FDNY is most concerned with which ASHRAE refrigerant classification?

• A. A1
• B. A2
• C. B3
• D. A3

Answer: (D)

Flammability is the decisive safety factor in fire department concerns. ASHRAE 34 ids a refrigerant by two aspects: toxicity (A = lower, B = higher) and flammability (1 = nonflammable, 2 = moderately flammable, 3 = highly flammable). In a fire, the risk comes primarily from how easily the substance can ignite and spread, so the classification with the highest flammability rating draws the most attention. The designation that combines high flammability with relatively low toxicity points to a refrigerant that is highly flammable but not extremely toxic, which is the scenario FDNY would prioritize for hazard planning. That’s why the relevant classification is the one with a flammability rating of 3 and an A toxicity rating.