If you have a fire, it is of the upmost importance that you use the appropriate fire extinguisher for that specific fire. The wrong type of fire extinguisher can be ineffective and dangerous.
Class A Fires: Class A fires are fires in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics.
Class B Fires: Class B fires are fires in flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, alcohols, and flammable gases.
Class C Fires: Class C fires are fires that involve energized electrical equipment.
Class D Fires: Class D fires are fires in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium.
Class K Fires: Class K fires are fires in cooking appliances that involve combustible cooking media (vegetable or animal oils and fats).