Essentials of Fire Fighting, 5th Edition

Chapter 6 — Portable Fire Extinguishers

Firefighter I

Firefighter I6–2

Chapter 6 Lesson Goal

• After completing this lesson, the student shall be able to operate portable fire extinguishers effectively and safely following the policies and procedures set forth by the authority having jurisdiction.

Firefighter I6–3

Specific Objectives

1.Describe methods by which agents extinguish fire. 2.List mechanisms by which portable extinguishers expel their contents. 3.Distinguish among classifications of fires and the most common agents used to extinguish them. (Continued)

Firefighter I6–4

Specific Objectives

4.Describe types of extinguishers and their common uses. 5.Discuss extinguishers and agents for metal fires. 6.Explain the portable extinguisher rating system.

(Continued)

Firefighter I6–5

Specific Objectives

7.Describe factors to consider in selecting the proper fire extinguisher. 8.Describe items to check for immediately before using a portable fire extinguisher. 9.Describe the PASS method of application. (Continued)

Firefighter I6–6

Specific Objectives

10.Summarize procedures that should be part of every fire extinguisher inspection. 11. Discuss damaged portable fire extinguishers and obsolete portable fire extinguishers.

(Continued)

Firefighter I6–7

Specific Objectives

12. Operate a stored pressure water extinguisher.

13.Operate a dry chemical (ABC) extinguisher. (Skill Sheet 6-I-2)14. Operate a carbon dioxide (CO2) extinguisher. (Skill Sheet 6-I-3)

Firefighter I6–8

Fire Extinguishment Methods

• Smothering• Cooling• Chain breaking• Saponification

Firefighter I6–9

Portable Extinguisher Expulsion Mechanisms

• Manual pump• Stored pressure• Pressure cartridge

Firefighter I6–10

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 I6–11

Fire Classifications

• 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 I6–12

Fire Classifications

• 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

ordisconnect electrical power before using appropriate extinguisher

(Continued)

Firefighter I6–13

Fire Classifications

• 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 I6–14

Fire Classifications

• 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

Firefighter I6–15

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

Firefighter I6–16

Stored-Pressure Water Extinguishers

• Air-pressurized water extinguishers or pressurized water extinguishers

• Useful for all types of small Class A fires

(Continued)

Firefighter I6–17

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

Firefighter I6–18

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

Firefighter I6–19

Wet Chemical Stored-Pressure Extinguishers

• Specifically designed to control/extinguish Class K fires in deep fryers

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

Courtesy of Ansul Corp.

Firefighter I6–20

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)

Firefighter I6–21

Aqueous Film Forming Foam (AFFF) Extinguishers

• 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)

Firefighter I6–22

Aqueous Film Forming Foam (AFFF) Extinguishers

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

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

(Continued)

Firefighter I6–23

Aqueous Film Forming Foam (AFFF) Extinguishers

• 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

Firefighter I6–24

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

Firefighter I6–25

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 Badger Fire Protection

Firefighter I6–26

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

Firefighter I6–27

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.

Firefighter I6–28

Dry Chemical Extinguishers

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

• Commonly used dry chemicals• Handheld units• Wheeled units

Firefighter I6–29

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)

Firefighter I6–30

Controlling/Extinguishing Metal Fires

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

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

(Continued)

Firefighter I6–31

Controlling/Extinguishing Metal Fires

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

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

(Continued)

Firefighter I6–32

Controlling/Extinguishing Metal Fires

• Operation– 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

Firefighter I6–33

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

Firefighter I6–34

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

Firefighter I6–35

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

Firefighter I6–36

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

Firefighter I6–37

Extinguisher Selection Factors

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

(Continued)

Firefighter I6–38

Extinguisher Selection Factors

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

Firefighter I6–39

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

Firefighter I6–40

Extinguisher Check

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

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

Firefighter I6–41

Fire Extinguisher Operation

• All modern extinguishers operate in similar manner

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

(Continued)

Firefighter I6–42

Fire Extinguisher Operation

• 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)

Firefighter I6–43

Fire Extinguisher Operation

• Be sure agent reaches fire• Apply agent from point where

stream reaches but does not disturb fuel

• After fire knocked down, move closer to achieve final extinguishment

(Continued)

Firefighter I6–44

Fire Extinguisher Operation

• 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)

Firefighter I6–45

Fire Extinguisher Operation

• 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

Firefighter I6–46

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)

Firefighter I6–47

Fire Extinguisher Inspections

• Servicing responsibility of property owner/building occupant

• Firefighters should include inspections in building inspection program

(Continued)

Firefighter I6–48

Fire Extinguisher Inspections

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

• NFPA® 10 describes procedures for hydrostatic testing of cylinders

Firefighter I6–49

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)

Firefighter I6–50

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

Firefighter I6–51

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)

Firefighter I6–52

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

Firefighter I6–53

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)

Firefighter I6–54

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

Firefighter I6–55

Halon Fire Extinguishers

• Included in Montreal Protocol• U.S. stopped producing halogens

at end of 1993• Units may still be in service

Firefighter I6–56

Summary

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

(Continued)

Firefighter I6–57

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)

Firefighter I6–58

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.

Firefighter I6–59

Review Questions

1.What are the five classes of fire and what do they involve?2.What fires are aqueous film forming foam (AFFF) extinguishers most effective on?3.How do carbon dioxide (CO2) portable extinguishers work?

(Continued)

Firefighter I6–60

Review Questions

4.What are the three most common combinations for extinguishers with multiple markings?5.List three factors that affect the selection of the proper portable fire extinguisher.

(Continued)

Firefighter I6–61

Review Questions

6.What should be checked immediately before using a portable extinguisher?7.What is the PASS method of application?8.What procedures should be part of every fire extinguisher inspection?