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SAHARA® INLINE TETHERED PIPELINE INSPECTION PLATFORM

The Sahara platform is a tethered inspection tool for assessing pressurized water and wastewater pipelines six inches and larger. The platform detects leaks and gas pockets, collects visual condition, and maps pipelines in a single deployment, without disrupting regular service. With this condition assessment data, pipeline owners can make informed rehabilitation and management decisions on a pipe-by-pipe basis.

Video

SmartBall® Inline Free-Swimming Pipeline Inspection Platform

The SmartBall platform is a free-swimming inspection tool used to detect leaks and gas pockets and map pipeline networks. This platform assesses pressurized water and wastewater pipelines in a single deployment, without disrupting regular service. The SmartBall platform provides utilities with pipeline condition data to make informed rehabilitation and management decisions on a pipe-by-pipe basis.

Video

PureRobotics® Tethered Robotic Pipeline Condition Assessment Platform

The PureRobotics platform is a modular, multi-sensor condition assessment tool for depressurized water and wastewater pipelines. Using accurate electromagnetic and other sensor data paired with live video, this platform provides utility owners with comprehensive pipe wall condition data used to make rehabilitation and management decisions on a pipe-by-pipe basis.

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PipeDiver® Inline Free-Swimming Pipeline Condition Assessment Platform

The PipeDiver platform is a free-swimming pipeline condition assessment tool that is easy to deploy and operates while the pipeline remains in service. This tool provides utility owners with pipe wall condition data used to make rehabilitation and management decisions on a pipe-by-pipe basis.

Video

WSSC Proactively Avoids Water Main Breaks Using Acoustic Fiber Optic Technology

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

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

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

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

This white paper will highlight:

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

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

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

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

This white paper will highlight:

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

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.

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

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

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

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

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

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

Project background

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

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

Prepping the PipeDiver tool for the electromagnetic inspection.

Understanding the pipe material determines inspection methods

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

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

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

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

As a precaution, two models of PipeDiver tool assembled

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

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

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

That was good call.

Getting the PipeDiver tool ready for the first insertion.

Sections of pipeline 3 inches smaller than anticipated

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

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

From here, the inspections went off without a hitch.

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

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

A beautiful way to end a successful inspection.

TOSA has a better understanding of their linear assets

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

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

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

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

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

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

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

Acoustic intensity of anomaly and actual leak located

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

Inline technologies for leak detection

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

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

SmartBall inside a pipe

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

SmartBall leak detection technology

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

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

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

Tethered Sahara inspection platform

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

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

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

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

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

City of Vancouver SmartBall inspection

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

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

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

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

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

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

Sahara inspection for City of Norman, Texas 

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

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

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

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

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

Two leaks detected, located and repaired

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

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

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

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

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

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

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

Island community concerned about pipeline risk of failure.

Sensitive location and potential environmental consequences strike nerve with community.

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

The assessment challenges began from the get-go.

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

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

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

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

Pipeline alignment follows along the Vancouver Island coast.

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

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

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

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

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

PipeDiver tool collects electromagnetic data regarding the pipe wall.

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

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

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

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

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

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

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

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

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

Data analysis indicated no electromagnetic distress on inspected pipes.

Based on the inspection data, Pure analysts identified zero (0) leaks, one (1) acoustic anomaly associated with trapped gas, five (5) acoustic anomalies characteristic of transient gas and two (2) acoustic anomalies associated with entrained gas. In particular, gas pockets are of significant concern in force mains, as concentrations of hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall.  This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

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

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

 

Case Study

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

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

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

Project Details

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

Project Highlights

AFO hears “pings” on 16-foot segment

15 wire wrap breaks identified over 2-week period

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

Project Photos

Challenge

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

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

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

Solution

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

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

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

Results

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

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

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

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

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

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

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

Jeffery Raymond

DPW spokesman

Case Study

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

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

Project Details

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

Project Highlights

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

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

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

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

Challenge

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

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

Solution

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

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

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

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

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

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

Results

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

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

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

Case Study

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

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

Project Details

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

Project Highlights

SmartBall survey identified 4 leaks and 3 air pockets

Only 1% of BWP sections identified as distressed

TRA verified and repaired 3 high-risk BWP sections

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

Challenge

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

Solution

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

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

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

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

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

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

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

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

Results

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

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

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

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

SoundPrint® AFO

SoundPrint Acoustic Fiber Optic (AFO) Monitoring technology is an industry-leading system that tracks and records pipeline deterioration.

Continuous real-time structural monitoring
for PCCP pipelines.

Pure’s Soundprint technology is an industry-leading Acoustic Fiber Optic (AFO) monitoring system that tracks and records pipeline deterioration on PCCP water and wastewater pipelines.

As the monitoring system records breaks and the pipe section approaches its limit, pipe sections can be proactively rehabilitated in advance of an expensive failure.

This proven approach has been successful in selectively rehabilitating PCCP assets – while preventing critical failures – for only a fraction of the cost.

Benefits

  • Saves Money on PCCP inspection
  • System installation does not affect pipeline operation
  • Proven history and the most reliable acoustic monitoring technology for PCCP
  • Flexible monitoring solutions for installation around valves, bends, and outlets

Related Article

Acoustic Fiber Optic (AFO) technology helps identify problematic water mains.

Pure Technologies near real-time AFO technology is now embraced by a growing number of pipeline operators across North America and Asia.

learn more

Featured Case Study

City of Baltimore

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

In May 2017, analysts from Pure Technologies notified DPW that something was wrong with a 16-foot segment of the Southwest Transmission Main that runs beneath Desoto Road (under the Interstate-95) and carries potable water for southwest portions of the City of Baltimore, Baltimore County, and portions of Anne Arundel and Howard Counties.

Case Study

The Netherlands faces unique challenges with their underground pipe networks due to their proximity to numerous dykes that regulate water levels.

Because pipe failures can lead to drastic consequences for Dutch infrastructure, Waternet undertook a leak detection program for three major pipelines that pass various critical infrastructure including dykes, motorways and airport runways.

Extensive testing was done by officials and Pure Technologies prior to the inspection to ensure the technology could offer a comprehensive leak assessment of the pipeline’s condition.

Project Details

Services
SmartBall® leak and gas pocket inspection
Timing
2013-2014
Pipe Material
PCCP
Inspection Length
195 km (121 miles)
Diameter
1200mm-1500mm (48-60 inch)
Transmission Type
Water

Project Highlights

195kms

of pipelines inspected

3

leaks located

3

leaks verified

Risk mitigated on critical pipeline
Challenge
Most of the Netherlands is situated under sea level, and a large system of dykes protects the land from rising water, while also connecting villages and cities. Water pipelines are often laid in close proximity to the dykes, meaning burst pipes would have devastating e­ffects on the road infrastructure and the surrounding communities.

Today, the aging dyke system is eroding the pipelines foundation causing stress and increasing the likelihood of failures. As a result of several incidents with failing or leaking pipelines in the vicinity of dykes, their owners issued a decree that required water utilities to prove the integrity of its buried assets. Waternet, the regional public water authority for Amsterdam, identified several pipelines of particular concern where a small leak from a pipeline could impact dyke integrity and a risk analysis discovered areas of pipe weakness. Based on these results, authorities determined that further testing in the form of inline leak detection should be performed.

Before embarking on inline leak detection, local officials required several rounds of extensive testing of the proposed technology to demonstrate e­ffectiveness in detecting and locating small leaks in the pipeline. In addition, since the scope of inspection included approximately 180 km of concrete pipelines, the leak detection technology had to demonstrate the ability to inspect long sections of pipe for the project to be most e­ffective.

Solution
Waternet partnered with Pure Technologies to perform inline inspections on three separate pipelines.

The SmartBall® leak detection tool was chosen to assess the integrity of the pipelines and to find leaks along the length of the pipe. The SmartBall tool is a free-flowing leak detection platform that operates while the pipeline remains in service. It is capable of completing long inspections in a single deployment and is equipped with an acoustic sensor that identifies acoustic anomalies associated with leaks and air pockets.

Typically inserted through an existing valve, it travels with the water flow recording the acoustic environment within the line. The SmartBall tool is then removed by either deploying a net at a predetermined extraction point or at another discharge point of the pipeline. The data is stored on the device and analyzed upon completion of the inspection. It is able to travel through long sections of pipe gathering approximately 18 hours of data, making it the ideal solution for the long pipelines of the Waternet leak detection program.

Calibration tests were done to conform to the strict requirements implemented by the dyke owners who wanted clear indications on the lower leak detection limit specific to the composition of the pipe. A calibration stack was developed and extensive tests were performed, simulating leaks to create a calibration curve for various leak sizes. The tests proved SmartBall could detect the leaks smaller than the threshold set by the dyke owners.

Results
Pure Technologies performed SmartBall inspections for Waternet along the WRK pipelines. These pipelines run mainly through rural farmland but also cross through critical dyke systems.

The first portion of the inspection began in 2013 when 146 kilometres of pipeline was broken into eight lengthy inspections. In 2014 the remaining 49 kilometres were inspected. Three leaks were found and verified during the inspection of the entire 195 kilometres of pipeline.

Pure Technologies worked closely with Waternet to fulfill the comprehensive requirements of the leak detection program required by the utility. The importance the dyke system to the protection of the country’s infrastructure and communities mean the integrity of the pipelines must be maintained. The inline leak detection program gave Waternet the necessary information to fulfill their commitment to the dyke owners, and help extend the life of these critical pipelines.

Case Study

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

Project Details

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

Project Highlights

0.68 miles (1.09kms) total distance inspected

117 pipes inspected

31 pipes with broken wire wraps

25 repaired and replaced pipes

Challenge

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

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

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

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

Solution

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

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

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

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

Results

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

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

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

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

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

Case Study

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

Project Details

Services
PureRobotics® electromagnetics (EM) condition assessment

PureRobotics HD-CCTV inspection

Inertial measurement unit for GIS component

Risk prioritization

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

Project Highlights

EM data identified 17 anomalies warranting further investigation

HD-CCTV identified longitudinal cracks consistent with overloading

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

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

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

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

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

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

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

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

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

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

Case Study

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

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

Project Details

Services
PureRobotics® electromagnetic condition assessment

PureRobotics® HD-CCTV inspection

Risk Prioritization

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

Project Highlights

Condition assessment on 2.92 miles (4.7 kms) of feedermain pipes

Data identified 8 pipes with electromagnetic anomalies consistent with broken pressing wire wraps

HD-CTTV identified 3 pipes with damaged internal mortar and exposed cylinder

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

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

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

In BWP, the technology identifies and locates broken bars and areas of corrosion on the steel cylinder, which are the main indication this type of pipe will eventually fail. Although BWP looks similar to PCCP in cross section, the design and materials are significantly different.

PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water membrane. With BWP, the cylinder plays a much larger role in the structural integrity of the pipe. BWP is essentially designed as a steel pipe with mild steel used to manufacture the steel cylinder and steel bars. PCCP utilizes mild steel for the cylinder, but high strength steel is utilized for the wire, which is wrapped under high tension. As a result, the bar in BWP and wire in PCCP respond differently to environmental conditions that facilitate corrosion.

The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage. The mild steel bars in BWP are thicker in diameter and wrapped under less tension, therefore corrosion takes significantly longer to lead to breakage. The type of failure is also much different; PCCP tends to fail suddenly with a large dispersion of energy. This type of failure is less likely in BWP where failures are similar to steel pipe with long periods of leakage occurring prior to rupture. Because of the differences in make-up, BWP and PCCP are inspected using unique methods to determine their structural condition.

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

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

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

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.

The first time new parties come together to work on a pipeline inspection project, they face a lot of pressure to perform.

The team must instill trust and understand each other to ensure the project goes off without a hitch. In this instance, that’s what happened when Pure Technologies (Pure) and its long-time partner WRc came together with;Irish Water, Cork County Council (CCC) to assess and address the condition of a critical water main in the City of Cork, Ireland.

As this was the first collaborative project among the four groups, it was also a test of the planning expertise, engineering skills and technology advances for Pure Technologies and WRc to impress upon Irish Water and Cork County Council. In the end, the inspection was successful, lessons were learned, and a positive new relationship was forged.

Aerial view of the City of Cork

Project Begins With Six Months of Planning

After six months of planning, in March 2017, Irish Water and its consultant WRc engaged Pure Technologies to conduct a non-destructive evaluation of approximately six (6) kms (3.7 miles) of 1500mm (60-inch) and 1200mm (48-inch) prestressed concrete cylinder pipe (PCCP) sections in the water main between Chetwynd reservoir and Carrs Hill, using the SmartBall® pipeline inspection platform.

 

 

SmartBall tool provides acoustic signature related to leaks and gas pockets

For the Inniscarra Water Main inspection, Pure Technologies 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, because as the device travels along the pipeline, it continuously records the acoustic environment within the line. All data is stored onboard the device and later evaluated to determine the presence and location of any leaks or pockets of trapped gas.

Tool tracked at known points along the pipeline alignment

 

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

From insertion to extraction, the SmartBall inspection took a little over six hours, with no unexpected events that were not anticipated during the planning stage.

As the SmartBall was extracted, it was met with a round of roaring applause from assembled team members.

Results lead to effective management of finances and risk

Based on the inspection data, our analysts reported three (3) anomalies characteristic of leaks, and zero (0) acoustic anomalies characteristic of pockets of trapped gas.

Overall, both Irish Water and Cork County Council were 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 Inniscarra Water Main. The project demonstrates how Irish Water and CCC can use actionable data to effectively manage their finances and risk, while continuing to provide the community with a safe and reliable delivery of drinking water.

 

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

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

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

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


Robot's faster speed important for time-critical shutdowns

 

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

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

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

 

PureRobotics deployed on reclaimed water line for nuclear plant

 

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

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

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

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

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

 

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

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

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

It’s a major event when you’ve been asked to perform a first in terms of a pipeline inspection.

For starters, you must feel confident in the inspection technology you recommend. Second, you hope that all your planning for deployment and unexpected contingencies has been anticipated. And finally, with so many eyes focused on the outcome, you hope the first inspection of its kind goes off without a hitch.

That was the case in May 2017, when the Dutch utility Brabantse Delta retained Pure Technologies (Pure) to perform a SmartBall® inspection on a critical untreated wastewater pipeline near the city of Zevenbergen, located in the North Brabant province.

For Pure Technologies, this project marked the first SmartBall acoustic inspection of a rising [force] main in the Netherlands.

Brabantse Delta operates AWP-1, a pre-stressed concrete cylinder pipe (PCCP) pipeline that transfers industrial wastewater from the Moerdiijk pump station to the Hoven pump station. The 800mm (32-inch) pipeline traverses a lot of farmland near the city, which made accessing buried manholes somewhat of a challenge, as many of these were located on private land, making excavation difficult.

Gas pockets are of concern on wastewater lines

The pipeline has not experienced regular failures, but Brabantse Delta was looking for solutions to establish a baseline condition and manage the risk of this critical asset. The primary purpose of the SmartBall inspection was to identify and locate leaks and pockets of trapped gas along the approximately 8.3 km (5.1 mile) pipeline.

We were pleased the overall execution and excited that the SmartBall tool was able to collect inspection data while the force main remained in operation.” Ing. R van Wanrooij, Adviser Civil Engineering, Brabantse Delta

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

The SmartBall tool was chosen as an inspection platform for its sensitivity to small leaks and gas pockets and for its ability to inspect long distances in a single deployment. Minimal pipeline modifications are required for insertion and extraction.

SmartBall tool tracked at known points along the pipeline alignment

The free-swimming, acoustic-based SmartBall® tool is inserted into the pipeline flow, and after traversing the inspection length, the tool is captured and extracted at a point downstream.

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

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.

Prior to the execution of the project, Pure Technologies reviewed the site and all pipeline drawings. The only real inspection challenge was taking into account the limited number of SmartBall receiver tracking units, as some of the buried manholes were located on private farms.

Inspection results

The inspection went smoothly, and all data successfully collected. From insertion to extraction, the SmartBall inspection took under 5 hours, with no unexpected events thanks to cooperative planning and full support of the Brabantse Delta team.

Preliminary data indicated no leaks and zero (0) acoustic events associated with pockets of trapped gas. Entrained air was present throughout the pipeline, but no events of significance were detected. Entrained air is a migratory event, meaning its location is dynamic and changes over time with the operational flow. These events are expected to move throughout the pipeline, and locations are specific to the time of the inspection.

Overall, Brabantse Delta was pleased with the execution, and excited to know there was an inspection tool that gave them a better understanding on the overall condition of the AWP-1 pipeline. The project demonstrates how Brabantse Delta uses actionable data to effectively manage risk, while continuing to provide the community with a safe and reliable delivery of untreated wastewater.

Case Study

The City of Montreal supplies drinking water and wastewater services to a population of nearly 1.9 million people. Starting in 2007, Pure Technologies (Pure) began working with the City’s potable water transmission division on a pipeline assessment program that included electromagnetic (PureEM) inspection and acoustic monitoring.

In 2015, as part of a pre-emptive program to reduce loss of non-revenue water and understand the condition of their pipes, the City partnered with Pure to conduct an ongoing, three-year leak detection survey on a series of critical pipes within its potable water network located mostly in the downtown core.

Project Details

Services
Sahara® leak detection

CCTV visual inspection

Timing
2015-Ongoing
Pipe Material
BWP, Steel, Cast Iron, PCCP
Inspection Length
28.9 km (18.5 m)
Diameter
500mm – 1200mm (20-inch – 48-inch)
Transmission Type
Water

Project Highlights

20.8 miles (33.5 kms) inspected to date

46 insertions completed

24 leaks identified

9 leaks identified as feature leaks

Challenge
The City recognized the value of detecting leaks, however small, to prevent these from developing into greater problems. While leaks occur most frequently on small-diameter distributions mains, leaks and ruptures on trunk mains are a much bigger concern for utility operators due to the relatively higher consequence of failure.

In addition to physical losses of water caused by a series of small leaks, the escaping water can eventually erode the surrounding soil making the area more prone to washouts or sinkholes, a major headache especially in densely populated areas. Leaking water can eventually find its way to the surface, or into sewers, overburdening the system. Unplanned excavations to repair unforeseen leaks can also erode consumer confidence in a public utility.

Solution
For its multi-year leak detection program, the City requested Pure to deploy its highly reliable and precise Sahara® acoustic video inspection on 46 kilometers of pipelines chiefly in the downtown core. The pipeline sections consist of PCCP, BWP, cast iron and steel.

The Sahara platform comes with a variety of sensor tools to perform the inspection. This includes an acoustic sensor to perform leak and gas pocket detection, and high-resolution video camera to assess internal pipe conditions.

Because the Sahara tool is drawn by product flow via a small drag chute, 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 visual anomalies. The tool can visually confirm pipe irregularities, continuously recording, allowing for both real-time and post-processing analysis.

For the Montreal project, the purpose of the Sahara inspection was to assess the condition of the pipeline by identifying and locating leaks, pockets of trapped gas and to identify larger visual anomalies utilizing Closed Circuit Television (CCTV) footage collected during the inspection. The data would help shape the rehabilitation urgency and timing.

 

Results
To date, Sahara has had 46 insertions and a total of 33.5 kilometers (20.8 m) have been assessed. Analysis of the data identified 24 leaks and zero (0) gas pockets in the pipeline sections inspected. The Sahara sensor was tracked above ground using the Sahara Locator® device to track the Sahara tool and locate any potential leaks or anomalies found.

 The assessment is proving its worth from a verification viewpoint, and the leaks have been either repaired or addressed for prioritization. The current program is scheduled for completion by 2017.

With its pre-emptive leak detection program, the City is Montreal is a great example of a smart water manager taking proactive efforts at keeping its network in healthy shape.

Speak to One of Our Experts





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


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

SmartBall inside a pipe.

Detect and locate acoustic sounds related to leaks and gas pockets

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

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

Cam White

Business Line Manager, SmartBall

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

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

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

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

Multiple insertion and extraction options available

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

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

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

Rideau Canal, Ottawa

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

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

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

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

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

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

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

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

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

SmartBall inside a pipe and working zone map

Ground microphones fail, SmartBall tool succeeds

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

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

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

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

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

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

Water Department Supervisor, City of Southlake

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

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

Workers with horses in a field

Soggy ground, horse pasture and and muddy conditions hamper inspection

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

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

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

Sahara device

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

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

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

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

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

Pipe inner surface

Second attempt to find the leak

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

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

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

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

Sahara platform inside a pipe filled with water

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

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

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

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

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

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

Worker digging to reveal the leak

Surprise, surprise, 4 leaks verified

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

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

Small leak before being fixed

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

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

Big City Landscape View

Rand Water is the largest bulk water utility in Africa and one of the largest in the world, providing bulk potable water to more than 23 million people in Gauteng, parts of Mpumalanga, the Free State and North West – an area that stretches over 31,000 square kilometres. Rand Water’s distribution network includes over 3,300 kilometres of large-diameter pipelines.

In 2015 Rand Water embarked on the largest proactive bulk water pipeline condition assessment  investigation ever in South Africa. An important part of the assessment includes inline non-disruptive leak detection inspections covering just over 2,200 kilometers of Rand Water’s bulk pipeline network.

SmartBall in a case with the laptop used to control it.

SmartBall leak detection platform used for most inspections

The free-swimming SmartBall™ leak detection system is utilized to perform the majority of these inspections. The multi-sensor tool is used to detect and locate the acoustic signature related to leaks and gas pockets in pressurized pipelines. 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, it can inspect every inch of the main to detect leaks and gas pockets.

Big pipes

High pressure, high flow pipelines can make insertion and extraction difficult

Due to the vast transfer distances and varying topography within the supply area, the Rand Water system is characterized by pipelines operating under extreme pressures (higher than 16 bar [232 psi] and up to 40 bar [580 psi]) and high flow velocities (higher than 2 m/s), historically beyond safe operating limits of the standard SmartBall insertion and extraction equipment.

This rendered some of the pipelines unsuitable for inspection unless a solution could be found to safely insert and extract SmartBall from a high pressure/high flow pipeline.

Worker inspecting pipe

Pure works with SSIS PIpeline Services to help solve this unique challenge

Pure Technologies embraces research and development (R&D), with a strong design focus on continuously developing new inspection technologies and improve existing systems. SSIS Pipeline Services, which represents Pure Technologies in SA, challenged the Pure R&D team to find a solution for this unique high pressure Rand Water problem.

From this challenge, the Titan system was born.

Introducing Titan insertion and extraction system

Following extensive R&D and pre-delivery testing, the first-of-its-kind enlarged Titan insertion and extraction system was delivered to South Africa in May 2016. The system included a retrofitted high pressure LDEN (Large Diameter Extraction Net) kit capable for use in pressure environments up to 40 bar (600 PSI) and higher.

Workers with high pressure pipes

SSIS staff underwent shop training at the hands of one of the mechanical design engineers from Pure, followed by hands-on training on a number of high pressure, high velocity Rand Water pipelines.

To date, the Titan system has been used safely and successfully on pipelines up to 2900mm in diameter, operating at 2.5 m/s and at pressures up to 18 bar (261 psi). The system’s highest recorded operating pressure was at 23 bar (333 psi) on a 900mm diameter pipeline with 1.5 m/s flow.

Testing the waters, pushing the limits

The Titan system now enables SSIS to safely perform SmartBall leak and gas pocket inspections on high pressure pipelines previously off limits.

The latest successful test illustrates the SSIS commitment to the local water industry through innovation and dedicated support from Pure Technologies. It again proves that no problem is too big to solve, and every challenge can be overcome through dedicated teamwork and cutting-edge innovation.

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.

Staff members behind an open pipe

When you’re a regional water authority with a sound way to identify problems with your aging water pipeline before the problems get bigger, it’s cause for a celebration, highlighted with speeches, live demonstrations and cake included in the ceremony.

In late November 2016, a delegation of government officials, special guests and educators gathered in London, Ontario Canada  to celebrate the successful funding, installation and commissioning of a 60 km (37 miles) Acoustic Fiber Optic (AFO) system installed on the Lake Huron Water System’s water transmission pipeline.

Map with pipeline location

Pipeline draws water from near Grand Bend to terminal reservoir north of London

The pipeline, which supplies drinking water to more than 500,000 people in southwestern Ontario, draws water from the Lake Huron water treatment plant near Grand Bend to the terminal reservoir just north of London. Constructed of 1200mm (48-inch) prestressed concrete cylinder pipe (PCCP), the Lake Huron-to-London pipeline has ruptured four times, most recently in 2012.

To mitigate the chance of a future catastrophic failure on such a critical line, the water authority for the Lake Huron Primary Water Supply System collaborated with Pure Technologies (Pure) to install an acoustic-based monitoring system, designed to ensure the success of the Region’s long-term comprehensive pipeline management program.

The $7.5 million upgrade to the Lake Huron-to London water line is part of $179.1 million in water safety infrastructure investments across Southwestern Ontario.

SoundPrint® AFO Fiber Optic wire

SoundPrint Acoustic Fiber Optic technology tracks and records pipeline deterioration

Pure’s SoundPrint Acoustic Fiber Optic (AFO) monitoring technology is an industry-leading system that that listens, identifies and locates pipeline deterioration in real time. Once installed on a pipeline, the SoundPrint AFO system remotely detects the acoustic signature of wire breaks or “pings” in prestressed concrete cylinder pipe, and records their specific pipe location. If break activity increases, utility staff are alerted and can intervene on the deteriorating pipe in advance of failure.

Under the new system, “We will get an email to say a section of pipe has a break, and they even give us the map location of where it happens,”

John Walker

Operations Manager, Lake Huron and Elgin Area Primary Water Supply

The AFO system remotely detects the acoustic signature of breaks in the pipeline structural reinforcement and records the specific pipe location of the deterioration, alerting operating staff who can intervene in advance of a catastrophic failure of this regionally significant water transmission pipeline.

“A snapping wire or two won’t sound an alarm bell,” says Heather Edwards, project manager at Pure. “But when our monitoring team listens and identifies a large number of pings from 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.”

By managing their pipelines with innovative technologies, utilities can save millions of dollars

The project was special for Pure as it showcased the innovative SountPrint AFO technology upon which the company was founded more than 20 years ago.

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

Pure surpasses 700 miles (1,100 km) AFO monitoring milestone

Globally, Pure has surpassed 700 miles (1,100 km) of active AFO monitoring. Currently within North America and China, Pure monitors 56 mains from a combined total of 17 clients, including London Region. Pure’s active AFO system has recorded more than 43,600 wire breaks from its managed roster of pipelines located in North America and China alone.

With the installation of AFO technology in place, the London Region utility ensures active management of their most valuable buried assets, for the life of the asset.

That’s a comforting thought, well worth celebrating.

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

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

Optic Fiber inside a pipe and Press Conference

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

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

Water supply safeguard comes down the pipe

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

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

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

Staff members behind an open pipe

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

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

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

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

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

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

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

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

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

Celebration Cake

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

Working on a new potable water transmission main

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

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

Outside and inside a tunnel

Some pipeline sections tunneled in excavated depths of 50 meters

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

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

SoundPrint® acoustic fiber optic (AFO) inside a pipe

Acoustic monitoring versus electromagnetic inspection technology

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

AFO monitoring is an innovative monitoring technology for identifying wire breaks in PCCP pipes. Unlike EM, which identifies the number of wire breaks that exist at a point in time, acoustic monitoring identifies the number of wire breaks that occur during the monitoring period, effectively identifying the location of active deterioration for the lifespan of the asset.

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

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

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

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

Pipeline construction along a road

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

Contract 1 (underway) includes visual inspection and mapping

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

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

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

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

Fiber optic

24-Detector PipeDiver tool

Advanced PipeDiver tool developed for condition assessment of metallic pipes.

Pure Technologies (Pure) never says no to an engineering challenge. If a client has a particular pipeline assessment or monitoring challenge to overcome in order to make a rehabilitation decision, we’ll do whatever it takes to help our clients solve the problem.

Pure Technologies embraces research and development (R&D), with a strong dedication to continually develop new technologies and improve upon existing inspection systems. This attitude of taking a winning platform and making it better was demonstrated again with the introduction of the optimized PipeDiver, an advanced, multi-sensor tool developed specifically for the condition assessment of metallic pipes within pressurized pipe networks.

PipeDiver inspection tool operates while the pipeline remains in service

As a technology platform, PipeDiver is a versatile, free-swimming condition assessment tool that operates while the pipeline remains in service, often providing an easier and less costly alternative than inspection methods that require a shut-down or dewatering.

Two men working with a PipeDiver device

The PipeDiver platform is ideal for critical, large-diameter lines that cannot be removed from service due to operational constraints or lack of redundancy. The PipeDiver tool requires only a 12-inch access, and can be deployed on pipelines that range from 16 inches up to 120 inches.

The tool can be deployed, collect information on pipeline condition and extracted in a single mobilization.

As the PipeDiver platform can be equipped with a closed circuit television (CCTV) camera, the tool is able to record and deliver video images from the inside of the pipeline (quality depends on water clarity).

PipeDiver Cammera working

Tool able to navigate most butterfly valves, tees and pipeline bends

To begin an inspection, the tool is balanced to be neutrally bouyant and inserted into a pressurized or depressurized pipeline through a tap connection, or an existing access point. The tool travels with the product flow, and utililzes flexible petals to navigate butterfly valves, tees and bends in the pipeline.

Originally designed for use in pressurized concrete cylinder pipes (PCCP), the tool has specialized electromagnetic sensors (PureEM) to identify and locate broken prestressing wire wraps, (one of the main structural components and failure modes of a prestressed concrete pipe).

Historically, technologies available to assess the condition of metallic pipe have been full diameter tools (“Smart Pigs”) unable to traverse most water or wastewater pressure pipelines due to inline valve restrictions and limited access for insertion and retrevial of a full diameter tool. These challenges led Pure’s R&D to develop the specialized PipeDiver for metallic pipes, equipped with advanced electromagnetic technology to identify localized areas of wall loss.

The PipeDiver electromagnetic (EM) technology can also be used in bar wrap pipelines to identify broken bars and steel cylinder damage, the two main structural components bar wrap pipe.

PipeDiver device inside a pool of water

Utilities Kingston welcomes PipeDiver to assess its metallic pipeline

Since its introduction, the optimized PipeDiver platform has been deployed for various projects in Europe, Canada and the U.S.

This year Utilities Kingston agreed to pilot the new technology as part of a comprehensive condition assessment on its Dalton Avenue (North End) Pump Station Force Mains. The pipelines are both approximately 1,550 meters long and follow a parallel route for approximately 1 kilometer.

The older of the two force mains is 450 mm (18-inch) in diameter, constructed of ductile iron built in the late 1950s, and had failed several times over its lifetime. The newer of the two force mains is 600 mm (24-inch) in diameter, built from an unspecified concrete pipe from the early 1960s. As the pipe material specifics were still unknown at the time of the inspection, the Pure elected to conduct a PipeDiver run to accommodate both possible types of pipe material – assumed by all to be bar wrapped pipe (BWP) and prestressed concrete cylinder pipe (PCCP).

Force main defects can vary from one pipe material to another

During a forensics exercise on the 600 mm force main using earlier PipeDiver technology, it was revealed that the actual pipe material included 102 suspected metallic pipes, which were not identified as such in the original plan and profile drawings.

This included ductile ironsteel and unexpectedly, reinforced concrete pipe (RCP), which is not usually used in pressurized environments. Electromagnetic inspection of the RCP can only reveal anomalies on the circumferential cage and not the longitudinal bars.

Inserting the PipeDiver device through an inspection hole

Optimized PipeDiver tool deployed in wastewater

Pure deployed its optimized PipeDiver tool to conduct a quality analysis of the 450 mm pipe. The purpose of the inspection was to locate and identify steel and ductile iron pipes that have indications of wall loss.

This marked the first condition assessment of metallic pipe using the optimized PipeDiver in wastewater, an exercise that confirmed the validity of the tool’s sensor technology.

Results lead to actionable information regarding rehabilitation

Of the 650 pipes inspected with the PipeDiver tool, a total of 55 pipes in the 450 mm Dalton Avenue Pump Station Force Main had electromagnetic anomalies characteristic of localized wall loss.

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

PipeDrive device revision after the inspection has finished
City of Vancouver from the air

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

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

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

PipeDiver device

PipeDiver inspection identifies electromagnetic anomalies

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

The PipeDiver electromagnetic inspection covered a cumulative distance of 4.57 kilometers and spanned 676 pipes. Unlike more restrictive assessment tools, PipeDiver is a flexible, free-swimming tool that flows with the product and is able to easily navigate through most butterfly valves, apertures and bends in the pipeline, delivering electromagnetic (EM) data for a variety of pipe type and materials.

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

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

SmartBall inspection tool used to locate leaks and gas pockets

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

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

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

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

ROV camera shows a tool cart inside the pipe

Collective thinking clears the debris and all is well

By analyzing data from the earlier PipeDiver inspection, Pure determined that unknown debris likely lodged the SmartBall tool.

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

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

While no gas pockets were identified during this inspection, two (2) instances of entrained air were identified as migratory acoustic anomalies, and flagged for future inspection, as they may develop new pockets of trapped gas.

Validated results help the City manage its infrastructure

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

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

West Palm Beach Aerial View

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

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

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

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

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

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

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

Staff working at insertion site

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

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

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

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

SmartBall® inside a pipe

First inspection: SmartBall® acoustic leak and gas detection

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

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

PipeDiver® electromagnetic inspection

Next: PipeDiver® electromagnetic inspection

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

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

Results guide the success of the program

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

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

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

SmartBall extraction and retrieval

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

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

Inspection Prototype

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

Electromagnetic Inspector

Electromagnetic technology platforms recognized around the world

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

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

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

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

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

Tech inspecting a pipe with a tool

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.

 

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

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

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

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

Reasons why water mains crack, leak and burst

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

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

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

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

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

Pure AFO developed to replace limitations of hydrophone array technology

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

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

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

Tech working inside a pipe

 

Big boom theory helps promote AFO technology and PCCP management

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

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

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

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

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

Pure surpasses 1,120 km AFO monitoring milestone

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

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

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

City of Ottawa Skyline

When your inspection task is to survey a critical pipeline for leaks, nothing is more satisfying than trusting your technology to predict the leak location and then standing by as the client excavates the area to find a flow of water within one meter of exactly where you said it would be.

The above-described “leak-where-predicted” recently happened with the City of Ottawa, when Pure Technologies (Pure) deployed its SmartBall® inspection platform to locate leaks along a critical transmission main, as part of a long-term condition assessment program for the municipality. Over the past five years, Pure has used its suite of platform tools, including Sahara®PipeDiver®, and PureRobotics®, as well as the free-swimming SmartBall device, for deployment on the City’s ongoing Drinking Water Transmission Main Condition Assessment Program.

Transmission main comprised of 1220mm (48-inch) lined cylinder pipe

The City’s potable water distribution system consists of 3,728 km of both local water mains and large-diameter transmission mains that move large volumes of water throughout the capital. The City has approximately 230 kms of transmission mains ranging in diameter from 600mm to 1980mm, (24-inch to 78-inch) subdivided into 96 segments for the purpose of a risk-based prioritization.

For the subject project, the City of Ottawa retained the services of Pure to perform a SmartBall tool inspection to identify and locate leaks and pockets of trapped gas along the Baseline Road Water Transmission Main, a high priority pipeline. The 1220mm (48-inch) diameter pipeline is comprised of Lined Cylinder Pipe (LCP) mostly constructed in the 1970s.

Pipe leaking

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

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

SmartBall extraction process

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

For the City of Ottawa project, five (5) surface-mounted acoustic sensors were placed along pipeline to track the SmartBall tool during the inspection. SmartBall receivers were connected to the sensors on the pipeline at the locations indicated to track the tool during inspection.

The SmartBall device was inserted into the pipeline through a 100mm drain near a hospital. Acoustic and sensor data was collected and recorded as the SmartBall tool traversed the pipeline for more than three kilometers. The SmartBall was then extracted from a reservoir using a Remotely Operated Underwater Vehicle and data was evaluated to identify acoustic anomalies associated with leaks and pockets of trapped gas.

Verification with ground microphones turned up unexpected results

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

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

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

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

SmartBall extracted by Pure technicians

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.

Louisville Water Tower and Pumping Station house the WaterWorks Museum

To many history buffs, “the prettiest ornamental water tower and pumping station” in the U.S. belongs to Louisville Water Company (Louisville Water). In 1860, the water company, which today provides water to more than 850,000 people in Louisville, Kentucky and surrounding communities, built its first water tower and pumping station in the form of a Greek temple complex.

Today, the Louisville Water Tower and Pumping Station house the WaterWorks Museum, and Louisville Water continues to make history using modern technology from Pure Technologies to assess its extensive water network.

Focused on pipes with the potential to cause the most damage

Following a water main break in 2009 that resulted in the loss of 15 million gallons of treated water, Louisville Water began a Transmission Assessment Program, first deploying Pure’s PipeDiver® technology to conduct a practical and cost-effective way to inspect transmission mains. Over the succeeding years, this program has evolved to include with other assessment technologies from Pure’s toolbox.

Transmission Assessment Program utilizes a variety of assessment tools

In the summer of 2015, Louisville Water deployed PureRobotics to assess 3.41 miles of 24 to 30-inch transmission mains in its network. With over 4,100 miles of pipeline to maintain (200 miles of it transmission main), Louisville Water focused its condition assessment on its transmission main system – pipes that would cause the greatest amount of damage in the case of failure. The loss of non-revenue water, either in continuing small amounts or from a catastrophic failure, can result in massive costs to a water utility.

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

In May of 2015, PureRobotics was deployed on the Cross County Header, Ray Lane Easement pipeline, and Bardstown Road pipelines. For Louisville Water, PureRobotics used CCTV to provide a comprehensive high-definition visual inspection. The robotic crawler was also outfitted with specialized tools to conduct an electromagnetic assessment on the condition of the pipeline and inertial measurement unit (IMU) for a GIS component.

The Inertial Measurement Unit (IMU) deployed with PureRobotics uses a series of Fiber Optic Gyroscopes (FOGs) and accelerometers to track depth, lateral and horizontal movements from a known GPS reference point. The output is a GIS spatial map of the pipeline which depicts elevation changes as well as notable features of interest encountered during the inspection.

PureEM electromagnetic assessment detects anomalous regions in the pipe cylinder and prestressed wires. This data is correlated with odometer readings from the PureRobotics umbilical tether as well as HD recorded CCTV and IMU to attempt to locate areas of distress in the pipeline.

Anomalous pipe

One of the 11 anomalous pipes excavated.

Due to its mobility, PureRobotics is ideal for multiple isolated inspection runs where a quick setup and breakdown can improve efficiency.  The transporter can be deployed from a number of access styles including valves, open flange, and open pipe. In the case of the Louisville Water inspection, the PureRobotics system was inserted into the pipeline via newly installed vertical gate valves and existing boiler plate style hatches. Inspection lengths varied in length from 70 feet to beyond 2,000 feet.

Staff deploying PureRobotics

Louisville Water deployed PureRobotics to assess its transmission mains.

Results gave Louisville Water the confidence to prioritize its rehabilitation program

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

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

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

As one of the first utilities to deploy the third generation PureRobotics platform, Louisville Water now has defensible data to move forward with its ongoing rehabilitation program. For this historic water utility, modern technology really can help.

Kingston Pipe Material Map

Internal measurement map indicates various pipe materials detected during the conditon assessment of the Dalton Avenue force mains in Kingston.

The familiar adage, “never assume anything” certainly applies to the water and wastewater pipeline industry. The message was brought home to Utilities Kingston (UK) early this year when the utility was surprised to find unexpected pipe material on sections of pipe during a condition assessment on its Dalton Avenue (North End) Pump Station force mains.

Conducting a condition assessment on a pipeline can pose a particular challenge if the pipe material is unknown, as each pipe type exhibits specific characteristics that affect its structural integrity. Despite the challenge, UK managed to move forward thanks to assistance from Pure Technologies, 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.

Utilities Kingston is unique in Ontario, combining water, wastewater, gas and electrical services, and a broadband fibre optics provider under one company.  UK’s engineering and public works departments provide potable water and wastewater collection and treatment to 36,000 customers.  The utility owns and operates approximately 550 kilometres of water mains and 500 kilometres of sewer mains to service the local population of nearly 125,000.

With an average age of 35 years, each of their pipeline assets is entering a critical stage in its life-cycle.

The subject pipeline had experienced a failure and as a result, the utility was interested in exploring technologies to help them implement a comprehensive asset management program for their pipelines.

Condition assessment includes various screening technologies

UK retained Pure to perform a condition assessment inspection, consisting of a SmartBall® leak detection survey, a PipeDiver® electromagnetic inspection and a transient pressure monitoring on the Dalton Avenue Sewage Pump 450-millimeter and 600-millimeter force mains. The two sewage force mains are both approximately 1,550 meters long and follow a parallel route for approximately 1 kilometer.

The older of the two force mains is 450-mm (18-inch) in diameter, constructed of ductile iron, was built in the late 1950s, and had failed several times over its lifetime. The newer of the two force mains is 600-mm (24-inch) in diameter was an unspecified concrete pipe from the early 1960s. As the pipe material specifics were still unknown at the time of the inspection, Pure elected to conduct a free-swimming PipeDiver electromagnetic run to accommodate both possible types of pipe material – assumed by all to be bar wrapped pipe (BWP) and prestressed concrete cylinder pipe (PCCP). The 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.

Pure’s SmartBall tool was deployed on both pipes, checking for leaks and gas pockets.

PipeDiver on a street

Force main defects can vary from one pipe material to another

During a forensics exercise on the 600-mm force main using 12-detector PipeDiver technology, it was revealed that rather than BWP or PCCP, the actual pipe material included reinforced concrete pipe (RCP), which is not usually used in pressurized environments. Electromagnetic inspection of the RCP can only reveal anomalies on the circumferential cage and not the longitudinal bars.

Furthermore, the inspection identified 102 suspected metallic pipes, which were not identified as such in the original plan and profile drawings.

PipeDiver tool before insertion

Prepping the PipeDiver tool before insertion.

Pure first: metallic pipe condition assessment using mini PipeDiver tool in wastewater

Pure deployed its electromagnetic 24-detector mini PipeDiver tool to conduct a condition assessment of the 450-mm pipe. The purpose of the enhanced electromagnetic inspection is to locate and identify steel and ductile iron pipes that have indications of wall loss.

This marked the first condition assessment of metallic pipe using the 24-detector mini PipeDiver tool in wastewater, an exercise that confirmed the validity of the tool’s sensor technology.

Results lead to actionable information regarding rehabilitation

In the end, one (1) acoustic anomaly characteristic of transient gas on the 450-mm forcemain was identified during the analysis of the data collected during the SmartBall tool inspections.

No anomalies resembling leaks were identified within the 600-mm force main.

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

The data collected from both the inspections and transit pressure monitoring gave Utilities Kingston a better understanding of their real, not assumed assets. The results were used to complete a structural evaluation of the force mains, and have provided UK with actionable information regarding any necessary repairs or rehabilitation.

Team Members of Pure and UK

Members of the Pure and UK team pose after a long day of inspection.

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
Houston and Oaklahoma

Sahara® technology is winning accolades from satisfied owners and operators of buried infrastructure the world over. In North America, two recent projects demonstrate the benefits of using this in-line tethered tool for critical leak detection surveys, especially when speed and accuracy are paramount.

Sahara Diagram

Sahara is the first tool designed for live inspection of large diameter mains, and one of the most accurate tools available for detecting and locating real-time leaks, gas pockets and structural defects in complex networks typically found in urban environments.

The tool is inserted via a valved appurtenance, and then moves through the pipeline using the flow of water and a small drag chute – all without interrupting service. Once the sensor tool is inserted, it remains tethered to the surface. This allows for real-time results and maximum control, as the tool can be winched back and forth to immediately confirm suspected leaks and other anomalies. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

Oklahoma City welcomes Sahara leak detection survey on critical main

In March 2015, McKee Utility Contractors (McKee) retained Pure Technologies (Pure) to perform a quick-turnaround leak detection survey on a troublesome 72-inch Transmission Main (TM) in Oklahoma City. The critical TM, which is composed of prestressed concrete cylinder pipe (PCCP) and transmits potable water, is owned and operated by Oklahoma City Water Utilities (OCWU).

In this instance, OCWU suspected a leak along a low point of the line where surface water was noticed. A previous catastrophic failure on the line compelled the utility to call on the prime contractor McKee to dig, locate, and repair the leak.

Thwarted by two days of digging and not finding the leak, McKee called on Pure to assess approximately 4400 feet of pipe and to determine the location of the leak source and any gas pockets using Sahara leak detection technology.

Quick mobilization, short turnaround timing

The planning and execution took place in short order. McKee contacted Pure on Saturday, the project planned on Sunday and by Monday a field crew and equipment were mobilized to the site in Oklahoma City. On Tuesday, a single inspection was performed, and one (1) leak was detected 360 feet downstream from the Sahara insertion point. The leak was classified as a large leak based on the audible range.  The inspection continued for a total inspection distance of 546 feet.  No other leaks were detected at the time of inspection.

By the time Pure began extracting the Sahara tool, McKee had ordered a backhoe enroute, and by afternoon the pipe was excavated, the leak located, and the repairs were able to begin.

Shane McKee, president of McKee was extremely pleased with the accuracy of the Sahara technology and the fast turnaround from the Pure team.

“Based on the results I’ve seen, I’m never again digging up another pipe again without Pure and its technology to help guide the process.”

Shane Mckee

Shane Mckee, McKee Utility Contractors

Sahara Insertion Tool

Houston energy company deploys Sahara tool to quickly locate leak in chilled water line.

Large cities often operate central chilled water plants to cool water that is then sold to building owners for use in air conditioning.

In Houston, Enwave Houston delivers chilled water through 5.4 miles of pipe to air-condition 24 buildings, including Minute Maid Park, home of the Houston Astros. The 27,000 ton system uses ice storage technology to help keep central business district buildings comfortable in spite of summer`s high temperatures and humidity.

In December 2015, Pure was retained by Boyer Inc. to perform a Sahara inspection on Enwave`s 24-inch Chilled Water Supply pipeline (CWS) and also on their 24-inch Chilled Water Return pipeline (CWR). The purpose of the inspection was to locate a suspected leak on one of the dual lines that run parallel along the downtown core.

Data identified events associated with leaks and air pockets.

Boyer proposed two separate insertions during the planning phase. Pure completed both proposed insertions over a two-day period for a total of 795 feet of pipeline inspected. Acoustic data was collected and recorded during the inspections as the Sahara sensor traversed the main. The data was evaluated to identify events associated with leaks and pockets of trapped air.

During the inspections, one leak and zero air pockets were detected. The Sahara sensor was tracked above ground to track the sensor along each pipeline and verify the endpoint of each endpoint. The leak was located 144 feet downstream from the insertion point on the second day with sub-meter accuracy, allowing a pinpoint excavation to be made for repairs, minimizing disruption to downtown Houston traffic, and minimizing the contractor`s cost of excavation and road restoration.

When time and accuracy matter, utilities count on the Sahara platform.

The two case studies demonstrate the efficacy of the Sahara leak detection system. When time and pinpoint accuracy matter, the Sahara platform gets the job done right.

Dallas Water Utilities Discovers Massive Hidden Sinkhole And Achieves Huge Savings Through Annual Leak Detection Program

The year began with the Lone Star state experiencing its fourth year of drought, compelling State Governor Greg Abbott to reissue an Emergency Disaster Proclamation in early May to deal with the declining aquifer levels and severe water shortages. Only a few weeks later, torrential rains flooded so much of the state that the Governor issued another Emergency Disaster Proclamation to prepare for the new crisis. Then, another long stretch of baking heat.

Weather extremes push water utilities to the limit

For most utilities, weather can play havoc with buried infrastructure. While drought can cause the dry brittle ground to shift and pipes to break, excessive rain can result in washouts, loss of bedding and risk for accelerated pipe failures.

In 2015, weather extremes in such a short period taxed water utilities across Texas. Despite the challenging environmental conditions, Dallas Water Utilities (DWU) moved forward to carry out its annual leak detection program. Over the years, DWU has focused its water loss reduction efforts on both its critical large-diameter transmission mains, which have the highest consequence of failure, and on its distribution systems.

Pipe leaking

Detection results include discovery of a large pipe leak near a major roadway

Staff inserting Sahara tool

Crews successfully used the Sahara® tool to locate 10 leaks in 16 miles of inspection.

DWU’s first condition assessment program using electromagnetics was completed in 2001, followed by the use of newer leak detection technologies in succeeding years. The program is now in its 14th year of operation, and DWU has become a showcase utility for proactive pipeline management, a fact recognized by the Texas Water Development Board.

DWU adds 16 miles to its leak detection program in 2015

DWU’s distribution system is one of the largest in the United States, being a regional provider, the utility delivers water service to 2.4 million customers within the Dallas and surrounding city limits. The major distribution system includes over 4,900 miles (7,800 km) of distribution and transmission mains.

DWU’s goal is to continually evaluate, upgrade and replace its water and wastewater assets in order to make its systems operate efficiently. DWU’s long-time partner in this infrastructure endeavour is Pure Technologies (Pure). This year Pure was contracted to perform leak and air pocket detection for 16 miles (25.7 kilometers) of water mains made of a variety of materials, including prestressed concrete cylinder pipe (PCCP), cast iron pipe (CIP) and ductile iron pipe (DIP).

DWU deploys inline detection tools

For inspection of its transmission mains, DWU has long used Sahara leak detection and inline closed circuit video (CCTV) provided by Pure. More recently, DWU has also used SmartBall® technology for longer inspections.

Sahara is the first tool designed for live inspection of large-diameter mains, and one of the most accurate tools available for detecting leaks, gas pockets and structural defects in complex networks typically found in urban environments.

The tool is pulled by the flow of water by a small drag chute while the line remains in service. When the sensor is inserted into a 2-inch tap, it remains tethered to the surface. This allows for real-time results and maximum control, as the tool can be winched back and forth to immediately confirm suspected leaks and other anomalies. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

Detection results include discovery of massive sinkhole near major roadway

The 2015 inspections, conducted over 23 days, challenged the Pure and DWU crews as they faced an environment with temperatures soaring to 104°F (41°C) on many consecutive days.

In spite of the trying working conditions, the crews successfully used the Sahara tool to locate 10 leaks in 16 miles of inspection. This included the unexpected discovery of a very large leak in the barrel of a 12-inch ductile iron water main. DWU’s proactive repair prevented a collapse since the large leak was creating a cavernous sinkhole near a major roadway.

By locating and repairing the leak, which had been seeping water for an estimated year, DWU averted a potential catastrophic crisis and saved the utility at least 893,000 gallons of lost water per year, equivalent to filling 1353 Olympic-sized swimming pools.

Olympic-sized swimming pool

Large leak discovery saved DWU at least 893,000 gallons of lost water annually, equivalent to filling 1353 Olympic-sized pools.

Sahara and SmartBall inspections in Dallas have been extremely successful, locating 160 leaks in 209 miles. The estimated water savings from these leaks is about 4 MGD. For DWU, the reduction in failures has reduced loss claims and service interruptions, as well as reduced treatment and delivery costs.

Whatever the weather, DWU is moving forward.

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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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.

Small leaks sink big ships – the same can be said for large-diameter pipes in utility networks. While large leaks or ruptures are seen as newsworthy stories accompanied by images of water flowing down the streets; smaller leaks can often be more devastating. Left undetected, they can add up over time, contributing significantly to Non-Revenue Water, and eventually, they too can lead to catastrophic pipeline failures.

Many utilities focus leak detection efforts on locating and repairing large leaks, with less priority being placed on identifying smaller ones. While repairing these large leaks is integral to preventing major failures that are expensive to the utility and disruptive to the surrounding environment; finding and repairing small leaks may present the best opportunity for long-term reduction of NRW loss.

Non-Revenue Water loss in the United States is estimated to be between 14 and 16 percent on average, while some systems are suspected to have revenue loss of up to 40 percent. In developing countries this number is much higher, with NRW loss as high as 65 percent in some areas.

The Benefits of Finding Small Leaks

Identifying and repairing small leaks early in their life may be the best course of action to address the problem of future water loss. Catching a leak while it is small prevents decades of sustained water loss that may not otherwise be detected. Over the years, unreported water loss could mean significant financial loss for the utility. Additionally, utilities that fail to proactively find and fix unreported water main leaks allow a growing backlog of new leaks to occur slowly over time. The result is mounting water loss volumes and “hot spots” in some locations; as a number of small leaks can ultimately lead to a major pipeline failure.

Acoustic leak detection sensors have been developed to run through in-service water trunk mains, bringing the sensor to the leak sound, rather than relying on the leak sound to find the sensor. Inline surveys work exceptionally well on large-diameter water transmission trunk mains, which are often poor at transmitting leak sounds and have limited access points to the pipe.

Inline Leak Detection Case Studies

Inline leak detection services have been proven to reliably identify very small leaks on water trunk mains with pinpoint precision, without requiring the water main to be taken out of service.

Engineering staff from Metropolitana Milanese in Milan were able to reduce their water loss and renew the condition of one of their critical mains by conducting proactive inline leak detection using Pure Technologies’ SmartBall® inline leak detection tool. They found a concentration of eight small leaks in a 240 meter section of pipe, exposing a weak area of pipe that could eventually lead to a critical failure. Metropolitana Milanese was then able to take proactive measures to defend against major ruptures.

SmartBall with case and insertion tools

The SmartBall tool is a free swimming leak detection technology that follows the product flow of the pipeline, picking up acoustic anomalies that identify and locate very small leaks and gas pockets. Because it has very little operational noise, the sizes of the detected leaks are minute. In optimal operational conditions leaks as small as 0.028 gal/min have been detected.

With the ability to detect even smaller leaks at 0.005 gal/min (in optimal conditions), Pure Technologies’ Sahara leak detection platform is another tool that can be deployed. Because it is a tethered system that is operator controlled, it is also able to map the location of the leak within 0.5 meters (3 feet). The Sahara tool simultaneously provides real-time visual inspection of live pipeline conditions thanks to an inline video system that travels along the pipe with the acoustic sensor.

Carried out regularly, comprehensive leak detection programs can not only identify large, potentially catastrophic leaks, but also smaller leaks that over time contribute to NRW and eventually become damaging themselves.

Though not quite as old as Rome’s ancient aqueduct system, the water and wastewater infrastructure operated by many North American utilities might, to some observers, appear just as antiquated.

For many pipeline operators, failures on pipelines installed decades ago are increasing in frequency, and as large-diameter pipeline assets begin to fail more frequently, the results can be more severe. This ongoing problem leaves utilities between a rock and hard place on whether to maintain or replace their assets.

Pipeline operators might do as the astute Romans did – take a step-by-step proactive approach to manage their transmission systems, enhanced today with the help of modern inline technologies.

The U.S. Environmental Protection Agency and American Society of Civil Engineers estimate the funding costs associated with buried infrastructure ranges from more than $200 billion to $1 trillion over the next 25 years. Pure Technologies is helping utilities manage their buried infrastructure through its Assess and Address® approach to pipeline management. This approach has saved clients hundreds of millions of dollars in capital replacement costs.

Assess and Address the System for Potential Problems

Conventional pipeline management allowed a pipeline to fail multiple times before replacement. While this “three strikes and you’re out” approach may work well for small-diameter distribution pipelines, it isn’t a cost-effective solution for large-diameter pipelines, especially those built without redundancy and without practical options to shut down.

A capital replacement program for large-diameter pressure pipelines not only carries a high price, but also poses significant logistical challenges, especially in urban centers. The headaches get bigger if a section of problematic pipeline runs through the downtown core and is the main source of water for a hospital or office tower.

Through the assessment of more than 8,000 miles of large-diameter pipelines, it is clear that even problematic transmission mains can be managed. In fact, Pure has found that 96 percent of pipe sections do not have any deterioration at all and are in “like new” condition, while less than 1 percent of pipe sections require immediate repair.

Better Understanding Ensures Fewer Surprises

In order to effectively manage a pipeline system, utility operators must first understand their pipeline system. Since many systems were built decades ago, the drawings are often out of date, as features have been added or removed over the years. By completing the knowledge-gathering process before attempting inspections or repairs, utility operators can avoid surprises and create a streamlined pipeline management effort.

By working with a firm that specializes in condition assessment, utility operators can gain a better understanding of their network, and create a prioritized plan for inspection or renewal.

As an example of smart collaboration, Pure Technologies has partnered with Washington Suburban Sanitary Commission (WSSC) in a multi-year program to manage approximately 145 miles of prestressed concrete cylinder pipe (PCCP) water transmission mains that serve nearly 2 million customers outside of Washington, DC. By adopting the Assess and Address model, WSSC has been able to evaluate and actively monitor the condition of its PCCP inventory instead of completing an expensive capital replacement project. To date, over 70 miles of PCCP is being safely managed for approximately 6 percent of the capital replacement cost, saving WSSC nearly $2 billion, which was the estimated capital cost of replacing the assets entirely.

Pure’s fundamental approach to pipeline management programs is to maximize the life of the existing pipeline. Maintaining an existing pipeline though proactive repair and management is in the utility’s economic interest. Our approach identifies deteriorated pipe sections, allowing for isolated repairs that extend the life of a pipeline, rather than making broad recommendations to replace the entire pipeline with capital funds.

Based on the average annual capital spending of large water utilities, it would take decades to replace large-diameter assets entirely, without factoring in the need for other capital renewal projects. Not only is this expensive and time consuming, it is also logistically challenging and disruptive to replace large sections of pipeline.

The Assess and Address Approach Involves 4 Steps

To successfully implement a pipeline management program, utilities can generally follow four key steps:

  1. Understand – Review current pipeline data, complete a risk evaluation, and develop appropriately scaled condition assessment strategies for prioritized pipelines.
  2. Assess – Execute condition assessment using a variety of tools to collect data and evaluate the data to assign condition ratings. This step includes a report of findings and recommendations on how to manage the pipeline.
  3. Address – Problematic locations identified in the condition assessment can be renewed immediately or planned for future re-inspection.
  4. Manage – After rehabilitation, the risk of failure is lower and proactive management measures should be employed to maintain a low risk.

As a result of Pure’s pipeline management programs with clients that range from small towns to major cities, utilities have seen a significant per-mile reduction in costs, while obtaining technically superior data on the real condition of their most critical pipeline assets. With such impressive numbers, it’s something ancient Roman engineers would appreciate.

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

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

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

Authors

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

For water service providers in Texas, providing customers with consistent, reliable access to water is crucial, particularly in the summer months when dry conditions impact the water supply.

In order to ensure that residents receive consistent water supply, the City of Irving and a partnering agency have collaborated in times of need to supply the other with water.

In one specific instance, the City of Irving was able to keep customers of the partnering agency supplied with water from one of its 48-inch transmission mains. The combined effort between the utilities showed excellent organizational cooperation to achieve the most important goal for any utility – finding a way to provide consistent service.

In January 2014, the two agencies teamed up again, this time to assess the critical 48-inch Jamison Main that links the two utilities. The transmission main was constructed in 1955 and is made up primarily of Bar-Wrapped Concrete Cylinder Pipe (BWP). Since its construction, however, the main has had modifications: in 1965 and 1968 sections of Prestressed Concrete Cylinder Pipe (PCCP) were added to accommodate the construction of Texas Stadium, and in 2009, another section of PCCP was added during the reconstruction of Loop 12 Highway.

The Difference Between PCCP and BWP

While BWP and PCCP look similar in cross-section, the pipe materials deteriorate in different ways and therefore are assessed differently.

For BWP, it is important for operators to identify and locate corrosion on the steel cylinder, since it is the main structural component and the bars are made with mild steel and are wrapped under less tension than PCCP; BWP essentially behaves like a mortar-lined and coated steel pipe.

PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water barrier. The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage.

Electromagnetic inspection tool

Electromagnetic inspection tool

Robotic tool insertion

Pure Technologies staff insert the robotic tool for assessment

As the prestressing wires in PCCP begin to break, the pipe becomes weaker and is more likely to fail catastrophically. It is important to locate and quantify the amount of broken wires in PCCP as they are the main structural component.

Because of the differences, the two materials are assessed using electromagnetic (EM) technology that identifies different signs of deterioration in each pipe.

In BWP, inspections identify both the presence of broken bars – which could indicate corrosion on the cylinder – and broad areas of corrosion on the cylinder itself. This approach allows operators to renew pipe sections with an undesirable amount of corrosion that could lead to pipe failure.

In PCCP, EM technology locates and quantifies the amount of broken wires. This method is extremely effective in identifying pipe sections that are suitable for renewal once the number of wire breaks passes a certain limit.

The Condition Assessment Program

For the Jamison Water Transmission Main assessment, the SmartBall® leak detection and PureRobotics® platforms were used to identify deterioration on both the primary pipe material, BWP, and the added sections of PCCP.

Completing a leak detection survey is an important aspect of a condition assessment project, since leaks are often a preliminary indication of a potential failure location. Pre-screening is particularly important in in BWP, since the steel cylinder is the main structural component and the pipe behaves similarly to a mortar-lined and coated steel pipe.

The leak detection survey identified one acoustic anomaly associated with a leak in 2.7 miles of inspection. The screening of the pipeline helps determine the baseline condition of the asset.

The PureRobotics platform was used for the structural assessment portion of the project. The tool is equipped with PureEM™ technology, which can identify distress on both pipe BWP and PCCP, but also features CCTV and above-ground tracking. By completing a structural assessment, damaged areas of the pipe can be targeted for selective renewal.

The Condition Assessment Program

In addition to gaining a valuable baseline condition of the transmission main, the assessment provided both utilities with more information about the location of additions to the critical transmission main.

The CCTV and line-locating feature were used to identify the exact location of two unknown manholes, which in turn were used as additional tracking locations. With more tracking locations during inline inspection, areas of distress can be more accurately located. The CCTV inspection also identified the location of a 48-inch gate valve and 90-degree bends.

Another challenge surrounding this main was accurate mapping of the sections that were added on after the original construction. Additions or alterations to existing pipelines can sometimes lead to inaccurate drawings. By tracking the tethered robotics tool above the ground using a manned sensor, Irving and its partnering agency were able to map out the relocated portions of the pipeline. This provides valuable information for future maintenance, assessment and renewal programs.

Through close collaboration, these two service providers were able to effectively manage a shared asset with the goal of preventing disruptive and expensive pipe failures. The information gained from the structural assessment will allow for the implementation of a cost-effective long-term pipeline management plan and effectively defer the replacement of the pipeline for the foreseeable future.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Case Study

Case Study: Trinity River Authority of Texas

After completing leak detection and structural condition assessment on 8.5 miles of PCCP and Bar-Wrapped Pipe, Trinity River Authority verified the results of inspection, finding three distressed pipe sections.

Technical Paper

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

To proactively address its large-diameter Prestressed Concrete Cylinder Pipe (PCCP) for deterioration, Tampa Bay Water (TBW) completed a leak and gas pocket survey and electromagnetic (EM) condition assessment of the South-Central Hillsborough Regional Wellfield Transmission Main in April 2013. The results of the assessment were verified in 2014 to determine the remaining useful life of the pipeline, which is responsible for delivering 10 percent of TBW’s 24 million gallons of raw water per day.

Based on the EM inspection, only 0.5 percent (11 of 2,177) of pipe sections contained varying levels of distress; subsequent structural and finite element analysis determined that only a fraction of the distressed pipes warranted further consideration. In addition to the structural assessment, the leak and gas pocket survey identified only one small leak.

The results show the critical transmission main is in excellent condition and can be safely managed despite being nearly 30-years-old. Some PCCP users throughout the United States have experienced major failures as their assets approach 40 years of operation.

TBW maintains a large pipeline network that serves the Tampa Bay and St. Petersburg metropolitan area and includes approximately 80 miles of PCCP. The pipeline inspections were completed on 8 miles of 42-, 48- and 54-inch PCCP that convey wellfield supply to the Lithia Water Treatment Facility.

For the leak and gas pocket survey, SmartBall® technology was used as a forerunner for the EM condition assessment and provided TBW with an initial condition of the pipeline.

Early identification and repair of leaks can reduce Non-Revenue Water (NRW), but also helps determine the baseline condition of a pipeline, since leaks can be an indication that a pipeline might fail. In addition, locating and eliminating gas pockets reduces pressure on the pumps that are attempting to push water past a pocket. As pockets grow in size, they can significantly affect the flow of water and capacity of the pipeline if not released.

After the prescreening survey, TBW completed an EM inspection using PipeDiver®, a free-flowing EM tool that is able to accurately locate and quantify broken wire wraps in PCCP. The wire wraps in PCCP act as the main structural component; broken wraps are the main indication that this type of pipe will eventually fail.

TBW’s asset management program allowed them to prioritize and take the first steps in determining the remaining useful life of a critical asset. This will lead to more informed decision-making for the future management of this main through reinspection, monitoring or renewal.

 

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Technical Paper

Beyond the Wires: A Sustainable Approach to Prestressed Concrete Cylinder Pipe Management

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

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Critical large-diameter water transmission mains frequently run beneath city streets in busy urban environments. Like the majority of water infrastructure across North America, these pipes are reaching the end of their design life. However, pipelines in urban environments pose a significantly greater risk and challenge to water utilities.

These pipelines are high-risk because of their high consequence of failure; if a pipe beneath a busy downtown street fails, the repair costs can quickly escalate and the failure causes a massive disruption to businesses and commuters. In some cases, failures in urban environments have cost utilities upwards of $5 million to remediate. A failure not only carries a high repair bill, but contributes to a negative public perception of the utility which can harm consumer confidence and lead to negative public relations.

With such high risk, utilities often prioritize these mains ahead of those with lower consequence of failure. However, because these mains are located in high-traffic areas, assessing them is far more challenging than assessing a linear main in a rural area.

Dealing with above ground obstructions, commuter delays and a lack of access points means that operators need to have close control over inspection technologies. In addition, the technology must provide the best possible information to allow for accurate repair and excavation decisions.

Like other major metropolitan areas, the City of Montréal has aging pipeline infrastructure that runs through its downtown core. In Montréal – one of the oldest cities in North America – this infrastructure is very old and beginning to reach the end of its design life. In order to proactively identify problem areas in its Prestressed Concrete Cylinder Pipe (PCCP) assets, the City is in the midst of an inspection program using advanced non-destructive technologies. In total, the City will assess the condition of over 40 kilometers of PCCP by 2015.

In the majority of cases, assessing the condition of assets to identify problem areas has high value for utilities, since the majority of pipelines have remaining useful life, despite their age. This allows for selective rehabilitation in favour of full-scale replacement. This is particularly important in urban areas, since excavation costs are higher and more disruptive in urban environments.

PureRobotics platform

The PureRobotics platform remains tethered to the surface during inspection. 

Pipe with damaged areas

Verification showed large areas of damage to both the prestressing wires and steel cylinder.

Related Topics

For a large portion of the condition assessment, the City is using the PureRobotics™ platform, since it is ideal for challenging urban environments. The tool remains tethered to the surface during inspection and is controlled by an operator. It also features live high definition video to observe internal pipe conditions. These features allow the City to see internal pipe conditions and closely verify areas with potential problems.

In addition, the tool identifies broken prestressing wire wraps in PCCP. As PCCP ages, the prestressing wires, which make up the main structural component, begin to break due to a number of factors.

The presence of broken wires in PCCP is the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstrates how PCCP typically fails.

How PCCP Fails

Recently, the City has completed the assessment of just over 17 kilometers of its urban PCCP assets with diameters of 600, 750 and 900 millimeters (24, 30 and 36 inches). Of the 2,798 pipe sections assessed in this 17 kilometers, only 97, or 3.5 percent, have shown evidence of distress. This is slightly below the industry average of 5 percent of pipe sections with distress.

Using condition assessment, the City has been able to identify isolated distress on its critical urban mains, while leaving pipeline assets with remaining useful life in operation.

After completing the initial phases of condition assessment, the City has excavated certain sections of pipe for validation of the inspection results, as well as repair of any damage.

Both the excavation locations and presence of distress have been very accurate. This has allowed the City to repair isolated pipe sections, which restores the overall condition of the pipeline. This will help to prevent failures that would significantly disrupt day-to-day life in the city.
In addition, the City now has a baseline condition of all of the assessed pipelines, which helps in the development of future capital planning for monitoring or re-inspection.

By proactively assessing its PCCP mains, the City of Montréal is taking steps to prevent pipe failures, while allowing for more fiscally responsible asset management in the future.

 

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PureRobotics™ – Pipeline Inspection

Robotic Pipeline Inspection

PureRobotics uses powerful modular robotic pipeline inspection systems that can be configured to inspect virtually any pipe application 12-inches (30.5 centimeters) and larger.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Technical Paper

Beyond the Wires: A Sustainable Approach to Prestressed Concrete Cylinder Pipe Management

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

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.

For water service providers, providing customers with consistent, reliable access to clean water is crucial. In densely populated urban areas, such as the Greater Toronto Area (GTA), this often requires operators to manage and assess pipelines that cannot be removed from service, yet provide water to a large number of end-users.

In April 2013, The Regional Municipality of York, in conjunction with the Regional Municipality of Peel and the Ontario Clean Water Authority (OCWA), assessed the condition of the York-Peel Feeder Main, which stretches roughly 25 kilometers, (18 km in York Region and 7 km in Peel) through both Regions. The pipeline is made of 1800-mm (72-inch) Prestressed Concrete Cylinder Pipe (PCCP) and provides a crucial supply of water to residents and businesses in York Region.

In spring 2014, York Region repaired three leaks found through a prescreening survey and verified the condition of one pipe section showing signs of structural deterioration identified through electromagnetic (EM) inspection.
Identifying leaks in large-diameter transmission mains is important in reducing Non-Revenue Water (NRW) – which can be defined as water that is produced for consumption and lost before it reaches the customer. Reducing NRW helps eliminate waste and contributes to the conservation of a crucial natural resource.

In addition to the environmental benefit of reducing water loss, eliminating leaks plays an important role in pipe integrity. The presence of leaks often indicates a potential failure location and by identifying leaks, utilities can reduce pipe failures and gain a better understanding of the overall condition of their system.

For its prescreening survey, York Region used SmartBall® technology, which is a free-flowing tool that identifies the sound of leaks as it travels through a live, operational pipeline. In total, the prescreening survey identified seven anomalies that resembling leaks. Four of these leaks were matched up with existing pipeline features while the other three were verified and repaired by York Region. One of these leaks was located on a 1200mm, high-pressure line running adjacent to the 1800mm line.

While prescreening and leak detection is an important part of condition assessment, critical large-diameter transmission mains warrant a more detailed inspection to identify areas of structural deterioration. By doing this, utilities can identify specific pipe sections that are at risk of failure before they rupture.

Although inspection shows that a large percentage of pipe sections have no deterioration at all, eliminating the risk of one failure can be very beneficial, since the typical cost associated with a large-diameter pipe rupture is between US$500,000 and US$1.5 million, not including the reputational damage a failure can cause.

To identify distress in its PCCP transmission main, York Region completed a non-destructive EM inspection using PipeDiver® technology. 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. As the prestressing wires in PCCP begin to break, the pipe becomes weaker and is more likely to fail catastrophically. It is important to locate and quantify the amount of broken wires in PCCP as they are the main structural component.

When assessing PCCP, PipeDiver technology locates and quantifies the number of broken wires. This method is extremely effective in identifying pipe sections that should be target for renewal once the number of wire breaks passes a certain limit.

The inspection covered 4,280 pipe sections and identified 17 pipe sections that had signals indicative of wire break damage. This represents less than one per cent of the feedermain, meaning the asset is in very good condition. York Region accurately verified the condition of one section of pipe with an unacceptable amount of wire breaks.

A portion of the project also used the condition assessment data to complete detailed risk analysis that will provide York Region with a better understanding of how their pipes perform. This allows for the development of a baseline condition of the entire transmission main and aids the development of long term management, renewal and re-inspection plans.

Although this pipeline was constructed in 2005 and is relatively young, the condition assessment was completed proactively to ensure the continued safe operation of the asset. Managing risk through proactive condition assessment is an excellent tool for operators of large-diameter pipelines. The York-Peel Feedermain conveys roughly 165 million liters per day and in time, will achieve a maximum capacity of 380 million liters per day.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

For decades, the best way to manage aging pipeline assets was using instinct, which was a precarious method at best. However, with the development of new methods for managing critical water assets, operators are more equipped than ever to manage risk in a way that allows for scientifically defensible and cost-effective decisions.

In March/April edition of Water Canada Magazine, the Regional Municipality of Peel will be featured for its risk management approach to managing its existing and new infrastructure. The article outlines the project’s objectives and how Peel Region is attempting to manage risk with its new water assets.

Read Full Article in Water Canada Magazine »

The Peel water supply system has a total of 4,500 water mains that cover 700 kilometers. The pipe diameters in the system range from 300 to 2,100 millimeters with seven pressure zones.

Meanwhile, Peel’s population is expected to grow from its current 1.3 million to approximately 2.5 million in the next two decades. The region needs to fund new infrastructure while also maintaining the existing aging pipes, all within the constraints of a rate-based water supply system that is supplemented with new development charges.

One approach the region is taking to accommodate a growing population is constructing new transmission mains. The Hanlon Water Project will construct a new 2400-millimeter (96-inch) Prestressed Concrete Cylinder Pipe (PCCP) transmission main. The water main construction project is the largest in Peel’s history and will run approximately 14.5 kilometers from the Lakeview Water Treatment Plant on Lake Ontario to the Hanlan Reservoir and Pumping Station at Tomken Road and Britannia Road East.

With the construction of a new PCCP pipeline, Peel Region is taking the opportunity to make its infrastructure smarter using advanced monitoring technology. In total, 14.5 kilometers (9 miles) of new pipe will be equipped with SoundPrint® Acoustic Fiber Optic technology, which monitors the condition of PCCP in real-time.

The monitoring system is able to record the acoustic signature of prestressing wire breaks in the pipe. In PCCP, the high-strength steel prestressing wire wraps are the main structural component – as these wires begin the break, specific pipe sections become weaker and more likely to fail. Each time a wire wrap breaks, Peel Region will receive a notification with the location of the wire break, allowing them to track how many wire breaks have occurred on each pipe section. This will allow the region to intervene once a pipe section has an undesirable number of wire breaks and is at risk of failure.

However, beyond preventing potential pipe failures, the monitoring system will also allow the asset to be monitored for its entire service life, which is rare for most pipelines, which typically begin to get monitored at some point during their service life. In theory, with regular maintenance, the monitored PCCP mains could have an indefinite service life, since deterioration will be tracked and mitigated on an ongoing basis.

 

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Assess & Address Pipeline Management Program

Pipeline Monitoring

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

Cobb County-Marietta Water Authority (CCMWA) is the second largest drinking water supplier in Georgia, providing vital service to nearly 800,000 people through twelve wholesale customers. With two award-winning water treatment plants and over 200 miles of large-diameter transmission mains, CCMWA can deliver up to 158 million gallons per day. Two of CCMWA’s key objectives are to be financially viable and to reduce vulnerabilities by improving redundancy and implementing a comprehensive asset management program.

However, across the United States critical infrastructure is aging, causing utilities to see an increased number of water pipe failures. While these failures occur most commonly on small pipes – causing only minor disruptions – large-diameter mains do fail, resulting in major delays and enormous repair bills.

A large portion of CCMWA’s large-diameter pipeline inventory is made up of Prestressed Concrete Cylinder Pipe (PCCP). In order to successfully manage PCCP, the water industry has widely adopted the use of condition assessment techniques, which have a proven track record of identifying and averting PCCP failures. PCCP owners and operators continue to use these condition assessment methodologies combined with sound engineering analysis to effectively and safely manage their critical assets.

Cobb County’s Program

In 2012, CCMWA was in a similar situation to many predominant PCCP users; past failures on these critical assets had led to the decision to replace the majority of PCCP assets to avoid the risk of future failures. However, it was determined that replacing large sections of pipeline was not financially or logistically feasible.

Large-scale replacement programs are also unnecessary based on industry research, which confirms that pipe deterioration is not uniform or systematic. Specifically, electromagnetic inspection data (which identifies both the quantity and location of broken prestressing wires – the primary structural component of PCCP) collected by Pure Technologies over more than a decade indicates that less than 4 percent of pipe sections inspected have any level of wire break damage and less than 1 percent require repair – regardless of when it was manufactured.

SmartBall tool extraction

The SmartBall tool is retrieved from the extraction point.

PipeDiver retrieval

Staff remove the PipeDiver tool after the non-destructive assessment.

Therefore, by making the decision to replace entire alignments of PCCP, owners typically remove a majority of pipeline assets that are in like-new condition. A financial evaluation based on the cost of capital replacements compared with PCCP management (inspection, repair, re-inspection, and repairs) for the 48-inch diameter PCCP in CCMWA’s inventory indicates that the pipelines can be managed for approximately 10 percent of the capital replacement costs when extended over 25 years using a net present value calculation (Figure 1).

Capital Replacement vs Condition Assessment

Figure 1: Financial Evaluation of Capital Replacement vs Condition Assessment

Following a repair on a 30- and 42-inch Raw Water Line in 2012, CCMWA decided to manage its critical PCCP assets using condition assessment and engineering analysis as a proactive management strategy. In 2013, CCMWA completed its first full inline condition assessment to identify structural deterioration on its PCCP. The project focused on the 30- and 42-inch main that had previously been found to have defective joints and a deteriorating pipe wall to determine its remaining useful life.

The Inspection Program

The assessment featured two inspections – a leak and gas pocket survey and inline electromagnetic (EM) inspection – on roughly four miles of the 30- and 42-inch PCCP Raw Water Line. The subject pipeline acts as a redundant supply line from Lake Acworth to the Wyckoff Water Treatment Plant. The project also included engineering evaluations including structural analysis and remaining useful life evaluations to make management and renewal recommendations. For the prescreening survey, CCMWA used SmartBall® leak detection, a free-flowing tool that identifies the acoustic anomalies associated with leaks and gas pockets in large-diameter pipelines. Completing a prescreening leak and gas pocket survey is a prudent approach for operators of any pipe material, since leaks are often a preliminary indication of a failure location. For PCCP, leaks are usually located near the pipe joint, which is also a common failure area on PCCP. However, the inspection did not identify any leaks or pockets of trapped gas. For the more detailed structural evaluation, the PipeDiver® electromagnetic (EM) inspection platform was used. The tool uses electromagnetics to identify broken prestressing wires, which are the primary structural component in PCCP. As sections of PCCP begin to deteriorate, the prestressing wires begin to break, which weakens the pipe and makes it more likely to fail. Identifying broken wires is the most effective way of determining the condition of and preventing failures in PCCP. By completing an EM inspection on the PipeDiver platform, CCMWA was able to determine the baseline condition of the pipeline while it remained in service – a major benefit for operators who cannot remove mains from service to complete internal inspection.

The Results

For CCMWA, the inspection identified ten pipe segments amounting to less than 1 percent of the pipeline with evidence of broken prestressing wire wraps. On average, PCCP inspections across the country indicate that approximately 4 percent of the pipe segments have any level of damage. This confirms that the majority of CCMWA’s PCCP inventory is in good condition, with only a small number of pipe sections in need of immediate renewal. However, locating and renewing even one pipe section can help utilities maintain reliable service and avoid an expensive pipe failure. Beyond the prescreening and structural inspections, CCMWA was able to identify limitations in its potable water system through the planning portion of the project. The inspected pipeline is a redundant line which carries raw water to the Wyckoff Treatment Plant; the primary supply line to the plant is a 60-inch line. In order to ensure that the main was being operated safely within its limits, a hydraulic study was completed. This study found that the 30-inch section of the pipeline was incapable of supplying the treatment plant’s required operating flow rate while maintaining a safe operating pressure within the system. Operating the pipeline under the required pressures places the main at a higher risk of failure in the event that the primary raw water line is taken out of service. Based on the study, it was recommended that the approximately 1 mile of 30-inch PCCP be replaced to handle existing and future operating condition requirements of the treatment plant. This discovery allowed CCMWA to make defensible decisions about their 30-inch PCCP main and pumping station while contributing to the prevention of future pipe failures. By upgrading the 30-inch section of the pipeline, the raw water pipeline will remain a safe redundancy line for the main 60-inch line. By managing its PCCP assets using condition assessment, it has also been determined that less than 1 percent of pipe sections on the assessed main have any indication of wire break damage, which is consistent with industry standards. Additionally, the prescreening survey showed that there are no leaks or gas pockets that require maintenance. The results from the inspections will allow CCMWA to cost-effectively manage its PCCP assets in favor of completing a large-scale replacement.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Ecuador coast picture

Providing reliable access to clean water is a challenge faced by many Ecuadorian utilities; pipeline ruptures, leaks and unplanned shutdowns are not only inconvenient, but also represent the loss of a critical resource. Beyond the challenge of providing clean water, utilities are also tasked with finding a reliable method to assess critical water pipelines for structural damage.

Unlike oil and gas pipelines – which are typically designed to allow for inspection – critical water transmission mains are often hard to access. Many water mains also lack redundancy, meaning they cannot be shut down for proper inspection.

The Scope of Interagua’s Program

In a comprehensive program starting in 2011, the authority of Guayaquil (operated by Interagua Ltd.) addressed the challenges surrounding their water service delivery by assessing their critical transmission mains. The proactive condition assessment program identified defects on Interagua’s large-diameter Steel and Prestressed Concrete Cylinder Pipe (PCCP) transmission mains through the use of advanced inline inspection.

Specifically, the project included the prescreening of all pipelines using inline leak detection, structural condition assessment on PCCP pipelines using electromagnetic (EM) technology and internal close-circuit television (CCTV) and broadband electromagnetic assessment of steel pipelines. Through the program, Interagua ensured service reliability in the long run but also helped advance the technology available for assessing in-service steel pipelines.

Although ensuring service reliability was the primary reason Interagua began the program, there were several other factors that contributed to the need for assessment. In terms of external factors, the critical pipelines were set in aggressive soil, which threatened to deteriorate their condition. The pipelines are also under a variety of loads and operating pressures due to the growth of the city; this adds additional strain and can lead to structural damage.

Operationally, the pipelines have no redundancy and cannot be shut down for scheduled preventative maintenance. This made the pipelines high-risk because any disruption would interrupt service indefinitely. Also, because there is no redundancy, the pipelines had been in service for several years without interruption; finding a reliable inspection method for in-service pipelines was crucial for Interagua.

Broadband Electromagnetic inspection

Interagua and Pure completed Broadband Electromagnetic inspection on 5 kilometers of steel pipeline.

Staff prepare to insert the PipeDiver® tool

Staff prepare to insert the PipeDiver® tool to identify deterioration in Interagua’s PCCP.

Prescreening Using Inline Leak Detection

To begin assessing their critical pipelines, Interagua and Pure Technologies partnered in 2011. The scope of the project covered Interagua’s most critical pipelines that run through the north of the city. These mains are made of both steel and Prestressed Concrete Cylinder Pipe (PCCP) in diameters of 2000-mm, 1800-mm, 1500-mm, 1250-mm and 1050-mm. Considering that the 2000-mm steel main is only 20 years old and has a cathodic protection, the project focused on the other pipe diameters.

In total, roughly 66 kilometers of pipeline was surveyed for leaks and air pockets, and a significant portion of this was also assessed for structural deterioration. The main objective of inspecting the pipelines was to identify the actual condition of the pipes, including the specific amount and location of distress. From the results, a rehabilitation, replacement and maintenance plan could be created to ensure long-term service reliability. The inspections also provided Interagua with actionable information about pipe condition that could not be attained through conventional engineering studies.

In order to locate leaks and air pockets on all 66 kilometers of the transmission mains, Interagua used SmartBall® technology, an acoustic free-flowing leak detection tool that operates while a pipeline remains in service. The primary goal of the survey was to identify critical leaks that could be prioritized for repair by Interagua.

Locating and repairing leaks helps to reduce non-revenue water (NRW) and preserve a scarce resource. However, repairing leaks early also increases pipeline reliability, since leaks are often a preliminary indication of a failure location, particularly in metallic pipe materials. Failures in metallic pipe are often preceded by a period of leakage, so identification of leaks on metallic pipelines has the added benefit of ensuring structural reliability and preventing costly pipe failures.

Through the use of inline leak detection, Interagua identified 44 total leaks and four air pockets in the 66 kilometers of inspection. Of these leaks, 16 were identified as small, 17 as medium-sized and 11 as large leaks. Of the identified leaks, 14 were located on the 1250-mm sections of steel pipe.

Identifying Structural Deterioration through Condition Assessment

To identify structural deterioration on its PCCP mains, Interagua used the PipeDiver® platform, a free-flowing electromagnetic (EM) condition assessment tool. The tool finds structural defects by identifying and locating wire breaks in PCCP; the presence of broken wires is the main indication that PCCP will eventually fail.

The tool is able to effectively determine the baseline condition of PCCP while the pipeline remains in service. The ability to inspect live pipelines was a major factor for Interagua, as many of their critical PCCP mains could not be taken out of service for maintenance or inspection.
In total, Interagua completed almost 10 kilometers of EM inspection on its 1500-mm and 1800-mm PCCP mains that run north of the city. The inspection identified 90 pipe sections with some level of distress out of a possible 1429 pipe sections; after thorough engineering analysis, it was determined that only nine pipe sections should be replaced.

Through the use of EM condition assessment, Interagua was able to determine that only 6 percent of its PCCP inventory had distress, while less than one percent required immediate action. This approach saved a huge amount of capital budget by avoiding unnecessary replacement and also restored pipeline reliability.

For its 1250-mm steel pipeline inventory, Intergua also completed robotic CCTV inspection and Broadband Electromagnetic (BEM) inspection to identify areas of concern. Inline CCTV provides information about internal pipe conditions, while BEM technology can determine the remaining wall thickness of steel pipe through outer coatings of up to 50-mm.

In total, 21 kilometers of steel pipe was assessed, including 5 kilometers of BEM inspection. The results showed that Interagua’s steel pipe inventory was in good overall condition and had sufficient remaining wall thickness. Through the use of inline leak detection, CCTV and BEM inspection, Interagua identified the baseline condition of its critical steel pipes, which helped in the development of a future maintenance and repair plan.

The Results

Interagua’s large-diameter pipeline management program was very successful and determined that the vast majority of its large-diameter assets did not need to be replaced. The approach of assessing the pipelines to locate specific, isolated problems prevented the costly replacement of pipe with significant remaining useful life.

In addition to successful results, the project has been instrumental in the development of a reliable condition assessment method for mortar-lined steel pipelines; based on the initial results, Interagua will continue to assess its steel pipelines using the most advanced condition assessment technologies available, including free-flowing condition assessment of steel pipelines, which was unavailable at the inception of the project.

By investing capital resources into a condition assessment program, Interagua has successfully extended the useful life of its system and restored asset value by repairing isolated pipe sections and determining that the majority of pipelines have no distress and have significant remaining useful life.

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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.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Pipeline Inspection and Condition Assessment Services

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

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.

TRA Verification
Leaks on small-diameter distribution pipelines are the most common leaks a utility encounters. However, locating and repairing leaks on large-diameter transmission pipelines is also important in maintaining safe and reliable service delivery. These leaks are often more sparse, and therefore more difficult to locate which can lead to prolonged leakage and extensive water loss.

Utilities that have a leak detection program in place for their large-diameter transmission mains often achieve greater reductions in Non-Revenue Water (NRW), which is the amount of water lost before it reaches the customer. Furthermore, a leak detection inspection is a valuable step as part of a condition assessment program. Utilities can avoid expensive capital replacement programs by gathering real data on the condition of their pipelines, and addressing problems as they arise.

Bloem Water, who provides water services to the central region of South Africa, recently implemented an asset condition assessment project that included a comprehensive leak detection program using inline methods on a strategic 1200-millimeter (48-inch) Prestressed Concrete Pipe (PCP) that supplies the City of Bloemfontein with roughly 60 percent of its drinking water.

Inline leak detection is the most accurate method of locating leaks because it brings the acoustic sensor directly to the leak source, unlike traditional methods, such as correlators and listening sticks. These techniques lack the accuracy needed to locate leaks in larger pipes because the sound of a leak dissipates rapidly in large-diameter pipes.

Both SmartBall® and Sahara® leak detection technologies were successfully applied for Bloem Water. The total inspection covered 103 kilometers between De Hoek Reservoir and Brandkop Reservoir and identified 30 leaks.

To maximize efficiency, the SmartBall tool was used first to cover large sections of the distance in single deployments. The tool is a free-swimming leak detection platform that operates while the pipeline remains in service. It is equipped with an acoustic sensor that identifies acoustic anomalies associated with leaks; the acoustic signature is then analyzed to determine if it is a leak, air pocket, or an external noise.

SmartBall tool before insertion

The SmartBall tool prior to insertion.

Staff during tool extraction

Staff retrieving the tool at the end of inspection.

To maximize efficiency, the SmartBall tool was used first to cover large sections of the distance in single deployments. The tool is a free-swimming leak detection platform that operates while the pipeline remains in service. It is equipped with an acoustic sensor that identifies acoustic anomalies associated with leaks; the acoustic signature is then analyzed to determine if it is a leak, air pocket, or an external noise.

The SmartBall inspections were followed by selective Sahara audio and visual surveys to provide visual confirmation on the location of the leaks in order to aid in the interpretation of findings and plan interventions. The Sahara tool is a tethered inline leak location and condition assessment technology that pinpoints the location of leaks while at the same time inspecting the internal condition of the pipeline and verifying the cause of leakage using a combined acoustic hydrophone with an integrated CCTV camera.

Visual leak verification was also performed at all accessible components along the pipeline.

The leaks were identified and classified as either pipeline leaks (i.e. on the pipe barrel itself), component leaks (i.e. at valves, air valves, scour valves, etc.) or off-take leaks. The majority of the leaks were found to be at components while pipeline leaks were detected mainly on joints (i.e. where the PCP was connected with prefabricated steel joint pieces). Some of the leaks on these joints may be attributed to poor bedding, improper VJ connections, among other things.

The estimated water loss based on indicative leak sizing categories amounts to approximately 1200 kiloliters per day. Interestingly, of the pipeline leaks detected, only three leaks showed any surface signs of leakage. This reiterates the importance of not relying on surface inspections as the only means of detecting large-diameter pipeline leaks.

The findings of the latest leak detection surveys were compared to that of a previous Sahara leak detection inspection project performed in 2007-2009 to establish trends. This information, combined with a first order engineering evaluation of available pipeline design and manufacturing data, the failure history of the pipeline, operating records and the hydraulic behavior of the system were incorporated into a risk assessment model for the pipeline.

The leak detection findings, engineering evaluation and risk assessment were factored into the development of a pipeline-specific management strategy. Bloem Water can now implement this strategy as a guideline to proactively manage this valuable asset in order to prolong its remaining useful life, avoiding expensive capital replacement of the asset.

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Pipeline leak detection systems

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.

Smartball- Leak and Gas Pocket Detention

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.

Non-Revenue Water (NRW)

Non-Revenue Water (NRW)

Each day, billions of gallons of water are lost worldwide. Not only does this represent the loss of a precious resource that not everyone has access to; it represents a massive amount of lost revenue for the utilities that provide it.

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.

In the October 2013 issue of Trenchless Technology, the Lake Huron Primary Water Supply System (LHPWSS) was recognized for its proactive pipeline management program.

LHPWSS serves about 500,000 people in eight different municipalities in the London Region and provides about 44 million gallons of water per day (170 million liters). 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-millimeter (48-inch) Prestressed Concrete Cylinder Pipe (PCCP).

In October 2012, LHPWSS and Pure Technologies completed a 47-km condition assessment of Lake Huron Pipeline A using advanced non-destructive technologies. The system has about 25 km of non-redundant pipeline, making it very difficult to shut down for inspection and repairs without disrupting water supply to customers.

The proactive condition assessment allowed LHPWSS to selectively rehabilitate its most critical pipeline in favor of replacement.

All of the winners are featured in the October 2013 issue of Trenchless Technology magazine and will be formally recognized at the 2014 No-Dig Show, to be held in Orlando, Florida. Winners are chosen on the basis of technical advancement, technical complexity, milestones and records achieved, interaction and cooperation, and advancement of the trenchless industry.

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PipeDiver Device Extraction
Staff verifying EM results

Pure’s staff successfully verify the EM results on behalf of LHPWSS in spring 2013.

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.

About half of LWC’s 200 miles of large-diameter transmission mains are made of Prestressed Concrete Cylinder Pipe (PCCP). As PCCP ages, the prestressing wires, which make up the main structural component, begin to break due to a number of factors.

The presence of broken wires in PCCP is the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstates how PCCP typically fails.

How PCCP Fails
AFO Monitoring

Louisville Water completes annual rehabilitation of its large-diameter transmission mains.

MSW article

(Source: MSW Magazine)

In 2009, LWC experienced a large-diameter PCCP failure. Fortunately for LWC, it was in a relatively low-risk location which reduced its repair cost. The pipeline also had redundancy that prevented a long service disruption.

“Had it broken 2,000 feet down the line, the cost of that would probably have been $10 million,” said Keith Coombs, manager of infrastructure planning for Louisville Water in an article for Municipal Sewer and Water. “We considered ourselves very fortunate.”

After narrowly escaping an expensive pipe failure, LWC began a proactive annual condition assessment program that addresses deterioration in PCCP.

For structural assessment, LWC uses PipeDiver® technology, which is a free-swimming electromagnetic (EM) tool used to identify and quantify wire breaks in PCCP. The EM sensor collects a magnetic signature reading as the tool traverses the pipeline and identifies anomalies produced by wire breaks in PCCP. The tool operates while the pipeline remains in service, allowing LWC to avoid shutting down service to assess the condition of its most critical pipelines.

LWC inspects about 8 to 10 miles of PCCP annually. Typically, between 2 and 4 percent of LWC’s PCCP is found to have deterioration, while less than 1 percent needs to be addressed immediately. This is consistent with industry averages, meaning it is most cost-effective to complete condition assessment and address isolated problems before replacing large sections of pipe, which carries a huge cost.

Pure Technologies’ data from over 8,000 miles of pressure pipe condition assessment indicates that only a small percentage of pipes (less than 5 percent) are in need of repair and therefore have a significant remaining useful life. Condition assessment data also suggests that pipe distress is localized and a significant ROI can be achieved by locating and addressing isolated problems through structural inspection.

Read “Continuous Improvement” in Municipal Sewer and Water »

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Industry reports also offer a bleak outlook about infrastructure in the United States; the American Society of Civil Engineers 2013 Report Card on America’s Infrastructure gave water and wastewater infrastructure a ‘poor’ rating and estimated that the cost to renew these systems would range from US $200 billion to US $1 trillion over the next 25 years.

While most of the discussion surrounding American water infrastructure involves pipe failures and the fiscal impact of renewal, water loss from leaking pipes is a major problem for utilities that often goes unnoticed. The U.S. Environmental Protection Agency (EPA) estimate that on average, between 15 and 20 percent of water never reaches the consumer, but is as high as 60 percent in some municipalities.

This loss accounts for a huge financial cost for operators in terms of billing and wasted energy used to pump and treat the water, but also represents the waste of a critical natural resource.

The Challenge for Dallas Water Utilities

In places like Dallas, TX, managing water loss is an important matter for utilities, especially in the summer months when users are affected by severe droughts and forced to restrict consumption. The droughts also bring extreme heat and dryness which dries out the soil and causes pipes to shift. This can lead to the accelerated development of leaks.

To mitigate this problem, Dallas Water Utilities (DWU) has completed an annual summer leak detection program since 2004 on its large-diameter water transmission mains that range in size from 12-inches to 84-inches. The inspection program focuses on a variety of piping materials including Prestressed Concrete Cylinder Pipe (PCCP), Cast Iron Pipe and Ductile Iron Pipe.

To date, DWU has inspected 100 miles of pipe in the program, locating 120 leaks. This has allowed for a major reduction in water loss and helped ensure service reliability.

Staff insert the Sahara® tool into a live pipeline

Pure Technologies staff insert the Sahara® tool into a live pipeline.

Water systems in large metropolitan areas are made up of thousands of miles of pipe varying in size; the distribution system, which delivers water directly to taps, is very large and features small-diameter pipe; transmission mains, which transport high volumes of water throughout an area, are made up of a smaller amount of large-diameter pipe. Because so many areas depend of these pipelines for supply and their high consequence of failure, maintaining transmission mains effectively is a high priority for operators. For DWU, the criticality of these pipelines was a major factor in adopting a leak detection program that focused on its large-diameter pipe.

According to a study completed by the American Water Works Association, leaks on large-diameter pipelines account for roughly 8 percent of the total leaks, but almost 50 percent of the total water lost from leakage. The discrepancy is created because transmission mains have a much higher capacity and operating pressure than distribution mains, meaning small leaks are actually leaking at a very high rate.

By focusing leak detection programs on large-diameter pipes, operators can achieve a much larger reduction in water loss by identifying and repairing evena single leak.

There are several methods of locating leaks on large-diameter pipelines. Non-invasive methods, such as correlators or listening sticks, work very well on small-diameter distribution mains but often lack the accuracy needed to address large pipes, as the sound of a leak does not travel as well as pipe diameter increases.

Conversely, inline leak detection methods aren’t well suited for distribution mains due to pipe size and complexity, but are very effective in accurately locating leaks on large-diameter transmission mains because they bring the leak detection sensor directly to the source of the leak, unlike non-invasive systems.

For inspection of its transmission mains, DWU uses Sahara® leak detection – a tethered platform that combines acoustic leak detection and inline CCTV – offered by Pure Technologies Ltd. The tool is non-destructive and is pulled by the flow of water by a small drag chute while the line remains in service. When the sensor is inserted into a tap, it remains tethered to the surface to allow for immediate confirmation of suspected leaks and gas pockets, internal pipe wall conditions and pipeline features by winching the sensor back and forth from the surface. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

 

How DWU saves water using inline leak detection

“Since introduction to Dallas’ program in 2004, Sahara technology has been a reliable tool for locating and eliminating leaks on larger diameter pipelines,” says Randy Payton, Assistant Director of Dallas Water Utilities. “The program allows the Department to plan and prepare the repair in lieu of responding to a failure.”

The tool is capable of locating very small leaks due the sensitivity of the acoustic sensor. In terms of reducing water loss, small leaks may actually represent the best opportunity for long-term improvement. Leaks on large-diameter pipelines typically form and mature over a period of decades. They tend to grow larger over time, up until a point where the pipe fails or the leak surfaces.

Locating and repairing a large leak prevents it from leaking for the “tail end” of its life, and from failing catastrophically. Catching a leak while it is very small does this as well, but also prevents the decades of sustained water loss that would occur as it grows into a large leak. Using technologies that can locate small ‘pinhole’ sized leaks can identify small leaks early on before they grow into larger leaks or lead to pipeline failure.

In the annual pre-planning stage, DWU identifies the ideal access points needed for the inspections based on their knowledge of the Sahara platform from previous years – there are usually about 30 insertions through 2-inch access points each year. Inspections are usually done during the summer months when most of the leaks are developing, and higher volumes in the pipelines allow longer distances to be inspected. DWU also controls the water flow closely during inspections to optimize the inspection distance. After many years of inspection, DWU staff has become adept at identifying the best insertion points and controlling the flow rate to maximize the tool’s capabilities.

During tethered inspections, there is significant traffic control required when the transmission mains runs beneath busy streets, since the tool is controlled and tracked above the ground by staff members. To avoid major commuter disruptions, the City will reroute traffic and thoroughly plan the insertions to avoid high traffic times – for example, inspections frequently start in the mid-morning when traffic slows as opposed to during morning rush hour. Beyond traffic control, staff from DWU and Pure will often work on weekends when downtown Dallas is less busy.

There are also unavoidable environmental challenges that require adjustments. Sometimes the water main will run under a busy highway or an environmental obstacle like a river, making it impossible for the staff member on the ground to track the tool and mark exact leak locations. In this case, the operator needs to review potential leaks more closely by winching the tool back and forth to determine the exact location.

DWU’s leak detection program has been extremely successful, locating 120 leaks in the 100 inspected miles. The estimated water savings from these leaks is about 7.2 million gallons per day.

The CIty has also seen a 17 percent reduction in catastrophic water main failures, likely as a result of the proactive approach in fixing leaks. Leaks, particularly in metallic pipe materials, are often a preliminary indicator of a failure location as it is a preliminary sign of distress. The reduction in failures has reduced property loss claims and service interruptions, as well as reduced treatment and delivery costs.

“Several factors affect the success of leak detection,” adds Payton. “After nine years, the utility continues to be impressed with its accuracy within the varied environments and piping materials.”

 

Through continued commitment to leak detection on its transmission mains, DWU is improving service reliability and saving significant amounts of water. DWU also completes regular structural assessment of its transmission mains to identify distress that could lead to pipe failure.

 

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Pipeline Inspection and Condition Assessment Services

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Case Study

Case Study: Dallas Water Utilites Leak Detection Program

Dallas Water Utilties anually inspects its large-diameter water transmission mains for leaks using Sahara® technology. Through DWU’s efforts in identifying and repairing leaks, about 7.2 million gallons per day has been saved and major failures have been reduced by 17 percent.

Non-Revenue Water (NRW)

Non-Revenue Water (NRW)

Each day, billions of gallons of water are lost worldwide. Not only does this represent the loss of a precious resource that not everyone has access to; it represents a massive amount of lost revenue for the utilities that provide it.

Critical to its economic success is a reliable supply of water, which is supplied by Miami-Dade Water and Sewer Department through four major transmission mains operated by the City of Miami Beach’s Public Works Department that range in diameter from 20- to 36-inches.

A failure or disruption on one of these transmission mains would significantly reduce Miami Beach’s treated water capacity, and therefore its ability to act as a major tourism destination.

With infrastructure across the United States aging and reaching the end of its design life, utilities are experiencing more pipe failures that are both costly to repair and disruptive to local economies.

Although Miami Beach has never experienced a large-diameter water transmission main failure, it is proactively addressing deterioration on its critical pipelines using condition assessment.

In September 2013, Miami Beach completed an electromagnetic (EM) structural evaluation on 3.4 miles of its largest transmission main – the Julia Tuttle Causeway – which is made up of 36-inch Prestressed Concrete Cylinder Pipe (PCCP), Cast Iron (CI) and High Density Polyethylene (HDPE) pipe.

After completing a prescreening survey, Miami Beach completed an EM condition assessment survey using PipeDiver®, a free-swimming EM tool used to identify and quantify wire breaks in PCCP.

During an inspection, the tool collects a magnetic signature reading as it traverses the pipeline and identifies anomalies produced by wire breaks in PCCP. The tool is ideal for performing a baseline inspection of a PCCP pipeline that cannot be removed from service. The 3.4 mile inspection was completed successfully, with the tool tracked throughout the planned distance.

Staff with PipeDiver tool

The PipeDiver tool identifies and locates wire breaks in PCCP.

Tool insertion

The tool is inserted into a live pipeline in Miami Beach.

In PCCP, the prestressing wires are the main structural component; when wire breaks are found on a specific pipe section, it represents deterioration of its structural integrity. The ability to locate and quantify the amount of wire breaks in each pipe section allows a utility to make rehabilitation decisions and provides a baseline structural condition.

The data collected identified areas of prestressed wire breakage of varying degrees of criticality. The City is currently considering recommendations for rehabilitation, replacement and inspection of the remaining three transmission mains.

By managing its critical pipelines using a risk-based condition assessment approach, Miami Beach is proactively addressing deterioration in order to continue providing reliable service to a major economic hub.

 

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

Fast forward to 2012, and the Birmingham Water Works Board (BWWB) had the challenge of maintaining a critical pipeline that was constructed well before the board was even established in 1950.

In order to determine the baseline condition of nearly 8 miles of the RCP transmission main and proactively address Non-Revenue Water (NRW) loss, BWWB completed four inspections using SmartBall® technology, a free-flowing leak detection platform that operates while the pipeline remains in service.

The inspections using inline leak detection were very successful, locating 26 leaks of varying size with close location accuracy. Twenty of the leaks have since been verified and repaired by BWWB, while the remaining six leaks have been deferred due to their size or matched up with existing features.

In the August 2013 issue of Trenchless Technology, BWWB’s project was featured as an example of how utilities can manage their aging pipeline infrastructure through the use of advanced leak detection technology.

Read Full Article»

 

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Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

SmartBall® – Leak Detection for Water Trunk Mains

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

Case Study: Birmingham Water Works Board

In early 2012, the Birmingham Water Works Board (BWWB) ran a successful leak detection program on 7.7 miles (12 km) of 42-inch (1050-mm) Reinforced Concrete Pipe (RCP). The inspected pipelines are part of BWW’s system that transports water from the Shades Mountain Filter Plant to different areas of the city.

hese distinctions can make assessing BWP challenging for pipeline operators attempting to renew their large-diameter water transmission mains, since the methods for determining baseline condition in the similar-looking pipe types are different.

PCCP is a concrete pipe that remains under compression because of the prestressing wires, with the thin-gauge steel cylinder acting as a water membrane. With BWP, the cylinder plays a much larger role in the structural integrity of the pipe. BWP is essentially designed as a steel pipe with mild steel used to manufacture the steel cylinder and steel bars.

The high strength steel wire in PCCP is smaller in diameter and wrapped under higher tension, therefore corrosion makes it quite vulnerable to breakage. The mild steel bars in BWP are thicker in diameter and wrapped under less tension, therefore corrosion takes significantly longer to lead to breakage.

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

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

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

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

Pure Technologies staff verify the pipe condition

Pure Technologies staff verify the pipe condition

Crew verify and reveal corrosion on three pipe sections

Verification revealed corrosion on three pipe sections

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

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

Through the use of condition assessment, TRA was able to selectively rehabilitate its assets for roughly 4 percent of the estimated $25 million replacement cost. The project has also allowed TRA to increase service reliability for customers in the region.

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Case Study

Case Study: Trinity River Authority of Texas

After completing leak detection and structural condition assessment on 8.5 miles of PCCP and Bar-Wrapped Pipe, Trinity River Authority verified the results of inspection, finding three distressed pipe sections.

Technical Paper

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

Baltimore City features 130 miles of Prestressed Concrete Cylinder Pipe (PCCP), 15 percent of which is Class IV PCCP installed in the 1970s. This particular class of pipe has been prone to early failures across the United States, making it a major priority for BPW as it renews its water and wastewater infrastructure.
PCCP Diagram

The steel used in Class IV PCCP was the strongest used in the manufacturing of PCCP lines, but the same factors that gave the steel wires high strength have also made them vulnerable to brittleness when exposed to corrosive conditions, and therefore more likely to break.

Broken wires in PCCP are the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstates how PCCP typically fails.

How PCCP Fails

To prevent failures, BPW began installing monitoring equipment in its PCCP to alert staff when the prestressing wires break, BPW also regularly inspects its transmission mains for deterioration using EM technology that locates wires that are already broken.

Read “Ears Peeled for Trouble” in Municipal Sewer and Water »

 

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Assess & Address Pipeline Management Program

Pipeline Monitoring

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

Case Study

Case Study: Baltimore City

In summer 2012, Baltimore City Public Works (BPW) intervened on a critical 54-inch PCCP pipe that was showing signs of distress. The pipe section was replaced and service resumed after avoiding a major pipe failure.

The inspections are part of AWU’s proactive condition assessment program that focuses on leak detection and structural condition assessment through the use of advanced non-destructive technologies.

Focusing leak detection efforts on large-diameter pipelines is an excellent method to reduce Non-Revenue Water (NRW) and gather baseline condition information. While leaks on small-diameter distribution mains are the most common, leaks on large-diameter transmission mains account for a significantly higher percentage of the total water lost; repairing even one leak on a transmission main can achieve a significant reduction in NRW.

Identifying air pockets reduces pressure on pumps that are attempting to pump water past an air pocket. As pockets grow in size, they can adversely affect the flow and capacity of a pipeline.

In addition a reducing water loss, early identification of leaks helps reduce pipeline ruptures, as leaks are often a preliminary sign that a pipeline may eventually fail due to pipeline corrosion or loss of bedding support due to soil erosion. By identifying leaks early on, AWU is effectively reducing NRW, reducing their risk of failure, and gathering valuable baseline condition information on its pipelines.

SmartBall Tracking
SmartBall Tool

The inspections completed in June 2013 were completed on two separate pipelines, the Ulrich 72-inch Prestressed Concrete Cylinder Pipe (PCCP) potable water transmission main and the Airport Road 24-inch C-303 Bar Wrapped Pipe (BWP) and Cast Iron potable water transmission main.

AWU used SmartBall® technology for both inspections. The SmartBall tool is a free-swimming inline leak detection platform that identifies the acoustic anomalies associated with leaks and air pockets that operates while the pipeline remains in service. The tool is tracked via fixed or portable receivers that are positioned strategically throughout the planned inspection distance. Following an inspection, the collected data is analyzed to determine if the acoustic anomalies represent leaks or air pockets and verified by AWU staff.

The Ulrich inspection covered a total of 6.6 miles in 6 hours and located no leaks or gas pockets. In order to successfully complete the inspection, AWU staff had to overcome one major operational constraint to ensure the tool could complete the inspection distance. Shortly after the insertion near the Ulrich WTP, the pipeline travelled beneath the Colorado River before making a 200-foot vertical climb, which can be difficult for free-flowing technologies without proper preparation. To overcome the challenge, AWU and Pure Technologies completed comprehensive flow simulations during the project planning phase to ensure the tool could traverse the vertical incline; this allowed the SmartBall tool to successfully travel up the steep hill.

In the Airport Road inspection, 2.4 miles of inspection was completed, successfully locating three leaks and giving AWU confidence that there are no air pockets restricting flow capacity in this line.

During both inspections, AWU and Pure Technologies worked closely to overcome operational challenges that allowed for successful leak detection surveys.

AWU supplies water to nearly 890,000 customers within and outside the corporate city limits of Austin, as well as the communities of Rollingwood, Sunset Valley, one water control and improvement district, five water supply corporations, seven municipal utility districts, and three private utilities. To ensure reliable service to its customers, AWU proactively addresses its infrastructure needs through regular inspection and rehabilitation to prevent service disruption and costly emergency repairs.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

WSSC needed to repair a 54-inch Prestressed Concrete Cylinder Pipe (PCCP) that was near failure. The decision was made after WSSC’s Acoustic Fiber Optic (AFO) Monitoring system, which is installed on about 75 miles of WSSC’s PCCP, identified several wire breaks in a short period of time.

The alternative, however, would have been much worse.

Had the pipeline failed, residents in Prince George’s County would have been without water for much longer than a few days. A failure would have also been more expensive than proactively replacing a pipe section, since more excavation and restoration is required to remediate a failed pipe. Luckily, four WSSC workers were able to fix an old valve, which allowed water to be diverted to residents and prevented complete water shut off.

WSSC explains the seriousness of the situation

“We wouldn’t be doing this if there wasn’t an imminent problem with this pipe.”

WSSC spokesman Jim Neustadt on WTOP Radio.

“[The acoustic system] tells us this pipe is headed out… We can’t just sit back and wait.”
– WSSC spokesman I.J. Hudson in the Washington Post.

Another WSSC official suggested a failure to the 54-inch pipe would have similar effects to previous failures WSSC has seen.

“Think about River Road when that water main exploded in 2008, and there was a pouring of water going down River Road. We don’t want this situation to end up like that.”

– WSSC spokeswoman Lyn Riggins on WTOP radio.

PCCP is concrete pipe that’s reinforced by high-strength steel wires; as wires in a pipe section snap, the pipe becomes more likely to fail. The AFO system used by WSSC identifies these wire breaks as they occur, and when the number reaches a certain limit, WSSC is advised to intervene on specific pipe sections to prevent failures.

After WSSC began experiencing major PCCP failures in the 1970s, it developed a strong commitment to infrastructure management technology in favor of large capital replacements. Beginning in 2007, WSSC and Pure Technologies began a partnership to create and Assess and Address™ PCCP management program. The program combines the early-warning system with regular condition assessment of its large-diameter pipes using inline leak detection and electromagnetic technologies.

WSSC in the news

Several stories surrounding the pipe intervention focused on how WSSC is managing its PCCP pipelines to prevent costly pipeline failures.

WSSC early warning system
Watch how WSSC is addressing its aging infrastructure by identifying the most critical problems using state-of-the-art inspection and monitoring technology. [ Source: WUSA9 ]
WUSA9 Story
See how WSSC’s monitoring system identified the problem in Prince George’s County to avoid a major pipeline failure. [ Source: WUSA9 ]
Gary Gumm Interview at WYSA9
WSSC’s Chief Engineer Gary Gumm outlines how challenging managing critical infrastructure is and what WSSC is doing to ensure that its customers have reliable service. [ Source: WUSA9 ]

WSSC is the 8th largest water and wastewater utility in the United States, serving over 460,000 customer accounts and 1.8 million residents in Montgomery and Prince George’s County, Maryland (suburban Washington D.C.). WSSC operates nearly 5,500 miles of water mains, with approximately 145 miles comprised of large-diameter Prestressed Concrete Cylinder Pipe (PCCP) equal to or greater than 36-inches in diameter.

The Washington Post Covers the Pipe Intervention

The Washington Post produced two notable stories providing information for Prince George’s residents, as well as discussion on why the intervention happened.

Four WSSC workers helped avert disaster by fixing defective valve

For almost 12 hours on July 16, WSSC mechanics chiseled years of thick rust off gears that corrosion had frozen in place and then fashioned new gears out of the gunked-up pieces of metal. By doing this, WSSC was able to isolate a shorter section pipeline to make repairs on the damaged 54-inch pipe section and avoid shutting down water service completely to Prince George’s residents.

To see the full story in the Washington Postclick here.

To see a video from WUSA9 on how workers closed the valve, click here.

Through management of its critical PCCP transmission mains, WSSC continues to show strong commitment to renewing its aging infrastructure and providing quality service to residents in its area.

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Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Case Study

Case Study Download: Washington Suburban Sanitary Commission

Beginning in 2007, WSSC and Pure Technologies began a partnership to create a comprehensive PCCP management program for WSSC’s large-diameter transmission mains. The Washington Suburban Sanitary Commission (WSSC) is the 8th largest water and wastewater utility in the United States, serving over 460,000 customer accounts and 1.8 million residents in Montgomery and Prince George’s County, Maryland (suburban Washington D.C.)

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.

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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.

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.

Two utilities – TMVW in Belgium and the Department of Sustainable Waste and Water in Gothenburg, Sweden – completed successful inspections to locate leaks and gas pockets using SmartBall® technology in early 2013.

TMVW’s inspection covered almost 15 kilometers (9 miles) of a 900-mm (36-inch) Reinforced Concrete Cylinder Pipe transmission main that runs from Willebroek to Buggenhout, locating 10 acoustic anomalies resembling leaks. Most leaks are located where the pipeline is known to have non-welded joints, and joint movement is suspected as the cause for leaks. The same pipeline was inspected in 2010, locating several leaks that were later repaired by TMVW.

In Gothenburg, Sweden, Department of Sustainable Waste and Water completed a successful leak detection survey on almost 5 kilometers (3 miles) of a pipeline that ranged in size from 600-mm to 800-mm in April 2013. The inspection identified 17 anomalies resembling leaks, with four classified as large leaks. While the utility staff suspected that the pipeline had a few leaks, they were surprised at the amount detected by the inspection. Work is currently underway to verify and repair the leaks found by SmartBall.

SmartBall TMVW
Gothenburg SmartBall

The SmartBall inspection tool is a non-destructive, free-swimming technology that measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines. When acoustic anomalies are present, the data is analyzed to determine if it is a leak, gas pocket, or just an external sound. The tool is tracked using SmartBall receivers that are mounted along the pipeline at strategic locations.

Regular leak detection inspections can identify leaks that may not be visible at the surface and have presumably been leaking for a long time. By repairing leaks, utilities can reduce their non-revenue water and prevent pipeline failures, as leaks are often an indication of pipeline deterioration.

Locating and eliminating gas pockets is also beneficial because it reduces pressure on pumps that are attempting to pump water past a pocket. As they grow in size, gas pockets can significantly reduce the flow and capacity in a pipeline.

 

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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.

Two utilities – TMVW in Belgium and the Department of Sustainable Waste and Water in Gothenburg, Sweden – completed successful inspections to locate leaks and gas pockets using SmartBall® technology in early 2013.

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.

To proactively address its large-diameter Prestressed Concrete Cylinder Pipe (PCCP) for deterioration, Tampa Bay Water (TBW) completed a leak and gas pocket survey and electromagnetic (EM) inspection of the South-Central Hillsborough Regional Wellfield Transmission Main in April 2013.

TBW maintains a large pipeline network that serves the Tampa Bay and St. Petersburg metropolitan area and includes approximately 80 miles of PCCP. The pipeline inspections were completed on 8 miles of 42, 48 and 54-inch PCCP that convey wellfield supply to the Lithia Water Treatment Facility.

A leak and gas pocket survey was completed using SmartBall® technology as a forerunner for the EM condition assessment and provided TBW with an initial condition of the pipeline. The inspection was very successful, with the tool travelling steadily throughout and reaching all the tracking points. Several members of Tampa Bay Water were on hand at the retrieval to see the tool in action.

Early identification and repair of leaks can reduce Non-Revenue Water, but also helps determine the baseline condition of a pipeline, since leaks can be an indication that a pipeline might fail. In addition, locating and eliminating gas pockets reduces pressure on the pumps that are attempting to push water past a pocket. As pockets grow in size, they can significantly affect the flow of water and capacity of the pipeline if not released.

PipeDiver Team
Tool Insertion

In the following days, TBW prepared for the EM inspection using PipeDiver®, a free-flowing EM tool that is able to accurately locate and quantify broken wire wraps in PCCP. The wire wraps in PCCP act as the main structural component; broken wraps are the main indication that this type of pipe will eventually fail.

After completing inspection and analysis, Tampa Bay Water will have a wire wrap break estimate for each section of PCCP on this pipeline, which will allow them to make a prioritized rehabilitation and re-inspection plan.

The PipeDiver inspection was completed on schedule with the tool tracked throughout and retrieved successfully at the Lithia Water Treatment Plant. Results from both inspections are currently being analyzed for Tampa Bay Water.

 

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Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

Free-Swimming Pipeline Inspection

Electromagnetic Pipeline Inspection

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

The York-Peel Feeder Main provides a critical supply of water for residents and businesses in The Regional Municipality of York. The pipeline is made of 1800-mm (72-inch) Pre-stressed Concrete Cylinder Pipe (PCCP) and runs roughly 25 kilometres (about 16 miles) through both Peel Region and York Region.

Although the pipeline was built in 2005 and is relatively young, York Region conducted two proactive inspections in April 2013 using advanced inline technologies to locate leaks, gas pockets and structural deterioration. Multiple stakeholders, including Peel Region, the Ontario Clean Water Authority (OCWA), York Region and local municipalities necessitated careful planning to minimize service disruption for end users.

Regular leak detection can help utilities identify leaks that may not be visible at the surface. These proactive repairs can help to reduce their non-revenue water and prevent pipeline failures, as leaks are often a precursor to pipeline failure. Locating and eliminating gas pockets also helps to reduce pressure on pumps attempting to pump water past an air pocket. As pockets grow in size, they can adversely affect the flow and capacity of a pipeline.

The SmartBall® leak detection tool was used to assess the pipeline for leaks and gas pockets and is often used as a precursor to electromagnetic (EM) condition assessment of PCCP pipelines. The SmartBall platform is a non-destructive, free-swimming tool that measures the acoustic activity associated with leaks and air pockets.
The tool was launched just downstream of the Airport Road Pump Station in Peel Region and was tracked successfully throughout the inspection and retrieved at the Maple Reservoir in York Region.

An EM inspection was completed on the pipeline using PipeDiver®, a free-swimming EM tool used to identify and quantify wire breaks in PCCP. The EM sensor collects a magnetic signature reading as the PipeDiver traverses the pipeline and identifies anomalies produced by wire breaks in PCCP, which are the main indicator that a pipe of this type will eventually fail. The tool is ideal for performing a baseline inspection of a PCCP pipeline that cannot be removed from service.

During the inspection, the PipeDiver was tracked through the pipeline as it passed 17 Butterfly Line valves of various designs and sizes. For retrieval of the tool at the Maple reservoir, a tethered robotic device was used in favour of a trained diver, which increased the safety and efficiency of the retrieval process.

York Region was pleased with the inspection process and will be completing follow up engineering analysis as the leak and gas pocket survey and EM results become available.

 

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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.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

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.

In February 2012, The City of Montreal conducted a leak detection survey using the Sahara® platform on a water transmission main in downtown Montreal that had known leaks.

The pipeline on Pine Avenue is an 80-year-old, 34-inch cage and cylinder Bonna-type pipe – a variation of Reinforced Concrete Cylinder Pipe (RCCP) – that had an unknown number of leaks that were unsuccessfully located using other non-intrusive techniques during previous inspections.

The Sahara leak detection inspection was extremely successful, locating nine leaks ranging from small to large size in the 1.3-kilometer (0.8 miles) survey. The City was expecting to find one major leak and possibly another minor one and was surprised at the number of leaks identified.

The Pine Avenue pipeline is a critical supply of potable water to the western portion of a major sector in the city, which made it important for the City to locate and repair the suspected leaks.

The City had been working with Pure Technologies in pipeline assessment program since 2007 that included electromagnetic (EM) inspection and acoustic monitoring, which prompted the decision to use Sahara leak detection on Pine Avenue.

The Sahara platform is a non-destructive tool equipped with acoustic leak detection and inline video that is pulled by the water flow by a small drag chute and used to locate leaks, gas pockets, and internal pipe conditions in live, pressurized pipelines. When the sensor is inserted into a tap, it remains tethered to the surface to allow for confirmation of suspected leaks. The sensor is also tracked along the surface, allowing for precise marking of leaks in real time.

Regular leak detection surveys can help utilities identify leaks that may not be visible at the surface and may have been leaking for a long time. By repairing leaks, it reduces Non-Revenue Water and can potentially prevent pipeline failures, as the presence of leaks is often a preliminary indication that a pipe will eventually fail.

In August 2012, the City excavated all nine leaks for repair. The leak locations had been precisely identified and marked on-site during the inspection and all leaks were found within 1-meter (3-feet) of the marked location. All of the leaks also had a size that corresponded with the estimates made by Sahara technology.

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Pipeline Inspection and Condition Assessment Services

Pipeline Leak Detection Systems

Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.

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.

Abstract

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

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

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

Authors

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

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

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

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

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

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

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

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

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

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

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

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

 

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Sewer inspection hole

Sewer Force Main Inspection

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

In October 2012, Pure Technologies completed its first SmartBall® run in Casablanca, Morocco on 2 kilometers (1.2 miles) of 1000-mm (39-inch) Prestressed Concrete Pipe (PCP).

SmartBall was successful in precisely detecting and locating one leak along the transmission main and was tracked throughout the entire inspection by SmartBall Receivers (SBR) installed along the pipeline.

SmartBall is a free-flowing acoustic leak and gas pocket detection tool that is inserted into live pipelines. The tool measures acoustic anomalies associated with leaks and gas pockets, which are then analyzed and verified by data analysts.

Morocco SmartBall

The run in Casablanca was completed by the partnership of Pure Technologies and the Suez Environmental Group on behalf of Lydec, which operates more than 4,600 kilometers (2,850 miles) of pipeline in Casablanca.

Lydec is very pleased with the results of the inspection, as regular leak detection, condition assessment and monitoring of their pipelines is a main priority for the utility. Lydec has been very successful in saving water through various leak detection processes; saving 34 million m3 per year between 1997 and 2011.

 

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Sahara® - Leak & Gas Pocket Detection

Sahara® – Leak Detection for Water Trunk Mains

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

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

SmartBall® is an innovative free-swimming inline 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.

Pure Technologies completed a 47 kilometer (29 miles) inspection of the Lake Huron Primary Water Supply System’s Pipeline A using the SmartBall® and PipeDiver® inspection platforms in October, 2012.

After two successful inspections of the 1200-millimetre (48-inch) water transmission main, LHPWSS commended Pure’s staff for their effort.

“The staff members at Pure Technologies were extremely professional and their level of expertise with respect to PCC pipe is phenomenal. Truly, they are leaders in their own field,” said Brian Lima, P.Eng., Capital Projects Manager for the LHPWSS.

A video overview of the project can be seen below.

PipeDiver Insertion
SBR Tracking

Pure was contracted by LHPWSS for a condition assessment of its transmission mains after a failure to a 1200-mm (48-inch) pipe in May, 2012. This was the fourth failure on the system; the others were in March 2010, 1988 and 1983.

After the most recent failure, LHPWSS wanted to take a proactive approach in inspecting and maintaining its water transmission mains to ensure quality service to its customers. The information collected from this condition assessment will allow LHPWSS to understand the baseline condition of its pipeline, as well as selectively rehabilitate pipes to minimize capital costs.

Before the condition assessment project, Pure and LHPWSS – which serves several member municipalities – developed a comprehensive project plan to ensure that all stakeholders understood the work involved and each group’s responsibilities, as well as how the inspections would impact each stakeholder.

Prior to the inspections, Pure installed 33 SmartBall receivers (SBR) along the pipeline to track both inspection platforms as they travelled through the pipeline.

For the SmartBall inspection, Pure’s team mobilized at the Lake Huron Water Treatment Plant very early in the morning to launch the tool. A small portion of the pipeline was isolated and depressurized to allow for manual insertion of the SmartBall. Once the tool was in position, the pipeline was put back into service and the SmartBall started travelling down the pipeline. After traversing 47 kilometers, it was retrieved in the Arva Terminal Reservoir by commercial divers.

After a day off to prepare the PipeDiver and discuss any lessons learned from the SmartBall inspection, Pure’s staff returned to the Lake Huron Water Treatment Plant for the PipeDiver Inspection.

“The launch, tracking and retrieval of the PipeDiver is very similar to the SmartBall. So the SmartBall was an excellent trial run for the PipeDiver,” said Cameron White, Program Manager at Pure Technologies. “The PipeDiver is a larger tool and is generally harder to get in and out of the pipe, so the SmartBall run gave us good practice for the PipeDiver.”

The PipeDiver tool was also retrieved at the Arva Terminal Reservoir with the use of commercial divers.

Both tools were tracked successfully at all SBR locations during the inspections. In addition, Pure provided the client and its member municipalities with real-time updates using an online interactive map and messaging system after it passed each tracking point.

“It’s been a pleasure working with [Pure] and we look forward to a long working relationship as we continue our endeavors into inspection and ongoing monitoring of our system,” added Lima.

The Lake Huron system serves about 500,000 people over eight municipalities in the London area and pumps about 170 million litres of water per day. The transmission main, constructed in 1966, runs approximately 47 kilometers from the Lake Huron Water Treatment Plant near the community of Grand Bend, to a terminal reservoir located in the community of Arva, North West of the City of London.

 

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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.

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

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

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

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

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

AFO Installation
AFO Up Close

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

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

 

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Pipeline Monitoring

Pipeline Monitoring

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

Pipeline Inspection Services

Pipeline Inspection Services

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

Pure Technologies completed another successful year of its leak detection program with the City of Dallas and the Dallas Water Utilities (DWU) in July 2012.

This year, 16 leaks were found using Sahara® in just over 12 miles of inspection. The City and DWU are always efficient in repairing identified leaks, and since the conclusion of the 2012 inspection, have repaired about half of the leaks.

In 2004, DWU, which services 2.4 million customers in Dallas and nearby communities, began an ongoing proactive annual leak detection program using Sahara leak detection, though the DWU and Pure had been doing electromagnetic (EM) condition assessment since 2000. The leak detection program inspects pipes between 12-inches to 84-inches, and the transmission mains are made up mostly of Prestressed Concrete Cylinder Pipe (PCCP), but also feature Cast Iron Pipe and Ductile Iron Pipe. To date, approximately 86-miles have been inspected using Sahara.

The decision to implement an ongoing program with Pure stemmed from an internal study conducted by the City of Dallas of their large-diameter leak detection. The study found that it needed new technologies to improve efficiency.

Large-diameter water transmission mains in Dallas have a higher potential of developing leaks in the summer. Due to the high heat and lack of precipitation, the ground becomes extremely dry and hard, this shifts buried pipeline infrastructure slightly which can cause leaks to develop and ultimately water mains to break.

Sahara has been extremely effective in detecting leaks for DWU. Since the program began, 116 leaks have been found in DWU’s large-diameter transmission main network. The estimated water savings from all of the leaks detected by Sahara and repaired by DWU, is about 7.2 million gallons per day. DWU has also seen a 17 percent reduction in catastrophic water main failures since the start of the program; increasing service reliability.

 

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Sahara® - Leak & Gas Pocket Detection

Sahara® – Leak Detection for Water Trunk Mains

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

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

Pure Technologies pinpointed wire breaks on a large-diameter water main in Tucson using Acoustic Fiber Optic monitoring, possibly preventing a major failure.

On August 13, Tucson Water went into emergency mode when several wire breaks occurred in a short period of time on one of its 96-inch Prestressed Concrete Cylinder Pipe (PCCP) water transmission mains, indicating there was a high risk of failure. Tucson Water was able to react quickly to the wire breaks by reducing the pressure in the pipe and diverting water from another main to serve its customers, subsequently preventing a failure.

In the following days, Pure and Tucson Water verified the pipe and found it to be more damaged than originally expected, requiring more repairs. The condition of the pipe made it clear that Tucson Water’s decision to shut down and repair the line immediately prevented a failure.

This same pipeline failed in 1999 about 700-feet upstream from this pipe, dumping 38 million gallons of water into neighborhoods and costing the city $2.5 million. Since that time, Pure has been working with Tucson to develop a pipeline management program including electromagnetic (EM) assessment and AFO monitoring. Tucson Water was the first utility in North America to install an AFO system throughout their entire PCCP inventory.

Below is an ABC News 4 Tucson story outlining how Tucson Water’s AFO system identified an at risk pipe before it failed.

Pure and Tucson Water will continue to monitor the large-diameter water mains in Tucson to identify areas of distress and proactively repair pipe sections.

 

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Assess & Address Pipeline Management Program

Pipeline Monitoring

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

Pure Technologies worked with Baltimore City Public Works on July 16, 2012 to dig up a 54-inch pipe section that was ready to fail along the Gwynns Falls/Southwestern Transmission Main.

The excavated pipe section was severely damaged, and had it failed, would have caused significant damage, inconvenience and financial cost. The removal of the distressed pipe section shows Baltimore City’s commitment to preventing major failures in The City’s water system.

A feature story on WBAL-TV 11 from July 17 shows Pure working on verifying their results of the Gwynns Falls/Southwestern Transmission Main.

Pipeline Inspection in Baltimore
Water Main Repairs Get Expensive

Pure engineers inspected this line in March 2012 using PipeDiver® — a free-swimming tool that uses Electromagnetics (EM) to detect broken prestressing wires in Prestressed Concrete Cylinder Pipe (PCCP) – and found that the pipeline had wires broken in several sections.

In recent months, the situation became critical and removal of a severely damaged pipe section was strongly recommended when prestressing wires began breaking more frequently. The increase in wire break activity was detected early on through Pure’s Acoustic Fiber Optic (AFO) monitoring system that was installed during a 2007 project with Howard County. This system gives utilities an early warning alarm when pipelines begin to rapidly deteriorate, ultimately allowing the utility to resolve problems early on and prevent catastrophic failure.

After the city shut down and dewatered the transmission main, Pure’s team mobilized on site to inspect the distressed pipe section more closely. In the verification process, the wire break locations were confirmed through impact testing. Two large cracks were also found upon visual inspection, which created a hollow section in the pipe, confirming Pure’s suspicion that a failure could have occurred at any time.

Pure also inspected the distressed pipe section with an EM verification tool. After a combined analysis of data collected from the EM tool, PipeDiver®, and the AFO monitoring system, a good correlation was found between the distressed locations predicted by all three technologies. As a result, the damaged pipe was removed from the ground and the pipe was returned to operation on Saturday, July 21, 2012.

Through proactive measures, The City of Baltimore was able to avoid a major failure that would have caused significant disruptions to service and substantial financial cost. The City is committed to Pure’s proactive approach in pipeline management to continue preventing major failures.

 

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PipeDiver® Draws Media Attention for Baltimore

PipeDiver® Draws Media Attention for Baltimore

In early March, a group of reporters and video crews from local news stations gathered around the insertion site for a high profile PipeDiver® electromagnetic inspection in Baltimore, Maryland. It was necessary to perform the inspection without shutting down service to residents.

Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

PCCP Pipe

Managing Prestressed Concrete Cylinder Pipe (PCCP)

Large diameter prestressed concrete cylinder pipelines (PCCP) are a significant investment for many water and wastewater agencies. Assessing and monitoring the condition of these pipes is becoming an increasingly important and challenging task.

Louisville Water Company (LWC) needed an accurate condition assessment tool that didn’t require pipeline shutdown and lengthy cleanup. The utility turned to Pure to provide a solution. The PipeDiver® tool, moving with the flow of the water in the main, completed an 8.8-mile inspection of a 5-foot diameter PCCP main in eastern Jefferson County last month. Through a contract with LWC, Pure conducted the large-diameter PipeDiver electromagnetic inspection using the large launch and extraction stacks for the first time. View media coverage of the inspection.

In the past, inspections required such mains to be taken out of service, thus disrupting continuous service to customers. The pipeline may have been damaged during a pressure surge in 2009, prompting the utility to assess the main’s integrity.

The PipeDiver took five hours to travel from the B.E. Payne Water Treatment Plant through the main at an average velocity of 2.75 ft/s to a large water tank near North English Station, passing four 60″ butterfly valves in the 41-year-old PCCP pipe. This is the second phase in an 11-mile inspection project that started in May 2011 with a 2.5 miles robotic inspection, and will continue in October 2011. The PipeDiver tool is best suited for prestressed concrete lines as its electromagnetic sensors assess defects in the metal wires that give the prestressed concrete of the main its strength as it travels through the pipe.

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Free-Swimming Pipeline Inspection

PipeDiver® – Free-Swimming Pipeline Inspection

Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.

PCCP Pipe

Managing Prestressed Concrete Cylinder Pipe (PCCP)

Large diameter prestressed concrete cylinder pipelines (PCCP) are a significant investment for many water and wastewater agencies. Assessing and monitoring the condition of these pipes is becoming an increasingly important and challenging task.

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

The first PipeDiver project was recently completed on a fully operational prestressed concrete cylinder pipe (PCCP) wastewater force main for Baltimore County Department of Public Works. The inspection was completed as part of a comprehensive assessment of a 54-inch force main that also included Pure’s SmartBall® technology.

September 2011

PipeDiver’s electromagnetic assessment sensors provide a non-destructive method of evaluating the baseline condition of the prestressing wire (the primary structural component of PCCP) by estimating the quantity and location of wire breaks for each pipe section.

PipeDiver Insertion
“This is a significant advancement in wastewater force main condition assessment,” said Travis Wagner, P.E., Pure’s wastewater assessment leader. “The comprehensive condition assessment of PCCP force mains has historically proven difficult for wastewater collection system owners/operators since unlike potable water transmission mains, force mains generally lack redundancy and therefore, the ability to shut down the pipeline for a traditional comprehensive PCCP assessment.”

Thorough force main inspections often require significant operational and/or financial expenditures in order to bypass the wastewater flow via temporary pumping or a piped diversion. Through the successful implementation of the SmartBall and PipeDiver tools, PCCP force main owners/operators now have the ability to conduct comprehensive condition assessments of their wastewater PCCP assets with a significantly lower operational impact.

 

Case Study

Case Study

Baltimore County – Sewer Force Main Assessment

As part of Baltimore County, Maryland’s Wastewater Force Main Asessment Program, Pure Technologies inspected the 54-inch Patapsco PCCP Force Main using the SmartBall® and PipeDiver® pipeline assessment tools.

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

In the past, the focus for leak detection programs in water delivery systems has been primarily on distribution (reticulation) networks and service connections. Even today, trunk main leaks tend to be addressed only when there is a pipe rupture or when there is visual evidence of the leak above ground. So are leaks from trunk mains a problem?

The introduction of a new leak detection technology, called SmartBall®, has the potential to resolve the uncertainty about the rate of loss, if any, from trunk mains. Following two years of development, the system has been available commercially since June 2007 and experience to date has demonstrated that it a valuable tool for identifying, locating and quantifying leakage. Results indicate that trunk main leakage is indeed a concern for many agencies, and that most leaks are not evident from visual inspection or metering.

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.

Abstract

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

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

Authors

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

Introduction

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

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

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

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

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

Authors

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

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.