For which type of refrigerant is FDNY approval required?

FDNY approval is required for propane because it is classified as a flammable refrigerant. The use of flammable refrigerants poses unique safety hazards, particularly in terms of fire and explosion risk. Regulations are put in place to ensure that systems using such refrigerants are designed, installed, and maintained in ways that minimize these risks.

In contrast, while other refrigerants like Freon (R-12 or R-22), ammonia, and R-134a have their own sets of regulations, they do not require FDNY approval in the same way that propane does. Ammonia is also regulated under various safety standards due to its toxicity, but the flammability of propane necessitates a more stringent approval process to ensure public safety and compliance with local codes.