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To be
effective an
extinguisher:
Must be readily accessible
In working order
Suitable for the hazard
Large enough to control the size fire
Class A: fires
involving
ordinary
combustibles
water, class A dry
or wet chemical,
foam, and mist
A
Class B:fires
involving
flammable
and
combustible
liquids
Extinguished by dry
chemical agents,
foam, clean agents,
or carbon dioxide
B
Class C:fires
involving
energized
electrical
equipment
Extinguished with
nonconductive agents
such as carbon dioxide,
clean agents, mist, and
dry chemical
C
Class D:fire
involving
combustible
metals
Extinguished by Dry Powders Like sodium
chloride which is a material used to cover
the burning metals
Class D is never assigned as
multipurpose extinguisher
D
Class K: fires
that involve oils that are used in commercial cooking applications
These materials have been taken out of the Class B classification
Extinguished with wet chemical
K
Extinguishers must be marked for
which the class of fire they are rated
NFPA 10 recommends
pictographs indicating the fire
class and the types of fires on
which the extinguisher should
not be used
One system
uses colored
shapes with
the class letter
in the shape
Remove
Oxygen
Heat
Fuel
EXINGUISHING PRINCIPLES
EXTINGUISHER RATINGS
Class A and Class B
extinguishers will have a
numerical rating designating
the size fire an untrained
person should be able to
extinguish
Class A extinguishers: rated from 1-A to 40-A -
1-A requires 11/4 gallons of water
Class B extinguishers: rated from 1-B through
640-B
Every 1-B rating corresponds to 1-square-foot
of flammable liquid
No tests are
conducted for
capacity ratings
CLASS C EXTINGUISHERS
Extinguishing
agent is tested
for electrical
conductivity
CLASS D EXTINGUISHERS
No tests are conducted for capacity ratings
Tests are conducted for specific
metals for:
Reactions between the metal and agent
Toxicity of the agent
Toxicity of any fumes produced
Time to allow the fire to self-extinguish versus time to extinguish the fire
For a Class K
rating,
extinguishing
agents must be
able to extinguish
a fire involving
cooking oils with a
surface area of
2.25 square feet
WATER FIRE
EXTINGUISHERSExtinguisher Characteristics:
Size: 2.5 gallons
Discharge distance: 30-40 feet
Duration: 30-60 seconds
Method of expelling agent: pump or pressure
WATER FIRE
EXTINGUISHERS
Agent Characteristics:
Freezing temperature: 32oF
High surface tension
Needs expellant force
Extinguishment principle:
remove heat/cooling
Class A fires only
WATER FIRE
EXTINGUISHERS
Advantages
Limitations
Conducts electricity
Freezes
High surface tension
Reacts with certain chemicals
Absorbs large amounts of
heat
Can be used with specialized
agents
Dry Chemical Extinguishers
Extinguisher Characteristics:
Size: 2.5 to 350 pounds
Discharge distance: 5-20 feet
Duration: 8-25 seconds
Method of expelling agent: cartridge/stored pressure
Most Common Extinguisher Made
Sodium bicarbonate:
ordinary
Potassium bicarbonate:
Purple K
Potassium chloride:
Super K
Monammonium phosphate:
multipurpose, Tri-class
Agents:
Dry Chemical Extinguishers
Dry Chemical Extinguishers
Extinguishment principle:
Uses:
Breaking chain
reaction
Tri-class: smothering
Class A: Tri-class
Class B & C: all types
Dry Chemical ExtinguishersAdvantages
Limitations
Breathing difficulties
Insulating qualities
Corrosive properties
Not flash back resistive
Chemicals not interchangeable
Some not compatible with foam
Nontoxic
Nonconductive
Quick flame knockdown
Clean agent extinguishing agents were
designed to replace halogenated
extinguishing agents (Halon 1211 and Halon 1301)
CLEAN AGENT EXTINGUISHERS
Halon production was
stopped in 1994 due to its
effect on the ozone layer
There is still limited halon
production and much of
the halon in use is
recycled
Extinguish fires through a chemical
process which inhibits combustion
CLEAN AGENT EXTINGUISHERS
Used for Class B and Class C fires
and in areas with sensitive
electronic equipment
High expansion ratio
Needs no expellant
Nonconductive and noncorrosive
Carbon Dioxide Extinguishers
Extinguisher Characteristics
Size: 2.5 to 100 pounds
Discharge distance: 3-8 feet
Duration: 8-30 seconds
Method of expelling agent: stored pressure
Carbon Dioxide Extinguishers
Agent Characteristics:
Extinguishment principle:
smothering
Class B and C fires,
limited effect on Class A
Normally a gas
1.5 times heavier than air
Low temperature
Can be stored as liquid
Carbon Dioxide Extinguishers
Advantages
Limitations
Visibility
Noise
Short range
Dissipates rapidly
Displaces oxygen
Nonconductive
Non-reactive
No residue
WET CHEMICAL STORED-PRESSURE EXTINGUISHERS
Specifically
designed to
extinguish fires
involving
unsaturated cooking
oils in deep dryers
Contain a special
potassium-based,
low-pH agent for
class A & K Fires
Foam Fire Extinguisher
Contains: Water, Air, &
Foam Concentrate
Extinguishes A & B Fires
Water Mist Extinguishers
Contains: Deionized Water
Extinguishes with Fine Water
Droplets for A & C Fires
Stored Pressure Which is the most common
Contains an agent in a cylinder with an expellant gas
Discharge handle and may have a gauge
Types of Extinguishers
Manual Pump / Pressure Cartridge
Types of Extinguishers
Water CO2
Dry chemical Halon
Clean agents Dry powder
Stored Pressure
1 2 3 4 5
Can you Match the extinguishers below with the Types above?
Types of Extinguishers
2 Water 3 CO2
1 Dry chemical 5 Halon
5 Clean agents 4 Dry powder
Stored Pressure
1 2 3 4 5
All obsolete
extinguishers
should be removed
from service and
replaced with
approved
extinguishers
Soda water base with
an acid expellant
Carbon Tetrachloride
was a common
vapor agent used
manual pump &
fire grenade
Extinguisher selection depends on:
Characteristics of the fuels
present
Potential severity of any fire
Extinguisher location
Extinguisher effectiveness
Personnel available and experience
to use the extinguisher
Health and safety concerns
Extinguishers must be
conspicuously located
Installation and placement
Must be readily accessible
Should be located along
normal travel paths,
including exits
Must not be blocked by
storage or equipment
Must be visible or the location
marked conspicuously
Determine if extinguisher is
full and if the pressure gauge
reading in the operable range
Check the locking pin and
tamper seal to determine if it
has been used or tampered with
Check the inspection
tag for the dates of the
previous inspections,
maintenance, and
recharging
Examine for physical damage
Nozzle obstructions
Corrosion
Mechanical damage
Hose condition
Horns for cracks and obstructions
Hydrostatic testing
EXTINGUISHER OPERATION
Pull pin
Aim nozzle
Squeeze handle
Sweep nozzle
Check extinguisher before approaching
EXTINGUISHER SAFETY
Approach upwind
Don’t enter burn area
Don’t turn back on fire
Review
1. Know the 5 classes of fires and which fire
extinguishers are rated for each class?
2. What are the principals of how to extinguish a
fire?
3. How are all fire extinguishers rated?
4. List the different types of fire extinguishers?
5. What is the acronym for using a fire extinguisher
and what does it stand for?
1. Know the 5 classes of fires and which fire extinguishers are rated for each class?
Class A – Ordinary / Water, Wet or Dry Chemicals, Foam, or Mist
Class B – Flammable Liquids / Dry Chemicals, Foam, Clean Agents, or CO2
Class C – Energized Electric / Dry Chemical, Clean Agents, Mist or CO2
Class D – Flammable Metals / Dry Powders
Class K – Cooking Oil / Wet Chemicals
2. What are the principals of how to extinguish a fire?
By Removing any side of the fire tetrahedron; Remove Heat (Cooling), Oxygen
(Smothering), Fuel (Starving) or by Inhibiting the Chemical Reaction.
3. How are fire extinguishers rated?
A - 1 ¼ Gallons of water B - Per Square Feet C - If it will Conduct
Electricity D - Metal Specific K-Cooking Oils
4. List the different types of fire extinguishers?
Water, Dry Chemical (The Most Common Extinguisher), Clean Agents (Halon
Type), CO2 (Carbon Dioxide), Wet Chemical, Foam, and Mist
5. What is the acronym for using a fire extinguisher and what does it stand for?
PASS P-Pull the Pin A-Aim the Extinguisher S-Squeeze the Trigger S- Sweep
at the base of the fire
