Development of consequence of failure index for water and wastewater pipelines

Abstract

Water and wastewater pipelines form intrinsic constituents of the complex water infrastructure system. Given the serious consequences of failure of these pipes, risk assessment needs to be made an integral part of a comprehensive infrastructure asset management plan. This risk assessment comprises of two parts – likelihood and consequence of failure. As past literature has focused primarily on the former aspect, this paper attempts to focus on the latter. A comprehensive list of parameters has been identified with a two-level hierarchy structure; with five global parameters at the first level while certain sub-parameters under each one of them at the second. On the basis of questionnaire feedback from various utilities and industry experts, weights are determined using analytical hierarchy process and simple arithmetic average for global parameters and sub-parameters, respectively. These weights are used to develop the consequence of failure index using simple weighted summation. It is expected that this index will assist utilities in risk assessment of pipelines for making timely and appropriate decisions relating to the management of pipelines, and avoiding their failure and its catastrophic consequences.