Ch11 portable fire extinguishers

Chapter 11Portable Fire Extinguishers

Objectives• Discuss the fire extinguisher classification

system. • List the different extinguishing agents and

their applications. • Discuss the fire extinguisher rating system

and identify which classifications of extinguishers it applies.

Objectives

• Explain why a certain extinguisher classification requires a conductivity test.

• Describe the different types of fire extinguishers and how they operate.

Objectives• Explain the acronym PASS in relation to

fire extinguisher operation.• Discuss the inspection, testing, and

maintenance procedures for portable fire extinguishers.

Introduction• Portable fire extinguishers are valuable

suppression tools.– Used at incipient stage or when water is not

an option– Must be quickly accessible and correct type

for class of fire– Are labeled for type of fire, require (minimal)

training, and are designed for easy use

Introduction• Typically an

extinguisher needs only a few components:– Cylinder– Nozzle/horn– Carrying handle– Locking mechanism– Pressure gauge

Courtesy of Amerex Corporation

Introduction• Knowledge of extinguishers and

suppression agents enables proper selection and operation of extinguishers.

Code Requirements for Fire Extinguishers

• Code requirements for installation are included in all the model codes.– Use and occupancy conditions– Managing specific hazards, industrial

processes, equipment, special events– IBC® and IFC® follow installation requirements

of NFPA 10.

Code Requirements for Fire Extinguishers

• NFPA 1, NFPA 101, and NFPA 5000 require installation in new and existing use and occupancy classifications.– Some small exceptions and differences exist

between codes.• NFPA 10 establishes guidelines for

installation, maintenance, and testing.– Has been modified to keep up with changing

technology and research

Fire Extinguisher Classification

• The fire classification system is the basis for determining appropriate extinguishing agents.• Class A: Involves ordinary combustibles • Class B: Involves flammable and combustible

liquids and gases• Class C: Involves energized electrical equipment• Class D: Involves combustible metals • Class K: Involves cooking media that use

combustible vegetable or animal oils and fats



• The same lettering system used to classify fires is labeled on extinguishers to indicate the class of fuel they combat.– Some have multiple classifications because

the agent works well on different materials.– They have labels with multiple letters and

icons depicting the type of fire (e.g., ABC, AB, BC).

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Common Fire Extinguisher Agents

• Water– One of the best agents; can absorb most heat

per pound– Most effective on Class A fires– Extinguishers using water should not be

exposed to cold conditions.• Water can freeze unless mixed with antifreeze.


• Foam– Good for Class A and B fires– Becomes a vapor barrier between fuel and

atmosphere– Two types: AFFF and FFFP– Not as effective if flammable-liquid fires are

under pressure, or on cooking grease fires– Mixes with water so does not work well in

freezing temperatures


• Carbon dioxide– Good for Class B and C fires and has limited use

on Class A fires– Liquid state in tank; expands to gas upon release– No pressure gauges; agent quantity determined

by weighing tank– Works by depleting oxygen surrounding a fire– Must be discharged at close range

• In confined space, protect against asphyxiation.


• Dry chemicals– Small particles propelled by pressurized gas– Smothers the burning material– Not dangerous or toxic but can create cloud

that limits visibility/causes respiratory problems– Three categories:

• Sodium bicarbonate-based• Potassium-based• Multipurpose


• Wet chemicals– Primary agents for Class K fires– Water-based solutions mixed with potassium

carbonate, acetate, or citrate, or a mixture of these and other additives

– React with fat in cooking medium/food and create a soapy blanket that smothers fire

• Liquid in agents cools cooking media to help maintain foam blanket.


• Dry powders– Work best for Class D combustible metal fires,

which can be difficult to control– No one powder for every fire– Must know which agent works with which

particle type of combustible metal fire


• Halon and other clean agents– Halon is being phased out due to environmental

concerns.• Toxic and can cause physical problems• Halon 1211 and Halon 1301 still in use

– New generation of clean agents are more environmentally friendly and almost as effective.

• Halocarbon-based agents• Inert gases

Fire Extinguisher Ratings• The number represents how much fire the

extinguisher should be able to handle.• Class A and B groups have additional number rating

to indicate performance.– Class A: 1-A, 2-A, 3-A, 4-A, 6-A, 10-A, 20-A, 40-A

• Each increment above 1 equals same capacity as 1.25 gallons of water.

– Class B: 1-B, 2-B, 5-B, 10-B, 20-B, 30-B, 60-B, 80-B, 12-B, 160-B, 240-B, 320-B, 480-B, 640-B

• Tested by setting a flammable liquid fire in a pan and measuring square footage

Fire Extinguisher Ratings• Class C extinguishers do not have a rating

because there is no fire test.– Conductivity tests can determine conductivity

between agent, horn/hose and nozzle, and electrically energized source.

– Desired result is no conductivity to protect against arcing and shock, and to prevent injury.

Types of Fire Extinguishers• Pump extinguishers

– Manually operated via a pump mechanism

– Easy to use and refill – Pumping mechanism

• Internal: similar to a floor-type bicycle pump

• External: similar to a hand-held bicycle pump; used for backpack-type extinguishers

(c) Jones & Bartlett Learning

Types of Fire Extinguishers• Stored pressure

extinguishers– Pressurized gas and

extinguishing agent mixed in same tank

– Pressure gauge for operator’s reference

– Use a variety of agents

© A. Maurice Jones, Jr./Jones & Bartlett Learning

Types of Fire Extinguishers• Cartridge pressure

extinguishers– Gas cartridge that

is separate and attached to side of tank

– No pressure gauge– Removable top – Use various agents © A. Maurice Jones, Jr./Jones & Bartlett Learning

Types of Fire Extinguishers• Obsolete types of fire extinguishers

– Many types are no longer approved for use.• Some are unsafe.• Some contain corrosive or conductive products.

– A few examples include:• Soda acid• Carbon dioxide extinguishers with metal horns• Any that need to be inverted for operation• Stored pressure water extinguishers with fiberglass

shells

Fire Extinguisher Operation• Even with little to no training, a

person should be able to operate an extinguisher.– Most portables operate similarly.– Follow PASS.– Operators should also be aware

of extinguisher locations, limitations, and importance of evacuating occupants.


Inspection, Testing, and Maintenance

• These activities are keys to ensuring extinguishers work properly when needed.– They are responsibility of property owner or

representative.– Inspectors must be trained and certified.– There are many different activities, which can

identify impairments before they become problems.


• Visual inspection– General condition can be

determined quickly.– Takes place every 30 days (can

be more frequent) – Multiple parts to the visual

inspection. Examples: • Present, visible, accessible?• Inspection tag?• Physically damaged?



• Visual inspection (cont’d)– Some functions are now performed through

electronic monitoring systems.• Also through fire alarm system or monitoring panel• Changes in normal parameters alert monitoring

center so that investigation can begin immediately.• NFPA 1 and IFC recognize electronic monitoring

as viable technology.


• Maintenance– Follows manufacturer’s requirements and is more

thorough than visual inspection– Usually occurs annually (may be more frequent)– Internal examinations are required at various

intervals (every 1, 3, 5, or 6 years).– Inspectors must determine if problems can be

fixed.– Some tasks are dangerous; prepare personnel.


• Testing– Hydrostatic testing ensures extinguishers will

not fail due to unnoticed conditions (e.g., corrosion).

• Involves disassembling extinguisher, filling component with water, immersing it in water, and pressurizing it

– Tests occur every 5 or 12 years based on extinguisher type.

Summary • The intended use of portable fire

extinguishers is to suppress small incipient fires.

• Because portable extinguishers hold a fixed amount of suppression agent, there must be quick access, the operator must know the proper use and handling of the extinguisher, and the extinguishing agent must be suitable for the type of fire encountered.

Summary• The type of suppression agent determines

the extinguisher classification (Class A, B, C, E, or K).

• Suppression agents used in the different types of portable extinguishers include water, foam, carbon dioxide, dry chemical, wet chemical, dry powder, halon, and other clean agents.

Summary• Some suppression agents work well on

many different materials, but may not work with a particular category of extinguisher.

• In addition to receiving a classification, Class A and Class B extinguishers receive a rating that establishes their performance capability where a number rating expresses how much fire the extinguisher should be able to handle.

Summary• Generally, portable fire extinguishers fall

into three categories: pump extinguishers, stored pressure extinguishers, or cartridge pressure extinguishers.

• Pump extinguishers require a person to pump a handle manually to expel the suppression agent.

Summary• Stored pressure extinguishers use a gas

that is contained with the suppression agent in the extinguisher’s tank to expel the suppression agent.

• Cartridge pressure extinguishers have an external cartridge that holds a gas. Once punctured, these cartridges release the gas into the tank to expel the suppression agent.

Education

Ch11 portable fire extinguishers