic inspection

Handheld ultrasonic thickness testing

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

Remaining useful life projections using Monte Carlo simulation

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

Project Highlights

Survey covered 917 feet and spanned 125 pipes

12 pipes identified with electromagnetic anomalies

Defects identified ranged from 15 to 35 percent wall loss

Inspection deployed 48-detector electromagnetic tool

Challenge

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

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

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

Solution

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

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

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

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

Results

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

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

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

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

Quote

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

Underground pipelines are among the most valuable, yet neglected assets in the public arena. They provide essential services such as the supply of drinking water and collection of wastewater.

Despite their critical importance, for decades many municipal utilities have operated under a “bury and forget” mentality – with little emphasis on long-term management of their aging pipelines – at least until something goes wrong. Then they must fix the problem under emergency conditions, often considering only immediate needs and not the future operation of the pipeline in question.

Rocks balanced over a plank of wood

North American utilities face a tipping point

In many cases, the issue has less to do with “bury and forget” and more to do with financial constraints. Regardless, after years of funding deficiencies in pipeline network management, the situation facing North American utilities is at a tipping point.

Over time, it has become clear that most of the installed buried infrastructure – estimated to be approximately two-thirds of a utility’s total value according the United States Environmental Protection Agency (EPA) – will require strategic management to continue providing the expected level of service with acceptable budget constraints.

“Managing pipelines isn’t always about replacing old infrastructure,”

Travis Wagner

Vice President of the Pipeline Management Group, Pure Technologies.

Desktop indicators vs true condition assessment

In an interview with Water Online Radio, Wagner explained, “Just because a pipe is old, doesn’t mean it’s bad. The EPA came out with asset management information stating that 70 to 90 percent of the pipes that utilities pull out of the ground still have life in them. Utilities often base their decisions on desktop indicators like age and break history that tell them to replace out more pipe than is necessary.”

While desktop studies can help identify generalized likelihood and consequence of failure factors, condition assessment data has been particularly difficult to collect, especially in pressurized pipeline systems. This assessment information is critical, especially for estimating the remaining life in a pipe, or in making decisions on whether to initiate a replacement or repair program.

“I’ve seen hundred-year old pipe that looks as good as the day it was put in the ground and I’ve seen 15-year old pipe that was Swiss cheese,” said Wagner. “It’s all dependant on site conditions, how it was installed, all kinds of different elements that can cause a pipe to deteriorate and fail.”

Along with the sweeping digital revolution, the focus on maintaining buried infrastructure has come to involve robust data collection and management. To narrow down the root cause of pipeline failures, a comprehensive knowledge of the pipeline has become essential.

“We need to think better, smarter and put the right tools in the right place to get the information we need,” said Wagner. “Think about it in terms of your house or car. You put a little investment in now and it’s going to last years and years longer than it would otherwise. We need to be thinking of our pipes in the same manner.  Age discrimination has no place in pipe replacement strategies.

To help water utilities defensively address their pipeline conditions, Pure Technologies provides a suite of tools, technologies and engineering services that allow for a comprehensive condition assessment of pipelines, of all material types.

Matching the level of resolution to the risk of the line

While a variety of technological approaches are available for assessing a pipeline’s condition, much of the 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.

Worker's hands operating an electrical tester

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.

As Wagner summed up, “Knowledge is power. The more data you can collect, the more you can make confident decisions. But you’ve got to be able to manage, process, and analyze that 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
Historical pipe installation

An archived photo from installation of the pipeline five decades ago.

When your pipeline operates well for five decades, it’s easy to be lulled into a false sense of security about the condition of your buried assets. Out of sight, out of mind.

Then, in an instant, that mindset can change.

For Canadian River Municipal Water Authority (CRMWA), that wakeup call happened after dealing with two unexpected failures in quick succession earlier this year. The failure repercussions quickly introduced CRMWA to Pure Technologies, a leader in technologies for the inspection, monitoring and management of critical infrastructure.

CRMWA provides water to 11 member cities in the Texas Panhandle and South Plains region, near the cities of Amarillo and Lubbock. The water authority, which serves more than 500,000 people, draws water from Lake Meredith through a 358-mile aqueduct system completed in 1966. Comprised of approximately 55 miles of non-cylinder prestressed concrete pipe (PCP) along with approximately 300 miles of reinforced concrete pipe (RCP) and bar wrapped concrete cylinder pipe (BWP), the main aqueduct can deliver up to 118 million gallons of water daily to the 11 member cities.

Digging out failed pipes

One of the pipe failures that caused a blowout.

December 30: First blowout ends flow to 9 cities

The first indication of a problem occurred with a pipe rupture on Dec. 30, 2015, which abruptly ended the flow of water to nine of CRMWA’s member cities, leaving the cities to use precious reserves or their own water.

With the initial failure of a 72-inch (1830-millimeter) diameter non cylinder prestressed concrete pipe (PCP), the water agency lost millions of gallons of water, forcing a temporary pipeline shutdown to make immediate repairs.

January 5: Soon after the first blowout was repaired, an adjacent pipe began leaking

Five days later, on Jan. 5, CRMWA completed repair number one, and started to refill the system when an adjacent pipe began leaking.

This new leak lead to an emergency mobilization from Pure at the request of CRMWA. Pure’s condition assessment technologies have helped clients prevent more than 2,300 failures worldwide, resulting in billions of dollars in savings, and hundreds of billions of gallons in water savings. Pure has also located more than 4,000 leaks on water mains using its leak detection technologies.

Broken concrete pipe exposing the internal anatomy

One of the EM anomalies verified and excavated for repairs.

January 5-6: Pure mobilized to begin a manned electromagnetic survey

The same day, a crew of three mobilized from Dallas to the failure site near Amarillo. The purpose was to conduct a non-destructive evaluation using Pure’s electromagnetic inspection technology on the pipe immediately adjacent to the damaged sections. Over the next two days, Pure scanned 8,822 feet with internal manned electromagnetics.

January 8: Based on expedited EM analysis, Pure informed CRMWA of two large anomalies in two pipes near the first failure.  Over the next two days CRMWA completed the second leak repair, and hoped for more time to conduct a third repair where Pure called a large electromagnetic anomaly.

January 11: After Pure demobilized from the job site, the client turned on the pipeline, and after flowing for 12 hours, a second failure occurred, in the area located where Pure’s EM analysis indicated a potential problem.

January 12-13: Over the next few days, Pure verified five electromagnetic anomalies in three pipes near the failure site while CRMWA completed additional repairs. Based on the verified results, CRMWA requested a total of approximately 47 miles of manned EM inspection, which was completed by mid-March.

“The electromagnetic inspection was well worth the cost. Now we know the condition of our pipelines. We know the locations of our problems. The scan revealed 16 pipes where corrosion had put the lines at risk for developing additional blowouts. Those have been repaired much more cheaply and quickly than the costs of fixing blowouts.”

Kent Satterwhite

General Manager, CRMWA

Preparing the pipeline paid off by finishing ahead of schedule

CRMWA worked around the clock leading up to the inspections to dewater and prepare the pipeline for the internal inspections. The hard work paid off well, with no holdups on the inspection progress. The excellent planning by CRMWA and Pure allowed the inspection to wrap up ahead of schedule. Once the internal inspection was completed, Pure was also able to perform a destructive calibration on a pipe section which CRMWA provided, which was helpful for the analysis of the data collected. CRMWA was also able to repair 16 pipes that were very close to failure as identified by the electromagnetic surveys.

Sometimes one unexpected pipeline problem can compel long term planning and action, as it did with CRMWA. The Water Authority now has a defined plan to assess the condition of their pipeline, giving them the confidence to move forward with greater assurance and peace-of-mind.

Man with fish inside pipe

After a long day,  Pure and CRMWA celebrated with a fish dinner, caught while draining the raw water line.

Fish inside a cooler

Metallic pipes have a long history in distribution systems throughout North America, with cast iron and carbon steel making their debut in the early 1800s. In many states, pipelines deploying the early metal are still in service, including the cast iron water main buried in 1831 beneath what is now Greenwich Village.

Risk prioritization as a starting point

Before undertaking any metallic pipe inspection, a utility should first complete a risk prioritization of all their buried assets, factoring in a variety of consequence of failure (COF) and likelihood of failure (LOF) variables to determine the highest/lowest risk pipelines. A distribution pipe buried in a cornfield probably has a lower risk profile than a water main buried under a children’s hospital.

This first step in risk analysis is critical, and can help determine a prioritized strategy. The higher the risk, the more an operator requires reliable information for an action plan to replace, rehabilitate or inspect the pipes further to gather more precise data.

Using asset risk to guide the management strategies, an operator can feel confident about implementing the right approach, at the right time, with the lowest financial impact. Overall, this strategy ensures long-term service, reliability and safe operation.

Match the technology and inspection method with the risk

This initial process also allows operators to choose the most appropriate inspection method based on different pipe material and operational requirements, including lack of redundancy.

If the analysis ranks the mains as medium to high-risk pipes, it makes sense to utilize medium to high-resolution inspection technologies. High risk pipes are probably more expensive and more difficult to replace, and probably affect more people if taken out of service.

 

Medium Resolution Technology

Pipeline Inspection and Condition Assessment Services

PureEM™

PureEM technology represents a form of non-destructive testing that provides a snapshot of the pipeline`s condition by inducing electric currents/magnetic fields within the pipe to measure an electromagnetic response. By creating these fields, PureEM data identifies specific areas of the pipe wall with large EM anomalies. In the case of metallic pipes, these anomalies typically represent broad areas of corrosion.

Typically, metallic pipes are first assessed with a prescreening tool – including inline leak detection and pipe wall assessment – followed by PureEM testing, using one of three platform tools. This multi-tool approach provides the operator with a variety of condition information that can help inform renewal decisions.

With PureEM manned inspection tools, field technicians have the option enter the pipeline with a PureEM inspection tool (e.g. push cart, bicycle) and traverse the length of the pipeline, inspecting for damage. The tool can be used in dewatered water and wastewater pipelines.

Free-Swimming Pipeline Inspection

PipeDiver®

When configured with PureEM, the free-swimming PipeDiver tool is an effective medium resolution tool to assess areas of damage along a pipeline that is live or can’t be taken out of service due to a lack of redundancy or operational constraints. It is ideal for metallic pipes with a higher consequence of failure, since the tool operates while the pipeline remains in service.

PureRobotics™ – Pipeline Inspection

PureRobotics™

Pure`s long range, multi-sensor robotic inspection vehicles are capable of conducting PureEM inspections on steel and ductile iron pipes. The robotic vehicle can be used in depressurized and partially dewatered and wastewater pipelines.

No one solution for every pipeline

Every pipeline has a unique set of conditions, which is why there is no one silver bullet that works across the board.

However, 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 operators to develop a sustainable long-term strategy for managing their critical buried assets.

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.

Many utilities across the United States are dealing with the challenges of aging water and sewer infrastructure, much of which was installed many decades ago. Despite their age, buried water and wastewater pipelines remain the most valuable asset a utility owns. In many cases, the value of buried pipelines represents two-thirds of the utilities total assets.

For water service providers, an increased number of leaks and pipe failures have resulted in negative public perception about the condition of water infrastructure. For wastewater utilities, force main failures are leading to more strict regulation and consent decrees mandating renewal of wastewater assets.

As these challenges become more prominent with the media and public, utilities are under more pressure to renew this infrastructure through rehabilitation or replacement programs.

Unfortunately, the vast majority of utilities do not have nearly enough capital budget to embark on major rehabilitation or replacement programs. This reality has created a major funding gap between what is needed to rehabilitate, replace and expand water and sewer infrastructure and what is actually possible. Some estimates of this gap are as high as US$1 trillion over the next 25 years.

Bridging the Infrastructure Financing Gap

Even if adequate funding were available, the rehabilitation or replacement of assets based on age alone would be irresponsible with so much value tied up in these assets. Utility operators should treat these assets as they would their vehicle. In the case of a car, the first instinct when there is a problem is not to replace the entire car. Instead, the car would be evaluated by a professional and repaired where needed. This often represents a small fraction of the cost of replacing the entire car, and can restore it to fully working condition.

Embarking on a pipeline management program follows the same mentality – assess the condition of the pipeline assets before replacing them entirely. This is supported by the fact that the U.S. Environmental Protection Agency estimates that 70 to 90 percent of pipe that is replaced has remaining useful life. By replacing pipelines without first determining their condition, utilities are likely replacing a large amount of pipe with remaining useful life. This is particularly important for large-diameter pipelines, since the cost of replacement can be upwards of US$2.5 million per mile of pipeline.

One of the most important aspects of a management program is using risk to make a plan. Depending on the size of the utility and system, there might be hundreds of miles of large-diameter pipeline. While assessing an entire system can seem daunting, it is not as daunting as replacing the entire system, and can be made a lot more manageable by using risk to prioritize the pipelines.

This process involves analyzing various factors such as but not limited to: redundancy, location, operating pressure and environmental factors to identify pipelines that carry a high risk if they were to fail. After completing this process, asset owners are equipped with a risk-based pipeline-by-pipeline list that can be used to develop yearly prioritized inspection plans; the most critical assets are assessed and renewed first, while low-risk assets are scheduled for a later stage in the program.

Examples of successful pipeline management

This approach has been employed for several utilities across the United States, many of which have managed and renewed their critical assets for between 5 and 15 percent of the replacement cost estimate, which has at times is in the billions of dollars.

One example of this is the Washington Suburban Sanitary Commission (WSSC), who manages roughly 145 miles of prestressed concrete cylinder pipe (PCCP) for 6 percent of the US$2 billion replacement cost. Since employing this approach, WSSC has drastically improved the reliability of its water network by avoiding large-diameter pipe failures. To see a full WSSC case study, click here.

The Miami-Dade Water and Sewer Department (WASD) has also successfully managed its large-diameter pipeline assets using a risk based approach. The majority of WASD’s large-diameter water and wastewater pipelines is made of PCCP. In total, WASD has more than 250 miles of PCCP 48-inches and larger that has been installed since 1949. In 2010, WASD began the Infrastructure Assessment and Replacement Program (IAARP) to renew its water and wastewater assets, including pipelines, treatment facilities and pumping stations.

As WASD inspects its PCCP assets each year, the typical number of segments showing any type of degradation has not exceeded 2.5 percent on average; less than 1 percent requires some sort of rehabilitative action with no parts of the system being immune to rehabilitation, regardless of their age or manufacturer. Considering that less than 1 percent of pipes require immediate action, a full replacement program would end up replacing pipelines that, for 99 percent of the system, have a significant remaining useful life. To read the full article about WASD’s program, click here.

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.

Following a significant pipe rupture in December 2012, Tulsa Metropolitan Utility Authority (TMUA) performed a detailed structural assessment on a critical section of one of the city’s major drinking water pipelines in November 2013. This recent work builds upon the TMUA’s rapid response forensics investigation completed in January 2013.

To determine the baseline condition of this major transmission main – which is made of 48-inch (1200-mm) Prestressed Concrete Cylinder Pipe (PCCP) – the city dewatered the pipeline and performed a comprehensive internal inspection using visual and sounding techniques, and electromagnetic (EM) technology.

This specific pipeline was constructed in 1975 and had not experienced a failure before December 2012. The 2012 failure caused major commuter disruptions, evacuations and damage to a local church; in an article published in Tulsa World, City Engineering Director Paul Zachary said that this failure cost roughly $400,000 to rectify. The 2013 inspection will help prevent another failure on this transmission main by identifying pipe sections that have distress and could fail if left in operation.

In total, roughly two miles made up of 688 pipe sections were assessed in November using visual and sounding techniques and EM technology.

Visual and sounding inspections are a reliable method of detecting pipes in an advanced state of distress. The inspections require manned entry to the pipeline and dewatering; any pipes judged to be in a state of incipient failure will be reported to allow for immediate replacement or rehabilitation.

Broken pipe

The failed 48-inch pipe section from December 2012.

Staff inside a pipe working with tool

Pure Technologies staff complete verification work on Tulsa’s PCCP water mains.

EM inspections of PCCP pipelines identify the quantity and location of broken wire wraps. The wire wraps in PCCP are the main structural component – as wraps begin to deteriorate and break, the pipe section becomes weaker and more likely to fail catastrophically.

The inspections showed that 81 of 688 pipe sections had broken wire wraps, indicating some level of distress. Based on a structural analysis, it was recommended that 32 of the distressed pipe sections be replaced immediately. In addition, the pipeline has 120 deteriorating joints that should be repaired in the near term. As a result, the City is moving forward with a rapid response construction project to address the pipeline’s deficiencies in early 2014.

Through the use of comprehensive condition assessment, TMUA has increased service reliability and taken major steps toward ensuring another failure does not occur.

By identifying specific areas of distress along this critical transmission main, TMUA has also avoided completing an expensive and time-consuming replacement project of the entire transmission main. This approach helps to preserve capital budget for other projects by avoiding unnecessary replacement of pipe sections in good condition.

The City of Tulsa supplies drinking water to more than 133,500 metered accounts in the City and more than 500,000 people in the metropolitan area. Tulsa’s two water treatment plants treat between 90 and 190 million gallons of drinking water a day. The TMUA is a public trust organization created by City charter. TMUA’s primary responsibilities are to manage, construct, and maintain Tulsa’s water works and sanitary sewer systems, and to fix rates for water and sewer services rendered within its boundaries.

 

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Pipeline Visual & Sounding Inspection Services

Visual Inspections and Soundings have successfully been used to quickly identify pipes in the state of incipient failure. Issues other than wire breaks can also be identified through visual inspections, such as unusual cracking and poorly detailed or damaged joints.

Electromagnetic Pipeline Inspection

Electromagnetic testing provides the best condition assessment data for large diameter PCCP (AWWA C301) and BWP (AWWA C303) pressure pipelines.

Assess & Address Pipeline Management Program

Pure Technologies is helping utilities manage their buried infrastructure through its Assess & Address which can often be implemented for only a fraction of the capital replacement cost.

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.

Roughly US$14 billion in clean, non-revenue water is lost every year due to leaks and water main failures that could have been prevented.

If the loss of non-revenue water could be cut by half, an estimated US$2.9 billion could be generated and an additional 90 million people could have access to water.

Locating leaks on transmission mains represents the best opportunity for improvement.

Non-revenue water is defined as water that is produced for consumption but is lost before it reaches the customer. These losses are divided into three categories:

  • Physical (or real) losses due to poor operation and maintenance, lack of an active leak control system or the poor quality of underground assets.
  • Commercial (or apparent losses) include customer meter under-registration, data handling error or the theft of water in various forms such as illegal connections.
  • Unbilled authorized consumption includes water used for operational purposes, for fighting fires and water that is provided for free to certain consumer groups.

The best opportunity for improving this situation is by taking the first step in a NRW-reduction strategy and start focusing on leak and theft detection within transmission mains.

That’s where Pure comes in.

With over 2,000 miles of large-diameter pipelines inspected, Pure Technologies has located more than 4,000 leaks for an average of 2.2 leaks per mile using our advanced inline leak detection technologies significantly reducing NRW while saving millions of gallons of water and helping prevent failures for utilities around the world.

An article published on New Zealand Infrastructure Online discusses Hutt City’s proactive management of critical infrastructure through the use of advanced non-destructive technologies.

Hutt City used PureEM™ to assess the condition of the Main Outfall Pipeline – a rubber ring jointed, non-cylinder prestressed pipe – and locate broken prestressing wires.

This pipeline is 18 kilometers long and takes treated wastewater from Seaview to Pencarrow for discharge into the Cook Strait. It serves the combined Lower Hutt and Upper Hutt population of 140,000.

Built in 1962, the pipeline is made up of more than 4000 sections of pipe and has an internal diameter of 1300-mm (51-inches). The cost replacement estimate for this pipeline is $60 million and would be very difficult to complete because there is no longer sufficient space in the narrow road that winds around the Eastern Bays of Wellington Harbour.

NZ Insertion
Inspection Tool

In favour of capital replacement, Hutt City opted to find and employ advanced technologies to assess the pipeline and address the most distressed areas. MWH Global was contracted by Hutt City Council to investigate the repair or renovation of the pipeline and seek resource consents for pipeline inspection.

Assessing the condition of the pipeline was a challenging task but one MWH identified as being best performed using a combination of non-destructive testing technology, internal visual inspection and engineering science and judgement. MWH contracted Aqua-Environmental (a Pure Technologies company) for the condition assessment.

Read Full Article »

New Zealand Infrastructure (NZI) provides stakeholders in the infrastructure industry with timely information, critical insights and detailed developments from within the country and around the globe that influence the planning, design and implementation of New Zealand infrastructure.

NZI focuses on the information needed to create and maintain world class cities and suburbs and develop energy, environmental, transport, water and communication infrastructure. The magazine details security and partner services – like investment, finance, legal, management, product provision and contractors that support and ensure the viability and sustainability of infrastructure projects. NZI works with major industry organisations and government agencies that are influential in setting and implementing the agenda for the country’s infrastructure development.

 

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Free-Swimming Pipeline Inspection

Electromagnetic Pipeline Inspection

Electromagnetic testing provides the best condition assessment data for large diameter PCCP (AWWA C301) and BWP (AWWA C303) pressure pipelines.

In January 2013, Lake Huron Primary Water Supply System (LHPWSS) verified the results of a condition assessment project completed in October 2012 that included leak detection and electromagnetic (EM) assessment. The verification allowed LHPWSS to proactively repair of three sections of Prestressed Concrete Cylinder Pipe (PCCP) along its major transmission main.

While the majority of Pipeline A – LHPWSS’s major water transmission that runs 47 kilometers (29 miles) – was found to be in good condition, the inspection showed seven pipe sections had a relatively high level of distress. Of these seven pipes, two were located within a twinned section and therefore had a lower consequence of failure.

The remaining five high-distress 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.

Although the pipeline is primarily in good shape, the identification of several highly-distressed pipe sections has allowed LHPWSS to proactively plan targeted rehabilitation to ensure the continued delivery of quality service and the prevention of a major pipeline failure.

Verification Tool
Excavated Pipe

By determining the baseline condition of their entire primary large-diameter pipeline, LHPWSS now has a better understanding of the overall health of their system and can make informed decisions as they move forward with their pipeline management program and the rehabilitation of their assets.

LHPWSS serves about 500,000 people in eight different municipalities in the London Region and provides about 170 million liters (44 million gallons) of water per day. Its major transmission main, the Lake Huron Pipeline A, runs from the Lake Huron Water Treatment Plant near Grand Bend, ON to a terminal reservoir located near the community of Arva, North West of the City of London and features mostly 1200-millimetre (48-inch) Prestressed Concrete Cylinder Pipe (PCCP).

 

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 Electromagnetic 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.

 SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® – Leak Detection for Water Trunk Mains

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

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

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.