Characterisation of lead pipes used in the water industry: extrusion processing, alloy microstructure and their role in service failures

Abstract

The issue of leakage within the water distribution system is one of importance not only at an economic level for the industry, but also as a result of an environmental agenda addressing issues of water sustainability. The present work is concerned with leakage from lead based assets, in particular distribution pipes. Very little is known about the failure mechanisms within lead based assets. The present paper presents the findings from a study in which lead samples from intact and failed pipes, sourced from the Thames Water area, have been examined. The failure mechanisms have been identified at the macroscopic level and the pipe microstructure has been characterised – aspects of the microstructure control particular properties of the pipe (e.g. strength, creep and fatigue behaviour) and so may contribute to the potential failure modes. The present study is the first stage in a programme of work designed to develop a better understanding of the failure modes in lead assets, leading to the formulation of a more effective condition assessment model.