|
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. |
|||||
|
Fire Extinguisher Ratings
|
|||||
|
|||||
|
|||||
|
|||||
 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. |
|||||
|
Multi-Class
|
|||||
|
|||||
|
|||||
|
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. |
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.
|
||||
|
How To Operate 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: |
|||||
|
PAS S--Pull, Aim, Squeeze, and Sweep |
|||||
|
Pull the pin at the top of the extinguisher that keeps the handle from being accidentally pressed. Aim the nozzle toward the base of the fire. 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. 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! Courtesy of http://www.orp.doe.gov/fire/safety/extingrs.htm |
|||||
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.
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.
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. 
Water
Carbon Dioxide (CO2) 
Halon
extinguishers