Scenario: Manufacturing is shutdown for long holiday weekend. Upon their return after the long holiday weekend, the refrigeration techs find the refrigeration process shutdown and they are unable to restart the system for some reason. They call in their refrigeration contractor who determines that the system is EMPTY – NO NH3! The facility assumes that a PSV must have failed prematurely and thus changed all their PSV over the next three months; only to find out later that the release was caused by the failure of a high pressure cutout switch on the ammonia refrigeration compressor(s) which occurred due to inadequate preventative maintenance of the anhydrous ammonia refrigeration system and inadequate procedures and checklists for checks of the system by weekend operators. Imagine loosing your entire charge over a three day weekend… and your technicians trying to restart the process upon their return and none of them being wise to the fact that the process is EMPTY. EPA’s solution was a SEP that requires the company to change from NH3 refrigeration to a hydro-chlorofluorocarbon (“HCFC”) refrigerant. Here how it went down…