Which classes of fires are foam extinguishers specifically recommended for?

Foam extinguishers are specifically designed for use on Class "A" and Class "B" fires. Class "A" fires involve ordinary combustibles such as wood, paper, and textiles, while Class "B" fires involve flammable liquids like gasoline, oils, and solvents. The foam works by forming a barrier that smothers the fire and prevents oxygen from reaching the fuel, effectively extinguishing the flames.

The effectiveness of foam extinguishers in these scenarios is due to their ability to cool the burning material in Class "A" fires, as well as their capacity to seal off flammable vapors in Class "B" fires. Thus, they are a common choice for environments where both types of fires may occur.

In contrast, foam extinguishers are not suitable for Class "C" fires, which involve flammable gases or energized electrical equipment, and they are not effective for Class "D" fires involving combustible metals or Class "K" fires involving cooking oils. This specificity is important for ensuring safety and effectiveness in firefighting scenarios.