Dry powder extinguishing agents are rated for use on ______ fires.

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

Answer: (C)

Dry powder extinguishing agents are designed for fires involving metals (Class D). Metal fires burn at high temperatures and can react violently with water or foam, so they need a dry, specialized powder that coats the metal surface, isolating it from air and absorbing heat. The powder also helps smother the reaction, sometimes forming a crust that protects against re-ignition. It’s important to use the specific Class D powder that matches the type of metal involved, because different metals require different formulations. While multipurpose powders can handle ordinary combustibles, liquids, and energized electrical fires, the dedicated use of dry powder for metal fires is what sets Class D apart.