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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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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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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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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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Class K Extinguishers, or Wet Chemical, fire extinguishers are designed specifically for use in restaurant kitchens. They utilize a potassium acetate based, low PH agent - the same agent used in pre-engineered cooking equipment fire extinguishing systems. The agent discharges as a fine mist which helps prevent grease splash and fire re-flash while cooling the appliance. The Class K extinguisher is the ideal choice for use on all cooking appliances including solid fuel charbroilers. |
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MODULE 5.4 - PORTABLE FIRE EXTINGUISHERS
Fire Extinguisher Ratings
There are basically five 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.
