Pressure-based Leakage Characterisation of Bulk Supply Pipelines

Leakage from bulk pipelines has not received much attention in the research literature due to the difficulty of measuring it. However, recent developments in understanding the behaviour of leaks with changes in pressure have created opportunities for cost-effective field-based leakage characterisation. Field and laboratory studies have shown that leakage from water pipelines is substantially more sensitive to pressure than conventionally believed. It has now been established that the major cause of this phenomenon is that the areas of leaks are not static but vary linearly with pressure. The aim of this study was to determine the characteristics and extent of water losses on a number of bulk water pipelines in South Africa. The study used a specially designed device in combination with the latest models of leak area behaviour. Test pipes were first isolated and then pressurised using an external pump and water source. Measuring the leakage rate at different pressures allowed the leakage area to be estimated as a function of pressure. The study showed that the proposed method provides an efficient, non-intrusive and cost-effective way to characterise the leakage condition of bulk pipelines.