A2L Refrigerants and Certification

A2L refrigerants like R-32 and R-454B are "lower flammability" refrigerants, so techs are asking whether they need a new certification. The federal rule doesn't create a separate A2L card.

Section 608 certification applies to work on appliances using class I, class II or any non-exempt substitute refrigerant (40 CFR 82.161(a)(1)). R-32 and R-454B aren't on the exempt list (82.154(a)(1)), so your 608 card covers them. A2L safe-handling courses come from industry and manufacturers, and some employers and states require them.

What is an A2L refrigerant?

A2L is a safety class in ASHRAE Standard 34. The letter is toxicity: A means lower toxicity. The number is flammability: 2L means lower flammability, between nonflammable (1) and flammable (2). R-32, R-454B and R-454C are examples of A2L refrigerants (EPA GreenChill webinar slides, May 2022).

Does EPA require A2L certification?

No. As of the eCFR text current on October 22, 2026, 40 CFR 82.161 has four certification types (I, II, III and Universal) and no separate A2L credential (82.161). State and local codes may add training rules, so check yours.

Why the switch to A2Ls?

EPA's rules under the AIM Act limit high-GWP refrigerants in new equipment. Since January 1, 2025, new residential and light-commercial A/C and heat pump systems may not be installed with a refrigerant whose global warming potential is 700 or more. Systems whose components were all made or imported before that date may still be installed. Variable refrigerant flow systems follow later dates (40 CFR 84.54(c)). Lower-GWP refrigerants such as R-32 and R-454B are A2Ls, which is why they're showing up on new equipment.

A2L safety basics

EPA's GreenChill slides compare A2Ls with A3 refrigerants such as propane: A2Ls need much more refrigerant in the air to ignite, take more energy to ignite, and burn more slowly. That's why safety standards allow larger A2L charges (EPA GreenChill slides). They still burn, so follow the equipment maker's instructions and your local code.

Are A2L questions on the EPA 608 test?

EPA's Core outline covers substitute refrigerants and safety (EPA test topics). We can't say which questions are on the real test, because EPA keeps the bank private (82.161(c)).

Practice the 608 test

Start with the Core practice test or the free EPA 608 practice test. Background: EPA 608 certification. Pressure-temperature data for these refrigerants: refrigerant PT charts.