What class of fire includes combustible metals?

What class of fire includes combustible metals?

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

Answer: (D)

Combustible metals form fires that behave differently from other fuels, so they are categorized separately as Class D fires. Metals such as magnesium, titanium, sodium, potassium, and aluminum powders can burn intensely and may react with water or common extinguisher agents, so they require a specialized approach. The recommended extinguishing method uses a dry powder designed for metal fires (a Class D extinguishing agent). This powder coats the metal, absorbs heat, and helps isolate the metal from air, forming a crust that slows or stops the reaction and prevents re-ignition. Water can react violently with many reactive metals, producing hydrogen gas and potentially explosions, so it is avoided on these fires. In contrast, ordinary combustibles (wood, paper) are Class A, flammable liquids are Class B, and electrical equipment is Class C—each needing different extinguishing methods.