Fire Extinguishers

This page describes the basic uses of fire extinguishers. Typical home/business fire extinguishers are only designed to extinguish small fires. If you do have a fire I encourage you to still contact your local fire department to ensure the fire is extinguished entirely. Also, as a general rule of thumb, if the fire is much larger that the fire extinguisher itself and you are a novice user you may not be able to extinguish the fire entirely.

Fire extinguishers are classified according to their use on the four classes of fires. In addition to the alpha ratings, Underwriter's Laboratories (UL) rates extinguishers with a numerical rating. The numerical rating is used to determine the extinguishing potential for the size and type of extinguisher. However, for this page I will only be referencing the alpha ratings.

Determining the class of fires is based on two symbols. There is a graphic and letter designation with a figure. The four classes of extinguishers/fires are the following as specified by letter and figure color:

Type A- fires consist of normal combustibles such as wood crib, wood panel, and excelsior. A typical class A extinguisher is a water extinguisher.

 Type B -fires are flammable liquids such as gasoline, grease, and cooking oils. A typical class B extinguisher is Carbon Dioxide.

 Type C -fires are energized electrical equipment. Class C extinguishers are based on there ability to be nonconductive. Keep in mind if the equipment becomes de-energized (unplugged) it may become a type A fire.

 Type D -fires are combustible metals such as potassium and sodium. Class D extinguishers usually use sodium chloride as an agent.

You are probably familiar with the dry chemical extinguishers that are rated for type A, B, and C fires. Note that the term dry powder is associated with class D fires rather than ABC fires. A type ABC extinguisher sounds like a good deal for any location. However, even though it will extinguish the fire it may cause unnecessary damage in which another type of extinguisher may have been just as effective with less damage. For example, using a dry chemical ABC extinguisher that may be corrosive in a computer room may be better replaced by a carbon dioxide extinguisher.

General operating procedures of a fire extinguisher follow the letters P-A-S-S. However inspect your extinguisher for proper discharging techniques.

P - Pull the pin
A - Aim the nozzle or outlet towards the fire
S - Squeeze the handle to discharge the agent
S - Sweep the nozzle back and forth at the base of the flames

 Extinguishers should be checked regularly for pressurization. Even if you just partially use an extinguisher, it still needs to be refilled and recharged.

If you have any further extinguisher questions Contact Us