Recasting the Bow-Tie Method for Process Hazard Analysis

Bow-tie diagrams are often used to visually evaluate the barriers put on place to prevent and mitigate a loss of containment (LOC) incident from occurring. Although bow-tie diagrams are usually constructed after an incident, they can be useful during a process hazard analysis to help prevent LOC incidents. This article introduces the bow-tie method and discusses how it can be used in the chemical process industries (CPI) to prevent incidents. The article illustrates the use of bow-tie diagrams during process hazard analysis (PHA) via the Bhopal disaster and what a PHA team would have found.