Risk analysis for gas pipelines: A sustainability assessment approach using bow-tie analysis

Vast amounts of natural gas (NG) are consumed around the world everyday that are mainly transported and distributed through pipelines. Integrity of these pipelines is of primary interest to NG companies, consultants, governmental agencies, consumers and other stakeholder due to adverse consequences and heavy financial losses in case of system failure. Fault tree analysis (FTA) and event tree analysis (ETA) are two graphical techniques used to perform risk analysis, where FTA represents causes (likelihood) and ETA represents consequences of a failure event. 'Bow-tie' is an approach that integrates a fault tree (on the left side) and an event tree (on the right side) to represent causes, threat (hazards) and consequences in a common platform. The study also explores how inter-dependencies among various factors might influence analysis results to perform risk assessment for natural gas pipelines using triple bottom line (TBL)sustainability criteria, namely, social, environmental and economical consequences. The present study aims to help owners of transmission and distribution pipeline companies in risk management and decision-making to consider multi-dimensional consequences that may arise from natural gas pipeline failures. The research results can help professionals to decide whether and where to take preventive or corrective actions and help informed decision-making in the risk management process. A simple example is used to demonstrate the proposed approach.