chapter 6 portable fire extinguishers. 6–2 chapter 6 lesson goal after completing this lesson, the...

Chapter 6— Portable Fire Extinguishers

6–2

Chapter 6 Lesson Goal

• After completing this lesson, the student shall be able to operate portable fire extinguishers effectively & safely

6–3

Portable Fire Extinguishers

• Intended for incipient fires

• Quicker to deploy than hoselines

• Found in most facilities, i.e. homes, businesses

• Require little training to use

6–4

Portable Fire Extinguishers

• Most common fire protection device

• Most are re-chargeable

• FF’s should not rely on privately–owned fire extinguishers

6–5

Fire Extinguishment Methods

• Smothering

• Cooling

• Chain breaking

• Saponification

6–6

DISCUSSION QUESTION

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

6–7

Portable Extinguisher Discharge Mechanisms

All use some form of pressure:

• Manual pump

• Stored pressure

• Pressure cartridge

• Cylinder (wheeled units)

6–8

Fire Classifications

• Fire extinguishers classified & rated according to their intended use

• 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)

6–9

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)

6–10

Fire Classifications

Class C fires — Involve Class A or B fires created by electrical energy

• Do not use water or water-based agents until electricity is shut off

• Recommended method is to turn off ordisconnect electrical power before using appropriate extinguisher

(Continued)

6–11

Fire Classifications

Class D fires — Involve combustible metals, alloys

• Can be identified by bright white sparks & emissions from fire process

• Class D, dry powder extinguishers work best

(Continued)

6–12

DISCUSSION QUESTION

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

6–13

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

6–14

Stored-Pressure Water Extinguishers

• Air-pressurized water extinguishers or pressurized water extinguishers

• Useful for all types of small Class A fires

(Continued)

6–15

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

6–16

Stored-Pressure Water Extinguishers

• Affected by freezing weather

Loaded stream extinguishers have an anti-freeze added

• Not suitable for Class C & D fires

• Maximum size is 2A

6–17

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.

6–18

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)

6–19

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)

6–20

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)

6–21

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

• Not suitable for flowing fuels

• Most effective on static pools of flammable liquids

6–22

Clean Agent Extinguishers

• Designed to replace halons, & use “clean agents” that discharge as rapidly evaporating liquids that leaves no residue

Nonconductive so can be used on Class C

Approved by U.S. EPA

• Halon replacements work by inhibiting the chemical chain reaction

6–23

Carbon Dioxide (CO2) Extinguishers

• Found as both handheld/wheeled units

• Most effective in Class B, C fires

• Leaves no residue

• Have limited reach; gas can be dispersed by wind

(Continued)Courtesy of Ansul Corp.

6–24

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 they are bigger

Courtesy of Badger Fire Protection.

6–25

Carbon Dioxide (CO2) Extinguishers Hazards

• Do not touch horn during discharge

Static electricity shock

Cold injuries

• In confined spaces it displaces oxygen

Dry Chemical Extinguishers

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

• Two types:

Cartridge operated

Stored pressure

6–26

(Continued)

Courtesy of Ansul Corp.

6–27

Dry Chemical Extinguishers

• Puts out fire by breaking chemical chain reaction

• Two basic chemicals:

Regular B:C-rated

Multipurpose and A:B:C-rated

Courtesy of Ansul Corp.

6–28

Dry Chemical Extinguishers

Agent Common Names Class of Fire

Sodium bicarbonate Regular B&C

Potassium bicarbonate

Purple K B&C

Potassium chloride Super K B&C

Monoammonium phosphate

Multi-purpose ABC

Wheeled Fire Extinguishers

• Large units mounted on wheeled carriages

• Typically contain 150 to 350 lbs of extinguishing agent

• Indoor use requires wide doorways & aisles

6–29

Wheeled Fire Extinguishers

• Long delivery hoses allow operators to attack fire from multiple sides

• Usually pressurized by separate cylinders

• Installed in special hazard areas

6–30

6–31

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

• Agent is usually a powder

Note: Dry powder & dry chemical not the same thing

(Continued)

6–32

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)

6–33

Controlling/Extinguishing Metal Fires

Portable extinguishers for Class D come in both handheld & wheeled units

(Continued)

Courtesy of Amerex Corp.

6–34

Controlling/Extinguishing Metal Fires

Powder must be applied in sufficient depth to completely cover burning area to create smothering blanket

(Continued)

6–35

Controlling/Extinguishing Metal Fires

• 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

6–36

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

6–37

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

6–38

Classifications

• A Rating: Based on 1.25 gallons (5 L) of water

2A = 2.5 gallon (10 L)

• B Rating: Based on square foot or square meter

20B = 20 sq ft (1.8 sq m)

• C Rating: Bases on electrical shock hazard (no shock, it’s a Class C)

6–39

Classifications

• D Rating: Used for metals only, no rating

Must be specific to types of metal

• K Rating: Used for hot cooking oil application (deep fryers)

6–40

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

6–41

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

Classification of Fire Extinguishers

K

COOKING OILS

COOKING FATS6–42

Classification of Fire Extinguishers

• Red slash across pictograph means Do Not Use

• Use of the fire extinguisher on this type of fire could be dangerous

6–43

6–44

Extinguisher Selection Factors

• Classification of burning fuel

• Rating of extinguisher

• Hazards to be protected

• Size/intensity of fire

(Continued)

6–45

Extinguisher Selection Factors

• Outside conditions

• Availability of trained personnel

• Ease of handling extinguisher

• Life hazard/operational concerns

6–46

Extinguisher Selection Considerations

• Select those that minimize risk to life/property & 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

6–47

Extinguisher Check

• Immediately before use

External condition

Hose/nozzle

Weight

Pressure gauge

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

6–48

DISCUSSION QUESTION

Why should you always have an escape route?

6–49

Fire Extinguisher Operation

• Most extinguishers operate in a similar manner

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

(Continued)

6–50

Fire Extinguisher Operation

Once in position, use PASS method

• P — Pull the pin

• A — Aim the nozzle at the base of the fire

• S — Squeeze handles together

• S — Sweep nozzle back & forth

(Continued)

6–51

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 for final extinguishment

(Continued)

6–52

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)

6–53

Fire Extinguisher Operation

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

• If more than one extinguisher used, work together & maintain constant awareness

6–54

Fire Extinguisher Inspections

• NFPA 10 & 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)

6–55

Fire Extinguisher Inspections

• Servicing responsibility of property owner/building occupant

• FFs should include inspections in building inspection program

(Continued)

6–56

Fire Extinguisher Inspections

• Three factors determine usefulness of fire extinguishers

Serviceability

Accessibility

Simplicity of operation

• NFPA 10 describes procedures for hydrostatic testing of cylinders

6–57

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)

6–58

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

6–59

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)

6–60

DISCUSSION QUESTION

How should a defective fire extinguisher be repaired?

6–61

Damaged Fire Extinguishers

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

• If allowed by SOP, leaking hoses, gaskets, nozzles, & loose labels can be replaced by FFs

6–62

Obsolete Portable Fire Extinguishers

Since 1969

• Manufacturers stopped making inverting-type extinguishers

• All extinguishers are carried upright

• Manufacturing of extinguishers made of copper or brass with cylinders soft soldered or riveted together discontinued

(Continued)

6–63

Halon Fire Extinguishers

• Included in Montreal Protocol

• Damages the ozone

• World stopped producing halogens at end of 1993

• By 2010 all halons, fixed or otherwise, are to be removed

6–64

Summary

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

(Continued)

6–65

Summary

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

(Continued)

6–66

Summary

To use fire extinguishers safely & effectively, FFs must know capabilities & limitations of the extinguisher — & their own capabilities & limitations — as well as the proper techniques for their application

6–67

Skills

• Operate a stored pressure water extinguisher

• Operate a dry chemical (ABC) extinguisher

• Operate a carbon dioxide (CO2) extinguisher

• Clean, service & place a portable fire extinguisher back in service. (Skill Sheet FF-I-101)

• Operate a dry chemical wheeled unit (Exercise 2)