Archives

Video

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.

Video

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.

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.

Case Study

The Champlain Water District utilized a variety of methods, including high-resolution inline leak and air pocket inspection, transient pressure monitoring (TPM), and a structural design check to ensure a critical transmission pipe’s design was sufficient for current operational conditions.

Champlain Water District (CWD) is an award-winning regional municipal organization that supplies drinking water to 12 municipal water systems in Vermont. As the largest water supplier in the state, CWD serves approximately 75,000 residential, commercial and industrial users. CWD draws water from Lake Champlain, and three high-value water transmission mains supply water to the user municipalities. When evidence of corrosion-related breaks was revealed in nearby distribution mains, CWD became concerned that a critical metallic water main in their system could be next.

THE CHALLENGE

After conducting their own risk prioritization plan, Joe Duncan, Chief Engineer for CWD, and his team kept with the proactive mindset and began a transmission main asset management program.

While the transmission system is relatively “young” and had no real break history, visual feedback from crews showed distribution mains in the vicinity of the transmission mains were experiencing corrosion-related breaks and in some instances looking like “Swiss cheese”. Due to the high importance of the transmission pipeline, CWD wanted to understand its condition and forestall potential corrosion issues.

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

VIDEO CASE STUDY

Project Highlights

Design check confirmed that the pipe design was sufficient for current loading

Acoustic monitoring identified no leaks or gas pockets

Transient monitoring revealed no harmful pressure surges

Anticipated repair funding was re-allocated to other capital work projects

Project Details

Solutions
SmartBall acoustic leak detection
Transient pressure monitoring
Strucutral analysis
Pipe Material
Ductile Iron (DIP)
Inspection Length
1.8 miles (2.9 km)
Diameter
24 inches (600mm)
Transmission Type
Water

YOU MAY ALSO BE INTERESTED IN

Whitepaper:
Metallic Pipeline Condition Assessment

Case Study

The Town of Flower Mound, Texas (Town), worked closely with Pure Technologies to conduct a leak and gas pocket detection survey of approximately 1.91 miles of potable water mains, which included nearly 1.4 miles of metallic pipelines. The Town is home to 70,000 residents and manages both the water and sewer utilities within Flower Mound.

THE CHALLENGE

In 2001 the Town suffered an uncontrolled leak and lost pressure to a third of their system for a two-day period due to a valve that could not be located. This led to an asset management program, and through this program, the 3.5 mile potable water main was identified in 2015 as a main due for inspection.

Inspecting metallic pipelines has been a challenge for utilities because historically there have been few assessment solutions available. Utilities often used indirect methods of assuming the condition of the pipeline or replaced based on age and consequence of failure, not on the actual condition of the infrastructure. The Town enlisted the help of Pure Technologies to provide a comprehensive condition assessment of key sections of their steel, ductile iron and BWP pipes in order to make balanced and accurate decisions and improve the reliability of service within the system.

How was Pure Technologies able to help the town of Flower Mound address this challenge? Find out and explore the results we achieved together by downloading the full case study below.

VIDEO CASE STUDY

Project Highlights

17 sections with defects identified

1 leak found

1 air pocked identified

1 undocumented outlet located

1 defect validated and replaced

Project Details

Services
PipeDiver® electromagnetic inspection

Sahara® acoustic leak and gas pocket detection & visual inspection

Structural design review

Transient pressure monitoring

Timing
September 2015 – December 2015
Pipe Material
Steel, Ductile Iron, Bar Wrapped
Inspection Length
3.5 miles (5.6 kilometers)
Diameter
20-30 inches
Transmission Type
Water

YOU MAY ALSO BE INTERESTED IN

Whitepaper:
Metallic Pipeline Condition Assessment

Case Study

In order to better understand the condition of their buried pipeline network and proactively address potential water loss issues, the city of Park City, Utah engaged Xylem in creating a condition assessment program utilizing acoustic and transient pressure monitoring.

While the Park City Municipal Corporation set a goal for Park City to become the “The Best Resort Town in America,” its relatively small Public Utilities Department is also gaining accolades for its forward-thinking approach to leak detection and to addressing water loss in a city which receives about half as much rainfall as the national average. The city chiefly relies on melting snow to recharge the groundwater system, and the next viable source is much more expensive. The city also realized that rapid residential and commercial developments near Park City are placing increased demands on groundwater resources — and as the population swells, more expensive water sources will have to be pursued.

THE CHALLENGE

Jason Christensen serves as Water Resources Manager for Park City, which has more than 120 miles of pipe in its distribution network. Many of the pipes are more than 60 years old and are covered in mineral soil that is corrosive in nature. By reviewing SCADA and Sensus AMI consumption data, as well as results from a previous leak detection survey, Christensen was aware of leaks in their system that attributed to a loss of 100 GPM.

Park City engaged Xylem to deploy their intelligent sensor hardware and monitoring solutions as part of a condition assessment program to understand their system and reduce non-revenue water. The project involved monitoring 6 pressure zones and reporting on anomalies such as leaks and bursts and identifying assets that are likely to fail through predictive analytics.

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

VIDEO CASE STUDY

Project Highlights

$50,000 reduction in operating costs

Deployed 20 stations capable of measuring pressure and acoustics

7 previously unknown leaks detected (water loss of 200 gallons per minute)

Program costs expected to be repaid in under 3 years from water savings alone

Project Details

Solutions
Acoustic leak monitoring
Transient pressure monitoring
Pipe Material
Steel (transmission main) Ductile Iron & PVC (distribution mains) HDPE (service lines)
Inspection Length
13 miles (4.8 km)
Diameter
1-in (25mm) to 12-in (300mm)
Transmission Type
Water

YOU MAY ALSO BE INTERESTED IN

Whitepaper:
Metallic Pipeline Condition Assessment

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.

Case Study

To manage remaining useful life of a critical metallic force main, City of Cape Girardeau deploys SmartBall® as screening tool for condition assessment to identify gas pockets and high likelihood areas of internal corrosion.

Desktop studies commonly incorporate data such a pipe material, class, age, and failure history to assist in preliminary condition assessment programs without someone necessarily ever seeing the pipeline. Utilities often use desktop data as an initial step to help shape a management strategy.

For a higher level of condition assessment data, the health of a pipeline can be determined by combining desktop studies with an inline SmartBall leak and gas pocket survey, leading to focused test pits in areas where gas pockets indicate potential internal corrosion, the most common cause of ductile iron force main failure.

As proof of concept, Pure Technologies used the free-flowing SmartBall platform as part of a recent DIP force main condition assessment for City of Cape Girardeau, Missouri.

Project Details

Services
SmartBall leak and gas pocket survey

Condition assessment aided by SmartBall gas pocket location

Field service verification

Ultrasonic Thickness (UT) Testing for structural evaluation

Remaining Useful Life (RUL) analysis

Pipe Material
Ductile Iron Pipe (DIP) HDPE
Inspection Length
3 miles (4.8 km)
Diameter
20-in (500mm) & 24-in (600mm)
Transmission Type
Wastewater

Project Highlights

3 miles total distance inspected

26 gas pockets detected

5 pipes excavated, visually inspected and wall thickness measurements obtained

RUL data determined failures may occur within 2 years where gas pockets detected and 15 to 30 years where gas pockets were not present

THE CHALLENGE

The City of Cape Girardeau (Cape G) proactively manages 550 miles of water and wastewater pipelines for a population of nearly 40,000.

In January 2017, Cape G retained the services of Pure Technologies to field verify and further assess the condition of the Riverfront Force Main, a three-mile pipeline comprised of 20 and 24-inch ductile iron pipe (DIP), with a few replacement sections of HDPE.

Cape G had experienced a failure on Riverfront Force Main on the Memorial Day weekend of 2016. As the force main is relatively new (installed in 2000) and runs along the Mississippi River, the condition assessment of the non-redundant main was critical for the City.

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

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

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

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

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

Gas pockets are of significant concern in rising mains.

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

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

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

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

Four steps to a risk-based approach.

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

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

Most common reasons for pipeline failure.

Preliminary analysis.

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

Acoustic-based SmartBall® tool locates leaks and gas pockets

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

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

Internal corrosion potential survey.

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

Pipe wall assessment.

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

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

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

Condition assessment analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

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

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

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

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

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

Gas pockets are of significant concern in force mains.

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

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

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

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

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

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

Preliminary Risk Analysis

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

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

Acoutic-based SmartBall® tool locates leaks and gas pockets

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

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

Internal Corrosion Potential Survey.

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

Pipe Wall Assessment.

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

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

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

Condition Assessment Analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

 

Case Study

Intermunicipal Service Oeiras and Amadora is a water management company responsible for the distribution of drinking water for the municipalities of Amadora and Oeiras in the Lisbon region of Portugal. SIMAS Oeiras e Amadora distributes water to more than 350,000 customers who have come to rely on the public company for their water services.

Project Details

Services
SmartBall leak detection inspection
Pipe Material
Ductile iron
Inspection Length
2781 meters (2.6 miles)
Diameter
600mm (24-inch)
Transmission Type
Water

Project Highlights

Total of 1.7 miles (2.78kms) of 5-year-old pipeline inspected

Inspection located one (1) leak 863 meters from insertion

Leak repaired and allowed SIMAS Oeiras e Amadora to recover costs associated with the loss of non-revenue water

Challenge

The F. Passarinhos-Atalaia duct is a pressurized pipeline that supplies water to one of eight reservoirs operated by SIMAS Oeiras e Amadora in the municipality of Amadora. Installed in 2007, the large 600 mm (24-inch) transmission main, made from ductile iron material, delivers drinking water to approximately 31 percent of Amadora’s residents, making it a critical part of the municipality’s buried infrastructure.

In 2012, SIMAS Oeiras e Amadora detected a noticeable pressure drop in the system, indicating the possibility of a critical leak, the predecessor of a potential rupture that could negatively impact the environment and significantly disrupt day-to-day life in the community.

In addition to physical losses of water caused by a small leaks, the escaping non-revenue water can eventually erode the surrounding soil making the area more prone to washouts or sinkholes, a major headache especially in densely populated areas. Unplanned excavations to repair unforeseen leaks can also erode consumer confidence in a public utility.

Solution

When traditional leak detection methods—geophones and acoustic correlators­ were unable to detect the location and size of the leak, SIMAS Oeiras e Amadora called on its contractor to perform a leak detection survey using the innovative SmartBall tool from Pure Technologies (Pure).  Because of the criticality of the line, the survey was conducted while the pipeline remained in operation.

Pure’s patented SmartBall tool is an aluminum-core, foam-shell ball packed with several different sensors that can be launched into a water main without any disruption to client service.

Unlike traditional external listening tools that have limited success on large diameter pipes, SmartBall is the industry’s only free-flowing multi-sensor technology that provides the highest degree of accuracy, since as the ball rolls, it can inspect every inch of a water main to detect potential problems such as leaks and gas pockets. Its highly sensitive acoustic sensors can locate ‘pinhole’ leaks and gas pockets within a location accuracy of 1.8 meters.

Results

The SmartBall was inserted into the pipeline through a 6” gate valve and the journey took two hours and 49 minutes. One small leak was detected, 863 meters from the insertion site. This leak was repaired and allowed SIMAS Oeiras e Amadora to recover costs associated the loss of non-revenue water, had it remained undetected.

Although the SmartBall tool detected just one leak, the inspection gave SIMAS Oeiras e Amadora the capacity to assess assets from inside the pipe rather than drawing conclusions from indirect, external clues. If leaks are discovered early, operators can take necessary action to makes repairs before they become a major problem.

This process allows progressive operators like SIMAS Oeiras e Amadora to develop a sustainable long-term strategy for managing their critical buried assets.

Case Study

In March 2014, Pure Technologies completed a successful leak detection survey on behalf of Mancomunidad Comarca de Pamplona (MCP). The inspected pipeline is part of the MCP’s water supply network, was constructed 20 years ago, and traverses from Olaz – El Cano Pump Station to the Gorraiz Reservoir for 2.4 kilometers.

The main’s purpose is to keep water supply to the town of Egües, which features a hotel and golf course. The pipeline has an operating pressure of 12 bar and is pump operated with 50 litres per second during winter months and 100 litres per second during summer season because of increased demand. The inspection was performed in two runs to proactively address water loss on the transmission main.

Project Details

Services
SmartBall® Leak and Gas Pocket Detection
Timing
March 2014
Pipe Material
Ductile Iron
Inspection Length
2.4 km (1.5 miles)
Diameter
400mm (16-inch)
Transmission Type
Water

Project Highlights

SmartBall® leak detection located 4 leaks in 1.49 miles (2.4 kms) of inspection

3 of 4 leaks have been verified and repaired by MCP

Leaks as small as 1 litre per minute identified by SmartBall technology

Challenge
MCP is very dedicated to controlling water loss and completing regular leak detection; they have a permanent internal group with the unique mandate of finding leaks. Typically, they use an advanced SCADA system to identify an area with a leak and then experienced technicians use geophones to establish the exact location of the leak. Using this procedure, MCP has reached a Non-Revenue Water (NRW) level of roughly 10 percent of in their entire network. However, the Impulsión de Gorraiz had a known leak that could not be pinpointed precisely. MCP knew its elevation coordinates but couldn’t identify its exact location using traditional methods.

Solution
With a philosophy of continuous improvement, MCP used Pure’s services to perform a leak detection survey with SmartBall. To supplement its internal leak detection team and SCADA system, MCP wanted to test the validity of an inline leak detection tool and locate the known leak on this pipeline. MCP places equal importance on identifying large leaks and small leaks.

While large leaks leak at a much higher rate, identifying them only eliminates a leak at the tail end of its life. In terms of reducing NRW, locating small leaks may actually represent the best opportunity for long-term water loss reduction. Catching a leak while it is very small prevents the decades of sustained water loss that would occur as it grows into a large leak. While large leaks are important to locate, using technology that can find small leaks on large-diameter pipelines can prevent the development of large leaks and play a vital role in the safe management of a pipeline network.

MCP used SmartBall® leak detection for the inspections. The tool is a free-swimming 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; the acoustic signature is then analyzed to determine if it is a leak, air pocket, or an external noise.

To track the tool as it traverses the pipeline, SmartBall receivers (SBR) are placed strategically throughout the planned inspection route. As the tool traverses, it makes a sound that is recorded by the receivers to determine its position on the pipeline; this system allows leak locations to be estimated typically within 1.5- meters (6-feet) of the actual leak location.

Due to a 12 bar pressure at the pump station, a new high pressure insertion cap was designed and fabricated to assist with insertion procedure together with a pulley system that allowed the SmartBall insertion claw to be pushed into the pipeline. In order to ensure the highest level of accuracy, additional SBR points were mounted to track the tool closely and a mobile SBR unit was also used. At the reservoir, a small-diameter net was used to retrieve the tool after the inspection was completed.

Results
Upon completion of the inspection, data analysis revealed four acoustic anomalies resembling leaks despite MCP expecting only one leak along the main. Using updated client estimates and the SmartBall tool’s joint detection feature, Pure identified the exact location of three of the four leaks with an accuracy of less than 0.5 meters, including the known leak. The fourth leak verification has been deferred by MCP until a later date. The close location accuracy was confirmed after MCP excavated the leak locations for repair. In addition to the accuracy, the inspection was also successful in identifying small leaks. The leaks confirmed through excavation were as small as ~0.1 liters per minute.

Based on the inspection, MCP was very satisfied with the technology and information that will be used for future management of their network.

In North America, the material and size of pipes that make up water and sewer networks range widely. Because these pipeline systems are so complex, it requires a strategic approach based on risk and real data for effective long-term management.

Worker inspecting pipe

Historically, however, it has been challenging to gather real data that can shape defensive capital decisions for an entire system. The assessment of metallic pipelines — which make up most water and pressurized sewer networks — differs from prestressed concrete cylinder pipes (PCCP), both in terms of failure modes and in the fact that metallic pipe materials are featured in both transmission and distribution networks.

While PCCP assessment and management have been successfully used by utilities for years, effective assessment solutions for ferrous pipe have only recently been commercialized.

In 2011, Pure Technologies began an initiative to help close the gap in metallic pipe assessment technologies, and focus attention on gathering honest feedback from proactive utilities on what solutions are needed to effectively manage metallic pipe.

Seven years later, Pure Technologies reports that notable progress has been made with the development and advancement of assessment technologies for metallic pipeline networks.

Team of workers with a metallic pipe

Many proactive utilities involved in guiding Pure’s research efforts

Proactive utilities have been involved in the metallic pipe initiative, and instrumental in the development of new inspection tools for metallic pipe, both by providing feedback that helps guide research and development, and by providing opportunities that allow solution testing in live operating conditions. As a result of these efforts, there has been significant improvements to the technologies available to utilities for assessing the condition of metallic pipelines in both transmission and distribution networks.

For large-diameter transmission mains, there is a well-developed business case for assessing these mains as they approach the end of their useful life. These pipelines typically carry a high replacement cost and are higher risk — due primarily to their size and criticality — making it important for utilities to fully understand the condition of the asset.

Armed with real condition data, utilities can make a defensible renewal or replacement decision about the pipeline. Based on well over 14,000 miles of data, Pure Technologies has found that only a small percentage of pipes are in need of immediate renewal.

Small diameter metallic pipe leak

Case for using inline tools for small diameter pipelines

In distribution networks, however, the case for condition assessment is more challenging as smaller pipelines can sometimes be replaced cost-effectively. Despite this, the process for making a replacement decision should be based, whenever possible, on risk and real data.

With the EPA suggesting that between 70 and 90 percent of pipes being replaced have remaining useful life, the case is even stronger for collecting condition data to drive the decision making to help utilities spend their replacement dollars more efficiently and avoid replacing pipe with remaining useful life.

In some instances with smaller diameter pipes, it is often cost-efficient to use inline tools to gather detailed screening data on a pipe-by-pipe basis to determine if replacement is necessary.

A new approach to metallic pipeline management

While there is no silver bullet technology for assessing metallic pipelines, Pure has developed a flexible, risk-based approach to help utilities better understand their infrastructure, gather actionable data and prioritize both short and long-term management efforts.

Over the past few years, Pure has worked along proactive utilities to develop its data-driven Assess and Address® approach, which focuses on four main areas:

  • Understand
  • Assess
  • Address
  • Manage

Through the implementation of programs across North America, Pure has found that the majority of pipelines 16 inches and above can be cost-effectively managed for between 5 and 15 percent of the replacement cost.

Starting an effective pipeline management program

The first step of any pipeline management program is understanding the system-wide risk along with the benefits and limitations of assessment solutions. This allows for the development of a defensible management strategy that can be implemented to maintain and extend the life of the assets.

Many technologies now exist to provide a snapshot of a pipeline condition at various levels of confidence. It is therefore prudent for utilities to approach technology selection and subsequent analysis based on the risk of each pipeline.

A more thorough risk assessment involves estimating the Consequence of Failure (CoF) and the Likelihood of Failure (Lof) of each pipeline based on internal knowledge, operational history and pipeline characteristics. This initial risk assessment determines which areas of the system require further assessment to acquire real condition data and provides the utility with the necessary information to make an informed technology selection.

By using risk to guide management strategies, owners can ensure they are implementing the right approach, at the right time, with the lowest financial impact. The goal of a management program should always be o focus resources on managing the asset while safely getting the most service life out of the pipeline.

Sinkhole in a street

Reducing the Consequence of Failure

Reducing CoF comes down to improving emergency events through field operations efficiency. Studies have shown that the time to shut down a pipeline had more impact on the consequence of failure than the diameter of the pipeline.

Utilities can reduce CoF — and in turn risk — by gaining a better control on their system, which can be achieved two ways:

  • 1. Adding valves and redundancy in the system
  • 2. Knowing the location, condition and operability of control points

For example, if a pipe fails and utility operations staff are unable to locate valves — or the valves are inoperable when they are located — it will take longer to isolate a pipe failure. This will result in greater damage, more water loss and longer outages and repair times as a result of the failure. Implementing a proactive program for control assets that focus on providing better data for field staff reduces CoF by decreasing emergency response time.

Reducing the Likelihood of Failure through condition assessment

Many factors influence the likelihood that a pipeline will fail. Metallic pipelines, specifically, have a variety of failure modes and require a wide array of technologies to accurately assess their condition. Until recently, technologies for metallic pipe assessment have been unavailable or limited in their viability.

As a result, lower risk metallic mains have historically been prioritized for replacement using age, material and break history, while higher risk mains have sometimes been assessed with test pits along the length of the pipeline. After test pitting, statistical methods are used to extrapolate the condition of the test pit locations along the entire pipe length.

Through the development of metallic assessment solutions, condition data shows that pipe distress is often random and localized, meaning that an area of distress identified during the test pit method may inaccurately identify the entire pipeline as distressed, conversely, identify the entire length of pipeline as in good condition.

The development of reliable inline condition assessment tools provides owners with pipe-by-pipe data that gives a more complete picture of the actual condition of the pipeline. This allows for a more targeted management of small sections of pipe instead of generalizing the condition of an entire pipe length. It also allows for the collection of real data to drive pipeline renewal, which allows for more defensible capital decision making.

Case Study

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

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

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

Project Details

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

Project Highlights

Inspection identified 13 pipe sections with electromagnetic anomalies

Defects ranged from 20-55% wall loss

Transient pressure monitoring indicated pipeline operating within design capacity

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

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

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

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

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

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

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

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

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

Massive pressured water lleak on a street

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

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

Asset management begins with condition assessment

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

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

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

Matching assessment technology with the pipeline conditions and project goals

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

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

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

Sahara® Leak and Gas Pocket Detection

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

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

SmartBall® Leak and Gas Pocket Detection

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

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

PipeDiver® Condition Assessment

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

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

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

PipeWalker™ Condition Assessment

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

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

PureRobotics® Pipeline Inspection

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

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

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

Matching the level of resolution to the risk of the line

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

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

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

Case Study

K-water, the national bulk water utility in South Korea, supplies water across the country to smaller cities and controls everything from collection, treatment and pumping to maintenance, inspection and rehabilitation of the nation-wide pipeline system.

In addition to supplying treated water to these small cities, many have contracted K-water to manage and maintain their distribution systems as they battle the challenges of aging infrastructure. Beginning in 2011, K-water has used Sahara® Leak Detection to address non-revenue water and collect condition information about its metallic pipelines.

Project Details

Services
Sahara® Leak Detection
NRW reduction program
Baseline condition assessment
Timing
2012-ongoing
Pipe Material
Steel, Cast Iron, Ductile Iron
Diameter
6-inch (150mm) to 90-inch (2300mm)
Transmission Type
Water

Project Highlights

22 leaks located in 25 miles (40.23 kms) of inspection

Pinhole leaks identified within 5 cm of actual location

Estimated 350,400 m3 of water saved per year in Tongyeong City

Challenge

In 2009, K-water was searching for a large-diame­ter leak detection tool for its critical trunk mains. While K-water has done an exemplary job of maintaining its nation-wide pipeline network, which totals about 5,000 kilometers and has a Non-Revenue Water (NRW) rate of about 2 per­cent, many of its client municipalities suffer from high levels of NRW as their infrastructure ages and begins to leak. K-water was also interested in a tool that would allow them to compare actual pipeline conditions with their extensive pipeline engineering knowledge, allowing for quality con­dition assessment and failure prevention. In 2011, K-water began a knowledge-transfer program with Pure Technologies to become independent operators of Sahara leak detection.

Solution

K-water has built up expert knowledge in pipe­line engineering, a database of information on their pipe materials and pipe failure methods, and has adopted the best condition assessment technologies in the market to help inspect their pipelines so that efficient, prioritized rehabilita­tion and replacement plans can be made.

One condition assessment tool K-water has adopted is the Sahara platform – a tethered system with acoustic leak detection and inline video. While many utilities around the world use this tool for large-diameter leak detection, K-wa­ter has adopted it in an innovative way, choosing to use it as a complete condition assessment tool to provide information on its pipelines and accu­rate location of leaks.

The tool is non-destructive and is pulled by the flow of water by a small drag chute. When the sensor is inserted into a tap, it remains tethered to the surface to allow for immediate checking 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. Sahara also provides real-time inline video, which allows the operator to see live pipe conditions as the tool surveys for leaks and gas pockets.

Operating with a national mandate and several stakeholders, K-water faces a number of logistical challenges with its pipeline infrastructure.

One challenge is population density; South Korea is roughly 2 per cent of the size of Canada with almost double the population, meaning large, densely populated regions rely on K-water for consistent water service. A failure or service interruption to a critical trunk main could be disastrous K-water’s credibility with customers.

South Korea is also a very mountain­ous region, meaning pipelines supplying water throughout the country often pass through areas that are difficult to inspect using traditional methods. In addition to the landscape, many of K-water’s large diameter pipelines are buried deep in the ground, making excavation projects com­plex and expensive to complete.

By becoming certified Sahara tool operators, K-water staff can deploy the tool at their own descretion and are able to overcome these chal­lenges to complete inspections in difficult regions.

Results

Tongyeong City, South Korea, which has a high NRW and features 32-inch (800-mm) steel pipe, has been inspected twice; first as part of Pure’s Sahara training program and subsequently by K-water as an independent operator. The inspec­tions in Tongyeong City were extremely success­ful, locating 10 total leaks with high accuracy in 2.5 kilometers of inspection for an estimated sav­ings of 350,400 cubic meters of water per year.

During the training inspections, Pure and K-wa­ter were able to locate pinhole leaks as close as 5-cm above and below the actual leak location – meaning service disruption, excavation and repair times were minimal. In K-water’s subsequent inspection of the same pipeline in Tongyeong City, they were able to excavate and repair all three identified leaks in 5.5 hours each during the night (3 separate repairs), causing little disruption to customers.

In total, K-water has inspected 25 kilometers of pipeline and located 22 leaks of varying sizes. K-water has inspected both its own pipelines as well the regional pipelines that it operates and has covered pipes with diameters as small as 150-mm and as large as 2300-mm, with most pipe being either steel, ductile iron or cast iron pipe. K-water’s 2012 program will cover about 52 kilometers of pipeline for leaks and gas pockets

While the tool has been effective in locating leaks for K-water, its value as a complete condition assessment tool has also been helpful due to the unique challenges faced in South Korea. K-water has been able assess the state of its pipelines by combining the inline video data and its extensive engineering knowledge. By doing this, K-water has become a thought-leader in large-diameter pipeline management.

K-water has successfully applied the Sahara platform for condition assessment in its transmission mains and for leak detection in municipal trunk mains.

Se-Hwan Kim

General Manager, Water Supply Operation & Maintenance Department, K-water

Speak to One of Our Experts





Case Study

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

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

Project Details

Services
SmartBall® leak and gas pocket detection

PipeDiver® electromagnetic inspection

Pressure monitoring

Structural engineering

Timing
2015
Pipe Material
Ductile Iron
Inspection Length
2.9 miles
Diameter
20-inch to 30-inch
Transmission Type
Wastewater

Project Highlights

Condition assessment on

4.7km

of feedermain pipes

Data identified

8

pipes with electromagnetic anomalies consistent with broken pressing wire wraps

HD-CTTV identified

3

pipes with damaged internal mortar and exposed cylinder

Challenge

The Franklin-Muskego Force Main carries wastewater along approximately 3 miles of 24-inch and 30-inch ductile iron pipe (DIP).

One of the challenges in assessing DIP is determining if the pipe has undergone any wall thickness loss due to internal or external corrosion, which are the primary causes of failure. DIP in water service with a cement mortar lining generally has fewer internal corrosion failure rates, unless damaged during handling and installation, or later as a result of 3rd party damage.

This is not the case when DIP is used in a force main, where internal corrosion is the primary cause of failure. Gas pockets are of significant concern as concentrations of hydrogen sulfide gas within wastewater may cause corrosion and eventual breakdown of the pipe’s exposed surface.

In a force main, identifying internal areas with potential corrosion is challenging, as traditional gravity pipeline inspection techniques are often not applicable to in-service pressurized pipelines.

One method for assessing gas pockets is to locate air release valves (ARVs) or other high points along the alignment and conduct test pit investigations in those areas. While this is a valid method for locating potential gas pocket locations, additional gas pockets may occur due to differential settlement, improper installation or non-functioning ARVs.

Desktop surveys may not identify and locate all gas pockets along a pipeline, which is why Pure recommends other more precise survey methods.

Solution

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

In October 2015 Pure performed a SmartBall leak and gas pocket detection survey and a PipeDiver electromagnetic inspection of the Franklin-Muskego Force Main.

The SmartBall platform is a free-swimming tool that uses acoustics to detect leaks and gas pockets while the pipeline remains in full service.

Pure’s flexible, free-swimming PipeDiver tool collects electromagnetic (EM) data that is used to measure the relative wall thickness of the cylinder – the main structural component of the pipeline. With PureEM® onboard, PipeDiver can identify localized areas of wall loss in the cylinder of the pipe, and broken bar wraps in BWP, all while the pipeline remains in service.

Results

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

Through the PipeDiver inspection, 13 pipes were found to have a total of 16 electromagnetic anomalies consistent with localized wall loss, ranging between 20 percent to 55 percent wall loss. At the time of writing, MMSD was making plans to excavate and repair one pipe section with three areas of pipe loss ranging from 35 percent to 55 percent wall loss.

The results of the condition assessment indicate that the Franklin-Muskego Force Main is in good condition.

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

Case Study

Daphne is located along the eastern shore of Mobile Bay, an area served by Daphne Utilities, which provides water, wastewater, and natural gas services to approximately 25,000 residents.

In 1985 the City purchased the Lake Forest Utility, and in doing so, Daphne Utilities took over their existing wastewater treatment plant, which was built in the 1970s.  The facility discharges through the Daphne Outfall, a 6,000-foot, 18-inch ductile iron effluent pipeline that discharges treated wastewater into Mobile Bay. Although the main was critical to the City, little information about it was transferred when Daphne Utilities acquired the facility.  Daphne Utilities later officially named the facility the Water Reclamation Facility.

Project Details

Services
Mapping deliverable

Pipeline alignment

Sahara® leak and gas pocket detection

Timing
One (1) day
Pipe Material
Ductile Iron
Inspection Length
1000 feet (304 meters)
Diameter
18-Inch (457mm)
Transmission Type
Treated Wastewater

Project Highlights

Pipeline assessment hampered by

non-existent plans

Obstacles in pipeline path include

urban development and wildlife sanctuary

Zero (0) leaks

eight (8) gas pockets detected

One (1) day

mobilization
1000ft inspected

Challenge
For many years after Daphne Utilities took over the Water Reclamation Facility the outfall line operated as a gravity discharge line. As the population grew and flows to the plant increased, Daphne Utilities installed pumps to occasionally increase the volume of treated wastewater passing through the discharge line. As development expanded, the situation progressed from a time when the pumps occasionally ran, to the point where the pumps ran almost continuously.

Gravity main transformed into a force main

Now, a pipe designed as a gravity main had transformed into a force main, pumping under pressure at all times, with its location and condition unknown – and with no redundancy.

To proactively manage this critical asset, in June 2015, Daphne Utilities retained the services of Pure Technologies (Pure) for a one-day Sahara® leak and gas pocket detection inspection of the Daphne Outfall, with a mapping deliverable.

The primary purpose of the inspection was to determine the pipeline alignment, since you can’t maintain what you can’t locate.  Since the 18-inch outfall was built, the terrain had changed markedly.  The original shoreline had been extended by hundreds of feet to accommodate the construction of a major highway and several hotels and restaurants.
In fact, based on best guesses and poor drawings, Daphne Utilities suspected that a five-story Hampton Inn had been built on top of the 18-inch outfall!
In short, Daphne Utilities didn’t know the exact pipeline location or its operational conditions.

Solution
To ascertain the alignment and condition of the 18-inch outfall, Daphne Utilities engaged Pure Technologies for a single day inspection.  In addition to the challenge of not knowing the exact pipeline alignment, it also appeared that the pipeline traversed under a swamp sanctuary for hundreds of alligators and other wildlife, in an area known as “Gator Alley.”

To conduct the mapping and assessment survey, Pure recommended the Sahara leak and gas pocket detection platform. Sahara is an inline tethered tool that can assess pipelines 6 inches and larger, without any disruption to service.

Because the sensor tool is tethered, an operator can stop and reverse the tool to investigate acoustic events such as leaks, gas pockets and visual anomalies. At the same time, an above-ground operator locates the sensor above ground, marking the exact location of the pipeline at any point along the pipe with sub-meter accuracy.

The mapping capability of Sahara allows utility owners to determine the exact location of their pipeline at any point, as well as the location of any leaks or gas pockets.

Results
Analysis of the acoustic data identified zero (0) leaks and eight (8) air pockets, which were impacting the efficiency of the line, as gas pockets occupy space within the already maxed-out pipeline. During the inspection, the alignment of the pipeline was determined and recorded from the treatment plant to the edge of the marsh where Mobile Bay starts, confirming the pipeline does indeed pass underneath the Hampton Inn.

In a single day, the Sahara crew determined flow velocity, inserted the tethered tool, inspected 1,000 feet, determined the pipeline alignment, and confirmed its location and the location of 8 gas pockets. As a result, Daphne now knows they have gas pockets and they now know the line location in order to execute a plan to deal with the gas pockets.

Not bad for a day’s work.

Case Study

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

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

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

Project Details

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

Project Highlights

 

3.05 kms cumulative distance of survey

 

1 acoustic anomaly associated with transient gas (SmartBall inspection)

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

 

Zero leaks detected

 

Challenge

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

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

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

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

Solution

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

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

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

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

Results

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

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

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

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

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.

Lyon City Square

With a population of nearly 500,000, Lyon is the third largest city in France, a vibrant metropolis known for its modern Confluence district as well as Renaissance palaces and Roman ruins that date back more than 2,000 years.

While Lyon’s historic architecture has aged well, the same cannot be said for its buried infrastructure. In June of 2016, Suez retained the services of Pure Technologies (Pure) to perform a SmartBall® inspection of two critical water mains, the Grigny Water Main and Les Halles Water Main, both located near Lyon. The inspections, conducted over two days, were part of a long-term condition assessment program for the city.

As an industrial services and solutions company specialising in securing and recovering resources, Suez provides its customers (local authorities, industry and consumers) with concrete solutions to address new resource management challenges.

Pipelines constructed of ductile iron and cast iron

The Grigny Water Main is a 500mm (20-inch) cast iron pipeline that transfers Water from the Grigny Pump Station to Saint Romain en Gier. The SmartBall inspection started at a previously installed 150mm (6-inch) tap and ended at a previously installed 150mm tap in Saint Romain en Gier, and covered a distance of approximately 8.6 kilometers (5.3 miles).

The following day Pure deployed a second SmartBall inspection, this time on the Les Halles Water Main, a 400mm (16-inch) ductile iron pipeline that transfers water from Les Halles to Saint Laurent D Chamousset. The purpose of the inspection was to locate and identify leaks and pockets of trapped gas along the 2.9 kilometer (1.8 mile) section of pipeline.

SmartBall under a gas pocket inside a water pipe

SmartBall® tool chosen for ease of use and sensitivity to gas pockets and 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 its ability to inspect long distances in a single deployment. 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 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 this project, 13 surface-mounted acoustic sensors (SMS) were placed along the Grigny pipeline to track the SmartBall tool during the inspection. For the Les Halles inspection, five (5) SMS were used to track the tool. SmartBall receivers were connected to the sensors on the pipeline at locations to track the tool during inspection.

An extraction net was used to extract the SmartBall tool once it traversed the entire length of both pipelines, and the data was evaluated by Pure analysts to identify acoustic anomalies associated with leaks and pockets of trapped gas.

Screen with Data Analysis

SmartBall survey detects two leaks and zero (0) gas pockets

The acoustic data recorded by the SmartBall tool was analyzed and cross-referenced with the position data from each SmartBall Receiver (SBR) to determine a location for each acoustic anomaly.

From the results conducted on the Grigny Water Main, Pure detected a total of two (2) acoustic anomalies characteristic of leaks and zero (0) anomalies consistent with pockets of trapped gas. Pure analysts classified one leak as a small leak, and a second as a large leak.

For the survey of the Les Halles Water Main, Pure detected zero (0) anomalies characteristic of leaks and zero (0) acoustic anomalies characteristic of pockets of trapped gas.

The results gave Suez actionable data regarding the condition of the pipelines, and the confidence to move forward on fixing the leaks. It’s a great example of a water authority taking proactive efforts at keeping its network in healthy shape.

SmartBall with case and insertion tools

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.

Mackay City Coast

Justification of an ongoing condition assessment program can, at times, be difficult for water utilities. However, successful inspections that deliver actionable outcomes on how to manage aging assets make this justification much easier.

Certainly that was the case for Mackay Regional Council (MRC) when it engaged the services of Pure Technologies to conduct a variety of condition assessment inspections on their critical mains in order to improve their understanding of these aging assets.

For MRC, the goal of the 3-year Condition Assessment Program is to undertake and then analyze the results from the preliminary inspections, followed by a commitment to explore secondary condition assessments, where warranted.

Mackay satellital image with mains map

About Mackay Regional Council

Mackay Regional Council is a small but progressive water utility that serves a population of nearly 124,000 on the eastern coast of North Queensland, Australia. The utility has a total of 2,150 km of water and wastewater mains in its network. MRC is proactive in its approach to water management, and takes pride in the development of its industry-leading condition assessment program, initiating the first leg of the program with Pure mid-2016.

SmartBall with case and insertion tools

First SmartBall inspection on two sewer rising mains

In June 2016, MRC retained the services of Pure to perform a SmartBall® inspection of the Coles Road Sewer Rising Main (SRM), also known as force main. The Coles Road SRM is an asbestos cement (AC) and ductile iron (DI) pipeline that transfers wastewater from the Coles Road Sewer Pump Station (SPS) to the Mount Basset Sewer Rising Main. The purpose of the SmartBall inspection was to identify leaks and pockets of trapped gas along the pipeline.

Pure recommended the SmartBall tool for its relative ease of insertion and extraction of in-service pipelines, and its ability to inspect long distances in a single deployment. The tool’s acoustic sensor can detect ‘pinhole’ sized leaks and gas pockets within a location accuracy of plus or minus 1.8 m (6 feet), a critical factor in urban environments where excavations can be costly and disruptive to the public.

After the review of data integrity and backup from the Coles Road site, the crew moved to the Beaconsfield SRM, where a further SmartBall inspection was completed. The inspection went as smoothly as the first, and all data was confirmed for quality.

This technology has assisted us in assessing the operational and potential structural integrity of some hard to access buried mains of high failure consequence without significant service outage or worker safety in a way not previously utilised.  It certainly lifts us out of the purely reactive mode toward the proactive assessment of buried infrastructure in terms of service delivery risk management and maintenance/renewal planning…”

MRC Project Leader

Second SmartBall inspection on a sewer rising main and raw water main

During the next phase of the project, Pure conducted a preliminary condition assessment of two more critical mains, the Mount Basset SRM and the following day, on Marwood Bore Raw Water Main. Pure always utilizes separate inspection sets for potable and wastewater to eliminate any risk of contamination.

SmartBall extraction

Second SmartBall inspection on a sewer rising main and raw water main

Results of the preliminary condition assessment were utilised to identify whether a secondary condition assessment is required.

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

Gas pockets are of significant concern in rising sewer 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.

Utilizing Sahara™ platform with CCTV

For the third phase of the Program, MRC engaged Pure for a condition assessment of the Gordon Street Water Main. In order to inspect this critical main, Pure conducted three (3) separate insertions using the Sahara inspection platform. The Sahara system uses an innovative tethered platform to conduct non-destructive inline leak and gas pocket detection, and an internal visual inspection via closed circuit television (CCTV), without disruption to service. This allows for real-time reporting of acoustic anomalies detected in the pressurized lines.

The inspection occurred over a period of two nights to minimize traffic disruption. The targeted portion of the main consists of cast iron (CI) and asbestos cement (AC) pipe in three diameters.

“We are still to progress fully into this mode of operation, however this technology appears to provide us a firm foundation to step off from…”

Don Pidsley

Working during the night

Collected data gives MRC actionable information on necessity for secondary assessments

All in all, the data collected to date has given MRC a better understanding of their critical assets. By undertaking a preliminary condition assessment approach, MRC now has actionable information regarding the necessity of future secondary assessments.

Based on preliminary results, minimal disruption and collaborative cooperation between the mobilization teams, MRC has inquired about additional inspections under their in their industry-leading condition assessment program.

Workers meeting in a parking

Some pipeline inspections are more daunting than others, as Daphne Utilities recently found out. Not only was the planned condition assessment on a critical pipeline hampered by non-existent plans, there were also obstacles in the pipeline path that included urban development atop the pipe and an alligator-infested swamp.

In the end, to map and assess their pipeline, Daphne Utilities opted for the Sahara® leak and gas pocket detection platform, which includes the ability to determine pipeline alignment with sub-meter accuracy.  With the Sahara platform, Daphne Utilities could not only determine the exact pipeline location, but also assess its operation and condition.

Daphne’s Story

Affectionately known as the “Jubilee City”, Daphne was incorporated in 1953 and due to its location, serves as a suburb of Mobile, Alabama. Daphne is located along the eastern shore of Mobile Bay, an area served by Daphne Utilities, which provides water, wastewater, and natural gas services to approximately 25,000 residents.

In 1985 the City purchased the Lake Forest Utility, and in doing so, Daphne Utilities took over their existing wastewater treatment plant, which was built in the 1970s.  The facility discharges through the Daphne Outfall, a 6,000-foot, 18-inch ductile iron effluent pipeline that discharges treated wastewater into Mobile Bay. Although the main was critical to the City, little information about it was transferred when Daphne Utilities acquired the facility.  Daphne Utilities later officially named the facility the Water Reclamation Facility.

For many years after Daphne Utilities took over the Water Reclamation Facility the outfall line operated as a gravity discharge line. As the population grew and flows to the plant increased, Daphne Utilities installed pumps to occasionally increase the volume of treated wastewater passing through the discharge line. As development expanded, the situation progressed from a time when the pumps occasionally ran, to the point where the pumps ran almost continuously.

Satellite view with sewer location

Over the years the gravity main transformed into a force main

Now, a pipe designed as a gravity main had transformed into a force main, pumping under pressure at all times, with its location and condition unknown – and with no redundancy.

To proactively manage this critical asset, Daphne Utilities retained the services of Pure Technologies for a one-day Sahara® leak and gas pocket detection inspection of the Daphne Outfall, with a mapping deliverable.

The primary purpose of the inspection was to determine the pipeline alignment, since you can’t maintain what you can’t locate.  Since the 18-inch outfall was built, the terrain had changed markedly.  The original shoreline had been extended by hundreds of feet to accommodate the construction of a major highway and several hotels and restaurants.

In fact, based on best guesses and poor drawings, Daphne Utilities suspected that a five-story Hampton Inn had been built on top of the 18-inch outfall!

In short, Daphne Utilities didn’t know the exact pipeline location or its operational conditions.

Bridges over a river

Section of the outfall traverses area known as “Gator Alley”

To ascertain the alignment and condition of the 18-inch outfall, Daphne Utilities engaged Pure Technologies for a single day inspection. In addition to the challenge of not knowing the exact pipeline alignment, it also appeared that the pipeline traversed under a swamp sanctuary for hundreds of alligators and other wildlife, in an area known as “Gator Alley.”

Due to the location that the line traverses, extra safety precautions were needed for the inspection crews. Project planning included the deployment of an alligator watchman to watch specifically for a notorious 14-foot alligator known to inhabit the area in the vicinity of the 18-inch outfall.

Sahara inspection technology chosen for accuracy at pinpointing leaks and gas pockets

To conduct the mapping and assessment survey, Pure recommended the Sahara leak and gas pocket detection platform. Sahara is an inline tethered tool that can assess pipelines 6 inches and larger, without any disruption to service.

Because the sensor tool is tethered, an operator can stop and reverse the tool to investigate acoustic events such as leaks, gas pockets and visual anomalies. At the same time, an above-ground operator locates the sensor above ground, marking the exact location of the pipeline at any point along the pipe with sub-meter accuracy.

The mapping capability of Sahara allows utility owners to determine the exact location of their pipeline at any point, as well as the location of any leaks or gas pockets.

Results give Daphne jubilant confidence moving forward

Analysis of the acoustic data identified zero (0) leaks and eight (8) air pockets, which were impacting the efficiency of the line, as gas pockets occupy space within the already maxed-out pipeline. During the inspection, the alignment of the pipeline was determined and recorded from the treatment plant to the edge of the marsh where Mobile Bay starts, confirming the pipeline does indeed pass underneath the Hampton Inn.

Not bad for a day’s work

In a single day, the Sahara crew determined flow velocity, inserted the tethered tool, inspected 1,000 feet, determined the pipeline alignment, and confirmed its location and the location of 8 gas pockets.  As a result, Daphne now knows they have gas pockets and they now know the line location in order to execute a plan to deal with the gas pockets.

As for dealing with alligators, that’s unnecessary now.

Alligator watching to the cammera

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

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.

 

City of Milwaukee Skyline

Milwaukee is a water hub, and not just because of its location along the shores of Lake Michigan, which holds 4.3 percent of the world’s supply of fresh drinking water. The City also boasts of global leadership in water technology, having won a U.S. Water Prize for innovative watershed-based approaches toward water sustainability.

The City takes a proactive approach to water management initiatives, as evidenced in the recent condition assessment of the Franklin-Muskego Force Main. Ownership of the pipeline is shared between the City of Muskego and the Milwaukee Metropolitan Sewerage District (MMSD), the government agency that provides water management services for about 1.1 million people in 28 communities in the Greater Milwaukee Area.

Metallic valves

MMSD and Muskego request detailed structural assessment on metallic force main

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

Notably, the latest investigation used electromagnetic technology delivered on the 24-sensor mini PipeDiver platform to validate inspections conducted the previous year along the same lines.

Ductile iron pipe is a challenging material to assess

The Franklin-Muskego Force Main carries wastewater along approximately 1.6 miles of 24-inch and 1.3 miles of 30-inch ductile iron pipe (DIP). A small section of 20-inch DIP force main was also included in the survey.

One of the challenges in assessing DIP is determining if the pipe has undergone any loss of wall thickness due to internal or external corrosion, which are the primary causes of failure. DIP in water service with a cement mortar lining generally has fewer internal corrosion failure rates, unless damaged during handling and installation, or later as a result of 3rd party damage.

This is not the case when DIP is used in a force main, where internal corrosion is the primary cause of failure. Gas pockets are of significant concern as concentrations of hydrogen sulfide gas within wastewater may 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.

Gravity mains vs pressurized mains

In a force main, identifying internal areas with potential corrosion is challenging, as traditional gravity pipeline inspection techniques are often not applicable to in-service pressurized pipelines.

One method for assessing gas pockets is to locate air release valves (ARVs) or other high points along the alignment and provide pipe wall assessment in those areas. While this is a valid method for locating potential gas pocket locations, additional gas pockets may occur due to differential settlement, improper installation or non-functioning ARVs.

Therefore, these desktop surveys may not identify and locate all gas pockets along a pipeline, which is why Pure recommends other more precise survey methods.

SmartBall with case and insertion tools

SmartBall inspection summary

In June 2014 and October 2015 Pure performed a SmartBall leak and gas pocket detection survey of the Franklin-Muskego Force Main. Acoustic and sensor data was collected and recorded as the free-flowing SmartBall device traversed the pipeline.

During the 2014 survey, Pure detected zero (0) anomalies characteristic of leaks and one (1) anomaly that characterized a fully developed gas pocket.  During the 2015 survey, the SmartBall tool detected zero (0) anomalies characteristic of leaks and four (4) acoustic anomalies characteristic of fully developed gas pockets on the force main.

PipeDiver tool. insertion

24-sensor PipeDiver electromagnetic inspection

In 2014 Pure conducted a PipeDiver electromagnetic inspection, followed by a re-inspection in 2015, utilizing the new, 24-sensor electromagnetic PipeDiver tool. The technology ascertains a magnetic signature for each pipe section to identify anomalies that are produced by areas of corrosion or reduced wall thickness.

During the 2015 electromagnetic inspection using the mini PipeDiver, 13 pipes were found to have a total of 16 electromagnetic anomalies consistent with localized wall loss.

The electromagnetic inspection conducted in the 2015 inspection used an enhanced exciter coil allowing the electromagnetic field to return a more pronounced response. In addition to the enhanced exciter coil, the tool used in the 2015 inspection had a total of 24 receiving sensors, improving the ability of the tool to identify defects.

Confident conclusions

The results of the condition assessment indicate that the Franklin-Muskego Force Main is generally in serviceable condition, which was confirmed after an excavated pipe established a true baseline condition.

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

Longboat Key Aerial View

When much of your critical sewer pipeline lies buried under a bay of shimmering ocean water, the challenges required to assess its condition may seem daunting. That task faced the Town of Longboat Key, an affluent retirement community located on the barrier island of the same name off the west coast of Florida.

Sensitive to environmental, health and safety issues, the Town has been concerned about their 20-inch ductile iron pipe (DIP) force main installed in 1973. Inspections have been conducted in 1996, 2007 and 2011 with ultrasonic and visual methodologies for assessment.

Aside from being the only wastewater discharge from the island, approximately two miles of the four-mile pipeline runs under the Sarasota Bay before heading to the mainland, where it discharges into the Manatee County Southwest Water Reclamation Facility. The Town designated this force main as a priority pipeline due to the high consequence of failure, and is proactively managing this asset.

With talks of constructing a redundant pipeline, an island resident inquired about the condition of the existing force main and so the Town’s familiar engineering consultant, Greeley and Hansen, contracted Pure Technologies (Pure) as part of the comprehensive condition assessment project.

One of the challenges in assessing DIP is determining if the pipe has undergone any loss of wall thickness due to internal or external corrosion, which are the primary causes of failure.

SmartBall with case and insertion tools

SmartBall® platform provides a variety of condition data in a single deployment

To maximize the amount of actionable information to be gleaned from the force main project, Pure proposed leak and gas pocket detection services coupled with a pipe wall assessment (PWA) utilizing the SmartBall technology platform.

SmartBall is a multi-sensor inspection platform that provides utilities with a variety of pipeline condition data in a single deployment. Because the tool doesn’t disrupt service, it integrates easily into a management strategy to help pipeline owners reduce water loss, screen their network for problem areas and gain a better understanding of the condition of their assets.

SmartBall PWA technology is a screening tool that provides an indication of pipe wall stress on metallic pipes. The technology can be used as a first stage of pipeline condition assessment to help make informed decisions to focus higher resolution investigations, inspections, data collection and subsequent management of the pipeline.

SmartBall was also used to locate leaks and gas pockets in the line. Pipeline leaks are of concern for all pipe materials as they are often found to be the precursor of major failures. A pipeline failure can begin with weakening of the joint or barrel that may include a small leak.

In wastewater pipelines, identifying gas pockets is an important part of safely managing the asset, 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.

Project challenges include underwater tracking throughout inspection

From inception, the biggest challenge was tracking the SmartBall over the 12,000-feet (2.27 miles) subaqueous portion of the pipeline. The Town was very concerned about sedimentation in that section under the bay, and insisted on Pure tracking the SmartBall PWA sensor tool throughout the inspection.

To accommodate the Town’s tracking request, 11 surface-mounted acoustic sensors (SMS) were placed along the pipeline to track the progress of the SmartBall tool during the inspection. SmartBall receivers (SBRs) were connected to the sensors on the pipeline to track the tool during the inspection based on information and drawings supplied by the Town.

Monitoring data collected during inspection

Results from acoustic and electromagnetic anomalies

From the data collected and analyzed, SmartBall detected zero (0) acoustic anomalies characteristic of leaks and zero (0) gas pockets during the inspection. This indicated no leaks within the detection limits of the detection technology.

At the same time, of the 1,133 identified pipe segments, 95 (8.4 percent) showed signals not attributed to known features.  The anomalies identified from the SmartBall PWA analysis included one large anomaly, 18 medium-sized anomalies and 76 small -sized anomalies. The electomagnetic signals associated with 28 of the 76 small anomalies appeared to be similar or repeatable, leading to the likelihood that a manufactured difference in pipe design exists between these 28 pipe sections.

More accurate GIS data revealed

Based on the PWA results, Pure recommended choosing a diversity of pit locations and assessing these with external verification techniques (e.g. high resolution magnetic flux leakage, pulsed eddy current, ultrasonic thickness testing, etc.) to further evaluate the probability of pipeline failure.

As well, Greely and Hansen (and the Town) now have a better handle on the spatial data of the system (GIS) and by statistically analyzing the data, can now develop pipe management strategies for the short-term management and long-term renewal strategies for the force main. By its proactive approach to asset management, the Town sets itself apart as a great example of how a community can plan for its long-term infrastructure needs.

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.

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.

Lisboa Map

SIMAS Oeiras e Amadora distributes drinking water to 350,000 customers in the Lisbon region of Portugal.

Drinking water systems degrade over time, with the useful life of the pipe and component parts often lasting for decades. Of course, age is only part of the equation. The deterioration of any particular pipeline depends on a multitude of factors, including pipe material and class. To complicate matters, factors such as soil environment, chemical properties of the water, climate changes, and operational particulars can all contribute to weakened pipes.

All that said, when a suspected leak develops in a pressured main after only five years in operation, it’s important to locate and repair the leak and determine what operational, environmental or installation factors led to the failure.

That was the situation faced by Intermunicipal Service Oeiras and Amadora, a water management company responsible for the distribution of drinking water for the municipalities of Amadora and Oeiras in the Lisbon region of Portugal. SIMAS Oeiras e Amadora distributes water to more than 350,000 customers who have come to rely on the public company for their water services.

The F. Passarinhos-Atalaia duct is a pressurized pipeline that supplies water to one of eight reservoirs operated by SIMAS Oeiras e Amadora in the municipality of Amadora. Installed in 2007, the large 600 mm (24-inch) transmission main, made from ductile iron material, delivers drinking water to approximately 31 percent of Amadora’s residents, making it a critical part of the municipality’s buried infrastructure.

Pressure drop indicated possibility of critical leak

In 2012, SIMAS Oeiras e Amadora detected a noticeable pressure drop in the system, indicating the possibility of a critical leak, the predecessor of a potential rupture that could negatively impact the environment and significantly disrupt day-to-day life in the community.

When traditional leak detection methods—geophones and acoustic correlators­ were unable to detect the location and size of the leak, SIMAS Oeiras e Amadora called on its contractor to perform a leak detection survey using the innovative SmartBall tool from Pure Technologies (Pure).  Because of the criticality of the line, the survey was conducted while the pipeline remained in operation.

Since 2007 utilities all over the world have been using Pure’s SmartBall pipeline inspection technology to save millions of dollars in water loss and prevented water main breaks.

SmartBall inside a pipe

Pure’s SmartBall tool can be launched while the main remains in operation.

SmartBall tool launched without disrupting service

Pure’s patented SmartBall tool is an aluminum-core, foam-shell ball packed with several different sensors that can be launched into a water main without any disruption to client service.

Unlike traditional external listening tools that have limited success on large diameter pipes, SmartBall is the industry’s only free-flowing multi-sensor technology that provides the highest degree of accuracy, since as the ball rolls, it can inspect every inch of a water main to detect potential problems such as leaks and gas pockets. Its highly sensitive acoustic sensors can locate ‘pinhole’ leaks and gas pockets within a location accuracy of 1.8 meters.

The SmartBall was inserted into the pipeline through a 6” gate valve and the journey took two hours and 49 minutes. One small leak was detected, 863 meters from the insertion site. This leak was repaired and allowed SIMAS Oeiras e Amadora to recover costs associated the loss of non-revenue water, had it remained undetected.

Assess assets from inside the pipe rather than from external clues

Leak detection is a necessary step to reduce water loss and prevent major water main breaks. The benefits of leak detection are obvious in increased revenues, lower risk of contamination, lower liability due to a reduction of main breaks, and increased public trust.

Although the SmartBall tool detected just one leak, the inspection gave SIMAS Oeiras e Amadora the capacity to assess assets from inside the pipe rather than drawing conclusions from indirect, external clues. If leaks are discovered early, operators can take necessary action to makes repairs before they become a major problem.

This process allows progressive operators like SIMAS Oeiras e Amadora to develop a sustainable long-term strategy for managing their critical buried assets.

SmartBall on a net at the end of a pipe

For this leak detection survey, Pure’s innovative free-swimming acoustic tool gathered critical information about the aging pipeline assets of this historic Arabian city.

This large public utility supplies bulk water to this bustling, historic resort city located in the Arabian Penninsula region. The city’s infrastructure – above ground and below – has recently been modernized to keep up with growth and support the expanding tourist industry.

Recognizing that its underground infrastructure was reaching the end of its service life, the water utility called on Pure Technologies Abu Dhabi (Pure) and its local agent International Aramoon Company, to perform a series of SmartBall leak detection surveys on 150 kilometers (93 miles) of its ductile iron pipe (DIP) water network.

SmartBall gathers critical information about the city’s buried pipeline assets

Every pipeline is unique and comes with its own set of assessment challenges. When an operator has a strong understanding about the risk and operational conditions of their system, an appropriate and defensible inspection plan can be developed.

For this project, Pure introduced its proprietary SmartBall leak detection platform to identify and locate leaks and pockets of trapped gas along the water pipeline.

Pure began the SmartBall inspection project facing a number of challenges. For starters, due to limited access to historical drawings, the pipeline system and route was relatively unknown, with only a scanned copy of the schematic available for review.  Operational challenges included fluctuating flows within the pipeline, as well as a lack of access points for insertion and extraction.

To make matters more difficult, Pure faced issues related to the isolation of branches during the inspection.  The utility could not provide the option for a valve exercise prior to the trial “dummy” SmartBall run, which was decided on to eliminate the chances losing the real SmartBall.

Acoustic intensity of anomaly and actual leak located

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

SmartBall acoustic tool collects data as it rolls through the pipeline

Pure began the project with an ocular visit attended by the client and a pipeline maintenance operator to understand the right of way and alignment of pipeline sections. The distances between pipeline features were measured using an odometer, while bend locations were assumed based on street references from the schematic drawing.

Since the pipeline was non-redundant and could not be shut down, insertion and extraction points were provided by hot tapping the pipeline.

Prior to the official SmartBall launch, Pure conducted a trial run with a dummy ball on each pipe section to eliminate the chance of losing the SmartBall on its journey. Both the dummy ball run and SmartBall inspection were deployed on the same day to reduce the possibilities of flow fluctuations.

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 water flow and increase strain on pumps.

Easy to deploy, SmartBall also makes it easy to screen the pipeline for leaks, which could indicate a structural problem that deserves further attention.

Assessment identifies 21 leaks on 68 kilometers of pipe

To date, the SmartBall tool has inspected more than 68 kilometers (29 miles) of pipe within the city’s network, with additional runs planned. The inspection resulted in the identification of 21 leaks of various sizes. Of the total, 14 leaks have been verified and repaired by the utility.

The investigation confirmed that with good condition assessment, asset life can be extended, while managing utility’s exposure to risk. This mindset sets a good example for other Arabian cities to follow in developing a sustainable long-term strategy for managing aging infrastructure.

Flower Mound Sign

Named for a prominent landmark mound with more than 175 species of wild flowers, the Town of Flower Mound is ranked as one of the ten best places to earn a living and raise a family in Texas.

To complement these natural and economic positives, the scenic Town of 70,000 is also known for its municipal water stewardship and proactive approach in maintaining the quality of its buried infrastructure. This includes 430 miles of water mains and 230 miles sewer pipes serving 22,000 residential and industrial connections.

As part of the ongoing program for condition assessment of its buried infrastructure, the Town recently retained the services of Pure Technologies U.S. Inc. (Pure) to conduct a Sahara® leak and gas pocket detection inspection of approximately 21,200 feet of the Potable Water Main (PWM), which connects the Pintail Pump Station to the Waketon Water Tower. Constructed in 1973, the critical section of 20-and 30-inch pipeline is comprised of bar-wrapped (AWWA C303)steel and ductile iron pipe.

“Most pipelines are designed for 50 to 75 years expectancy, and service life can vary depending on factors such as depth, soil conditions and pipe material,” said Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District. “Rather than waiting for breaks to happen, the Town strives to assess the condition of the assets before that happens.”

The Sahara inspection followed a structural assessment using a PipeDiver® inspection of this same pipeline conducted one month earlier and covered many of the identical pipeline sections. FMPW chose CCTV inline video and enhanced electromagnetic (EM) assessment to provide a comprehensive condition assessment.

PipeDiver platform carried to the insertion point

Pure’s free-flowing PipeDiver platform, which preceded the Sahara inspection along the same pipeline, is being carried to the insertion point.

Detecting small leaks with Sahara inspection platform

The Sahara® pipeline inspection platform is one of the most accurate tools available for leak detection, gas pocket detection, and locating structural defects in complex networks of large diameter water and wastewater pipes.

The tethered tool is capable of locating very small leaks typically within 1.5 feet (0.5 meters) of their actual location. The tool also features inline video that allows operators to observe internal in-service pipe conditions.

Added value: Flower Mound inspection included design and installation of taps

The insertion locations for the Sahara inspection were dictated by the previous PipeDiver inspection, which indicated a large number of bends and long distances to cover with less than ideal access.

In light of the limitations, and within a very short time frame, Pure took on the responsibility to manage the tapping process in-house, including the design, excavation and installation of the taps to insert and extract the Sahara tool from the pipes. Although this task was atypical of work normally provided, it is an example of the added value Pure can bring to a project.

Detected: one leak, one large gas pocket, plus improved GIS information

It’s still early in game, and the electromagnetic results have yet to be fully evaluated. Nonetheless, the Sahara inspection detected a leak on an undocumented offtake installed on pipe suspected to have been blanked off and buried, and now leaking.

In addition to pinpointing the leak and gas pocket, the condition assessment located an additional six undocumented outlets the Town was previously unaware of, leading Pure and FMPW to surmise that the outlets were installed and equipped with blind flanges for future expansion. Additionally, during this inspection, sections of pipeline alignment were discovered to be quite different than what FMPW expected.

FMPW now has a true comprehensive condition assessment of their pipeline that includes GIS quality mapping, video inspection and recording of the pipeline interior, leak and gas pocket identification and repair, and assessment of the structural integrity on a pipe-by-pipe basis — allowing for localized verification and repair. Overall, GIS information has been improved, with location and images of possible leaks, defects or anomalies.

“The proactive approach we’re taking allows us to predict water main breaks, which improves our reliability of service,” said Williams. “When you locate a defect, you can schedule a repair, notify people, and get it done at the right time of day, and at a schedule of our choosing. Everybody benefits.”

Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District, talks about the Utility’s approach to condition assessment.

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.

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

PureRobotics device

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

Force mains have unique signs of impending failure

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

SmartBall with extraction tool and controls

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

Addressing the high consequence of failure in wastewater pipes

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

Low risk assessment

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

Medium resolution assessment

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

High resolution assessment

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

No one solution for every pipe or pipeline

While there is no silver bullet for assessing every pipeline, if a utility has a strong understanding of the risk and operational conditions of different areas in their system, an appropriate and defensible inspection plan can be developed. This process allows force main owners to develop a sustainable long-term strategy for managing their critical force main assets.

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

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

Surprising results in spite of critical importance

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

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

Old main

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

Helping water utilities embrace sustainability

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

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

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

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

Pipe Surface Inspection

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

Capital savings can be invested back into the system

The numbers continue to impress. Based on Pure’s condition assessment data, we have found that 96 percent of pipe sections do not have any deterioration at all and are in “like new” condition, while less than 1 percent of pipe sections require immediate repair. This is comforting information to utilities with aging pipelines still in operation, as is the case with the remarkable cast iron water main buried in 1831 beneath what is now Greenwich Village.

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

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

Public pressure to do the right thing

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

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

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

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

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

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

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

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

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

Staff inserting tools

Defining Risk and Pipeline Priorities

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

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

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

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

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

Using Risk to Select Condition Assessment Techniques

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

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

Tech monitoring results

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

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

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

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

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

Across the United States, there are many thousands of water and wastewater utilities that serve populations less than 50,000. Although the majority of attention surrounding aging infrastructure focuses on the challenges of large utilities, these small utilities are often faced with greater challenges.

Smaller utilities often have fewer resources – both financial and personnel – devoted to managing their water and wastewater systems. At times, this can lead to the utility having  less information available about their system, such as pipe drawings, break and leak history and condition data.

Coupled with having fewer resources, small utilities often have primary mains that are non-redundant and represent the sole source of supply or collection for the population, making a leak, rupture or shutdown of any kind very disruptive.

The City of Tarpon Springs, FL serves a population slightly less than 25,000. With limited resources and a mandate to provide both reliable water supply and wastewater collection for its customers, the City decided to assess the condition of one of its primary 14-inch force mains that experienced a failure in summer 2013.

The Dixie Highway Force Main is made of 14-inch ductile iron pipe (DIP) and poly-vinyl chloride (PVC) pipe, which was installed after the failure. In summer 2014, the City decided to complete condition assessment on nearly 1 mile of the force main to identify specific areas of concern before investigating further replacement.

Since internal hydrogen sulfide corrosion is the primary cause of DIP force main failure – and was the cause in 2013 – an inline survey was completed to collect relevant condition data.

For the inspection, the City used the SmartBall® tool, which can locate leaks, gas pockets and pipe wall stress in metallic pipelines. Leaks or failures on wastewater pipelines can have a devastating effect on the environment and can lead to litigation and consent decrees. In addition, gas pockets in force mains are of significant concern as hydrogen sulfide gas within the wastewater can 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.

Leaking Pipe

The SmartBall PWA tool is removed after the 1-mile inspection.

Sahara Insertion

Staff at Tarpon Springs Water were onsite during the inspection.

While inline leak and gas pocket assessment is a well-developed approach for force main operators, the development of pipe wall assessment (PWA) technology provides a more comprehensive level of condition information – areas of the pipe wall with damage will be under more stress than areas with limited or no damage.

By identifying stress anomalies, it provides operators with a detailed report of areas that warrant a more detailed assessment or testing.

The SmartBall assessment identified no leaks and nine gas pockets along the force main. Three of the gas pockets are located along the PVC section of pipe, indicating that gas pockets re-emerged in the PVC section of pipe in less than a year after replacement. It was recommended that air release valves be installed along the force main to clear gas pockets.

In addition, the PWA survey identified six areas that indicated stress within the pipe wall. One of the stress anomalies corresponds with a transition from buried pipe to exposed pipe, and therefore is caused by the change in load. The remaining five PWA anomalies do not correspond to any known features and could represent pipe degradation. The City during the insertion of the air release valves will be performing some field validation of these pipes.

By assessing the entire force main in advance of replacement, the City of Tarpon Springs is now able to make more informed decisions about its critical asset while avoiding the costly and mostly unnecessary strategy of replacement of the entire force main length. This mentality is an excellent example for other small utilities that are looking for ways to manage aging critical infrastructure, since replacing assets is very expensive within limited capital budgets.

Learn More

SmartBall Pipe Wall Assessment

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.

Frankfort Electric and Water Plant Board Verifies Distress on Ductile Iron Pipe Using Electromagnetics

In June 2013, FEWPB agreed to utilize an electromagnetic (EM) assessment technology on 700 feet of 1974 era DIP after the successful assessment of almost five miles of its prestressed concrete cylinder pipe (PCCP). The 700-foot section of 48-inch DIP runs directly from one of FEWPB’s water treatment plants and connects with the primary transmission main.

Ductile Iron Pipe

Ductile Iron Pipe (DIP)

Introduced into the U.S. marketplace in 1955, ductile iron pipe (DIP) is pressure pipe commonly used for potable water and sewage distribution. The predominant wall material is ductile iron, a spheroidized graphite cast iron, although an internal cement mortar lining usually serves to inhibit corrosion from the fluid being distributed, and various types of external coating are used to inhibit corrosion from the environment.

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

Across the United States, there are thousands of miles of water and wastewater pipes buried beneath communities. These pipes come in a variety of materials and sizes, but all provide necessary services to customers across the country.

In recent years, several industry studies have warned that a large majority of these assets are aging and reaching the end of their designed lifespan. Although this is true, it is often prudent for municipalities to manage their assets – especially their large-diameter pipelines – in favor of replacement.

Replacement is expensive – industry experts estimate that the costs could reach $1 trillion over the next three decades. But beyond this massive expense are the unassailable logistical challenges of replacing thousands of miles of pipe.

Fortunately for municipalities, some pipe materials that make up the nation’s infrastructure have well-developed assessment methods that allow operators to determine the location of deterioration so that pipes can be renewed. Pipe deterioration is often due to localized problems – such as soil, loading and operating conditions – meaning pipelines do not fail systematically across their entire length and can often be effectively managed.

Unfortunately for some municipalities that own large-diameter metallic pipe, like Padre Dam Municipal Water District (PDMWD), the technologies available for assessing its condition have only recently been developed.

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 using Mini PipeDiver®, a free flowing tool that can determine the baseline condition of metallic pipes.

The tool is equipped with PureEM™ technology and can detect broad areas of corrosion on metallic pipelines. While its resolution is not as high as other metallic inspection platforms, such as Magnetic Flux Leakage which can identify very small defects, PureEM is capable of detecting areas of corrosion that could lead to near-term pipe failure. It is also able to assess long distances in a single deployment, making it ideal for pipelines that cannot be removed from service.

Pure Technologies staff calibrate the Mini PipeDiver tool prior to inspection.

Pure Technologies staff calibrate the Mini PipeDiver tool prior to inspection.

Staff extract the PipeDiver tool from the pipeline.

Staff extract the PipeDiver tool from the pipeline.

In total, the inspection identified six pipes with signals consistent with localized circumferential anomalies and 15 pipe sections showed signal shifts indicative of a pipe class change.

Starting in February 2013, PDMWD began validating the results of the inspection by excavating the six pipes with circumferential anomaly signals. All six anomalies were confirmed to have some level of defect including:

  • Unknown concrete encasement covering a 2-foot longitudinal weld at a pipe joint; this pipe was damaged and repaired during the installation phase without proper documentation
  • Damaged mortar lining and steel cylinder after the pipe was installed on a rock
  • Localized cylinder and wire mesh corrosion
  • Excessive wire wraps caused by a manufacturing defect

While the six anomalies represented different forms of damage, the information collected using PipeDiver was accurately verified and was very useful for PDMWD. In addition, the anomalies that indicate a pipe class shift provide the District with valuable information about their system that was previously unknown.

Based on the results of the condition assessment, PDMWD determined that a large replacement or renewal project was unnecessary and could be deferred. This allows the District to be confident in the condition of this pipeline while maintaining safe and reliable service for its end-users.

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.

Managing Metallic Pipelines

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

In Pinellas County – Florida’s most densely populated county – residents and government work together to conserve water. A major component of this water reclamation process is the South Cross Bayou Water Reclamation Facility, which is designed for an average flow of 33 MGD. After a failure in June 2013 on a 42-inch ductile iron pipe in the reclamation facility, the Pinellas County Department of Environmental and Infrastructure rehabilitated and replaced portions of the facility’s pipeline. In September 2013, the Division of Engineering and Technical Support suspected that a small leak (estimated at 19 gallons/hour) had developed on a section of pipeline, originally thought to be in good condition, which was not rehabilitated after the failure. In metallic pipe materials, pipe failure is often preceded by a period of leakage. After already having a significant failure and investing in rehabilitation on a significant amount of pipeline, the County was adamant about identifying the location of any further leaks, which were impacting normal facility operation. After unsuccessfully trying a number of different leak detection techniques, the County turned to inline leak detection to identify the leak on the 627-foot (191-meter) stretch of pipeline. However, one of the challenges was that the pipeline had no flow due to implemented bypass procedures. To locate the leak, the County and Pure Technologies (Pure) took an innovative approach by using a tethered SmartBall® tool.

The SmartBall tool is a free-flowing leak detection technology that identifies the acoustic anomalies associated with leaks and gas pockets. Typically, it travels with the product flow in live pipelines, however, in no-flow conditions it will not move.

To overcome this challenge, the County and Pure temporarily pressurized the pipeline, tethered the tool using a mule tape and winched it through the planned inspection distance 627-feet (191-meters). The County took this approach because the insertion point was in the middle of one of the facility treatment trains– meaning a compact tool was needed to meet the logistical difficulties.

During inspection, the tethered SmartBall tool collects data twice since it is winched back to its insertion point. For this inspection, two runs were completed to confirm the leak size and location accuracy for the County. Upon review of the data and during the actual inspection, a leak was determined to be on a sleeve at the invert near the inline magmeter, which was the downstream limit of our inspection. The area outside of the magmeter vault was difficult and expensive to expose. Therefore, the County filled the area with grout and placed the pipeline back into service.

 

Learn More

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 inline leak detection technology designed to operate in a live water mains.

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.

 

Learn More

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.

Each of the various pipe designs used in water networks across the United States has a specific life expectancy and operational requirements. Although some pipeline materials have well-developed, effective inspection technologies, assessing metallic water pipelines with mortar lining has historically posed a challenge for utilities, including the San Francisco Public Utilities Commission (SFPUC).

Without a reliable way to assess the condition of cement-mortar-lined pipelines, the San Francisco Public Utilities Commission set out to develop its own technology.

The third-largest municipal utility in California, SFPUC operates and maintains a large, complex water-delivery system for 2.6 million people and businesses in San Francisco, Alameda, Santa Clara, and San Mateo counties. The gravity-fed system reliably delivers water across the state without using energy-intensive pumping. Eighty-five percent of this water comes from the Upper Tuolumne River Watershed in the Sierra Nevada Mountains, where it’s stored in the Hetch Hetchy Reservoir and then transported 47.5 miles via the San Joaquin Pipeline (SJPL) across California’s Central Valley to the Bay Area. The SJPL system includes three large-diameter pipelines (56–78 in.), generally consisting of cement–mortar-lined steel that have been operating for more than 80 years. The pipelines can deliver 300 mgd.

To minimize the number of unplanned outages and determine the remaining pipeline life, SFPUC sought a technology that could assess the wall thickness of steel pipelines. Unfortunately, no technology was available, so SFPUC funded research to develop such technology. The project focused on SJPL. Because capital improvement funds were limited, however, SFPUC officials knew they needed a technology that would do the job and allow the utility to efficiently administer SJPL rehabilitation funds, according to Margaret Hannaford with the Hetch Hetchy Water and Power Project (HHWP), SFPUC.

In the August issue of AWWA Opflow, read about how SFPUC developed Magnetic Flux Leakage technology for reliable assessment of mortar-lined steel water pipelines.

Read Full Article»

Magnetic Flux Leakage (MFL)

Magnetic Flux Leakage (MFL)

Magnetic flux leakage (MFL) is an electromagnetic method of nondestructive testing that is used to detect corrosion, pitting and wall loss in lined and unlined metallic pipelines.

Case Study

Case Study: San Francisco Public Utilities Commission (SFPUC)

Without a reliable way to assess the condition of cement-mortar-lined pipelines, the San Francisco Public Utilities Commission set out to develop its own technology. In a project from 2007 to 2010, SFPUC developed and used MFL technology to inspect its critical San Joaquin Pipeline.

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.

 

Learn More

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.

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.

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

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

Single-step blowouts of pipe walls are quite rare; pinhole leaks, hairline cracks, corrosion and leaking gaskets tend to occur first. Most catastrophic failures are caused by a sudden unexpected stress such as a water hammer acting on an existing weak point in the pipe. There is a widely held belief that the failure process is a simple one, where a pipe corrodes to the point at which it can no longer withstand the applied internal and external forces, resulting in a main break. However, research has shown that the failure process is more complex than expected. Corrosion plays a significant role in water main failures, but soil-pipe interactions, manufacturing techniques and human error are also important factors. Failures also take place in multiple stages rather than in a single episode. Early damage not only weakens portions of the pipe, it also allows water to escape, causing corrosion and washing out of the supporting soil.

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

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

Types of pipe material and typical causes of failure:

Prestressed Concrete Cylinder Pipe (PCCP) has a unique failure mechanism: high strength steel pre-stressing wires that provide strength to the pipe can become distressed and reduce the structural integrity of the pipe. Broken wires can be caused by physical damage to the pipe, corrosion, or hydrogen embrittlement. Regions of broken wires may be accompanied by leaks, especially in pipelines smaller than 48 inches in diameter, where the internal steel cylinder corrodes at the same rate as the wires or where water escaping through the joint encourages corrosion. Leakage has been proven to be a key indicator of structural condition in lined cylinder pipe, a type of PCCP in which the prestressing wires are placed directly on the steel cylinder. These types of leaks can create voids around the pipe and introduce added stress at an existing weak point.

Corroded Wires, Embrittled Wires, Cylinder Perforation

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

Tuberculation, Bell Cracking, Longitudinal Cracking, Corrosion

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

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

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

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

Introduction

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

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

Authors

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