What are the four classes of fire extinguishers?

The classification of fire extinguishers into four categories—A, B, C, and D—corresponds to the types of fires they are designed to combat. Class A extinguishers are used for ordinary combustible materials such as wood, paper, and certain textiles. Class B extinguishers are for flammable liquids, like gasoline, oil, or grease. Class C extinguishers are suitable for fires involving electrical equipment, while Class D extinguishers are specifically for combustible metals.

Understanding these classes is crucial for selecting the appropriate extinguisher based on the nature of the fire. Each class represents a distinct type of fire hazard and thus requires a specific extinguishing agent tailored to effectively address that hazard. This categorization helps firefighters and individuals alike to respond quickly and safely in emergency situations.