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SAHARA® INLINE TETHERED PIPELINE INSPECTION PLATFORM

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

Video

SmartBall® Inline Free-Swimming Pipeline Inspection Platform

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

Video

PureRobotics® Tethered Robotic Pipeline Condition Assessment Platform

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

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.

Case Study

In order to maximize their existing capital assets, reducing overflows and optimizing overall operation efficiency, the Metropolitan Sewer District of Greater Cincinnati (MSD) engaged Xylem in utilizing BLU-X, a drainage network optimization solution that uses a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

Cincinnati’s sewers discharge an average of 11.5 billion gallons of combined sewage every year into the Ohio River and its tributary streams within Cincinnati’s urban watershed.

In 2002, the EPA entered into a federal consent decree with MSD, mandating the elimination of sanitary sewer overflows and significant mitigation of combined sewer overflows into receiving waterways. Engineers estimated the cost to mitigate the sewer overflows at $3.1 billion, an unacceptable capital expense to pass along to MSD’s customers.

THE CHALLENGE

Recognizing the generally inadequate stormwater management capabilities of their existing combined sewer system, MSD prepared a comprehensive wet weather improvement plan. MSD recognized that full sewer separation and deep tunnel construction are massive capital investments that have a very low return on investment because they create only episodic benefits during peak flow events and are single-use assets with little additional community wealth creation.

Instead, MSD’s objective was to maximize existing capital assets — such as sewer interceptors, storage and treatment facilities, and pump-stations — to reduce overflows and gain system-wide benefits through advanced control logic that will optimally operate MSD’s urban watershed.

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

Project Highlights

Overflow volumes reduced by 247 million gallons annually

More than a 90% reduction in cost compared to initial capital work estimated at $38 million

CSO mitigation achieved at a price of less than$0.01/gallon

Services Provided

• BLU-X real-time decision support system (RT-DSS) to manage storage and conveyance
• RT-DSS integrated into MSD’s existing SCADA and IT networks
• All sensor data presented on one unified platform

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.

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

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

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

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

Gas pockets are of significant concern in rising mains.

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

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

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

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

Four steps to a risk-based approach.

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

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

Most common reasons for pipeline failure.

Preliminary analysis.

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

Acoustic-based SmartBall® tool locates leaks and gas pockets

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

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

Internal corrosion potential survey.

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

Pipe wall assessment.

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

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

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

Condition assessment analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

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

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

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

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

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

Gas pockets are of significant concern in force mains.

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

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

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

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

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

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

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

Desktop studies are not always reliable.

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

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

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

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

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

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

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

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

Preliminary Risk Analysis

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

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

Acoutic-based SmartBall® tool locates leaks and gas pockets

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

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

Internal Corrosion Potential Survey.

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

Pipe Wall Assessment.

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

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

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

Condition Assessment Analysis.

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

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

Diagnostic analytics helps utilities move risk assessment forward.

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

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

 

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

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

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

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

Island community concerned about pipeline risk of failure.

Sensitive location and potential environmental consequences strike nerve with community.

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

The assessment challenges began from the get-go.

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

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

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

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

Pipeline alignment follows along the Vancouver Island coast.

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

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

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

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

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

PipeDiver tool collects electromagnetic data regarding the pipe wall.

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

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

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

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

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

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

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

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

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

Data analysis indicated no electromagnetic distress on inspected pipes.

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

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

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

 

Case Study

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

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

Project Details

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

Project Highlights

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

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

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

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

Challenge

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

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

Solution

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

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

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

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

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

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

Results

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

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

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

Case Study

Hutt City’s main outfall pipeline (MOP) is one of its most critical assets, taking treated wastewater from the Seaview treatment plant to the outfall at Pencarrow Head. The MOP is 18 kilometres long and has an average flow is about 550 litres per second. It was commissioned in 1962 and has an expected life of about 60 years.

Project Details

Services
Assess and Address®Technology Driven Pipeline Solutions
Electromagnetic Inspection
SmartBall® Leak and Gas Pocket Detection
3D Finite Element Analysis and Structural Modelling
Timing
2007- ongoing
Pipe Material
PCCP
Inspection Length
18 km (11 miles)
Diameter
1295mm (50-inch)
Transmission Type
Treated Wastewater

Project Highlights

EM inspection showed 354 of 4,662 pipe sections with some distress

92% of Hutt City’s main outfall pipeline had no deterioration at all

Hutt City was able to extend the life of the critical asset through proactive pipeline management

Challenge

Monitoring the condition of underground assets is a major challenge; much of the New Zealand’s infrastructure was constructed more than 60 years ago and is beginning to reach the end of its design life. While councils search for solutions to manage infrastructure, there is increasing public pressure to minimise rates and improve environmental performance.

Over time, Hutt City’s MOP has showed signs of deterioration, culminating with one pipe section failing catastrophically during normal operation. While replacing the ageing MOP is one solution, it is very difficult and expensive to complete. While the main has a replacement value of $60 million, the costs associated with replacement would likely be much higher due to the logistical challenges associated with constructing a new main.

Solution

In May 2013, Hutt City Council and Hutt Valley Water Services contracted MWH Global to assess the possibility of repairing or replacing of the MOP. In order to complete a comprehensive condition assessment of the main, MWH contracted Pure Technologies, a Calgary-based company.

In order to fully understand the condition of an asset, it is important to use a variety of solutions that identify different aspects of deterioration. This approach is called Assess and Address®, which focuses on identifying and locating isolated areas of distress along a pipeline for renewal. Through this approach, Hutt City can avoid replacing the entire MOP – which is challenging and costly – while increasing its reliability and extending its useful life. Pure used multiple solutions for to assess the MOP for leaks, gas pockets, and structural deterioration. The SmartBall® tool was used to identify leaks and pockets of trapped gas, as well as validate the results of the electromagnetic (EM) inspection. The tool is a free-swimming and measures the acoustic activity associated with leaks and gas pockets in pressurized pipelines.

To identify structural deterioration, electromagnetic technology was used on the PipeRider platform in the dewatered pipeline. Once calibrated above the ground using spare pipe sections – with one of the pipes having some wires exposed and cut for the calibration – the bike was disassembled and placed in one end of the pipeline. The inspection was completed by generating an eddy current and measuring the signal as it conducts through the reinforcing steel within the concrete pipe wall as the tool traverses the pipeline. In Prestressed Concrete Pipe (PCP), the reinforcing steel wires are the main structural component. As these wires begin to deteriorate, specific pipe sections become structurally weaker and are more likely to fail.

Upon completion of the inspection, Pure performed 3D Finite Element Analysis and Structural Modelling on specific sections of the MOP. This process determines how the specific pipe material will perform under different operating conditions, which will guide Hutt City on how to safely operate its main to prevent pipe failures.

This analysis also provides an estimated remaining useful life for the asset, which aids in the development of re-inspection and replacement planning.  

Results

By managing the MOP in favour of replacement, Hutt City was able to determine that one of its most critical assets had remaining useful life. This prevented a very expensive and challenging replacement project, allowed for the deferral and redeployment of capital to other projects.

The data collected and subsequent structural analysis provided an understanding of the condition of the pipe’s main structural component while being non-destructive to the pipe itself. In total, 8 percent of pipe sections had some level of deterioration (354 of 4,622), meaning a complete replacement was unnecessary and the asset has remaining useful life.

By managing its critical infrastructure, Hutt City demonstrated its commitment to providing safe, reliable and sustainable service while ensuring that capital works budget is efficiently and responsibly allocated.

It’s fantastic we’re able to use this world-class technology in our city and benefit from the advanced results it can give us to help plan for the future.

Bruce Sherlock

General Manager, Hutt Valley Water Services

PureNet

PureNet enables utility managers to more effectively manage their infrastructure data.

Streamlining utility databases into one platform for improved efficiency

Providing safe and reliable access to clean water becomes more difficult to manage as infrastructure ages, and populations continue to grow.

However, innovative asset management strategies can provide utilities with information on their buried assets. Knowing what assets they have and when they will need rehabilitation is crucial for planning and fiscally responsible decision making.

PureNet streamlines information from existing utility databases such as billing systems, hydraulic models, workload programs and maintenance management systems into one platform to improve efficiency.

Benefits

  • Prioritize asset management activities
  • Postpone network expansion by demand management
  • Postpone pipeline replacement
  • Adopt a selective assess and repair strategy

Article

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

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Featured Case Study

The City of Tacoma

Tacoma, WA, USA

In early 2015, Pure Technologies (Pure) conducted a condition assessment of Pipeline No. 1 owned and operated by The City of Tacoma (Tacoma Water), as part of their proactive asset management program.

PipeWalker

Access comprehensive information on the integrity of water and wastewater pipelines

Comprehensive condition assessment data for pipelines

Pure Technologies PipeWalker tools offer a steady, stable, and methodical option for pipeline condition assessment in situations where the pipe is dewatered or where the option to dewater is available.

In addition, because the operators walk the pipeline with the tool, visual inspection gives immediate feedback on joints and the condition of mortar.

Using Pure Technologies electromagnetic technology, the PipeWalker condition assessment tools offer condition assessment information on both PCCP and metallic pipes of a variety of sizes. With solutions for both PCCP and metallic pipe (Pure Technologies electromagnetic technology detects and locates broken wire wraps in PCCP and localized areas of corrosion on metallic pipe).

Combined with Pure Technologies advanced engineering solution, PipeWalker condition assessment gives utility owners comprehensive information on the integrity of their water or wastewater pipelines in order to make confident decisions on the management of their pipelines today and into the future.

Pure Technologies has inspected the largest PCCP pipe in the world using this platform!

Benefits

  • Visual inspection of the pipeline with condition data
  • Provides actionable information on both PCCP and metallic pipes
  • Can be used to inspect large pipes

Related Article

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

learn more

Featured Case Study

Queensland Urban Utilities

Queensland Urban Utilities is one of the largest water distributors-retailers in Australia, supplying drinking water, recycled water and sewerage services to a population of more than 1.4 million in South East Queensland.

Sahara®

The Sahara platform is a tethered tool with live video that can accurately detect leaks and gas pockets in water and wastewater pipelines.

Real-time feedback and precise leak location details for pipeline operators

The Sahara platform is a tethered tool that offers a variety of solutions for water and wastewater pipelines, including leak and gas pocket detection, inline CCTV and pipeline pre-commissioning.

Sahara gives clients a cost-effective option for precise leak location in both complex and pipelines, while also giving utilities the option of live video footage and pipeline mapping. Using this actionable data, utilities can confidently make decisions relating to water loss and condition assessment of their network.

Sahara leak detection is tracked above ground using sensors, which also allows for the precise marking of leaks. This information can be used by utilities to greatly improve excavation accuracy when excavating the pipeline for repairs and maintenance, especially in complex urban environments. The tool allows the operator close control and sensitivity during inspections with no disruption to regular pipeline service.

Benefits

  • Easy to deploy through existing pipeline features
  • No disruption to regular pipeline service
  • Sub-meter mapping technology for all pipeline materials
  • Tethered system ideal for complex and urban systems
  • Real-time results with live video feed
  • Finds leaks that cause pre-commissioned water mains to fail

Related Article

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.

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Featured Case Study

K-water

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.

Beginning in 2011, K-water has used Sahara® Leak Detection to address non-revenue water and collect condition information about its metallic pipelines.

PureRobotics®

PureRobotics is a powerful robotic pipeline inspection system that can be configured to inspect virtually any pipe application.

Identify problem pipeline areas more easily through a robotic crawler

PureRobotics is a modular, powerful robotic inspection system that helps utilities screen their network for problem areas and gain a better understanding on the condition of their assets.

The robotic crawler is designed to easily transport sensors and tools through dewatered pipe, or while submerged in potable, raw water, or wastewater.

The robot is a multi-sensor platform that carries a variety of condition assessment tools inside the pipeline in a single deployment that also provides live video that can aid in detecting anomalies within the pipe. In addition, the tethered tool is an unmanned solution which makes inspections significantly safer.

Combined with Pure Technologies’ advanced engineering solution, PureRobotics condition assessment delivers comprehensive and actionable condition assessment data in a flexible manner giving utilities reliable information to act on with confidence as part of an asset management program.

Benefits

  • Quick and easy to deploy
  • Modular to adapt to many pipe conditions
  • No dewatering required
  • Live video stream
  • Safer than manned entry

Related Article

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

Learn more

Featured Case Study

Milwaukee Metropolitan Sewerage District (MMSD)

The Milwaukee Metropolitan Sewerage District (MMSD) takes a proactive approach to water management initiatives.

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.

PipeDiver®

PipeDiver is an innovative, free-swimming condition assessment platform for water and wastewater pipelines that operates while a main remains in service.

Confidently manage your pipes without the need to shutdown or dewater

PipeDiver is a long distance, free-swimming condition assessment tool that operates while the pipeline remains in service, providing utility owners with an easier and less costly alternative to inspection methods that require shutdown or dewatering.

Its flexibility allows the tool to travel through a variety of pipe configurations including butterfly valves and sharp bends and tees, and because it deploys through existing appurtenances it often reduces cost and effort to the utility. Pipeline owners receive comprehensive data on the condition of the pipe wall. For PCCP that means identifying broken prestressing wire wraps, while on metallic it identifies localized areas of corrosion.

PipeDiver inspections and Pure’s advanced engineering give clients data for their pressure pipe assets that tell them what needs to be addressed today and what to plan for in the future.

Benefits

  • No disruption to regular pipeline service
  • Long inspection distances can be covered in a single deployment
  • Accurate results that pinpoint areas of damage
  • Cost-effective method that don’t require shutdown and dewatering

Related Article

To assess the condition of its Newmore Raw Water Main, Scottish Water used PipeDiver™ inline inspection technology, the first use of the technology in Europe.

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Featured Case Study

Flower Mound, Texas USA

The Town of Flower Mound, 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.

SoundPrint® AFO

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

Continuous real-time structural monitoring
for PCCP pipelines.

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

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

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

Benefits

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

Related Article

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

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

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Featured Case Study

City of Baltimore

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

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

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.

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

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

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

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

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

Gas pockets are of concern on wastewater lines

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

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

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

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

SmartBall tool tracked at known points along the pipeline alignment

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

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

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

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

Inspection results

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

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

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

State of the Water Industry Report 2017

The American Water Works Association (AWWA) has formally tracked issues and trends in the water industry since 2004 through its State of the Water Industry (SOTWI) study. The Association continues to conduct this annual survey in order to:

  • Identify and track significant challenges facing the water industry
  • Provide data and analysis to support water professionals as they develop, implement, and communicate strategies to address current and future issues
  • Inform decision makers and the public of the challenges faced by the water industry
“Water professionals are feeling overwhelmed,” said AWWA president-elect, Brenda Lennox. “A perfect storm of issues is coming together. Crumbling infrastructure is overwhelming enough, but we’re also experiencing huge workforce turnovers and feeling the backlash of that.”

Top Issues

The top five most important issues facing the water industry were identified as follows:

  1. Renewal and replacement (R&R) of aging water and wastewater infrastructure (#1 in 2016)
  2. Financing for capital improvements (#2 in 2016)
  3. Long-term water supply availability (#4 in 2016)
  4. Public understanding of the value of water systems and services (#3 in 2016)
  5. Public understanding of the value of water resources (#5 in 2016)

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.

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.

Gateway of The North City of North Bay

On one hand, it may seem like a waste of capital dollars if you perform a pipeline condition assessment and the final analysis turns up no leaks. Alternatively, you can also look at the no-leak report as a good news validation story, especially when using the information to help establish an asset management plan.

Such was the case for a city of 51,000 situated between the shores of lovely Lake Nipissing and Trout Lake in Northern Ontario.

In September 2016, the  City of North Bay (City) retained the services of Pure Technologies (Pure) to perform a two-phase condition assessment on the Marshall Avenue Force Main (MAFM). The MAFM is a critical 508mm (20-inch) asbestos cement pipeline that services approximately half the city, and transfers wastewater from the Marshal Avenue Pump Station to the North Bay Sewage Treatment Plant.

Aerial picture with sewer map

The City was interested in exploring technologies to help them better understand the actual condition of their force main in order to implement a comprehensive asset management program using the inspection data.

To assist in the assessment, Pure Technologies elected to first conduct transient pressure monitoring, followed by a SmartBall® inspection to acoustically identify and locate leaks and pockets of trapped gas along the pipeline.

Transient pressure monitoring helps understand structural integrity of the pipeline

First, transient pressure monitors were installed at the pump station discharge header. For approximately six weeks, the recorded pressure data was used to understand the operational and surge pressures within the force main and their impact on the structural integrity of the pipeline.

When pipe wall degradation is combined with surge pressures, the likelihood of pipe failure can be significantly increased.  Evaluation of the pump station operation, such as pump start-up mode, typical and peak flows, operating and surge pressures, and surge protection, can provide important information on the stress.

SmartBall with its controls and tools

SmartBall tool provides acoustic signature related leaks and gas pockets

While transient pressure data was collecting, Pure deployed its proprietary SmartBall technology, a multi-sensor tool used to detect and locate the acoustic signature related to leaks and gas pockets in pressurized pipelines. The tool has the ability to inspect long distances in a single run, and while the SmartBall is deployed, the pipeline remains in service, limiting disruption to customers.

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

From insertion to extraction, the SmartBall inspection took a little over four hours, with no unexpected events as anticipated during the planning stage.

SmartBall functionality chart

Results lead to effective management of finances and risk

Based on the inspection data, Pure analysts reported zero (0) anomalies characteristic of leaks, and 13 acoustic anomalies characteristic of pockets of trapped gas, mostly around air valves.  In particular, gas pockets are of significant concern in force mains, as concentrations of hydrogen sulfide gas within wastewater may be subsequently converted to sulfuric acid by bacteria in the slime layer on the pipe wall. This may cause corrosion and eventual breakdown of the pipe’s exposed surface.

Gas pockets combined with pressure transients can have significant impact on the pipeline, as vacuum conditions may be created. This can cause cavitation at the gas pocket as the transient gas passes, increasing stress on the pipe wall and therefore increasing the risk of failure if the structural capacity has been compromised.

City considering adding more air valves to help expel collecting gas

Based on a hydraulic evaluation of the pipeline, structural fatigue was not a concern, although test pits were recommended to determine asbestos cement thickness and gas pocket mitigation using swabs also recommended. In the near term, the City is considering adding more air valves to the pipeline to help expel collecting gas.

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

Pensacola view from the air

The introductory meeting was pure happenstance. After a well-timed phone call, two unfamiliar parties – a public utility and a business development team from an engineering technology-solutions firm – agreed to meet, learn about each other, and within weeks, begin to collaborate on a master plan of action to comply with a consent order agreement.

The story begins in late 2015, when staff from Emerald Coast Utilities Authority (EUCA), a progressive utility that services water and wastewater systems of Escambia County and the City of Pensacola, Florida, received a call from Pure Technologies. The inquiry was for permission to set up an educational meeting to discuss the pipeline inspection technologies, solutions and engineering services provided by Pure.

SmartBall in a case with the laptop used to control it.
Coincidental to the consent order, ECUA welcomed the opportunity to hear what Pure could bring to table. ECUA commented, “your timing is perfect, and we appreciate the educational meeting and not a sales pitch.”

That fortuitous encounter set the wheels in motion and led to the partnership between Pure, ECUA and its asset management consulting partner, Arcadis – a three-way cooperative that is now helping ECUA develop a comprehensive risk management program for its wastewater network.

Consent order issued for wastewater division

Backtrack to June 2012, when the Florida Department of Environmental Protection (DEP) issued a consent order to Emerald Coast Utilities Authority, with the agreement citing 24 spill events occurring between 2009 and 2010 that the state deemed avoidable within the utility’s collection of wastewater force mains. These force mains range in size from eight to 30-inches in diameter, and are comprised of cast iron pipe (CIP), ductile iron pipe (DIP) polyvinyl chloride pipe (PVC) and high-density polyethylene pipe (HDPE).

Sanitary Sewer Overflows (SSO), or spills, can result from a break in the pipe, or when the system is overwhelmed by heavy rain events. While spills can be caused by accidental breaks in the pipe, an aging infrastructure, with its inherent inflow and infiltration issues, makes a system all the more susceptible to SSO events.

Emerald Coast Pipe Risk Map

ECUA intrigued by the risk model focus offered by Pure and Arcadis

While ECUA engaged with Arcadis as the lead consultant to assist with the requirements of the consent order, the meeting with Pure Technologies gave ECUA the opportunity to learn about Pure’s expertise in developing a comprehensive risk prioritization plan. It also gave them an introduction to Pure’s suite of condition assessment technologies, which includes the innovative SmartBall® leak detection platform, a free-swimming tool that collects acoustic data associated with leaks and gas pockets.

With more than 315 miles of force mains within its network, it was critical for ECUA to first have the right data to make the right decisions on the prioritization of what assets to first Assess and Address®, in order to make effective use of a limited budget and resources. Pure’s experience indicates that less than 10 percent of pipelines have indicators of distress, while even fewer require repair or replacement to extend their useful life.

All the more reason why ECUA was intrigued by the risk model focus offered by Pure and Arcadis.

Using data-driven decision making as part of a risk management program

Pure recognizes the importance of data-driven decision making as part of an effective, comprehensive risk management program. A Pipeline Risk Prioritization (PRP) is good starting point for a larger proactive program as it helps to focus resources on the highest risk assets and provides justification as to which assets to assess first.

For ECUA, the goal of the PRP is to develop a risk model (likelihood and consequence of failure) to be used as a guide to determine the assets to inspect first, as well as to select the appropriate assessment technique based on risk. ECUA can use this model to put the right amount of money towards the most appropriate asset at the right time. This provides a utility like ECUA with an effective and defensible approach to managing their assets, and it actually defers long-term funding needs by maximizing the life of an asset.

Given Pure’s unique focus on pipeline asset management, its engineers and scientists have developed a risk model that allows for the input of base asset data, operational history and information, as well as condition assessment techniques and technologies. This model, unique to the industry, provides an output that clients can use in their capital and operational budgeting processes.

 

SmartBall inside a pipe.

Latest services include transit pressure monitoring and acoustic leak detection

To date, Pure has been working with Arcadis on a risk prioritization for the ECUA force main network, in which data is collected with transient pressure monitors, as well as from SmartBall acoustic inspections in order to assist in creating a Master Plan for the ECUA wastewater division. ECUA is currently five (5) years into the 15-year calendar agreed to with DEP.

In addition to the transient monitoring, during 2016 Pure inspected approximately 13.6 linear miles of force mains through seven (7) SmartBall deployments, giving ECUA more evaluative information on their aging infrastructure.

As this project is still ongoing, both ECUA and Arcadis have expressed an interest into additional wastewater projects, with the hope to ultimately address the water transmission and distribution system.

And to think, the plan all began with a simple phone call.

Massive pressured water leak

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

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

Worker inspecting pipe

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

Single-episode blowouts garner all the attention

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

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

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

Broken water pipe on a street

Age alone does not indicate high-risk pipes

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

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

Broken pipe

Types of pipe material and typical cause of failure

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

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

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

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

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

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

Workers digging with mechanical shovel

Making ongoing condition assessment part of proactive asset management

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

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
AWA State of the Water Industry Report

Since 2004 the American Water Works Association has been tracking issues and trends in the water industry. The Association continues to conduct this annual survey in order to identify significant challenges facing the water industry, as well as provide analysis to support water professionals as they develop and communicate strategies to address current and future issues.

In September 2015, emails were randomly sent to a general list of AWWA members and contacts inviting participation in the 2016 study.

A few of the major highlights from the 2016 report

AWWA received 1,468 completed surveys during the survey period, which serves as a good barometer on the state of the industry.

  • The current health of the industry (i.e., soundness) as rated by all respondents was 4.5 on a scale of 1 to 7, the same score observed in 2015; this score has fallen into a range of 4.5 to 4.9 since the survey began in 2004.
  • Looking forward five years, the soundness of the water industry was expected to decline to 4.4 (also on a scale of 1 to 7), which is the same score observed in 2015; this score has fallen into a range of 4.4 to 5.0 since the survey’s inception.
  • Some 30% of utility personnel reported their utilities are currently struggling to cover the full cost of providing services, including R&R and expansion needs, through customer rates and fees, and this jumps to 38% when respondents considered the full cost of service in the future. Notably, 11% of respondents felt that their utilities were currently not at all able to cover the full cost of providing service.

 

Top five most important issues facing the water industry

  1. Renewal & replacement (R&R) of aging water and wastewater infrastructure
  2. Financing for capital improvements
  3. Public understanding of the value of water systems and services
  4. Long-term water supply availability
  5. Public understanding of the value of water resources

 A note on gender: 77% of the 2016 SOTWI respondents were male, but the gender gap diminishes as age decreases; the greatest gender imbalance occurred for those 65 and older (only 3% women), but this imbalance decreased almost linearly as the age category decreased until parity is reached for those 25 years old and younger (i.e., 50% female/50% male ratio).

 

  • Some 30% of utility personnel reported their utilities are currently struggling to cover the full cost of providing services, including R&R and expansion needs, through customer rates and fees, and this jumps to 38% when respondents considered the full cost of service in the future. Notably, 11% of respondents felt that their utilities were currently unable to cover the full cost of providing service.
  • The most important issue in the area of infrastructure R&R was “establishing and following a financial policy for capital reinvestment,” with 42% of respondents rating this a critical issue. Other important R&R issues included prioritizing R&R needs, justifying R&R programs to ratepayers, and justifying R&R programs to oversight bodies such as boards and councils.
  • Interesting change: 56% of respondents reported that their utilities’ access to capital was as good or better than at any time in the last five years, up from 53% in 2015 and 46% in 2014; only 10% reported that their utilities’ access to capital was “as bad or worse than at any time in the last five years”, down from 11% in 2015 and 17% in 2014.
  • 38% of utility respondents reported declining total water sales while 31% of respondents reported their total water sales were flat or little changed in the last 10 years; similar results were observed on a per-account basis. Taken altogether, this means that a large majority of utilities could potentially face issues associated with low or declining water demand if these trends continue while the costs for water services increase.
  • When utility personnel were asked how their utilities are responding to cost recovery needs in the face of changing water sales and consumption patterns, the most reported response was shifting more of the cost recovery from consumption-based fees to fixed fees within the rate structure. Other commonly reported strategies included changes in growth-related fees and shifting the rate design to an increasing block-rate structure. Only 8% of the respondents indicated no changes were needed at their utilities.

 

To view the entire report, make yourself comfortable, pour yourself a coffee, and download the document from the AWWA site, which you can access below.

Download full PDF

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
West Palm Beach Aerial View

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

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

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

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

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

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

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

Staff working at insertion site

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

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

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

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

SmartBall® inside a pipe

First inspection: SmartBall® acoustic leak and gas detection

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

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

PipeDiver® electromagnetic inspection

Next: PipeDiver® electromagnetic inspection

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

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

Results guide the success of the program

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

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

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

SmartBall extraction and retrieval

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

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

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

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

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

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

Hanging rock with a sheep above

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

Oil and gas pipeline owners conduct routine inspections of their pipelines using inline inspection (ILI) tools known as pigs. ILI pigs can identify defects within the pipe wall and need to be tracked when they are travelling through a pipeline.

Pig tracking can be expensive (as much as 25% of the ILI budget) and costs can vary from vendor-to-vendor, especially when you factor in the different methods used to track pigs, such as remote tracking and conventional tracking. In order to ensure that tracking budgets are used efficiently and defensibly, each ILI run should be thoughtfully planned to determine the most appropriate tracking method.

Per Mile Cost Fluctuations

Drawing of a worker

Even after thorough planning, cost estimates can vary from vendor-to-vendor, raising questions about per mile cost fluctuations. To reduce the per mile cost of tracking, service providers often reduce the quality of tracking per mile. In traditional tracking, sending out lesser-trained technicians at cheaper rates, enacting only minimum safety measurements and using only one tracking sensor to identify pig passages are all ways that vendors can reduce per mile tracking costs.

An important consideration for pipeline owners and ILI vendors is determining how much risk they are willing to take when tracking their ILI programs. In most cases reducing the per mile costs by 10 to 15 percent is not worth the risk of using low-quality tracking techniques. A single missed or lost pig can easily negate the savings from using the lowest-cost provider.

In most cases, using remote tracking can decrease both the risk and cost of an ILI run. Remote tracking requires fewer staff and equipment resources than conventional tracking and is much safer.

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

Download full PDF

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.

City of Belmont Skyline

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

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

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

Variety of solutions and technologies used to assess inventory

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

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

SmartBall with extraction tool and controls

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

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

Transient pressure monitoring and hydraulic evaluation used on the smaller mains

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

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

Satellite image with location map

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

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

Each main evaluated with an overall risk rating

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

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

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

Assessment includes life cycle and financial analysis

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

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

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.

City of Saskatoon

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

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

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

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

First priority: where to start?

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

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

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

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

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

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

Risk graphic and aerial map of water main conditions

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

2. Define risk category and establish relevant risk factors

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

3. Compute the risk analysis

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

4. Calculate pipeline and neighbourhood risk

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

5. Model budgetary needs for different management scenarios

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

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

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

Replacement model versus condition assessment model

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

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

What’s next?

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

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.

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

Risk prioritization as a starting point

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

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

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

Match the technology and inspection method with the risk

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

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

 

Medium Resolution Technology

Pipeline Inspection and Condition Assessment Services

PureEM™

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

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

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

Free-Swimming Pipeline Inspection

PipeDiver®

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

PureRobotics™ – Pipeline Inspection

PureRobotics™

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

No one solution for every pipeline

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

However, if a utility has a strong understanding of the risk and operational conditions of different areas in their system, an appropriate and defensible inspection plan can be developed. This process allows operators to develop a sustainable long-term strategy for managing their critical buried assets.

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

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

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

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

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

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

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

Staff inserting tools

Defining Risk and Pipeline Priorities

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

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

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

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

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

Using Risk to Select Condition Assessment Techniques

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

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

Tech monitoring results

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

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

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

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

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

Renowned for its reliability, cost effectiveness and durability, bar-wrapped pipe (BWP) has been used in large-diameter transmission and sewer force mains since its introduction in 1942. Since then, thousands of miles of BWP have been installed in the western and southwestern regions of United States as well as Canada.

Typically, BWP is manufactured with mild steel for the welded steel cylinder and reinforcing bars. While BWP looks much like prestressed concrete cylinder pipe (PCCP) in a cross section comparison, the pipe materials differ, as do the rates of deterioration. Although covered by an inner and outer mortar coating, BWP performs much like steel pipe, and the cylinder plays a much larger role in the structural integrity of the pipe.

Despite its historic acceptance with pipeline operators, the downside to BWP has been the difficulty to effectively assess the pipe’s condition, where failures are often precipitated by deterioration of the reinforcing bars and long periods of leakage that often go undetected. Failure can also result from transient pressure or other sudden catastrophic events.

Technologies to Assess Condition of BWP are Relatively Recent

For BWP, inspection methods that locate cylinder corrosion have only been recently developed and commercialized.

Pure Technologies leads the way with a suite of technology tools that can identify both bar breaks and broad areas of corrosion on the steel cylinder. Based on data analysis, pipe sections with broken bars or cylinder corrosion may warrant a more thorough condition assessment to better understand the pipe integrity or can be immediately repaired or replaced. This approach allows operators to only renew pipe sections that could  be at risk of pipe failure. In one specific case with the Trinity River Authority of Texas, 8.5 miles of a 30- and 54-inch (750- and 1350-millimeter) BWP transmission main was assessed and renewed for roughly 4 percent of the US$25 million capital replacement estimate. This inspection found that the majority of the BWP transmission main was in good condition, with only 3 pipe sections being repaired immediately.

In general, the condition of metallic pipe – and in particular BWP – is typically first accessed with leak detection technology, followed by some level of pipe wall assessment (PWA) via medium or high resolution methods. This multi-tool approach provides the operator with a variety of condition information that can help inform renewal decisions.

Low Resolution Assessment Methods

Sahara® Technology
The first tool designed for live inspection of large-diameter water mains, the Sahara® Pipeline Inspection Systemis one of the most accurate tools available for detecting leaks, pockets of trapped gas, and pipe wall stress in large-diameter water mains.

Sahara pipeline inspections are conducted while the main remains in service by inserting a sensor into any standard tap. A small parachute uses the flow of water to draw the sensor through the pipeline. The sensor is tethered to the surface, allowing for real-time results, and maximum control and sensitivity.

SmartBall® Technology 
Pure’s SmartBall® platform can complete long assessment surveys in a single deployment without disruption to regular pipeline service. The tool is inserted into a live pipeline and travels with the product flow for up to 12 hours. It can collect both pipe wall stress data and acoustic leak data. It requires only two access points; one for insertion and one for extraction and is tracked throughout the inspection as it passes available access points on the pipeline.

Both the Sahara and Smartball prescreening tools can accurately identify leaks and gas pockets, as well as pipe wall stress. Areas of the pipe wall that are under more stress could potentially be damaged. These sections warrant a further investigation via excavation or higher resolution assessment.

Medium Resolution Assessment Methods

PipeDiver® 
For structural inspection of BWP, operators can use PipeDiver® technology, a free-swimming electromagnetic tool that identifies bar breaks and broad areas of cylinder corrosion using PureEM™ technology. The tool operates while the pipeline remains in service.

PureRobotics™ 
Another option for locating BWP bar breaks and cylinder corrosion is to use PureRobotics® technology. This powerful robotic system, equipped with PureEM™ technology, can be configured to inspect a variety of pipelines and materials with different operational conditions.

Using PureEM technology, both PipeDiver and PureRobotics are capable of identifying broad areas of corrosion on the pipe wall and bar breaks. These areas should be investigated further or repaired to restore pipeline reliability.

Good News for BWP Owners

In reviewing data gleaned from more than 8,000 miles (12,000 kilometers) of pressure pipe condition assessments, Pure has found that pipe distress is often localized and that the majority of pipelines can be safely managed.

For operators of BWP pipelines, the news is comforting, and confirms their trust in this reliable and enduring pipe material, as there is now a well-established method for safe management of BWP.

In August 2011, Pure Technologies brought out the redesigned PureRobotics wastewater crawler unit to conduct an electromagnetic inspection on a 42-inch (1050mm) sewer force main for a major utility in Ontario, Canada. Pure was able to inspect 3,400 feet from a single access in both directions of the line. New improvements to the tracks assisted in pushing the crawler through the heavy debris at the bottom of the pipe that would otherwise entrap other robotic inspection systems.

Sewer pipes below a road

A critical component of Queensland Urban Utilities’ sewerage network is a series of large-diameter sewer rising mains – also known as force mains – which are responsible for transporting 50 per cent of raw sewage in the Brisbane area for treatment. The mains are made of mild steel cement-lined (MSCL) pipe and prestressed concrete pipe (PCP), of diameters ranging from 1295 to 1840 millimetres (52 to 74 inches). The reliability of these sewer rising mains are important from both a customer and environmental perspective.

Building upon previous assessments conducted by Pure Technologies’ Engineering Services, Queensland Urban Utilities sought to identify industry best practices for assessing these critical large-diameter rising mains. The goal of the assessment was to understand the current condition of the mains and identify what remedial works or condition monitoring approaches would help maintain the safe operation of the mains, while extending the life of the assets in accordance with management plans.

In consultation with Pure Technologies, a comprehensive assessment methodology was developed which included: SmartBall® leak and gas pocket detection; ground surveys to determine residual ground cover; isolation, dewatering and cleaning of the mains; CCTV and laser profiling to determine internal deterioration; valve inspections; PureEM™ inspection to determine structural deterioration of the pipe walls; internal visual inspection to confirm and further document findings; transient pressure monitoring to identify loading conditions; and an engineering assessment with rehabilitation recommendations.

PureNET Overhead

A customised EM tool was designed to assess the condition of QUU’s
steel pipe.

Field Data Collection

The inspection provided QUU with actionable information about their assets.

 

Related Topics

“Queensland Urban Utilities is keen to embrace new technologies to improve our customer service and the reliability of our water and sewerage network,” says Jonathan Farrell, Design Manager at QUU. “The technical expertise provided by Pure has allowed us to undertake an accurate condition assessment and have the appropriate data to make an informed decision on the current condition of the mains. This will allow us to plan cost-effective, timely upgrades to ensure the asset reaches its design life.”

This was a first-of-its-kind assessment in Australia applying new inspection technologies, including the customisation of a 48-detector PureEM tool, as well as a new risk assessment technique for metallic pipes. Detections from the PureEM inspection (i.e. discrete areas of structural deterioration) were validated utilising alternate electromagnetic and ultrasonic techniques, which provided supplemental condition information for the structural assessment.

Inspection and assessment work on two of these critical mains has been completed at this point. The inspection identified specific pipes along the mains with deterioration; but more importantly, the engineering assessment with structural modeling determined that less than 1 per cent of pipes are at a higher risk of failure, meaning the main is in primarily good shape. This data coupled with engineering recommendations is enabling Queensland Urban Utilities to make informed decisions on the mains, including: selective repair or replacement, condition monitoring, and operational changes (i.e. safe working pressure), all for a fraction of the capital replacement costs.

In addition, the work associated with the assessment has provided Queensland Urban Utilities with some valuable lessons learned on the safe management and operation of the mains.

 

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Cast Iron Pipes

Managing Metallic Pipelines

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

Padre Dam Municipal Water District Assesses Steel Pipeline with Advanced Inline Technology

In November 2012, PDMWD wanted to assess the condition of a 1.2-mile (2-kilometer) stretch of 20-inch (500-mm) mortar-lined steel pipeline that was thought to be in poor condition and may need replacement. Before committing to the large capital project, PDMWD completed a non-destructive inline assessment.

Steel Pipes

Steel Pipe

In an article from the August 2013 Issue of Municipal Sewer and Water, the author explores how Baltimore City Public Works (BPW) is managing its again water system using Acoustic Fiber Optic Monitoring and free-flowing electromagnetic (EM) technology.

Abstract

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

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

Authors

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

Abstract

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

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

Authors

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

Abstract

Bar-wrapped pipe (“BWP”) is commonly used in pressure pipelines due to its reliability, cost effectiveness and durability. Failure of BWP can occur as a result of long term leakage and subsequent corrosion or as a result of leakage and deterioration of the reinforcing bars over time. The failure can also be the direct result of a transient pressure or other sudden catastrophic events.

The consequence of failure may result in a significant disruption of operation and service for a water utility without any warning. This is a concern because assessing the condition of a damaged BWP is very challenging. In this paper, a nonlinear finite element analysis was used to evaluate the performance of a damaged BWP.

For the structural evaluation, stresses and strains developed in the damaged BWP were evaluated. Cracking and spalling of the mortar lining will eventually lead to the corrosion of the steel components. In an effort to account for the steel deterioration, the model was adjusted by reducing the thickness of the steel cylinder. This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

Authors

  • Ali Alavinasab, Pure Technologies, Branchburg, NJ, USA.
  • Muthu Chandrasekaran, Pure Technologies, Columbia, MD, USA.
  • Edward Padewski III, Pure Technologies, Branchburg, NJ, USA.

Abstract

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

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

Authors

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

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

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

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

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

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

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

Engineers analysing data

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

Worker performing assessment

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

Defining Risk

To determine risk, operators must measure the probability and consequence of uncertain future events – in this case, pipe failure. This can be determined by multiplying two factors, consequence and likelihood of failure. Consequence of Failure (COF) refers to the damage a failure would cause based on factors such as its location, the amount of users it supplies and its size and operating pressure. Likelihood of Failure (LOF) refers to the probability of a failure occurring based on factors such as age, pipe material, soil conditions, operating pressure, failure history, among others.

Generally, the Consequence of Failure is well-defined by the potential damage a pipeline failure would impose on the surrounding environment and is generally fairly static, or, once defined it is unlikely going to change rapidly. With this in mind the key to managing risk – or the uncertainty that a pipeline could fail – is in understanding the likelihood of failure. This can be achieved by quantifying the physical condition of the pipeline and understanding and quantifying the factors that affect the potential for deterioration of the assets.

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

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

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

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

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

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Pipeline Inspection and Condition Assessment Services

Pipeline Inspection and Condition Assessment Services

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

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

To protect a thriving economy, Californian water utilities require a reliable and predictable supply of clean water; any water lost through leaks not only threatens the ability to provide adequate service, but also represents the waste of a scarce resource.

In order to ensure reliable service delivery and reduce Non-Revenue Water (NRW) – which can be defined as water that is produced for consumption and lost before it reaches the customer – two Californian utilities completed leak detection surveys on their critical water transmission mains in December 2013, while a third utility assessed a force main with a suspected leak.

While reducing NRW can be challenging, one of the most effective methods in reduction is having a well-developed leak detection program for both small- and large-diameter water mains. For large-diameter pipes, the most effective method of identifying leaks is through the use of inline leak detection. This method brings the leak detection sensor directly to the source of the leak, which provides the highest level of accuracy.

Accurately locating and repairing leaks on large-diameter mains is the best way to reduce NRW through leak detection, as almost 50 percent of the water lost through leaks is through large-diameter assets. Identifying leaks also increases service reliability and reduces the likelihood of a pipeline failure, as the presence of leaks is often a preliminary indication of a failure location.

In December 2013, the Los Angeles Department of Water and Power (LADWP) completed an inline leak detection survey on 8 miles of the 45-mile Second Los Angeles Aqueduct, which is made of 76-inch mortar-lined steel.

Identifying leaks on metallic pipe materials is particularly important for water utilities, since leakage is a main indicator that metallic pipes will eventually fail. LADWP’s inspection using SmartBall® leak detection confirmed that this section of the aqueduct is leak-free.

Although addressing NRW is a major priority for utilities, operators of wastewater force mains should also be concerned with leakage. 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.

In order to conduct a leak and gas pocket screen on an 18-inch force main, the Vallejo Sanitation and Flood Control District completed a 1.3-mile survey using SmartBall technology. The inspection identified three acoustic anomalies that were associated with pockets of trapped gas.

Through the inline assessment of this force main, the District was able to identify areas of potential concern, which will focus resources and guide future investigations.

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.

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.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

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

Smartball- Leak and Gas Pocket Detention

SmartBall® – Leak Detection for Water Trunk Mains

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

In the latest issue of Water and Wastewater International ( WWi), Pure’s director of research and development, Xiangjie Kong, participated in the monthly executive technology comparison which features commentary from different industry experts on a specific issue. In this issue, executives provided insight about how utilities can identify and locate leaks in difficult operational conditions.

The most challenging conditions that operators encounter are:

  • Locating leaks on large-diameter transmission mains
  • Inspecting non-metallic mains
  • Leak detection in low pressure mains
  • Challenging operating conditions such as urban areas
AWWA ACE12
Mark Holley

Check out the full article in WWi to find out how operators can overcome challenging conditions using inline leak detection technologies.

Read the full article in Water and Wastewater International »

Kong has led the development of some of the most advanced water pipeline inspection techniques and tools. In addition to publishing over 30 papers in academic and industry journals, he was the co-principal investigator of a research project sponsored by American Water Works Association Research Foundation.

 

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Pipeline leak detection systems

Pipeline Leak Detection Systems

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

Water utilities across the United States face a major funding gap related to buried pipeline infrastructure. The U.S. Environmental Protection Agency (EPA) estimates the difference between what is needed for infrastructure renewal and what utilities can afford to spend is between $200 billion and $1 trillion over the next 25 years. An increased number of pipeline failures that disrupt everyday life and are expensive to mitigate is adding additional scrutiny despite the fact that many utilities do not have sufficient funding to implement traditional pipeline management strategies to renew or replace their aging infrastructure.

AWWA ACE12

This new reality has forced utilities to squeeze more remaining life out of existing assets, creating more demand for condition assessment programs and proactive management of pipelines. Historically, there have been a few specialized firms that respond to high profile failures; however, the recognition of the value and implementation of condition assessment programs by many utilities has made pipeline management a significant industry. This has resulted in many utilities successfully managing risk and extending the life of assets for a fraction of the cost of a replacement program.

According to a study by Pure Technologies, large diameter pressure pipe can be inspected, repaired and managed for roughly 4 percent of the capital replacement cost. Pure has found that pipeline distress is typically not systematic across the entire length of a pipeline, but is usually related to localized problems due to design, manufacturing, installation, environmental, operational or maintenance factors. Proactively locating and repairing specific pipe sections with distress is proving to be a cost-effective method of addressing the infrastructure gap associated with buried pipelines.

As utilities move toward condition assessment programs that focus on entire transmission or distribution systems, it is clear that there is no single condition assessment strategy that works for all pipelines. Several variables affect which strategies and technologies should be used to assess a given pipeline, including likelihood of failure, consequence of failure, pipe material, and available budget.

Proactive utilities have realized that when implementing condition assessment for a system of pipelines, a risk-based approach should be used to ensure resources are invested in an intelligent manner that maximizes the benefit of a program.

Read Full Article in The Water Conservation Guide 2013 »

North American utilities are beginning to take notice of aging water and wastewater infrastructure as leaks, consent decrees and critical pipeline failures become more frequent. Coupled with increased service disruptions is an economic climate where large-scale capital projects aren’t possible; utilities are being forced to rehabilitate aging systems within tight capital budgets.

One solution utilities have to address their infrastructure is to manage risk through selective rehabilitation of critical pipeline assets. Through more than 8,000 miles of large-diameter pressure pipe assessment, Pure Technologies has found that roughly 4 percent of pipelines have some level of deterioration, while even less requires immediate attention.

While the logistics – and cost – of full-scale capital replacement is very daunting, pipelines can typically be safely managed for a fraction of this cost, in most cases between 5 and 15 percent. Through the use of condition assessment, many utilities across the United States have been successful in renewing their assets by prioritizing their assets and making the most critical repairs.

In the second of two parts of an interview conducted by Water Online Radio, Pure Technologies Vice President of Business Development Muthu Chandrasekaran discusses how utilities can address their aging infrastructure.

AWWA ACE12
Mark Holley

On the Pure’s Inspection Data:

“We’ve shown many utilities that the majority of their pipelines are in good shape and that they need to address only a few critical pipes,” says Chandrasekaran. “From a risk perspective, it gives them a way to proactively manage that infrastructure, because the cost to replace it is often in the hundreds of millions.”

On how Pure’s solutions work:

“A challenge for many utilities is how they are going to inspect pipelines that are non-redundant,” says Chandrasekaran. “One of the things that Pure Technologies has been good at with our R&D group is finding innovative ways to get tools that can find and get the data the utility needs into a live pipeline and then out of a live pipeline.”

On Pure’s work with utilities:

“We are there to be a trusted advisor to our utility partners, to help them manage their large-diameter pipeline assets. We’ve actually started getting more into the small diameter sector as well, to help them on all of their buried infrastructure,” says Chandrasekaran. “It’s very challenging for utilities with very tight budgets to manage many miles of buried infrastructure. We’ve developed a suite of technologies to help them understand where their problems are occurring and how to mange these assets.”

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

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

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

Field Data Collection

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

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

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

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

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

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Pipeline Asset Management Software

PureNET™ – Integrated Non Revenue Water and Asset Management Software

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

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

In April 2012, the District signed a Federal Consent Decree requiring improvements to the collections system aimed to eliminate illegal discharges of untreated raw sewage. As part of the requirements outlined within Consent Decree, a force main non-destructive testing and condition assessment program must be developed and implemented. The force main condition assessment program incorporates an asset management approach and risk categorization scale that classifies each of its force mains as high, medium, or low risk based on a previously conducted prioritization. The District and Jason Consultants (a wholly owned subsidiary of Pure Technologies) have developed individualized assessment strategy for each high and medium risk force main including the implementation of various inspection techniques and technologies.

Condition assessment and management of wastewater force mains has historically proven difficult for pipeline owners and operators. Conventional gravity sewer inspection methods (e.g. visual inspection, sonar and laser profiling) do not provide a full condition assessment of most pressure pipes since the loss of structural capacity cannot be quantified with these methods. As part of the condition assessment of force mains, leak and gas pocket detection is crucial since their presence is often a preliminary indicator of a potential failure location. Gas pockets in force mains are of significant concern as they are the primary failure mode for these critical pipelines. Hydrogen sulfide gas within the wastewater may be converted to sulfuric acid by bacteria in the slime layer on the pipe wall, which may cause corrosion and eventual breakdown of the pipe’s exposed surface.

SmartBall Insertion
Tool Tracking

Based on Pure Technologies’ assessment of over 8,000 miles of pressure pipe, including over 400 miles of wastewater force mains, our clients have found that pressure pipes typically do not deteriorate or fail systematically along their full length. Rather, pipe condition is usually related to localized problems due to design, manufacturing, installation, environmental, operational, or maintenance factors. By identifying the localized areas of deterioration and performing “surgical” repair techniques, utilities can manage their pressure pipelines for often less than 10% of the replacement cost.

After completion of the SmartBall inspection and other screening techniques such as pressure transient monitoring and external corrosion evaluations, the District and Jason Consultants have identified locations for external evaluation for several force mains to determine the condition of the pipe wall. These evaluations will be conducted using various techniques including visual, physical measurements, and ultrasonic testing with the goal of District staff providing most of these inspection services. Jason Consultants will then work with District staff to deliver force main specific management strategies including:

  • Repair, rehabilitation, or replacement recommendations;
  • Recommendations for modifications to the force main including future inspection needs and air release valves;
  • Re-evaluation of force main risk based on inspection results and condition assessment;
  • Remaining useful life estimations;
  • Emergency response planning for high and medium risk force mains.

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Sewer access

Sewer Force Main Inspection

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

Assess & Address Pipeline Management Program

Assess & Address Pipeline Management Program

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

Case Study

Case Study: Baltimore County Department of Public Works

Baltimore County Department of Public Works (DPW)has been working with Pure Technologies to manage its force main inventory since 2011. Through proactive and regular assessment, DPW has been able to identify select areas of pipeline deterioration, thereby avoiding unnecessary pipe replacement.

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

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

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

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

NZ Insertion
Inspection Tool

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

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

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

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

 

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Free-Swimming Pipeline Inspection

Electromagnetic Pipeline Inspection

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

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

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

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

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

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

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

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

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

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

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

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

 

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Sewer inspection hole

Sewer Force Main Inspection

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

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.

1.  Avoid replacing pipelines that are still in good condition. Pure inspections of over 175,000 lengths of Prestressed Concrete Cylinder Pipe (PCCP) have shown active distress in only 4% of the pipes. Customers were delighted to know that in the majority of cases an entire pipeline replacement was not necessary. The cost of advanced condition assessment is only a small fraction of the total cost of a full line replacement. Every utility is looking to stretch/maximize their budget. By identifying individual pipe at risk of failure and selectively addresing those pipe, a utility can obtain the dreamed of 50-100 year asset—without replacing the entire line.

2.  Rehabilitate individual pipes for a fraction of the full line replacement cost. On average, a strategic repair and replace program based on the results of a Pure condition assessment program costs up to 80% less vs. replacement of an entire pipeline. This strategic approach allows you to cost-effectively manage your underground water infrastructure.

Pipe replacement

3. Minimize the risk of significant pipeline failures. Condition assessment programs can significantly minimize the risk of large diameter pipeline ruptures that can have serious consequences on many fronts including public health and safety, economic, political and litigious. The cost of a Pure inspection program is only a small fraction compared to the potential cost of a large diameter pipeline break.

4. Increase revenue by stopping water loss and illegal connections. The bigger the pipe, the bigger the return on leak and tap detection programs. On average Pure inspections have shown 1.1 leaks per mile of large diameter pipe in North America and 2.2 leaks per mile in Europe, England, Middle East and Africa. The average volume of a leak is 40,000 gallons per day. Large municipalities have been able to achieve an ROI of over 500% from ongoing programs.

5. Ensure regulatory compliance. Water and wastewater pipeline operators are expected to meet stringent government regulations to ensure public safety and environmental protection. Condition assessment programs provide you with critical information about the integrity of your line – when and where you need it. Pure services can inspect operating lines, there is no need for dewatering or service shutdown.

6. Understand the true valuation of your underground infrastructure. Condition assessment is a quick and simple way to understand the up-to-date value of your underground infrastructure, allowing you to comply with GASB 34 accounting standards.

Contact us to find out how your municipality can implement a long-term Pure condition assessment program and realize the benefits listed above.

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Introduction

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

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

Authors

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

Introduction

This paper summarizes two Prestressed Concrete Cylinder Pipe (PCCP) assessment projects, including the findings of the inspections and the decisions that WSSC was forced to make in light of the inspections results. The inspection revealed that there were isolated problematic locations on the mains that were classified to be in a moderate to high level of risk of failure. Given the condition of the pipelines, WSSC evaluated four options: continue pipeline operation without mitigating risk, capital project to eliminate risk, a periodic re-inspection to track their condition, or proactive asset management to manage risk.

For several reasons described in the paper, WSSC opted to implement a proactive asset management system that relied on continuously monitoring the condition of the pipelines and detecting problems as they develop. Proactive repairs are then focused on individual pipe sections as needed. Several immediate repairs were performed on the mains and a monitoring system installed. WSSC is presently monitoring the condition of these pipelines and will implement structural strengthening/repair solutions to ensure their safety as needed.

Authors

  • Michael S. Higgins, P.E.; Pure Technologies, Columbia, MD, USA.
  • Nathan Leshner, P.E., Gregory Fick; Washington Suburban Sanitation Commission, Laurel, MD, USA.