Empirical evaluation of acoustical signals for leakage detection in underground plastic pipes

In this paper, an empirical evaluation of acoustical signals for leakage detection and quantification in underground plastic pipes for main water distribution networks is presented. Several experiments have been carried out to collect acoustic signals generated from various leakage volumes. Upon signals analysis, it is noticed that the acquired signals are so weak and they are buried in the background noise caused by fluid flow, specially for small leakage volumes. In this work, a simple and easy to implement method for detecting and quantifying leakages in underground plastic pipes is developed. In this method, sound data are sampled and frequency spectrum of the acoustic signals is obtained by calculating the Fast Fourier Transform (FFT). Detection and quantification of existing leakages are carried out using the integral of the spectrum over frequencies below 500 Hz. The results obtained are very useful in cases where remote detection and quantification of existing leakages in underground plastic pipes are needed.