IFSTA CH 6 - Portable Fire Extinguishers Flashcards
fire extinguisher primarily intended use
for occupants to use on small, incipient fires or on fires in the early growth stage
classifications of portable fire extinguishers
are classified according tot he type of fire that each is designed to extinguish
there are five classes (A, B, C, D and K)
certain extinguishing agents are only effective on certain classes of fire or fuels
Class A
involve ordinary combustible such as:
textiles
paper
plastics
rubber
wood
Class A fire extinguishers are rated
from 1-A through 40-A
primarily based on the amount of water and the duration and range of the discharge used in extinguishing test fires
Dry chemicals
will also extinguish fires fueled by class A materials
Class B
involve flammable and combustible liquids and gases
Agents used to extinguish class B fires
include Carbon dioxide, dry chemicals and class b foam
flammable and combustible liquids and gases include
alcohol
gasoline
lubricating oils
liquefied petroleum gas (LPG)
Class B ratings range from 1-B through 640-B
the rating is based on the approximate square foot area of a flammable liquid fire that a nonexpert operator can extinguish using on full extinguisher
Class C
involves energized electrical equipment
rating confirms that the extinguishing agent will not conduct electricity
Class D
those involving combustible metals and alloys such as
titanium
magnesium
sodium
lithium
potassium
Magnesium fires
can be identified by the bright white emissions during the combustion process
Class D extinguishing agents
Dry powder
Class D extinguishers are only to be used on class D fires
Class K
involve combustible cooking oils such as vegetable or animal fats and oils that burn at extremely high temperatures
wet chemical systems and portable fire extinguishers are used to control and extinguish class k fires
Saponification
smothering
excluding oxygen from the burning process
cooling
reducing the burning material below its ignition temperature
chemical flame inhibition
interrupting the chemical chain reaction in the burning process
saponification
forming an oxygen-excluding soapy foam surface
manual pump extinguisher
the operator physically applies pressure to the pump that increases pressure within the container which forces the agent out a nozzle at the end of the hose
stored pressure
compressed air or inert gas within the container forces the agent outa nozzle at the end of a hose when the operator presses the handle
pressure cartridge
a separate cartridge on the side of the container contains an inert gas
when the operator punctures the cartridge seal, the expellant enters the container and forces the agent out a nozzle on the end of a hose
pump-type water extinguishers
are intended primarily for use on ground cover fires although they may also be used for small class A fires
stored-pressure water extinguishers
useful for all types of Class A fires
there are also useful for extinguishing confined hot spots during overhaul operations
Stored-pressure water-mist extinguishers
used deionized water as the agent and nozzles that produce a fine spray instead of a solid stream
the deionized water makers these Class A extinguishers safe to use on energized electrical equipment
stored pressure wet chemical extinguishers
they are intended for use on Class K fires involving cooking fats, grease and vegetable and animal oils in commercial kitchens
Aqueous film forming foam (AFFF) extinguishers
are intended for class B fires
they are particularly useful in combating fires in or suppressing vapors from small liquid fuel spills
AFFF differ from stored-pressure water extinguishers in two ways
AFFF tank contains a specified amount of AFFF concentrate mixed with the water to produce a foam solution
has an air-aspirating foam nozzle that aerates the foam solution, producing better quality foam than a standard extinguisher nozzle provides
clean agent extinguishers
effectively cool and smoother fires in class A and B fuels and inhibit the sustained chemical reaction in class C fuels
the agents are nonconductive and can extinguish energized electrical equipment fires
halogenated extinguishing agents
carbon dioxide extinguishers
are most effective in extinguishing class B and Class C fires
Dry Chemical extinguishers
are for use on Class A-B-C and/or Class B-C fires
dry powder agents are only for use on
Class D fires
There are two basic types of dry chemical extinguishers
regular B-C rated
Multipurpose A-B-C rated
two basic designs for handheld dry chemical extinguishers
cartridge-operated
stored-pressure
cartridge-operated handheld extinguishers
employ a pressure cartridge connected to the agent tank
stored-pressure handheld extinguishers
the agent stored tank maintains a constant pressure of about 200 psi
wheeled units
Class A, B and C fires
position the unit and then extend the hose
Dry powder extinguishers
fires involving class D combustible metals require special dry powder extinguishing agents and application techniques
selecting the proper fire extinguishers, consider
classification of the burning fuel
hazards to be protected against
atmospheric conditions
ease of handling the extinguisher
rating of the extinguisher
size and intensity of the fire
availability of trained personnel to operate
any life hazard or operational concerns
when inspecting an extinguisher immediately before use, check the following
external condition - no apparent damage
hose/nozzle - in place
weight - feels as though it contains the agent
pressure gauge (of available)
PASS application method
pull
aim
squeeze
sweep
