Extinguishers are classified by a number and letter symbol. The number indicates the relative size of the extinguisher, and the letter indicates the type of fire it will extinguish.
- Type A fires are of combustible solids such as wood. On Type A extinguishers, the number relates to how many gallons of water the extinguisher is equal to for a Type A fire.
- Type B fires are of flammable liquids such as gasoline or oil. On Type B extinguishers, the number tells you the square footage of the fire the extinguisher can put out.
- Type C fires are electrical fires. Type C extinguishers do not use numbers.