Fire fighters must be able to:

Understand the limitations and capabilities of extinguishers Select the appropriate extinguisher Safely carry portable extinguishers Safely approach a fire with portable extinguishers Operate portable extinguishers

Extinguishing agents put out fires by one of these methods: Smothering - oxygen exclusion Cooling - reducing the burning material's temperature Chain breaking - interrupting the chemical chain reaction Saponification - forming an oxygen-excluding soapy foam

Fire fighters should never rely on privately-owned extinguishers as they may be: Improperly maintained Vandalized Obsolete

Personnel should rely only on the extinguishers carried on fire apparatus

Class A:

fires involving ordinary combustibles Water or Class A dry chemical A

Class B:

fires involving flammable and combustible liquids B Extinguished by dry chemical agents, halogenated agents, or foams

Class C:

fires involving energized electrical equipment C Extinguished with nonconductive agents such as carbon dioxide, halon, and dry chemical

Class D:

fires involving combustible metals Extinguished by a sodium chloride material which is used to cover the material D

Class K:

fires that involve oils that are used in commercial cooking applications

These materials have been taken out of the Class B classification

T YPES OF F IRE E XTINGUISHERS Mechanically pumped water extinguishers Non-pressurized container with a hand operated pump Limited to small Class A fires Hand propelled Buckets or drums of water for Class A fires Class D agents that can be shoveled onto the fire

S TORED P RESSURE W ATER E XTINGUISHERS Water is stored in a tank with compressed air as the expellant Also called air-pressurized water extinguisher (APW) Small Class A fires only Extinguisher characteristics Size: 2.5 gallons Discharge distance: 30-40 feet Duration: 30-60 seconds

W ATER -M IST S TORED -P RESSURE E XTINGUISHERS Similar in appearance to standard stored-pressure water extinguishers For use of Class A and Class C fires Use deionized water and nozzles which produce a fine mist making them suitable to use on energized electrical equipment

W ET C HEMICAL S TORED -P RESSURE E XTINGUISHERS Specifically designed to extinguish fires involving unsaturated cooking oils in deep dryers Contain a special potassium-based, low-pH agent

A QUEOUS F ILM F ORMING F OAM (AFFF) E XTINGUISHERS Suitable for Class A and Class B fires Contain AFFF concentrate mixed with water Has an air-aspirating nozzle Expelled by compressed air or nitrogen stored in the tank with the solution

A QUEOUS F ILM F ORMING F OAM (AFFF) E XTINGUISHERS Should not be applied directly into a burning fuel but allowed to gently rain down or bounced off an object onto the fuel Finished foam floats on the surface of lighter-than-water fuels Forms a blanket which seals the vapors to extinguish the fire and prevent re-ignition Not suitable for Class C or Class D fires

C LEAN A GENT E XTINGUISHERS Clean agent extinguishing agents were designed to replace halogenated extinguishing agents (Halon 1211 and Halon 1301) Halon production was stopped in 1994 due to its effect on the ozone layer There is still limited halon production and much of the halon in use is recycled

C LEAN A GENT E XTINGUISHERS Halon replacement agents – “clean agents” Haltron FE-36 hexafluoropropane Inergen FE-24 chlorotetrafluoroethane These replacements may require up to 20 times as much as halon to provide an equal extinguishing capacity

C LEAN A GENT E XTINGUISHERS Extinguish fires through a chemical process which inhibits combustion Used for Class B and Class C fires and in areas with sensitive electronic equipment High expansion ratio Needs no expellant Nonconductive and noncorrosive

C ARBON D IOXIDE E XTINGUISHERS Found as handheld extinguishers and wheeled units

Wheeled units commonly found at airports and industrial facilities Wheeled units have a hose and nozzle attached to the gas cylinders

C ARBON D IOXIDE E XTINGUISHERS Effective for Class B and Class C fires Have limited reach and can be dispersed by wind Stored as a liquefied gas under its own pressure Displaces available oxygen and smothers the fire

D RY C HEMICAL E XTINGUISHERS Suitable for use on Class A-B-C Should not be confused with dry powder extinguishers for Class D fires Some may be rated only for Class B:C fires Sodium bicarbonate Potassium bicarbonate Potassium chloride Monoammonium phosphate

D RY C HEMICAL E XTINGUISHERS Some are not compatible with foam Nontoxic and safe to use Can reduce visibility and create respiratory problems On Class A fires, the discharge should be directed at whatever is burning to cover it

D RY C HEMICAL E XTINGUISHERS

Handheld units

Stored pressure: a constant pressure of about 200 psi is maintained in the agent storage tank

Cartridge-operated

A separate gas pressure cartridge is attached to the agent tank The agent tank is pressurized when a plunger is pushed releasing the gas into the agent tank

D RY C HEMICAL E XTINGUISHERS

Wheeled units

The extinguishing agent is in one tank with a separate gas cylinder Before use, the hose must be completed completely stretched out The nozzle should not be opened for a few seconds until the agent tank is fully pressurized

M ETAL F IRE A GENTS & E XTINGUISHERS No single agent will control or extinguish fires in all combustible metals Portable extinguishers for Class D fires may be handheld or wheeled units When the extinguishing agent is applied, it must completely cover the burning material

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XTINGUISHERS For a small amount of burning metal: First cover the fire with powder Then spread a layer of powder 1 to 2 inches deep nearby Shovel the burning metal onto this layer and apply more powder if needed

All obsolete extinguishers should be removed from service and replaced American manufacturers stopped making inverted-type extinguishers in 1969 Inverted type had a soda water base with an acid used as an expellant If the shell of the extinguisher was weakened by the soda water base it could explode when the acid was introduced

Vaporizing liquid extinguishers became obsolete in the 1960‘s Typically was a one quart pump gun Carbon tetrachloride was the common agent used - liquid carbon tetrachloride in contact with heat becomes phosgene gas

Class A and Class B extinguishers have a numerical rating to designate the size fire the extinguisher should be able to extinguish Class A extinguishers rated from 1-A to 40-A 1-A requires 1 1 / 4 gallons of water 2-A will extinguish twice as much as 1-A

Class B extinguishers: rated from 1-B through 640-B

Based on area of a fire involving a 2-inch layer of n-heptane that a non-expert operator can extinguish Every 1B rating corresponds to 1-square-foot of flammable liquid

C LASS C E XTINGUISHERS No tests are conducted for capacity ratings Extinguishing agent is tested for electrical conductivity

C

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XTINGUISHERS

No tests are conducted for capacity ratings Tests are conducted for specific metals for: Reactions between the metal and agent Toxicity of the agent Toxicity of any fumes produced Time to allow the fire to self extinguish versus time to extinguish the fire

For a Class K rating, extinguishing agents must be able to extinguish a fire involving cooking oils with a surface area of 2.25 square feet

Extinguishers may have multiple markings if suitable for more than one type of fire Most common are Class A-B-C, Class A-B, and Class B-C Ratings for each class do not affect each other

Extinguishers must be marked for which the class of fire they are rated One system uses colored shapes with the class letter in the shape NFPA 10 recommends pictographs indicating the fire class and the types of fires on which the extinguisher should not be used

Check extinguisher before approaching Approach from upwind and out of the smoke Do not enter burn area Do not turn back on fire

Apply the agent from a distance that reaches the fire but does not scatter the burning materials After the fire is knocked down, move in closer for final extinguishment Withdraw if the fire cannot be fully extinguished with the extinguisher The fire has been reduced to a smoldering stage, it can be overhauled with a tool

Extinguishers must be conspicuously located Must be readily accessible and not obstructed Must be visible or the location marked conspicuously Check the hose and nozzle for obstructions and damage Inspect extinguishers for corrosion or mechanical damage

Determine if extinguisher is full and if the pressure gauge reading in the operable range Check the locking pin and tamper seal to determine if it has been used or tampered Check the inspection tag for the dates of the previous inspections, maintenance, and recharging

Damaged extinguishers can fail at any time and cause property damage and injuries Leaking, corroded, and damaged extinguishers should be removed from service and repaired by qualified individuals Damaged extinguishers may also fail when needed in an emergency

Fire fighters should rely only on those extinguishers carried on fire apparatus and not depend on those in any occupancy