NFPA Class D fires are used for which materials type?

• A. Metal fires
• B. Electrical fires
• C. Hydrocarbon fires
• D. Aqueous fires

Answer: (A)

NFPA Class D fires involve combustible metals. These metals—like magnesium, titanium, aluminum (and their powders) as well as sodium or potassium—ignite at very high temperatures and can react with water, so they require specialized extinguishing methods. The usual approach uses a dry powder extinguishing agent designed for metal fires (often sodium chloride- or graphite-based powders) that coats the burning metal and separates it from oxygen. Sometimes smothering with a noncombustible covering is used, or other metal-fire–specific techniques are employed. By contrast, electrical fires involve energized electrical equipment, hydrocarbon fires involve flammable liquids, and there isn’t a standard NFPA class called “aqueous.”