OSHA 30 Hour Construction Program Practice Test

Class C fires are associated with which type of materials?

1. Ordinary combustibles

2. Flammable liquids

3. Electrical equipment

4. Combustible metals

The correct answer is: Electrical equipment

Class C fires specifically involve electrical equipment and are classified this way because they require special handling due to the potential for electrical shock and the specific fire-fighting techniques needed. When an electrical device is energized, traditional fire extinguishers, especially those that can conduct electricity (like water), may pose a significant danger by providing a path for electrical current. Therefore, when fighting Class C fires, it is critical to first disconnect the power supply, if safely possible, before addressing the flames. The appropriate extinguisher for Class C fires often includes dry chemical or carbon dioxide, which do not conduct electricity and can safely cool or smother the flames. The other classifications relate to different types of materials and fires: ordinary combustibles are linked to Class A, flammable liquids to Class B, and combustible metals are associated with Class D. Understanding these classifications is crucial for ensuring safety and employing the correct response strategies in the event of a fire.