Dangers for users and technicians
Especially during commissioning, maintenance and repair, in some cases during failures and in small amounts during operation, refrigerant can be released to ambient air. The so called safety refrigerants were developed to serve as non flammable and non toxic or low toxicity refrigerants. Through these properties, the handling became less dangerous and thus easier.
But almost all refrigerants displace oxygen and are thus suffocating from approximately 10 .. 20% in air.
Almost all synthetic and naturally appearing refrigerants with low global warming potential (GWP) are flammable. Therefore, the risk at maintenance and repair activities on refrigeration systems will increase when refrigeration systems are developed for low GWP. This risk can be handled with appropriate measures and tools.
Refrigerants of safety class A2L or B2L are not easy to ignite and do not go on burning so easily. However, turbulence and high energy ignition cases can accelerate the combustion process suddenly and strongly. Thus, also here essential safety measures have to be taken (BITZER document A-541).
For refrigerants of safety class A3 like R290 (propane), the handling has to be even more careful. Here, the spark of a standard light switch or of a steel tool falling on a stone floor is enough to ignite it. With these, very high care, awareness and respect is necessary during work (BITZER document AT-660).
As the most refrigerants do have no or very little smell, it can be possible that people in the surrounding of refrigeration systems are exposed to small amounts for longer time. Thus, fluids that are carcinogenic or mutagenic or harmful to embryos are usually not taken as refrigerant. Amongst those are also some partly halogenated hydrocarbons.