“Appropriate Equivalent Methodology” for Pressure Relief System PHAs

This article presents the “Berwanger Method”, a step by step process for designing or analyzing a pressure relief system to meet OSHA 1910.119 Process Safety Information (PSI) and Process Hazard Analysis (PHA) mandates. The author demonstrates that, to ensure safe operation and regulatory compliance, the pressure relief design information management system must be based on an equipment list. The previously common practice of using a relief device list as the basis of “verifying” the design is now recognized as incomplete because this method cannot ensure and document that all equipment is in fact protected. The author also shows how an electronic relational database can be used to maintain the design information.