CVFD Training – Portable Fire Extinguishers SFFMA Training Objectives: 29-01.01 – 29-01.03.

transcript

CVFD Training – Portable Fire Extinguishers

SFFMA Training Objectives:29-01.01 – 29-01.03

Firefighter I 6–2

Fire Extinguishment Methods

• Smothering• Cooling• Chain breaking• Saponification

Firefighter I 6–3

DISCUSSION QUESTION

Has anyone in the class ever used a portable fire extinguisher to extinguish a fire?

Firefighter I 6–4

Portable Extinguisher Expulsion Mechanisms

• Manual pump• Stored pressure• Pressure cartridge

Firefighter I 6–5

Fire Classifications

• Class A fires — Involve ordinary combustibles– Easily extinguished with water, water-based

agents (foam), dry chemicals– Water most common agent used by fire service

(Continued)

Firefighter I 6–6

• Class B fires — Involve flammable/combustible liquids, gases, greases– Special fire hazards; should not be extinguished

until fuel gas shut off– Special-hazard fires get larger as fuel volume

increases– Extinguishing agents include carbon dioxide, dry

chemical, Class B foam(Continued)

Firefighter I 6–7

• Class C fires — Involve Class A or B fires created by electrical energy– Do not use water, water-based agents until

electrical energy eliminated– Recommended method is to turn off or

disconnect electrical power before using appropriate extinguisher

(Continued)

Firefighter I 6–8

• Class D fires — Involve combustible metals, alloys– Can be identified by bright white emissions from

combustion process– Class D, dry powder extinguishers work best

(Continued)

Firefighter I 6–9

DISCUSSION QUESTION

Why should water-based agents not be used on Class D fires?

Firefighter I 6–10

• Class K fires — Involve combustible cooking oils– Examples are vegetable fats that burn at

extremely high temperatures– Most fuels found in commercial kitchens; can also

be found in private homes– Wet chemicals used in extinguishing systems

Pump-Type Water Extinguishers

• Intended for use on small Class A fires only

• All operate in similar manner

• Equipped with single- or double-acting pump

Stored-Pressure Water Extinguishers

• Air-pressurized water extinguishers or pressurized water extinguishers

• Useful for all types of small Class A fires

(Continued)

Stored-Pressure Water Extinguishers

• Often used for extinguishing hot spots• Operation– Water stored in tank w/air or nitrogen– Gauge shows pressurization– Pressure forces water up tube, out hose

• Class A foam concentrate sometimes added

Water-Mist Stored-Pressure Extinguishers

Use deionized water as agent, nozzles produce fine spray instead of stream

Deionized water makes safe for use on energized electrical equipment

Fine spray enhances cooling/soaking characteristics, reduces scattering of burning material

Wet Chemical Stored-Pressure Extinguishers• Specifically designed to

control/extinguish Class K fires in deep fryers

• Contain special potassium-based alkaline agent to cool/suppress fires in unsaturated cooking oils

Courtesy of Ansul Corp.

Aqueous Film Forming Foam (AFFF) Extinguishers

• Suitable for Class A, Class B fires• Fires/vapors from small liquid fuel spills• Different from stored-pressure water

extinguishers– Tank contains specified amount of AFFF

concentrate mixed with water– Air-aspirating nozzle aerates solution

(Continued)

• Water/AFFF solution expelled by compressed air or nitrogen

• To prevent disturbance of foam blanket, do not apply directly onto fuel; allow to rain onto surface/deflect off object

(Continued)

• When AFFF/water mixed, finished foam floats on fuels lighter than water

• Vapor seal created by film of water extinguishes flame, prevents reignition

(Continued)

• Foam has good wetting, penetrating properties on Class A fuels; ineffective on polar solvents

• Not suitable for fires in Class C, D fuels• Most effective on static pools of flammable

liquids

Clean Agent Extinguishers

• Designed as replacement for Halon 1211, use “clean agents” that discharge as rapidly evaporating liquids that leaves no residue– Cool/smother fires in Class A, B fuels– Nonconductive so can be used on Class C– Approved by U.S. EPA

Carbon Dioxide (CO2) Extinguishers

• Found as both handheld/wheeled units

• Most effective in Class B, C fires

• Have limited reach; gas can be dispersed by wind

(Continued)Courtesy of Ansul Corp.

Carbon Dioxide (CO2) Extinguishers

• Carbon dioxide stored under its own pressure as liquefied gas ready for release at any time

• Wheeled units similar to handheld except wheeled are considerably larger Courtesy of Badger Fire

Protection.

DISCUSSION QUESTION

What is the danger of touching the horn on a carbon dioxide extinguisher shortly after it has been used?

Dry Chemical Extinguishers

• For Class A-B-C fires and/or Class B-C fires; dry powder used on Class D only

• Commonly used today

(Continued)

Courtesy of Ansul Corp.

Dry Chemical Extinguishers

• Two basic types– Regular B:C-rated– Multipurpose and A:B:C-

rated• Commonly used dry

chemicals• Handheld units• Wheeled units Courtesy of Ansul Corp.

DISCUSSION QUESTION

What happens when water is applied to a combustible metal fire?

Controlling/Extinguishing Metal Fires

• Special extinguishing agents, application techniques developed to control/extinguish metal fires

• No single agent controls/extinguishes fires in all combustible metals

(Continued)

• Some powdered agents applied with portable extinguishers, others with shovel or scoop

• Appropriate application technique described in manufacturer’s technical sales literature

(Continued)

• Portable extinguishers for Class D come in both handheld, wheeled units

(Continued)

Courtesy of Amerex Corp.

• Regardless of applicator, powder must be applied in sufficient depth to completely cover burning area to create smothering blanket

(Continued)

• If small amount of burning metal on combustible surface, fire should be covered with powder

• 1 to 2 inch (25 to 50 mm) layer spread nearby, burning metal shoveled onto layer

• After extinguishment, material left undisturbed until cooled

Portable Extinguisher Rating System

• Portable extinguishers classified according to types of fire they extinguish

• Class A, B also rated according to performance capability

• System based on tests by UL, ULC

Classifications

• Class A — From 1-A through 40-A• Class B — From 1-B through 640-B• Class C — No tests• Class D — Test fires vary• Class K — Recognized by UL, ULC since 1996

Multiple Markings

• Extinguishers for more than one class of fire identified by combinations of A, B, and/or C or symbols for each class– Most common are A-B-C, A-B, B-C– All must be labeled appropriately– Unlisted units should not be used– Ratings for each class are independent

Identification — Two Ways

• Geometric shapes of specific colors with class letter shown within shape

• NFPA® 10 recommended — Uses pictographs to make selection easier; shows types of fires on which extinguishers should not be used

Extinguisher Selection Factors

• Classification of burning fuel• Rating of extinguisher• Hazards to be protected• Size/intensity of fire

(Continued)

Extinguisher Selection Factors

• Atmospheric conditions• Availability of trained personnel• Ease of handling extinguisher• Life hazard/operational concerns

Extinguisher Selection Considerations

• Select those that minimize risk to life/property and are effective in extinguishing the fire type

• Dry chemical extinguishers should not be selected for use in areas where highly sensitive computer equipment is located

Extinguisher Check

• Immediately before use– External condition– Hose/nozzle– Weight– Pressure gauge

• After selecting size/type for situation, approach fire from windward side

DISCUSSION QUESTION

Why should you always have an escape route?

Fire Extinguisher Operation

• All modern extinguishers operate in similar manner

• Pick up extinguisher by handles, carry to point of application

(Continued)

• Once in position, use PASS method– P — Pull the pin– A — Aim the nozzle– S — Squeeze handles together– S — Sweep nozzle back and forth

(Continued)

• Be sure agent reaches fire• Apply agent from point

where stream reaches but does not disturb fuel

• After fire knocked down, move closer for final extinguishment

(Continued)

• If extinguishment not achieved after entire extinguisher discharged, withdraw/reassess

• If fire is in solid fuel reduced to smoldering phase, may be overhauled using appropriate tool

(Continued)

• If fire in liquid fuel, it may be necessary to apply foam through hoseline or simultaneously attack with more than one extinguisher

• If more than one extinguisher used simultaneously, work in unison and maintain constant awareness

Fire Extinguisher Inspections

• NFPA® 10 and most fire codes require portable extinguishers inspected at least once/year

• Verify that extinguishers– Are in designated locations– Not tampered with or activated– No obvious damage/other condition

(Continued)

• Servicing responsibility of property owner/building occupant

• Firefighters should include inspections in building inspection program

(Continued)

• Three factors determine value– Serviceability– Accessibility– Simplicity of operation

• NFPA® 10 describes procedures for hydrostatic testing of cylinders

Parts of Fire Extinguisher Inspections

• Ensure extinguisher in proper location/accessible

• Inspect discharge nozzle• Inspect extinguisher shell• Check for legible operating

instructions on nameplate

INACCESSIBLE

(Continued)

Parts of Fire Extinguisher Inspections

• Check locking pin, tamper seal• Determine whether full of agent, fully

pressurized• Check for date of previous inspection• Examine condition of hose/fittings• If any items deficient, remove from service

Damaged Fire Extinguishers

• Can fail at any time; could result in serious injury

• Leaking, corroded, otherwise damaged shells/cylinders should be discarded or returned to manufacturer for repair

(Continued)

DISCUSSION QUESTION

How should a defective fire extinguisher be repaired?

Damaged Fire Extinguishers

• Only slight damage/corrosion and uncertain whether safe — Should be hydrostatically tested

• If allowed by SOP, leaking hoses, gaskets, nozzles, and loose labels can be replaced by firefighters

Obsolete Portable Fire Extinguishers

• In 1969– American manufacturers stopped making

inverting-type extinguishers– Manufacturing of extinguishers made of copper or

brass with cylinders soft soldered or riveted together discontinued

(Continued)

Obsolete Portable Fire Extinguishers

• Extinguishers using carbon tetrachloride and chlorobromomethane prohibited in workplace

• If obsolete extinguishers are discovered and occupant requests, firefighters should follow SOP to dispose of them

Halon Fire Extinguishers

• Included in Montreal Protocol• U.S. stopped producing halogens at end of

1993• Units may still be in service

Summary

• In many cases, fire extinguishers can control or extinguish small fires in less time than it takes to deploy a hoseline.

(Continued)

Summary

• Even though portable fire extinguishers may be found in many of the homes, apartments, and businesses that must be entered to extinguish fire, firefighters should only rely on those carried on the fire apparatus.

(Continued)

Summary

• To use fire extinguishers safely and effectively, firefighters must know capabilities and limitations of the extinguisher — and their own capabilities and limitations — as well as the proper techniques for their application.

CVFD Training – Portable Fire Extinguishers SFFMA Training Objectives: 29-01.01 – 29-01.03.

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