What are the different techniques for identifying the source of a leak?
There are two techniques for identifying a network leak: the acoustic method and a gas tracer.
The acoustic method : is done in two phases
Detection: This consists in identifying, by means of listening devices placed at various access points on the network, the specific leak-induced sounds or vibrations. This phase can be carried out either by an operator and confirmed by an electroacoustic detector or by using noise analyzers (hydrophones) previously installed at determined points (mainly the block valves and PI valves) and programmed by the operator for nighttime analysis ( 2am-4am).
Localization: It consists in determining the exact location of the leak and uses a noise correlator which, by means of distance and sound measurements, determines the velocity at which leak noise propagates in terms of the distance between two sensor points. The correlation calculation performed by the device based on the lag time pinpoints where the leak is. This positioning will be confirmed by the operator who will perform acoustic listening tests at ground level where the leak has been found. .
Today’s technology means some systems can combine the two phases (detection and localization).
Gas tracer:;This technique consists in injecting a lighter-than-air gas into the pipe network, thereby detecting and pinpointing the presence of one or more leaks.
The gas can be a mix of nitrogen and hydrogen or helium.
It can be injected into working or out-of-order pipes.
Detection and localization is performed using suction, by scanning the surface of the ground along the line of the pipe(s).
NB:: This technique is commonly used to identify leaks in short-section PVC or polyethylene pipes;(connected before or after the water meter);
It is also used by used by professionals in the field to detect leaks in public water networks as a complement to acoustics where pressurized water pipes are directly injected, but this is a complex undertaking that requires trained professionals and specialized materials to avoid any disruptions to water users..
It can in some cases be used as a substitute for acoustic detection for localizing leaks in pipe installations where acoustics are limited (PVC and PE, low pressure...).
Is there a way to diagnose leaks in large diameter cast iron pipes before the leaks, no matter how small, turn into larger problems?