PSM/RMP covered processes that operate above 15 psi will have relief valves to protect pressure containing components such as vessels, piping, pumps, compressors, etc. It is standard practice that these relief valves get changed out at least every five (5) years or so; please follow your RAGAGEP and/or the RV manufacturer instructions for specific change/test schedules. But whenever we change these valves, we are in fact “opening the process” which means we have broken the pressure containment. When the new valves go on, it is necessary to pressure test the pressure containment once again. Of course, we MUST follow our RAGAGEP and/or the RV manufacturer instructions for installation of their RVs, but we also need to pressure test/leak test the installation of the new valves and this pressure test/leak test MUST be done properly. Here is what can happen when this is not done by the book. Please note that R-134a is a very low hazard refrigerant, but what if this incident occurred with a HHC/EHS?