What is dry powder used for?

• A. Class A fires only; safe with primary agents.
• B. Class D/metal fires only; it is not compatible with primary or auxiliary agents.
• C. All fire types; it replaces the need for water.
• D. Electrical fires only; safe with foam.

Answer: (B)

Dry powder extinguishing agents are designed specifically for metal fires (Class D). They work by coating and insulating the burning metal, cooling it, and interrupting the chemical reaction, which helps smother the fire and prevent re-ignition. Metals like magnesium, titanium, sodium, potassium, and lithium are the typical targets for this agent.

Because this powder is tailored for metal fires, it isn’t suitable for ordinary combustibles, liquids, or electrical fires. It also isn’t intended to replace water for other fire types, and it’s generally used on its own rather than mixed with water or foam or other extinguishing agents. This combination of being metal-fire–specific and not compatible with other extinguishing methods is why this choice is the best fit.