Which fire extinguisher class is least likely used for combustible metals?

The class of fire extinguisher that is least likely used for combustible metals is the one that corresponds to flammable liquids. Class B extinguishers are specifically designed for fires involving flammable liquids such as gasoline, oils, and solvents. Therefore, they are not appropriate for addressing fires caused by combustible metals, which require special extinguishing agents due to the unique properties of these metals.

When it comes to combustible metals, Class D extinguishers are specifically formulated to combat fires involving magnesium, titanium, sodium, and other similar metals. They use dry powder agents that can smother and cool the burning metal, preventing further reactions that could exacerbate the fire. Classes A and C, which cater to ordinary combustibles like paper and wood, and electrical fires respectively, do not directly tackle the type of combustion experienced with metals.

Therefore, the designation of the Class B extinguisher as least appropriate for combustible metal fires clarifies its intended use and helps in understanding the need for specialized extinguishing agents in certain fire scenarios.