A Class D fire is best defined as involving which?

A Class D fire is best defined as involving which?

• A. Water
• B. Wood
• C. Combustible metals or combustible metal alloys
• D. Cooking media

Answer: (C)

Class D fires involve combustible metals or metal alloys. These metals burn differently from ordinary combustibles and can react violently with water, so water-based extinguishing methods are unsafe. The best approach is to use a dry powder extinguisher or other metal-specific agents that absorb heat and form a crust to isolate the metal from oxygen. This is why the correct choice is combustible metals or combustible metal alloys. In contrast, wood fuels Class A fires, and cooking oils/fats are Class K (or older classifications list them differently), which is why those options don’t fit.

Class D fires involve combustible metals or metal alloys. These metals burn differently from ordinary combustibles and can react violently with water, so water-based extinguishing methods are unsafe. The best approach is to use a dry powder extinguisher or other metal-specific agents that absorb heat and form a crust to isolate the metal from oxygen. This is why the correct choice is combustible metals or combustible metal alloys. In contrast, wood fuels Class A fires, and cooking oils/fats are Class K (or older classifications list them differently), which is why those options don’t fit.