Refrigerant safety classes A1, A2L and A3: how to read them

Refrigerants are classified based on toxicity and flammability.

Letter A

Indicates lower toxicity compared to category B.

A1

Low toxicity and no flame propagation under specified test conditions.

A2L

Low toxicity and mild flammability with low burning velocity.

A3

Low toxicity but higher flammability.

Practical significance

The safety class affects charge limits, ventilation, equipment, and service procedures.