Transcript Essentials

Essentials of Fire Fighting,
5th Edition
Chapter 6 — Portable Fire
Extinguishers
Firefighter I
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 I
6–1
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 I
6–2
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 I
6–3
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 I
6–4
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 I
6–5
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 I
6–6
Fire Extinguishment Methods
•
•
•
•
Smothering
Cooling
Chain breaking
Saponification
Firefighter I
6–7
Portable Extinguisher Expulsion
Mechanisms
• Manual pump
• Stored pressure
• Pressure cartridge
Firefighter I
6–8
Fire Classifications
• Class A fires — Involve ordinary
combustibles
– Easily extinguished with water, waterbased agents (foam), dry chemicals
– Water most common agent used by fire
service
(Continued)
Firefighter I
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
Firefighter I
6–10
(Continued)
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 or
disconnect electrical power before using
appropriate extinguisher
(Continued)
Firefighter I
6–11
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 I
6–12
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 I
6–13
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 I
6–14
Stored-Pressure Water
Extinguishers
• Air-pressurized water
extinguishers or
pressurized water
extinguishers
• Useful for all types of
small Class A fires
(Continued)
Firefighter I
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
Firefighter I
6–16
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 I
6–17
Wet Chemical Stored-Pressure
Extinguishers
• Specifically designed to
Courtesy of Ansul Corp.
control/extinguish Class K
fires in deep fryers
• Contain special potassiumbased low-pH agent to
cool/suppress fires in
unsaturated cooking oils
Firefighter I
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)
Firefighter I
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)
Firefighter I
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)
Firefighter I
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
• Most effective on static pools of
flammable liquids
Firefighter I
6–22
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 I
6–23
Carbon Dioxide (CO2)
Extinguishers
• Found as both
Courtesy of Badger Fire Protection
handheld/wheeled units
• Most effective in Class B,
C fires
• Have limited reach; gas
can be dispersed by
wind
(Continued)
Firefighter I
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 wheeled are considerably larger
Firefighter I
6–25
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 I
6–26
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 I
6–27
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 I
6–28
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 I
6–29
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 I
6–30
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 I
6–31
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 I
6–32
Classifications
•
•
•
•
•
Class
Class
Class
Class
Class
1996
A — From 1-A through 40-A
B — From 1-B through 640-B
C — No tests
D — Test fires vary
K — Recognized by UL, ULC since
Firefighter I
6–33
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 I
6–34
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 I
6–35
Extinguisher Selection Factors
•
•
•
•
Classification of burning fuel
Rating of extinguisher
Hazards to be protected
Size/intensity of fire
(Continued)
Firefighter I
6–36
Extinguisher Selection Factors
•
•
•
•
Atmospheric conditions
Availability of trained personnel
Ease of handling extinguisher
Life hazard/operational concerns
Firefighter I
6–37
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 I
6–38
Extinguisher Check
• Immediately before use
– External condition
– Hose/nozzle
– Weight
– Pressure gauge
• After selecting size/type for situation,
approach fire from windward side
Firefighter I
6–39
Fire Extinguisher Operation
• All modern extinguishers
operate in similar
manner
• Pick up extinguisher by
handles, carry to point of
application
(Continued)
Firefighter I
6–40
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 I
6–41
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 I
6–42
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 I
6–43
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 I
6–44
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 I
6–45
Fire Extinguisher Inspections
• Servicing responsibility of property
owner/building occupant
• Firefighters should include inspections
in building inspection program
(Continued)
Firefighter I
6–46
Fire Extinguisher Inspections
• Three factors determine value
– Serviceability
– Accessibility
– Simplicity of operation
• NFPA® 10 describes procedures for
hydrostatic testing of cylinders
Firefighter I
6–47
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 I
6–48
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 I
6–49
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 I
6–50
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 I
6–51
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 I
6–52
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 I
6–53
Halon Fire Extinguishers
• Included in Montreal Protocol
• U.S. stopped producing halogens at end
of 1993
• Units may still be in service
Firefighter I
6–54
Summary
• In many cases, fire extinguishers can
control or extinguish small fires in less
time than it takes to deploy a hoseline.
(Continued)
Firefighter I
6–55
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 I
6–56
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 I
6–57
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 I
6–58
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 I
6–59
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?
Firefighter I
6–60