Non destructive testing of underground pipes

Low voltage current assesses pipe wall integrity

A California start-up has developed a system for performing underground NDT of pipe infrastructure to detect cracks and leakage.

City councils, public works departments, municipalities and utilities may be replacing leaking sewer and water pipes with rehabilitated pipes that leak as much, or more, than the old ones.

Recent studies also suggest that closed-circuit television (CCTV) and other inspection techniques may be causing engineers to design and implement projects that fix the wrong pipes.

Those are the findings using a new technology from a California start-up that detects leaks in brick, cement, clay, concrete, plastic and relined pipes that deliver sewerage, water and natural gas.

With billions spent annually to fix crumbling infrastructure, a recent poll found that 46% of respondents encountered significant defects after pipe repairs.

“Trenchless rehabilitation projects generally follow industry accepted guidelines but leaks not found by legacy inspection equipment often cause defective pipes to be unknowingly accepted by utilities,” says Chuck Hansen, Chairman, Electro Scan.

Recently, Trenchless Technology magazine, an underground infrastructure publication, and Electro Scan conducted a webinar that highlighted a city that recently completed a 5,500-foot cured-in-place pipe (CIPP) lining project. Using Electro Scanning Inspection 1,066 ft or 19% of the project had more leakage after rehabilitation.

“Leaks at service connections, cracks, defective joints, lining wrinkles and faulty point repairs are difficult to see or measure,” states Henry Gregory, former Deputy Assistant Director, City of Houston.

Serving as Special Advisor to the Company, Gregory also served as Peer Reviewer for the 1991 EPA Handbook: Sewer System Infrastructure Analysis and Rehabilitation – still referenced by EPA consent decrees.

The patented technology uses low voltage current to evaluate 360-degrees of a pipe wall, finding and measuring openings that provide a clear pathway to ground.

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