Trenchless Technology

OCT 2018

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Fountain Valley that began in 2016, the City methodically targets different portions of the city 's water distribution system to be surveyed each year, with Echologics •ield survey crews covering up to a mile of pipeline per day. Equipped with specialized acoustic correlation equipment, the •ield crews deploy multiple acoustic sensors positioned anywhere from 300 ft to 600 ft apart along pipe segments. Attaching sensors to connected •ire hydrants, valves, or directly to the exterior pipe wall, the crew performs the acoustic testing and measurements to determine pipe condition, average wall thickness — and the presence of potential water leaks. "A unique bene•it of ePulse technology is that it simultaneously analyzes captured acoustic data for the presence of pipeline leaks during a condition assessment survey," says Fricke. "Avoiding the need to conduct separate leak detection inspections boosts the overall value of a condition assessment program, especially when ePulse detects a tiny leak in critical transmission main long before it develops into a big expensive problem." Echologics •ield crews detected no leaks in Fountain Valley 's critical pipelines surveyed during the •irst two years of the project, which included the city 's largest water mains running directly underneath the I-405 interstate freeway. However, the condition assessment surveys determined precisely which pipe segments were in good shape, and those that most likely will need replacing in the near future. Bottom-line Results Condition assessment ratings involve assessing the percentage of pipe-wall " hoop" thickness loss, measured by comparing the measured hoop thickness to the original design or nominal thickness of the pipe wall. A loss of hoop thickness less than 10 percent results in a "good" rating , a loss of 10 to 30 percent results in a "moderate" rating , and a loss greater than 30 percent results in a "poor " rating for that section of pipe. The condition assessment reports detailing the surveys performed during the •irst two years were welcome news for Fountain Valley. Fountain Valley 's condition assessment surveys completed in the •irst two years of the project identi•ied 18 percent of the pipe segments as being in "good" condition, 65 percent in "moderate" condition, and 17 percent in "poor " condition. The pipe segments assessed as being in "poor " condition are mostly situated in isolated locations, possibly indicating localized corrosion or site conditions. It's a favorable pipeline condition assessment report for 50-year-old water distribution system, although Fountain Valley 's condition assessment program still has another three years to go. "This is what I was hoping for — the best-case scenario," says Sprague. "I was budgeting $1.5 million per year to prepare for future pipeline replacements, so spending a fraction of that amount on this multi-year condition assessment program has resulted in a big savings for Fountain Valley. The Echologics condition assessment program enables our city to plan and prioritize pipeline repairs and rehabilitation, and stay ahead of our aging infrastructure. That's the best part — it enables us to be proactive instead of reactive." David Stewart Jones is with BusinessWrite Inc. W W W.T R E N C H L E S S T EC H N O LO GY.C O M 49

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