I see severe risk-taking regarding “safety assumptions” in process safety in my travels. I guess I am just “old school” and believe that every Pressure Vessel (PV) deserves its very own Pressure Relieving Device (PRD). But in today’s economy, where “costs” can be a driver in decision-making, I have experienced numerous scenarios where a single PRD will be “assumed” to protect multiple PVs. This may be allowed by code/RAGAGEP; however, here are the most common failures I find in the Design Basis and Sizing Basis of these sole PRDs protecting multiple PVs…