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.
