Societal risk acceptance criteria for gas distribution pipelines based on incident data from the United States

Abstract

A significant number of pipeline operators use pipeline integrity management (PIM) to improve pipeline safety and reliability. Risk assessment is a critical step in PIM, because it determines the necessity of conducting the following steps in PIM for certain pipelines. Risk acceptance criteria are required in the process of risk assessment. Individual risk and societal risk are most frequently adopted as the two indicators of the risk acceptance criteria. To the best of the authors’ knowledge, quantitative societal risk acceptance criteria, especially for gas distribution pipelines, do not exit. The aim of this paper is to establish the societal risk acceptance criteria for gas distribution pipelines. Hence, FN curves were established using historical incident data from 2002 to 2017 provided by the U.S. Department of Transportation (DOT). Linear regression and the ALARP principle are used in evaluating the limits of the negligible line and intolerable line to obtain a graphical societal risk acceptance criterion for gas distribution pipelines. A line having a slope of −1.224, and an anchor point of (1, 8.413 × 10−7) is proposed as the negligible line. Further, the intolerable line has a slope of −1.224, and an anchor point of (1, 2.524 × 10−6). Both the negligible risk and the intolerable risk for the gas distribution pipeline are lower than the current societal risk acceptance criteria for hazardous installations. The reasons for these relatively lower risk acceptance criteria are discussed.