Which material is involved in Class D fires?

• A. Wood and paper
• B. Metals
• C. Oils and greases
• D. Electrical equipment

Answer: (B)

Class D fires involve combustible metals. Metals such as magnesium, titanium, sodium, potassium, and aluminum can burn fiercely and may react with water or many standard extinguishing agents, so they need special cooling and smothering approaches. The extinguishing media used for these fires are dry powders designed specifically for metal fires or other inert, non-reactive powders that isolate the metal from air and absorb heat without triggering a dangerous reaction. Water and ordinary fire extinguishers aren’t suitable because of the potential for violent reactions or inadequate cooling. This distinguishes metal fires from other types: wood and paper fuel fires are Class A, oils and greases are Class B, and electrical equipment fires are Class C; metals define Class D.