Only choose extinguishers that have been tested by an approved testing laboratory and labelled for their intended use. The extinguisher must be appropriate for the type and size of fire being fought. It is important to select the appropriate extinguisher the for correct fire classification. Using the wrong type of extinguisher can make the fire worse and is dangerous to the operator.
Classes of Fire
The three most common classes of fire are A, B, and C. The fourth class is D.
Class A extinguishers may be used on ordinary combustibles such as wood, paper, plastic or cloth. The symbol may be found on water, foam or multipurpose extinguishers.
Class B extinguishers are appropriate for use on flammable or combustible liquids. The symbol may be found on multipurpose dry chemical, dry chemical and carbon dioxide extinguishers.
Class C extinguishers may be used on fires involving energized electrical equipment. The symbol may be found on carbon dioxide, multipurpose dry chemical, and dry chemical extinguishers.
Class D extinguishers may be used on some types of combustibles metals, including combustible magnesium, sodium and potassium. The symbol may be found on dry chemical extinguishers. You will rarely encounter a Class D fire in the home or office.