Carbon dioxide extinguishers are generally rated for which types of fires?

Carbon dioxide extinguishers are specifically effective for Class B and Class C fires. Class B fires involve flammable liquids, such as gasoline, oil, and grease, which can be effectively smothered by carbon dioxide because it displaces oxygen, thus suppressing the fire. Class C fires involve energized electrical equipment; since carbon dioxide is non-conductive, it is suitable for extinguishing these types of fires without risking electric shock.

In contrast, carbon dioxide extinguishers are not suitable for Class A fires, which involve ordinary combustibles like wood or paper. While they may be somewhat effective on Class A fires, they do not cool the materials sufficiently, which can lead to re-ignition. Therefore, the best understanding of the class types for which carbon dioxide extinguishers are rated is that they are primarily designed for Class B and Class C fires.