Which class of fires can a dry chemical extinguisher be used on?

• A. Class A
• B. Class B
• C. Class B or C
• D. Class D

Answer: (C)

Dry chemical extinguishers work by coating the fuel and interrupting the chemical reactions occurring in the flame, which helps stop both the burning of flammable liquids and the flame on energized electrical equipment. Because of this, they are effective on fires from flammable liquids (Class B) and on fires involving live electrical equipment (Class C). The extinguisher’s non-conductive powder makes it safe to apply on electrical fires, which is a key reason it covers Class C. It’s not the right choice for metal fires (Class D), which require specialized agents, and while some dry chemical types can handle ordinary combustibles, the typical and specific use highlighted here is for B and C fires. That’s why the best answer lists Class B or Class C.