Portable Fire Extinguishers

Field's Fire Protection, Inc. is proud to distribute Buckeye Portable Fire Extinguishers.  Please contact one of our sales representative with any questions that you may have about the installation, inspection, or maintenance of portable fire extinguishers.

Portable Fire Extinguishers in the News:

How to Choose the Proper Portable Fire Extinguisher:

When choosing the proper portable fire extinguisher there are multiple questions that must be answered prior to installing an extinguisher.  You must answer the following questions:

What is burning?

What are the Extinguisher Sizes?

What is the Area Hazard Classification?

What is the Proper Extinguishing Agent?

What is burning?

There are five different classification of fires.  You must properly match the class of extinguisher with the potential hazards.

Class A Fires are considered ordinary or common combustibles including wood, paper, cloth, rubber, household rubbish, and some plastics. (Label is normally Green in color)

Class B Fires involve flammable liquids including oils, grease, tar, lacquers, flammable gases, oil-based paints, and some plastics.  (Label is normally Red in color)

Class C Fires involve energized electrical equipment including computers, building wiring, circuit breakers, light fixtures, and appliances.  (Label is normally Blue in color)

Class D Fires involve combustible metals including magnesium, titanium, zirconium, sodium, lithium, and potassium.  (Label is normally Yellow in color)

Class K Fires involve combustible cooking media including vegatable or animal fats and oils.  (Label is normally Black in color)

What are the Extinguisher Sizes?

In the past fire extinguishers were sized by the amount of chemical inside of the extinguisher.  Independent testing labs (i.e. Underwriters Laboratories and FM Approvals) test extinguishers to the UL/ANSI 711 Rating and Fire Testing of Fire Extinguishers for their ability to extinguish specific classes and sizes of fires.  In 2002 attempts to standardize the various test protocol differences between UL and ULC were initiated.  As of August 14, 2007 all fire equipment manufacturers are required to comply with the new testing standards.

Class A Extinguishers are labeled with a number from 1 to 40 -- for example, 1-A, 2-A, or 20-A.  The number is an expression of the extinguisher's fire-fighting effectiveness.  The larger the number, the larger the fire the extinguisher can be expected to extinguish.

Class B Extinguishers are labeled with a number from 1 to 640 -- for example, 5-B, 10-B, or 160-B. Again the number is an expression of the extinguishers fire-fighting effectiveness.  The larger the number, the larger the fire the extinguisher can be expected to extinguish.

There is no numeric designation for an extinguisher's effectiveness in fighting Class C, D, or K fires.  The letters C, D, or K tells you only that the unit has been rated to combat energized electrical equipment, combustible metals, or cooking oil fires.

Most fire extinguishers are rated to extinguish multiple classifications of fires and will have a rating label of:

1-4;10-B;C.

What is the Area Hazard Classification?

The class and the size of fire that is likely to occur in an area supplied with portable fire extinguishers are the key factors in determining which extinguishers to use.  Together, the class and size of a potential fire define the hazard for which your extinguisher installations must be designed.

Hazard Classification (as per the National Fire Protection Association Standard for Portable Fire Extinguishers):

Light (Low) Hazard.  Light (Low) hazard occupancies shall be classified as locations where the quantity and combustibility of Class A combustibles and Class B flammables is low and fires with relatively low rates of heat release are expected.  These occupancies consist of fire hazards having normally expected quantities of Class A combustibles furnishings and/or the total anticipated quantity of Class B flammables present is expected to be less than 1 gallon in any room or area.

Ordinary (Moderate) Hazard.  Ordinary (Moderate) hazard occupancies shall be classified as locations where the quantity and combustibility of Class A combustible materials and Class B flammables is moderate and fires with moderate rates of heat release are expected.  These occupancies consist of fire hazards that only occasionally contain Class A combustible materials beyond normal anticipated furnishings and/or the total quantity of Class B flammables typically expected to be present from 1 to 5 gallons in any room or area.

Extra (High) Hazard.  Extra (High) hazard occupancies shall be classified as locations where the quantity and combustibility of Class A combustible material is high or where high amounts of Class B flammables are present and rapidly developing fires with high rates of heat release are expected.  These occupancies consist of fire hazards involved with the storage, packaging, handling, or manufacture of Class A combustibles and/or the total quantity of Class B flammables expected to be present in more than 5 gallons in any room or area.

Determining the hazard level for an area may seem straightforward, but you have to consider that one area can contain multiple hazards.  You may be required to install multiple extinguishers or extinguishers with multiple ratings.  Restaurants are an example of having to install multiple extinguishers as you will have areas Low hazard dining areas with an area with cooking oils.  In this example you would have to install both a Class A and a Class K extinguisher.

Special considerations have to be made with Class B fires. There are four typical types of flammable liquid fires:

1.  Fire involving liquids at least 1/4" deep.

2.  Spill fires in which the burning liquid is less than 1/4" deep.

3.  Fires in which the burning liquid or gas is under pressure.

4.  Three dimensional fires, involving burning liquids that are in motion.

Deep liquid fires build up more heat than spill fires and are best extinguished with agents that smother the fire such as foam.  Spill fires can be brought under control with carbon dioxide or dry chemical. Gas under pressure can only be controlled with dry chemical.  Extinguishers for fighting pressurized Class B fires must be outfitted with a special nozzle and should be able to expel their dry chemical at a faster rate than a standard extinguisher.  These types of extinguishers are also known as fast flow extinguishers.

What is the Proper Extinguishing Agent?

An extinguishing agent is the substance that the portable fire extinguisher expels onto the fire to put it out.  To understand what agent to use, you must understand the nature of fire.  The fire tetrahedron is a four-sided geometric representation of the four factors necessary for fire: fuel (any substance that can undergo combustion), heat (heat energy sufficient to release vapor from the fuel and cause ignition), oxidizing agent (air containing oxygen), and uninhibited chemical chain reaction (sufficient exothermic reaction energy to produce ignition).  The fuel/air ratio must be within flammable limits, which describes the amount of vapor in air necessary to propagate flame.  Removing any of these four factors will prevent, suppress, or control the fire.

Basic Types of Extinguishing Agents:

Water.  Water is a suitable agent for only Class A fires.  Water will react with cooking oil to create a splattering effect that can spread the fire and endanger the portable operator.  Because water conducts electricity, it is also dangerous for Class C fires.  Water extinguishes fires by cooling the heat and fuel to below its kindling temperature.  One of the disadvantages of water is its susceptibility to freezing.  In potentially freezing climates the extinguisher must be outfitted with an anti-freeze charge (known as a loaded-stream). 

Dry Chemical. During the 1950's dry chemical was introduced as a fire suppressant.  It works by disrupting the molecular chain reactions that keeps the fire burning.  The major advantage of dry chemical is that it can be multi-purpose and be used on Class A, B, and C fires, though most are only rated for use on Class B and C fires. The disadvantages of dry chemical in today's workplace settings is that it is highly corrosive and can lead to damage of high priced assets.

There are five chemical compounds that make up dry chemical extinguishers:

Sodium bicarbonate (rated for Class B and C fires only)

Potassium bicarbonate (B:C)

Urea-based potassium bicarbonate (B:C)

Potassium chloride (B:C)

Ammonium phosphate (rated for Class A, B, and C fires)

Carbon Dioxide.  Carbon Dioxide is a colorless and odorless gas that is non-conductive of electricity.  The carbon dioxide is pressurized liquid internally in the fire extinguisher.  Upon discharge the liquid is expelled through a "horn" and upon contact with moisture in the atmosphere it turns into a gas. The gas is 1.5 times heavier than air and settles near the ground.  Carbon dioxide extinguishes the fire by reducing the amount of oxygen in the air surrounding the fire, which disrupts the fuel's ability to vaporize.  Carbon dioxide is rated for Class B and C fires, and has the major advantage of being non-corrosive.  The disadvantages of the carbon dioxide fire extinguishers are that they are heavier than dry chemical extinguishers. The extinguishers are manufactured with a thicker steel shell due to the carbon dioxide being stored inside the extinguisher under pressure.  This makes the extinguishers harder to handle.  The second other major disadvantage is that carbon dioxide is a gas and is susceptible to the atmosphere (i.e. wind) so the operator must stand closer to the fire. The third most dangerous disadvantage is that when used in confined areas the operator is at risk of removing too much of the oxygen in the air to the point that it is dangerous for anyone to be in the area.

Foam.  Foam extinguishing agents are water-based solutions that form foam when discharged from a specially manufactured nozzle that is designed to introduce air into the solution upon discharge. 

The two types of foam extinguishing agents are:

Aqueous film-forming foam (AFFF)

Film-forming Fluoroprotein foam (FFFP)

Foam is designed to coat and penetrate the fuel and cool it below its kindling temperature.  It is designed to be used on Class B fires (It can be used on some Class A fires) where upon application to the flammable liquid, the foam cuts off the fire's oxygen supply and discourage, re-ignition.  Foam is not designed to work on pressurized Class B fires or in freezing temperatures.  Some foam extinguishers are also appropriate for use on the special application of Class B polar solvent fires.  Polar solvents, such as alcohol, acetone, esters, and ketones are a specific fire hazard that can be extinguished with foam, but must be listed for that specific use.  Read the extinguisher label or documentation prior to installing one in this type of hazard.

Wet Chemical.  With the introduction of the Class K in the late twentieth century for cooking media fires, wet chemical extinguishing agents have become important in both portable fire extinguishers and fire suppression systems.  Test have shown that the previous school of thought protecting grease fires with a Class B:C extinguisher have failed with the introduction of vegetable oils.  Previously the primary grease used was animal fat based.  Test showed that the dry chemical would sink in the vegetable oil and the fire had a high potential to re-flash.  Class K are aqueous solutions of potassium acetate, potassium carbonate, and potassium citrate, singly or in combination.  These water based solutions produce a chemical reaction when applied to vegetable oils, creating a thick foam-like blanket that smothers the fire on top of the oil and prevents re-flash.

Halogenated Agents. Halogenated agents are also known as "clean agents" because they leave no residue when discharged.  These extinguishers are based on halogens element family that includes fluorine, bromine, iodine, and chlorine.  These are divided into two types of halogenated agents, halons and halocarbons.  Halon 1211 is a primary

How Many Extinguishers are Required?

There are four topics to review when installing portable fire extinguishers.  First you must identify the hazards that are present.  You must factor in even the most trace amounts of each fire classification for the type of extinguisher that is required.  Second you must determine the size of the fire extinguisher .  Third you must establish the quantity by the coverage that is allowed by the Local and National fire codes.  Lastly you must distribute the portable fire extinguishers per the allowable travel distance to each fire extinguisher.

Class A Locations

Source: NFPA 10, 2007 edition Table 6.2.1.1 Fire Extinguisher Size and Placement for Class A Hazards

Class B Locations

Source: NFPA 10, 2007 edition Table 6.3.1.1 Fire Extinguisher Size and Placement for Class B Hazards

Class C Locations

Class C extinguishers are required where energized electrical equipment is potentially directly involved in or surrounds electrical equipment.  Normally Class C fires are in direct location of Class A and/or B fires, the extinguisher shall be sized per the Class A or B hazard.

Class D Locations

Fire extinguishers for Class D locations shall not be located more than 75 ft. from the hazard.  Size determination for Class D locations is based on the specific combustible metal, particle size, area to be covered, and manufacturer recommendations.

Class K Locations

Class K hazards shall have a fire extinguisher located where there is a potential for a fire involving combustible cooking media (vegetable or animal oils and fats). The extinguisher shall be located no more than 30 ft. from the hazard.

How to Maintain Portable Fire Extinguishers:

Portable Fire Extinguishers must both be regularly maintenanced and inspected.

Portable Fire Extinguisher Inspection

Fire extinguishers are to be inspected when first placed into service and either manually or electronically every 30 days.  This periodic inspection shall include the following checks:

1.  Location in designated place.

2.  No obstruction to access or visibility.

3.  Pressure gauge is reading or indicator in the operable range or position.

4.  Fullness determined by weighing or "hefting" for self expelling-type extinguishers, cartridge-operated    

     extinguishers, and pump tanks.

5.  Condition of tires, wheels, carriage, hose, and nozzle for wheeled extinguishers.

6.  Indicator for non-rechargable extinguishers using push-to-test pressure indicators.

Source: NFPA 10, 2007 edition 7.2.2 Procedures.

Corrective Actions

When any portable fire extinguisher has a deficiency that is listed above, the appropriate action shall be taken.  With rechargeable fire extinguishers it shall be subjected to applicable maintenance procedures.  With non-rechargeable portable fire extinguishers it shall be removed from service, discharged, and destroyed.

Inspection Records

All personnel that perform the inspection shall document the inspection of all the extinguishers and shall label the extinguisher with initials and date of the inspection.

Maintenance

All fire extinguishers shall be maintainenced at intervals of not more than one year.  This maintenance is normally completed by a trained employee of a licensed company.  Fire extinguishers are also required to be internal maintainenced at the following intervals:

Source: NFPA 10, 2007 edition 7.3.1.1.2 Maintenance Involving Internal Examination

% - The extinguishing agent in liquid charge-type AFFF and FFFP extinguishers is replaced every 3 years and an internal examination is normally conducted at that time.  The agent in solid charge type AFFF extinguishers is replaced every 5 years during the periodic hydrostatically test and the teardown is done at that time.

Some extinguishers are required to have the chemical changed. See NFPA 10, 2007 edition for this information.

Hydrostatic Testing

Hydrostatic testing is a testing procedure that tests the strength of the shell to unwanted rupture.  Depending on the type of portable fire extinguisher this test shall be conducted as follows:

Source: NFPA 10, 2007 edition Table 8.3.1 Hydrostatic Test Interval for Extinguishers

*NFPA 10, 2007 edition covers this information in depth and is the best source of information www.nfpa.org