Are ammonia refrigeration systems safe?
In any mechanical refrigeration system, leaks will occur. This fact is exacerbated when the leaks involve odorless refrigerants as evidenced by the abundant supply of CFCs in the atmosphere today. The inherent safety of ammonia refrigeration is explained in part by ammonia's characteristic odor, which signals even the smallest leak, at concentrations far lower than any dangerous level. Ammonia's other physical characteristics such as its density and limited range of flammability, engineering advances for refrigeration systems, and the solid record of well-trained ammonia refrigeration systems operators all contribute to ammonia's excellent safety record.
Is ammonia dangerous because it smells so bad?
Ammonia's strong pungent odor gives it a self-alarming quality. The fact that it does smell so bad is one of its greatest safety assets. Even the slightest traces of ammonia in the air can be detected. This allows for the safe and immediate repair of system leaks or sources of leaks. Contrasted to the penetrating odor of ammonia, other commonly used refrigerants like the halocarbons are odorless and their escape difficult to detect without mechanical systems. The pungent odor of ammonia encourages individuals to leave the immediate area of a release before a harmful concentration builds up.
Is ammonia explosive?
Pure ammonia is difficult to ignite and has a very narrow range of flammability. Ammonia is flammable only at high concentrations and under extremely limited conditions. Ammonia vapor that contains oil or another flammable contaminant can increase the possibility of an explosion. However, ammonia will not sustain a flame on its own; ignition of ammonia vapor requires an uninterrupted external flame source.