Essentials of Firefighting (4th Edition)
Chapter 5-Fire Extinguishers
FF1 Test Review
What is one of the MOST COMMON fire protection appliances used today?
§ portable fire extinguishers
§ found in fixed facilities & on fire apparatus
What TYPE of fires are extinguishers most useful on?
§ incipient fires
What NFPA STANDARD provides additional info on rating, placement, & use of fire extinguishers?
§ NFPA 10
What types of extinguishers should NOT be used by FF's?
§ ones found in occupancies
What does NFPA 1901 require of pumping apparatus?
§ that they carry 2 approved portable fire extinguishers with mounting brackets
§ must be suitable for Class B & C fires
§ minimum size of Dry Chemical extinguisher is 80 B:C
§ required rating for CO2 is 10 B:C
§ for water extinguishers, they must be 2 1/2 gallon or larger to be used on Class A fires
How and When should WATER TYPE extinguishers be protected against freezing?
§ temps lower than 40oF
§ protected by adding anti-freeze or storing in a warm area
What are PUMP TANK water extinguishers used for?
§ small Class A fires only
§ equipped with a double-acting pump
What is a STORED-PRESSURE water extinguisher?
§ useful for small Class A fires & extinguishing confined hot spots during overhaul
§ may be used for chimney flue fires
§ water pressurized by compressed air or nitrogen
§ Class A foam is sometimes added as a wetting agent for use in deep-seated fires, vehicle fires, & wildland fires
§ Also called Air-Pressurized Water (APW) extinguishers
What are AFFF extinguishers?
§ Aqueous Film Forming Foam
§ For use on Class A & B fires
§ Useful in combating fires or suppressing vapors on small fuel spills
§ Has an air aspirating nozzle
§ Expelled by compressed air or nitrogen
§ Should not be applied directly onto fuel, gently rain down or deflect off an object
How does AFFF react with FUELS?
§ foam floats on top of fuels that are lighter than water
§ a vapor seal extinguishes the flame & prevents re-ignition
§ foam is ineffective on flammable liquids that are water-soluble (polar solvents) such as alcohol and acetone
§ not suitable for Class C & D fires or 3 dimensional fires such as fuel flowing down a hill
§ MOST EFFECTIVE on static pools of flammable liquids
What is important about the USE of HALON extinguishers?
§ halon causes ozone depletion
§ the Montreal Protocol on Substances that Deplete the Ozone Layer called for a complete phase out of halogens by the year 2000
§ the US stopped production of halogens in 1993
What is HALON?
§ a generic term for halogenated hydrocarbons
§ defined as a chemical compound that contains carbon plus 1 or more elements from the halogen series (flourine, chlorine, bromine, or iodine)
What are the 2 MOST COMMON Halon extinguishers?
§ Halon 1211 - bromochlorodifluoromethane
§ Halon 1301 - bromotrifluoromethane
What is important about HALOGENATED VAPORS?
§ nonconductive and effective in extinguishing surface fires in flammable and combustible liquids and electrical equipment
§ not effective on self-oxidizing fuels such as combustible metals, organic peroxides, and metal hydrides
§ long been used for protection of internal combustion engines
§ primary modern-day application is to protect sensitive electronic equipment
What is HALON 1211 mainly used for?
§ on Class B & C fires
§ extinguishers greater than 9 lbs. In capacity, also have a Class A rating of 1-A to 4-A
§ larger wheeled units may weigh up to 150 lbs.
How is HALON 1211 stored and used?
§ stored as liquified compressed gas & nitrogen is used to boost discharge pressure
§ discharged in a clear liquid stream giving greater reach than gas extinguishers
§ stream may be affected by wind
What are some features of HALON 1301 extinguishers?
§ not used by itself because gas discharge is nearly invisible
§ highly susceptible to wind
§ agent's volatility allows it to disperse faster that Halon
§ it is the agent of choice in total flooding systems using halogenated agents
What are some features of CARBON DIOXIDE extinguishers?
§ found in handheld and wheeled units
§ effective on Class B & C fires
§ discharge is in gas form and has a limited reach
§ DO NOT require freeze protection
§ Stored under its own pressure as a liquified compressed gas
§ Discharged through a plastic or rubber horn at end of short tube or hose
§ Discharge usually accompanied by ice crystals
§ Displaces oxygen and smothers fire
§ Re-ignition is always possible due to NO vapor-suppressing film produced
Where are WHEELED CO2 units usually found?
§ in airports or industrial facilities
§ hose may be up to 15 feet and MUST be unwound before use
What are some features of DRY CHEMICAL extinguishers?
§ for use either on Class A, B, & C fires and/or Class B & C fires
§ agents are mixed with small amounts of additives to keep agents moist to prevent caking
§ non-toxic, yet cloud of chemicals may reduce visibility & create respiratory problems
§ some dry chemicals are compatible with foam but others degrade foam
§ agent should be applied intermittently on any smoldering hot spots
§ many dry chemicals are corrosive to metal
What are the 2 basic TYPES of DRY CHEMICAL extinguishers?
§ regular B:C rated and multipurpose A:B:C rated
What are some of the chemicals used in DRY CHEMICAL extinguishers?
§ sodium bicarbonate
§ potassium bicarbonate
§ urea-potassium bicarbonate
§ potassium chloride
§ monoammonium phosphate
What are DRY POWDER chemicals used for?
§ ONLY Class D fires
What are the 2 TYPES of HANDHELD Dry Chemical extinguishers?
§ Stored-Pressure - similar to air-pressurized water extinguisher and have a constant pressure of about 200 psi
§ Cartridge-Operated - employ a pressure cartridge connected to the agent tank (not pressurized until plunger is pushed to release gas from the cartridge)
§ Both types use nitrogen or carbon dioxide as the pressurizing gas
§ Cartridge type uses CO2 unless subjected to freezing temps, dry nitrogen is used in freezing temps
What are some features of WHEELED Dry Chemical units?
§ ones rated for Class A, B, & C depending on the type of chemical in the unit
§ extinguishing agent is in one cylinder and the pressurizing gas in another cylinder
§ hose must be unwound before use (removing hose after charged is difficult)
§ powder can pack in sharp bend of hose
§ pressurizing gas should be given a few seconds before opening nozzle
§ top of extinguisher should be pointed away from FF when pressurizing
§ significant nozzle reaction should be accounted for
How are DRY POWDERS applied?
§ some with portable extinguishers and some with scoops and shovels
§ no single agent will control or extinguish all combustible metal fires
§ must be applied in sufficient depth to completely cover area by creating a smothering blanket
How must burning metal on a combustible surface be EXTINGUISHED?
§ first cover with a powder, then a 1-2-inch layer of powder should be spread nearby and burning metal shoveled onto this layer
What is a CLASS A RATING?
§ rated from 1-A through 40-A
§ primarily based on the amount of extinguishing agent and duration and range of discharge
§ for a 1-A rating, 1 1/4 gallons of water is required
§ a 2-A rating, must have TWICE the amount of extinguishing agent (2 1/2 gallons)
What is a CLASS B RATING?
§ rated from 1-B through 640-B
§ based on the approximate square foot area of a flammable liquid that a NON-EXPERT operator can extinguish
§ expected to extinguish 1 square foot for each numerical rating
What is a CLASS C RATING?
§ receive only a letter rating
§ fires in Class C are essentially Class A or B fires once electricity is taken away
§ agents are tested for non-conductivity
What is a CLASS D RATING?
§ vary with the type of combustible metal
§ factors include: reactions between metal and agent, toxicity of agent, toxicity of fumes produced, and time allowed to let metal burn out -vs- time to extinguish it
§ details of instruction should be printed on extinguisher face plate
§ no numerical rating is given and cannot be given a multi-purpose rating
What are MULTIPLE MARKINGS?
§ Suitable for more than one type of fire
§ three MOST COMMON combinations are Class A-B-C, Class A-B, and Class B-C
§ any extinguisher NOT properly marked should NOT be used
What are the 2 SYSTEMS of LABELING extinguishers?
§ geometric shapes: Class A = Green Triangle with A, Class B = Red Square with B,
§ Class C = Blue Circle with C, & Class D = Gold Star with D
§ NFPA pictographs - depicting the type of fires the extinguisher can be used on and also shows fires which it cannot be used on
What are the FACTORS for the proper selection of a fire extinguisher?
§ classification of burning fuel
§ rating of extinguisher
§ hazards to be protected
§ severity of fire
§ atmospheric conditions
§ availability of trained personnel
§ ease of handling
§ any life hazard or operational concerns
What is the BEST extinguisher for sensitive electronic equipment?
§ halon or carbon dioxide
What things should be CHECKED before use?
§ external condition - no apparent damage
§ Hose/Nozzle - in place
§ Weight - feels as though it contains agent
§ Pressure Gauge - in operable range
How should fires be APPROACHED with extinguishers?
§ from the windward side
§ must be sure extinguishing agent reaches the fire
§ radiant heat may prevent getting close enough for agent to reach fire
§ winds may also affect or limit reach of agent
§ discharging agent directly onto fire can sometimes scatter lightweight solid fuels or penetrate surface of liquid fuels
§ apply from a point where it reaches but does not disturb the fuel
§ after fire is knocked down, move in closer for final extinguishment
How should FINAL EXTINGUISHMENT be accomplished?
§ when reduced to smoldering phase, overhaul with appropriate tool and use charged hoseline to complete extinguishment
§ on fires in liquid fuels, apply appropriate foam or simultaneously attack with more than one extinguisher
What does an extinguisher on its SIDE mean?
§ signals an empty cylinder
§ reduces the chance of a FF trying to approach a fire with an empty extinguisher
Who is responsible for SERVICING fire extinguishers?
§ property owner or building occupant
What should fire inspectors include in their BUILDING INSPECTION and pre-incident planning?
§ fire extinguisher inspections
What 3 important FACTORS determine the VALUE of a fire extinguisher?
§ serviceability, accessibility, and user's ability to operate it
What NFPA STANDARD explains the procedures for hydrostatic testing of extinguishers?
§ NFPA 10
Where should extinguisher TEST RESULTS be recorded?
§ on the extinguisher
§ hydrostatic test results on low-pressure and high-pressure cylinders are recorded differently
What are the PROCEDURES for fire extinguisher inspections?
§ ensure proper location and accessibility
§ inspect discharge nozzle or horn for obstructions
§ check for cracks, dirt, and grease accumulation
§ operating instructions on nameplate legible
§ lock pins and tamper seals secure
§ full of agent and fully pressurized (check gauge, weigh extinguisher, or inspect agent level)
§ extinguishers deficient on weight by 10% should be removed from service and replaced
§ check inspection tag for last inspection, maintenance, or re-charging
§ examine condition of hose and fittings
What should REPLACEMENT extinguishers be?
§ of equal or greater rating
What should be done with LEAKING, CORRODED, or DAMAGED cylinders?
§ discarded or returned to manufacturer for repair
§ never attempt to repair a cylinder or shell
What if an extinguisher shows SLIGHT DAMAGE or CORROSION?
§ have it hydrostatically tested by manufacturer or qualified testing agency
When were INVERTED-TYPE tanks no longer manufactured?
§ American manufacturers stopped in 1969
§ Included soda-type, foam, internal cartridge-operated water and loaded stream, and internal cartridge dry chemical extinguishers
§ Also included cylinders made of copper or brass
What TOXIC CHEMICALS used in extinguishers were discontinued due to OSHA 29 CFR 1910.157, subpart L?
§ carbon tetrachloride and chlorobromomethane
§ removed from service by January, 1982
DON'T FORGET TO STUDY THE PICTURES!!!