Influence of pipe material on the transmission of vibroacoustic leak signals in real complex water distribution systems: case study

Water loss through leaky pipes is a worldwide issue leading to economic loss, environmental damage, and dangers to public health. Leak detection via leak noise correlation using vibroacoustic emission techniques is a common method for reducing water loss in water distribution systems (WDSs). This has been reported to be highly successful in detecting leaks in metallic pipes, but reports of its efficacy in plastic pipes is varied, highlighting a strong influence of pipe material on the performance of leak noise correlators. However, this has never been experimentally quantified in the context of other pipe materials with a good experimental methodology whereby other factors (such as leak flow rate) are standardized. Moreover, the majority of leak detection research using leak noise correlators is conducted on pipe rigs or buried test facilities, which bear little resemblance to the complexities of a real WDS. The overall aim of this research is to study the impact of pipe material on the transmission of the leak signal, investigating different pipe materials in a real, complex WDS. This article presents a rigorous, novel methodology whereby artificial leaks are created using standpipes on different pipe materials and the transmission of the leak noise studied. The results demonstrate a strong influence of pipe material on the transmission of the leak noise, influencing the frequency and amplitude of the leak signal, which varies with distance and leak flow rate. It was found that cross-correlation was a good method for identifying a leak’s location for cast iron and asbestos cement pipe materials, but had low efficacy on polyethylene pipe due to the high attenuative properties of the polyethylene material. This is shown to impact the cross-correlation of leak signals and therefore how effective leak noise correlators are at identifying leaks in plastic pipe.