Acoustic Leak Detection Used to Pinpoint Leak on Polyethylene Water Pipe

Renowned as one of the top ski destinations in Ontario, Canada, the Caledon Ski Club is a private ski and snowboarding club located about an hour outside of Toronto in the heart of the Caledon Hills and offers some of the best snow-making and grooming in the province.

The club boasts 23 groomed trails with two surface lifts, four quads and two triple chair lifts. It offers members access to its world-class ski school with expert instruction in downhill skiing and snowboarding, full racing programs, dining facilities and pro shop.

The Caledon Ski Club also maintains a water system that consists of approximately 1,200 ft of polyethylene (PE) and copper pipe. This water system provides drinking water to all of the club’s facilities and the chalets and cottages on the property that are home to more than 20 seasonal residents.

Abnormal water pressure levels alerted the club’s staff members of a leak. The leak threatened the club’s operations and was responsible for losing between 1 to 10 gals of water per minute (gpm). As a result, the Caledon Ski Club began looking for a leak detection service provider that could accurately detect the location of the leak, which was concealed by rocky soil — a distinguishing characteristic of the Caledon Hills terrain — without jeopardizing the underground primary and secondary voltage power lines, sewer lines and cable television lines that were part of the club’s dense infrastructure.

Action


The Caledon Ski Club selected Toronto-based Echologics Engineering Inc., a leading developer of acoustic-based technologies for water loss management, leak detection and pipe condition assessment, to non-invasively detect the location of the troublesome water leak.

A subsidiary of Mueller Water Products Inc., the company works with municipalities across North America and in Europe, South Africa, Singapore and Australia to isolate “silent” leaks that other acoustic systems often fail to find. Using proprietary sensor and acoustic signal conditioning technologies, Echologics’ Windows-based leak detection system—LeakFinderRT — is able to non-invasively detect underground leaks and assess the structural integrity of all pipes — irrespective of a diameter, geometry, material, etc.

Traditional acoustic leak detection methods often involve the insertion of hydrophones (water microphones) into a pipe and having the water carry it downstream as it listens for leaks. However, more advanced acoustic technologies, such as LeakFinderRT, are completely non-invasive, as they use standard pipe appurtenances such as hydrants, valves or direct attachments to the pipe’s outer wall. The technology works by placing acoustic sensors at two locations along the suspect water line, in most cases valves or hydrants. Sensors can be placed between 300 and 1,300 m apart. Noise is induced into the water column in the pipe, while a correlator compares the acoustic signature of the leak with the expected speed of sound in running water; a computer algorithm calculates the data to accurately pinpoint the location of the leak. The information collected by the system can also be used to assess the condition of selected water lines, providing an accurate measurement of remaining pipe wall thickness, corrosion, internal line diameter and pipe wall integrity.

The ability of Echologics’ system to accurately detect leaks on pipes of various materials is a result of an enhanced correlation function, which dramatically improves its ability to accurately identify and locate narrow-band leak noise, a capability that is ideal for plastic pipes, multiple leak situations, scenarios where leak sensors have to be closely spaced and environments that have considerable amounts of background noise.

Accurate, non-invasive leak detection capabilities made possible by acoustic technology developments are helping water service providers to accurately locate underground leaks while avoiding potential obstacles or hazards typically associated with more traditional leak detection methods, which can involve specialized ports, having to alter water flows, dewater pipes, or close service take-offs, disturbing existing sediment in pipes, introducing of foreign organisms into the pipe, or even the loss of testing components in the water system. Such advancements in acoustic leak detection technology are significant, as they can help water service providers improve the efficiency of their water systems and reduce non-revenue water; according to the U.S. Environmental Protection Agency (EPA), 700 water main breaks occur every day in the United States, amounting to approximately 250,000 breaks each year. And, on average, 14 percent of treated water is lost to leaks.

Results


A variety of challenges were presented by the project, which included a lack of knowledge as to the exact layout of pipes in the water system, a limited number of available appurtances and the large amount of PE pipe that comprised the club’s water system. And, a significant amount of noise was audible as a result of the proximity of the system’s pump, as well as a pressure reducing valve (PRV).

Despite the challenges, the club’s water system was surveyed and the leak, which was responsible for losing as much as 10 gpm of water, was accurately and non-invasively located in less than one day — without disturbing any of the property’s sensitive infrastructure components. Once the leak was pinpointed, service crews quickly excavated the leak site and made necessary repairs to stop further water loss.

“Our decision to leverage an advanced acoustic leak detection solution enabled us to quickly and non-invasively mitigate a leak that had been losing a significant amount of water for some time,” said Jamie Sievwright, operations manager for Caledon Ski Resort. “The other services we researched for this particular project appeared to have a ‘backhoe’ approach when it came to finding underground leaks. However, Echologics located the leak through a scientific approach which allowed us to fix the problem while preserving our infrastructure and keeping costs down.”

Marc Bracken is vice president and general manager of Echologics Engineering Inc.

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