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Fire Extinguisher Ratings |
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Multi-Class Ratings |
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Class A Extinguishers will put out
fires in ordinary combustibles, such as wood and paper. The numerical rating
for this class of fire extinguisher refers to the amount of water the fire
extinguisher holds and the amount of fire it will extinguish. |
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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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Class B Extinguishers should be used
on fires involving flammable liquids, such as grease, gasoline, oil, etc.
The numerical rating for this class of fire extinguisher states the
approximate number of square feet of a flammable liquid fire that a
non-expert person can expect to extinguish. |
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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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Class C Extinguishers are
suitable for use on electrically energized fires. This class of fire
extinguishers does not have a numerical rating. The presence of the letter
“C” indicates that the extinguishing agent is non-conductive. |
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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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Class D Extinguishers are designed
for use on flammable metals and are often specific for the type of metal in
question. There is no picture designator for Class D extinguishers. These
extinguishers generally have no rating nor are they given a multi-purpose
rating for use on other types of fires. |
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Types
of Fire Extinguishers |
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How to
Use a Fire Extinguisher |
P A S S -- Pull,
Aim,
Squeeze,
and Sweep |
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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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Pull
the pin at the top of the extinguisher that keeps the handle from being
accidentally pressed. |
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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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Aim
the nozzle toward the base of the fire. |
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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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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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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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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! |
