Foam fire extinguishers are primarily used for which classes of fires?

Foam fire extinguishers are primarily effective against Class "A" and Class "B" fires. Class "A" fires involve ordinary combustibles such as wood, paper, and textiles, while Class "B" fires are related to flammable liquids like gasoline, oil, and grease. The foam produced by these extinguishers works by smothering the fire and preventing oxygen from fueling it, as well as forming a barrier between the fuel and the air.

This makes them suitable for both types of fires, allowing for effective extinguishing capabilities in environments where such materials are present. In contrast, Class "C" fires involve electrical equipment and require extinguishing agents that do not conduct electricity. Class "D" fires pertain to combustible metals, which require specific extinguishing media. Thus, the use of foam extinguishers on these classes would be inappropriate and potentially dangerous, emphasizing the importance of understanding the correct applications of different types of fire extinguishers.