Class D corresponds to which type of material?

• A. Combustible Metals
• B. Flammable Fats
• C. Live Electrical Equipment
• D. Flammable Solids

Answer: (A)

Fire classes group fires by the fuel involved and the suppression method they require. Class D is reserved for combustible metals such as magnesium, titanium, sodium, and potassium. These metals burn intensely and can react violently with water, so they demand a special extinguishing approach—typically a dry powder designed for metal fires or smothering with inert material—rather than water. That makes combustible metals the best fit for Class D.

Other materials would fall under different classes with distinct suppression needs: flammable fats (cooking oils) are managed with agents for cooking-oil fires, live electrical equipment requires methods suitable for electrical fires, and flammable solids are addressed under a different class than metals.