Acoustic Emission Leak Detection on a Metal Pipeline Buried in Sandy Soil

An acoustic emission (AE) method was used to detect leaks and discern their location under flow conditions in a 304.8-m-long, 305-mm-diameter buried steel pipeline at the New Jersey Institute of Technology/U. S. Environmental Protection Agency (NJIT/USEPA) Buried Pipeline Test Facility in Edison, New Jersey. A 16.2 mL/s leak was successfully detected, and its discernible location was indicated to within 0.3 m, with a sensor separation of 65.5 m, and with water in the pipeline flowing at 11.4 L/s. Encouraging results were also obtained for a 1.3 mL/s leak that was discernible at a sensor separation of 21.3 m under the same flow conditions. Previous static pressure leak testing on this pipeline detected a 12.6 mL/s leak at sensor separations of up to 192.9 m, and it is expected that mitigating the effects of both externally produced and flow-induced background noise will allow for the detection of smaller leak rates under greater flow conditions. These results demonstrated that effective AE leak detection could be performed under flow conditions on water-filled buried metal pipelines in sandy soils. (C) 2013 American Society of Civil Engineers.