What extinguisher is recommended for class D fires involving metals?

For fires involving combustible metals, such as magnesium, titanium, or sodium, the recommended type of extinguisher is dry powder. These fires burn at extremely high temperatures and can react violently with water or foam. Water can exacerbate the situation by causing metal to react, potentially leading to explosions or the fire spreading. Foam, while useful for many flammable liquids, is ineffective on metal fires since it is primarily designed to smother flames by creating a barrier between the fuel and the oxygen.

Dry powder extinguishing agents, specifically those classified for class D fires, are designed to smother the burning metals and help to cool the reaction. These agents work by creating a barrier that separates the metal from the oxygen, preventing combustion. Some commercially available dry powder extinguishers use sodium chloride or other substances that effectively put out metal fires without causing additional reactions. Thus, using dry powder extinguishers is crucial for safely combating class D fires.