A safety feature (flanged connection) failure in a refrigeration system released 10 to 20 lbs of ammonia intended to be contained.
An ammonia release resulted in the evacuation and temporary shutdown of an ammonia plant in an Industrial food processing facility.
Ammonia refrigeration system is designed to operate at 250 Psig. The system uses welded or flanged connections to connect components such as compressors, condenser, evaporators, and liquid receivers. Piping and fittings including flanges, different types of valves, elbows, tee’s etc., makes the system complete. Gaskets are installed between the mating surfaces of the fittings to ensure a proper seal so that the refrigerant will not leak out into the atmosphere. When bolts on flanges and fittings are not tightened properly or become loosened from expansion and contraction or vibration the mating surfaces between fittings and gaskets can become loose allowing ammonia under pressure to escape from the system. Major components of the system are installed in a machinery room. A machinery room is an air tight room and it is equipped with ammonia detectors. The ammonia detector automatically starts the ventilation system and, also, actuate an alarm upon ammonia detection.