Interpretation of Acoustic Field Data for Leak Detection in Ductile Iron and Copper Water-Distribution Pipes

摘要

The acoustic emission (AE) method is becoming popular for detecting leaks in municipal water mains where leaks are identified and the locations are determined through the interpretation of measured acoustic signals without excavation or disruption of services. For the interpretation of signals, several parameters, such as the frequency band of signals, coherence between signals, and cross correlation between signals, are used. However, studies published in the literature lack data on the applicability of the AE method under various field conditions. This paper presents a number of case studies on the field application of the AE method performed by measuring acoustic noises at two points bracketing a leak along the pipe length. Relevant parameters for successful leak detection in ductile iron and copper water distribution pipes are identified. In the case studies presented, leaks were successfully determined for an estimated leak rate of 1.6L/s and with a sensor distance of up to 176 m. Acoustic signal frequency corresponding to the leak noise was found to vary from approximately 220 Hz to around 1,400 Hz. The magnitudes of coherence between the signals from two sensors were higher than 0.5. (C) 2017 American Society of Civil Engineers.