You should ONLY attempt to put out a fire in the early stages when it is small and contained and ONLY when there is a means of escape behind you that is clear of fire.  If the fire has spread beyond the early stages, it is time to evacuate the building.  Be sure that the fire extinguisher is large enough to put out the fire because many portable fire extinguishers will discharge completely within a matter of seconds.  It is important to know the capabilities of the extinguishers that you have in your facility before a fire starts.   

 

There are different types of fire extinguishers just as there are different types of fires. This FAQ sheet will provide information regarding the different types available to fight various fires.  Some fire extinguishers can only be used on certain types of fires.  It could actually be dangerous to use the wrong extinguisher.

All fire extinguishers must be (UL) Underwriters Laboratory approved. Underwriter’s laboratory is a nationally recognized testing laboratory that verifies compliance with applicable standards (29.CFR 1910.157(c)(2).  Fire extinguishers that pass the tests are given an alpha numeric classification based on the type and size of the fire it will extinguish; ie. 3A:40B:C

The letter represents the type of fire that can be extinguished with a particular type of fire extinguisher. The types of fires are given the following classifications:

Fire extinguishers have a number rating.  For Type A fires, a 1 would have the equivalent of 1¼ gallons of water, a 2 would be equivalent to 2½ gallons, 3 would be 3¾ gallons of water, and so forth.  For Type B and Type C fires, the number represents the square footage the extinguishing agent would cover. For example, a number 2 would cover two square feet and a 5 would extinguish an area five square feet and so forth. 

 

Fire extinguishers can also be made to extinguish more than one type of fire.  If the extinguisher's label reads 2A:5B, then the extinguisher would work on Type A fires with a 2½ gallon equivalence and for Type B fires with a 5 square feet equivalency.  

These classifications are right on the side of the fire extinguisher. You will also see labels for each type of fire that the fire extinguisher can be used for.

Building codes (for buildings) and OSHA Standards (for the workplace) include the requirements of when and where fire extinguishers are required in building structures.  The National Fire Protection Association (NFPA) writes the standard for fire extinguisher selection, use and maintenance.

 

Fire extinguishers should be inspected every month to insure that the units are in good working order.  This is essential to ensure that they will operate effectively if needed. The pressure gauge should be checked to make sure that the unit is fully charged.  Make sure that the needle on the gauge is in the green zone. Also, check that the pin and tamper seal (located at the top of the unit) are intact. Inspect each unit to make sure that they look to be in good physical condition.

Fire extinguishers should be mounted on brackets or in wall cabinets.  The carrying handle should be placed three and one half feet to five feet above the floor.  Larger units should be mounted at a lower height and the carrying handle should be approximately three feet from the floor

There is a simple pneumonic to remember when using a fire extinguisher.

P ull the pin at the top of the extinguisher and this will release the lock.

A im the nozzle at the back of the fire

S queeze the handle of the fire extinguisher

S weep the fire extinguisher from side to side (back and forth)

Paper 

Cloth

Wood               ORDINARY COMBUSTIBLES

Rubber

Plastics

The Air Pressurized Water (APW) Fire Extinguisher is labeled a Class A fire extinguisher. Water is one of the most commonly used extinguishing agents for fires involving ordinary combustibles.

The APW fire extinguisher can be recognized by its large silver container. The fire extinguisher stands about three feet in height and weighs about 25 lbs. when full.

Two thirds of the container is filled with water and the remainder is pressurized air.

Fire is extinguished by cooling the surface of the fuel to remove the HEAT element of the fire.

The National Fire Protection Agency (NFPA) does recommend that offices, classrooms and assembly halls that mainly contain Type A combustible materials have one 2:A fire extinguisher for every three thousand square feet..  For workers protection in the workplace OSHA requires that all employees have access to an extinguisher within seventy five feet of travel distance.

Flammable liquid fires and electrical fires should never be extinguished with an air pressured water fire extinguisher.  A flammable liquid fire could be spread with this type of extinguisher and an electrocution could occur if water is used to extinguish an electrical fire. Also, never use this type of fire extinguisher on a deep fat fryer fire in a commercial kitchen. An explosive type reaction could result.

Oils

Gasoline

Some Paints                             

Grease                                  FLAMMABLE LIQUIDS

Lacquers

Solvents

Flammable liquids

CO2 carbon dioxide fire extinguishers and dry chemical fire extinguishers are both labeled for Class B fires.

This type of fire extinguisher has a hard horn and NO pressure gauge. They are red and range in size from five to one hundred pounds or larger.

The fire extinguisher is filled with Carbon Dioxide (CO2), a non flammable gas under extreme pressure.

A CO2 fire extinguisher puts out fires by displacing oxygen. It takes away the oxygen from the fire. It has such high pressure that pieces of dry ice will shoot from the horn which has a cooling effect on the fire.

CO2 fire extinguishers should never be used with fires involving ordinary combustibles (paper, cloth, wood, rubber and plastic) because the fire could continue to smolder and then reignite after the dissipation of the CO2.

BC fire extinguishers are filled with sodium bicarbonate or potassium bicarbonate.

OSHA requires that all employees have access to a Fire Extinguisher for type B fires within fifty feet travel distance

According to the Standard for Portable Fire Extinguishers NFTA 10 (2007) Table 6.3.1.1.1, Fire Extinguisher Size and Placement for Class B Hazards the following information should be used:

This would be considered a low hazard because small amounts of flammable liquids are being used. The recommendation is to use a 5 B Extinguisher with 30” Spacing for this level of risk.

This would be considered a moderate hazard because flammable liquids are more prevalent than in a low hazard area. The recommendation is to use a 10 B Fire Extinguisher with 30’ Spacing or a 20 B Extinguisher with 50’ Spacing.

 

This would be considered a high hazard because flammable liquids are present and used in large quantities. The recommendation is to use a 40 B Fire Extinguisher with 30’ spacing/ 80 B Fire Extinguisher with 50’ Spacing

 

Wiring

Fuse boxes

Energized electrical equipment           ELECTRICAL EQUIPMENT 

Computers

Other electrical sources

BC and ABC fire extinguishers both leave a residue after the fire has been put out.  If the fire has started on delicate electrical equipment such as a computer or TV, it might be wise to consider a CO2 fire extinguisher because it does not leave a residue. A dry chemical fire extinguisher will leave a residue that can damage the equipment.

 Fire Extinguishers For Class A, B & C Fires

Yes, there is the ABC Fire Extinguisher. These fire extinguishers will be labeled that they are rated for B and C fires and may be marked multipurpose for use on A, B and C fires.

ABC fire extinguishers are red in color and range in size from five pounds to twenty pounds.

ABC fire extinguishers use dry chemical fire retardant powder made up of monoammonium phosphate. It is a yellow powder that will leave a sticky residue once the fire has been extinguished.

An ABC fire extinguisher is a dry chemical extinguisher that puts out fires by coating the fuel with a thin layer of a fire retardant powder.  It will separate the fuel from the oxygen.  The powder will also interrupt the chemical reaction of the fire.

The powder in dry chemical fire extinguishers can “pack” inside the unit over time so lightly rock this type of extinguisher every few months to ensure that this does not happen..

Yes, 5 and 10 pound ABC fire extinguishers represent over 80% of fire extinguishers sold.  They meet most codes for standard requirements.  It is important to note that code requirements are only minimum guidelines.

Powders, flakes or shavings of combustible METALS (such as magnesium, titanium, potassium and sodium).

Fire extinguishers labeled for a type D fire can contain a sodium chloride based dry powder extinguishing agent, but most of the fire extinguishers labeled Class D have components that are geared to a specific metal.

There is no picture for class D fire extinguishers.

OSHA recommends that these fire extinguishers are not more than 75 feet from the hazard.

Oils       

Fats                              COMBUSTIBLE COOKING FLUIDS

This type of fire extinguisher is now required to be installed in all applicable restaurant kitchens because of the higher heating rates of vegetable oils used in commercial cooking.  If a fire starts in a deep fryer, it is not always possible to extinguish it with a Class B fire extinguisher or traditional range hood installed in the kitchen. 

These fire extinguishers are only to be used AFTER the activation of a built-in hood suppression system.  If there is no built in hood suppression system, then there is no requirement to use a Class K fire extinguisher.

There are different agents that are used in fire extinguishers labeled Class K.  Some of these agents are dry and some are wet.  Potassium bicarbonate is used in some dry chemical fire extinguishers and some wet fire extinguishers spray a fine chemical mist.

The extinguishing agents in a fire extinguisher labeled for type K fires are sometimes electrically conductive and should only be used AFTER the power has been turned off in the electrical appliance.

These fire extinguishers must be placed at a maximum travel distance of thirty feet.

For more information on the use of a Class K fires extinguishers see Seattle Fire Department Bulletin #2000-2 -. Requirement Seattle Fire Department (2005,January) 135 KB PDF, 2 pages.  We have searched the internet for you and found that this bulletin has some good information pertaining to Class K fire extinguishers.

 

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