Classification of Fire and Extingushing Guideline
Fire extinguishers are divided into four categories, based on different ty pes of
fires. Each fire extinguisher also has a numerical rating that serves as a guide for
the amount of fire the extinguisher can handle. The higher the number, the more
fire-fighting power. The following is a quick guide to help choose the right type of
extinguisher.
1. Class A extinguishers are for ordinary combustible materials such as
paper, wood, cardboard, and most plastics. The numerical rating on these
types of extinguishers indicates the amount of water it holds and the
amount of fire it can extinguish.
2. Class B fires involve flammable or combustible liquids such as gasoline,
kerosene, grease and oil. The numerical rating for class B extinguishers
indicates the approximate number of square feet of fire it can extinguish.
3. Class C fires involve electrical equipment, such as appliances, wiring,
circuit breakers and outlets. Never use water to extinguish class C fires -
the risk of electrical shock is far too great! Class C extinguishers do not
have a numerical rating. The C classification means the extinguishing
agent is non-conductive.
4. Class D fire extinguishers are commonly found in a chemical laboratory.
They are for fires that involve combustible metals, such as magnesium,
titanium, potassium and sodium. These types of extinguishers also have
no numerical rating, nor are they given a multi-purpose rating - they are
designed for class D fires only.
Some fires may involve a combination of these classifications. Your fire
extinguishers should have ABC ratings on them.
