Using sound to predict flow rate of leaks in pipes

It's not surprising that leakages in water distribution systems is a worldwide issue with many consequences. These include the money required to fix leaks, the potential for contaminants to enter the water distribution systems, and the environmental impact of wastewater pipe leaks. Leaks can be found through a method called leak noise correlation, where sensors are placed to record and analyse the sound emissions from the leak. This method is widely used to find locations of leaks already, but the sensors record data that could potentially be used to find out the leak’s flow rate. Being able to predict flow rate could help those managing these systems to prioritise repairs based on flow rate. However, no reliable method has been found to predict the flow rate of a leak in distribution pipes using sound emissions. 

Joseph Butterfield, a STREAM researcher, set out to find a way to predict leak flow rate using leak noise correlation. The study aimed to predict the leak flow rate in medium-density polyethylene pipes using sound emission signals. The novel method involved four circular holes of different sizes being tested at several leak flow rates. 

The study was able to accurately predict the leak flow rate, regardless of the area and with no prior knowledge of the area. This shows the potential of this technique being used to assess and prioritise leak repair. As this was the first study, there would need to be much more testing, but now there is a first base case in leak flow rate prediction through sound emissions.

There were also attempts to predict leak area using this model. When contaminants enter water distribution systems through leaks, the leak area influences the level of contamination, and therefore development of this method could prove useful in judging the risk of contamination and therefore the threat to public health. Even further development of the use of leak noise correlation could include using it for detecting locations, flow rate, and leak area simultaneously.

Full article: Prediction of leak flow rate in plastic water distribution pipes using vibro-acoustic measurements, JD Butterfield, V Meruane, RP Collins, G Meyers, SBM Beck, Structural Health Monitoring 17 (4), 959-970