There are basically four different types or classes
of fire extinguishers, each of which extinguishes specific types of
fire. Newer fire extinguishers use a picture/labeling system to
designate which types of fires they are to be used on. Older fire
extinguishers are labeled with colored geometrical shapes with
letter designations. Both of these types of labels are shown below
with the description of the different classes of extinguishers.
Additionally, Class A and Class B fire extinguishers have a
numerical rating which is based on tests conducted by Underwriter’s
Laboratories that are designed to determine the extinguishing
potential for each size and type of extinguisher. Click on any of
the topics listed below for additional information that may be
helpful to know. |
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Fire
Extinguisher Ratings |
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Multi-Class
Ratings |
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Many extinguishers available today can be used on
different types of fires and will be labeled with more than
one designator, e.g. A-B, B-C, or A-B-C. Make sure that if
you have a multi-purpose extinguisher it is properly
labeled.
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| This is the old style of labeling indicating suitability
for use on Class A, B, and C fires. |
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This is the new style of labeling that shows this
extinguisher may be used on Ordinary Combustibles, Flammable
Liquids, or Electrical Equipment fires. This is the new
labeling style with a diagonal red line drawn through the
picture to indicate what type of fire this extinguisher is
NOT suitable for. In this example, the fire
extinguisher could be used on Ordinary Combustibles and
Flammable Liquids fires, but not for Electrical Equipment
fires. |
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Types of Fire
Extinguishers |
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Dry Chemical extinguishers are usually
rated for multiple purpose use. They contain an
extinguishing agent and use a compressed, non-flammable gas
as a propellant. |
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Halon extinguishers contain a gas that
interrupts the chemical reaction that takes place when fuels
burn. These types of extinguishers are often used to protect
valuable electrical equipment since them leave no residue to
clean up. Halon extinguishers have a limited range, usually
4 to 6 feet. The initial application of Halon should be made
at the base of the fire, even after the flames have been
extinguished. |
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Water These extinguishers contain
water and compressed gas and should only be used on Class A
(ordinary combustibles) fires. |
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Carbon Dioxide (CO2) extinguishers are
most effective on Class B and C (liquids and electrical)
fires. Since the gas disperses quickly, these extinguishers
are only effective from 3 to 8 feet. The carbon dioxide is
stored as a compressed liquid in the extinguisher; as it
expands, it cools the surrounding air. The cooling will
often cause ice to form around the “horn” where the gas is
expelled from the extinguisher. Since the fire could
re-ignite, continue to apply the agent even after the fire
appears to be out.
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How to Use a Fire
Extinguisher
Even though extinguishers come in a number of shapes and sizes, they
all operate in a similar manner. Here's an easy acronym for fire
extinguisher use: |
P A S S -- Pull,
Aim,
Squeeze,
and Sweep
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Pull the pin at
the top of the extinguisher that keeps the handle from being
accidentally pressed. |
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Aim the nozzle
toward the base of the fire.
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Stand approximately 8 feet
away from the fire and
squeeze the handle to discharge the
extinguisher. If you release the handle, the discharge will
stop.
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Sweep the nozzle
back and forth at the base of the fire. After the fire
appears to be out, watch it carefully since it may
re-ignite! |
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Congratulations --
you did it!!! |
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