A number of new-generation refrigerants, including HFOs , are classified as either A1 (“lower toxicity, no flame propagation”) or A2L (lower toxicity, lower flammability). In addition to use in new systems, these A1 solutions can also be used as sustainable replacements to extend the life of many existing systems, where the more hazardous industrial chemicals cannot.

The “lower toxicity, higher flammability” class (A3) includes hydrocarbons, such as propane and isobutane, while ammonia has a (B2L) classification, indicating “higher toxicity, mild flammability.” In the instance of an ammonia leak or discharge, vapors are highly toxic and harmful to humans, which pose increased safety risks. (Despite their different safety grades, these products are sometimes lumped together and marketed as “natural refrigerants”).

A U.S. survey on ammonia accidents showed an average frequency of 7 accidents and 2 fatalities/year between 1995 and 2006.1 More specifically, ammonia caused:

  • 981 people to be physically injured,
  • 236 to be severely harmed (after inhalation),
  • 95 fatalities.

Learn more about the risks associated with flammability here and toxicity here.

[1] https://www.fluorocarbons.org/wp-content/uploads/2013/12/fs-on-refrigerant-accidents-final_03.03.14.pdf.pdf