Some models are unsuitable for use on grease or electrical fires. Choose your extinguisher carefully. A fire extinguisher should bear the seal of an independent testing laboratory. It should also be labeled as to the type of fire it is intended to extinguish. The extinguisher must be large enough to put out the fire.
Most portable extinguishers discharge completely in as few as eight seconds.
All fire extinguishers are labelled with standard symbols for the classes of fires they can put out. A red slash through any of the symbols tells you the extinguisher cannot be used on that class fire. A missing symbol tells you only that the extinguisher has not been tested for use on a given class of fire. Ordinary combustibles such as wood, cloth, paper, rubber, and many plastics. Flammable liquids such as gasoline, oil, grease, tar, oil-based paint, lacquer, and flammable gas.