Which safety class is associated with mildly flammable refrigerants?

• A. A1
• B. A2L
• C. A3
• D. B2

Answer: (B)

Mildly flammable refrigerants fall into the A2L safety class. In this labeling system, the letter indicates toxicity (A = lower toxicity, B = higher toxicity) and the number/letter indicates flammability (2 means flammable, with the “L” standing for lower flammability within that 2 category). So A2L specifically designates refrigerants that are of low toxicity but only mildly flammable, not non-flammable or highly flammable. Examples include refrigerants like R-1234yf.

By contrast, A1 is non-flammable, A3 is highly flammable, and B2 would involve higher toxicity with flammability, not mild flammability. Hence the option describing the mildly flammable class is the correct one.