Dry powder extinguishers are rated for use on which type of fires?

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

Answer: (D)

Dry powder extinguishers designed for metal fires are rated for Class D fires. These extinguishing powders are formulated specifically to handle burning metals by coating and isolating the metal from oxygen and absorbing heat, which stops the combustion reactions typical of metal fires. They aren’t the right choice for ordinary combustibles, flammable liquids, or energized electrical fires, which require other types of extinguishing agents. So when the fire involves combustible metals, a Class D dry powder extinguisher is the appropriate tool.