Detecting leaks in pressurised pipes by means of transients

TLDR

Leak detection in pressurised pipes requires reliable, rapid techniques to minimise water loss. The study demonstrates that unsteady‑state tests producing small overpressure are suitable for leak detection. The method records the pressure‑time history at a single pipe section and analyses how leak size, shape, discharge conditions, and initial flow regime affect the pressure signal. The results provide a reliable criterion for first‑approximation leak size estimation using an inverse method and suggest applicability to pipes of various materials.

Abstract

Reliable and quick techniques are needed to locate and estimate leaks in pressurised pipe systems in order to reduce water loss as much as possible. The aim of the present paper is to show that the use of unsteady-state tests, which give rise to small overpressure, can be considered as an appropriate method. During these tests, it is necessary to record the pressure-time history - the ‘pressure signal’ - in just one section of the pipe, the ‘measurement section’. On the basis of a thorough laboratory investigation, the influence on the pressure signal of size and shape of small leaks, along with discharge conditions and initial flow regime, is analysed. Some remarks about the possible applicability of the obtained results to pipes of different material can be found. A reliable criterion is provided for a first-approximation estimation of leak size, based on the results of an inverse method procedure concerning pressure signals.