There are five different classifications of fires.
You must properly match the class of extinguisher with the potential hazard:
Class A Fires
These fires are considered ordinary or common combustibles including wood, paper, cloth, rubber, household rubbish, and some plastics. (Label is normally Green in color)
Class B Fires
These fires involve flammable liquids including oils, grease, tar, lacquers, flammable gases, oil-based paints, and some plastics. (Label is normally Red in color)
Class C Fires
These fires involve energized electrical equipment including computers, building wiring, circuit breakers, light fixtures, and appliances. (Label is normally Blue in color)
Class D Fires
These fires involve combustible metals including magnesium, titanium, zirconium, sodium, lithium, and potassium. (Label is normally Yellow in color)
Class K Fires
These fires involve combustible cooking media including vegetable or animal fats and oils. (Label is normally Black in color)