portable fire extinguishers 1. introduction portable fire extinguishers designed to fight: small...
TRANSCRIPT
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Chapter 8 Portable Fire
Extinguishers
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IntroductionPortable fire extinguishers
designed to fight:Small firesUnusual firesFires that cannot be reached quickly with
hoselines
Fire extinguishers are valuable tools.
Four basic PASS stepsFire extinguishers come in a
variety of types and sizes.
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Fire Classification and RiskType of material burning defines
class of fire.Classes of fire used to identify
type of extinguishers and agentsPre-incident plan for fuel types
and locations
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Class AInvolves ordinary combustiblesCan be extinguished with:
WaterWater-based agentsFoamMultipurpose dry chemicals
Water usually the agent used
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Class BFlammable and combustible
liquids, gases, and greasesSpecial hazardsCommon extinguishing agents:
Carbon dioxideRegular and multipurpose dry
chemicalFoam
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Class CInvolves energized electrical
equipmentWater-based agents cannot be used.Turn off electrical power.Categorized with another class of
extinguisher: BC or ABCAgents include:
Carbon dioxideRegular and multipurpose dry
chemicals
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Class DCombustible metals and alloysErratic behaviourWater and other agents can react
violentlyNo universal Class D extinguisher
for all metalsClass D agents called dry powders
Not to be confused with dry chemicals
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Class K
New classification as of 1998 Fires in combustible cooking fuelsAgents usually wet chemicalsAgents used in fixed systems
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Class K equipment.
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Types of Fire ExtinguishersFactors for selecting an
extinguisher:Type and amount of fuelPerson using extinguisherType of building construction and
occupancyType of equipment protected
Main objective extinguishing the fire
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Various types of fire extinguishers.
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Types of Extinguishing AgentsWater is the basic agent for Class A
materials.Loaded stream extinguisher Water-based foam extinguishers
Aqueous film-forming foam (AFFF) Film-forming fluoroprotein foam (FFFP) Better penetration for Class A materials Reduces surface tension of the water
Carbon dioxide Inert gas stored under pressure as a liquid
capable of being self-expelledDry chemical agents
Particles propelled by gaseous medium
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Kinds of ExtinguishersMany types:
Small and handheldLarge and require a wheeled cart
Pump-type extinguishersStored pressure extinguishersCartridge-operated
extinguishers
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(A) Older versions of fire extinguishers are labeled with colored geometrical shapes with letter
designations. (B) Newer fire extinguishers are labeled with a picture label system. (C) Many fire extinguishers can be used to fight more than one
type of fire.
(A) (B) (C)
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Inner workings of a stored pressure water extinguisher.
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Inner workings of a stored pressure dry chemical extinguisher.
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Inner workings of a carbon dioxide extinguisher with a fixed nozzle.
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Rating Systems forPortable Extinguishers
Each class of fuel subjected to a separate type of extinguisher test for its class
Conducted by independent testing agency
Appropriate ratings and symbolsClass A Class BClass C
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Class C test for electrical conductivity of agent.
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Limitations of PortableExtinguishers
Exceeding capabilitiesDesigned for specific purposesFirst-aid method for fire
extinguishmentPick the larger sizeWrong class extinguisher may not
do the job.
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Portable ExtinguisherOperation
PASS outlines four simple steps for extinguisher useP: Pull the pinA: Aim the nozzleS: Squeeze the handleS: Sweep the base of the fire
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Care and Maintenance ofPortable Extinguishers
Simple inspections and careful storage prevent most problemsMove unit from its bracket. Do hand test weight. Do visual check.
Recharging water extinguisher a simple process performed by any firefighter
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8.23
(A) Unscrew and remove the top. (B) Add the manufacturer’s recommendation of water. (C)
Add foam, if required.
(A)
(B) (C)
Re-servicing an Extinguisher
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8.24
(D) Replace the top. (E) Charge the extinguisher with the manufacturer’s recommendation of air.
(D) (E)
Re-servicing an Extinguisher
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Inspection RequirementsMany fire extinguishers are
obsolete.Inspection is usually a visual
inspection.If something does not look right, it
should be removed and replaced.Extinguishers returned to service
should be examined prior to their placement on apparatus.
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Lessons LearnedFire extinguishers can be used as:
Initial response toolsTo fight fires in special situations
Firefighters classify fires by their fuels.
Four-step process for using an extinguisher: PASS