Fire Safety: Extinguisher Classifications

Questions and Answers

A Class A fire extinguisher with a numerical rating of 2 contains __ gallon of water

2.5

A Class B foam extinguisher is not rated for which fuel?

Cooking oil

A Class C agent must

not conduct electricity

A Class C extinguisher is rated for use on

energized electrical equipment Signup and view all the answers

A Class K agent's effect on the fuel is known as

saponification Signup and view all the answers

A fire extinguisher's agent is stored within its

cylinder Signup and view all the answers

A loaded stream extinguisher is designed to

resist freezing Signup and view all the answers

A portable fire extinguisher is best suited for which situation?

Fire in a wastebasket Signup and view all the answers

A potential problem with application of a multipurpose dry chemical agent to a Class K fire is

neutralization of other agents applied to the fire Signup and view all the answers

According to NFPA 10, the maximum floor area that can be protected by each extinguisher depends on the

occupancy type Signup and view all the answers

All fire extinguishers are classified according to

the classes of fire on which they are effective Signup and view all the answers

All portable fire extinguishers use which means for expelling their contents?

pressure Signup and view all the answers

Bromochlorodifluoromethane is a ___ agent

halogenated Signup and view all the answers

Class D agents work primarily by

forming a crust over the fuel Signup and view all the answers

Combustion begins when a fuel is heated to its

ignition point Signup and view all the answers

Dry chemical extinguishers may be used on Class C fires because they

do not conduct electricity Signup and view all the answers

For an area to qualify for the classification of 'light hazard,' most of the combustible present must be

arranged so that a fire is unlikely to spread Signup and view all the answers

For an extinguishing agent to be approved for use on energized electrical equipment, it must

be electrically nonconductive Signup and view all the answers

For an extinguishing agent to be rated for a particular class of fire, it must

prevent rekindling Signup and view all the answers

For the purpose of extinguisher selection and placement, a woodworking shop is a(n) ___ hazard environment

extra Signup and view all the answers

For the purpose of extinguisher selection and placement, light hazard environments usually contain amount of combustibles of which class?

B Signup and view all the answers

For the purpose of extinguisher selection and placement, what is an example of a light hazard environment?

classroom Signup and view all the answers

For the purpose of fire extinguisher placement, what is the relationship between occupancy use category and hazard classification?

They are not necessarily related Signup and view all the answers

How do multipurpose dry chemical agents prevent rekindling of Class A fuel?

By forming a crust over the fuel Signup and view all the answers

If a private residence has a single fire extinguisher, where should it be located?

Kitchen Signup and view all the answers

In general, the maximum reach of CO2 extinguisher is __ feet

8 Signup and view all the answers

Requirements for placing and mounting portable fire extinguishers are found in NFPA

10 Signup and view all the answers

The 'P' in the acronym PASS, used in reference to fire extinguisher operation, stands for

pull Signup and view all the answers

The hydrostatic test interval for a dry chemical extinguisher with a stainless steel shell is every __ years

5 Signup and view all the answers

The traditional symbol for a Class D fire extinguisher is a(n)

yellow star Signup and view all the answers

The use of Halon 1211 is strictly controlled because it is

harmful to the environment Signup and view all the answers

The weight of carbon dioxide is about __ the weight of air

one-and-a-half times Signup and view all the answers

To qualify as a light hazard for the purpose of extinguisher selection and placement, the majority of materials in the area must

be noncombustible Signup and view all the answers

What does a rating of 40 on a Class B extinguisher mean?

Sufficient extinguishing power for 40 square feet of burning fuel Signup and view all the answers

What does it mean when a fire extinguisher has a pictograph with a red slash through it?

Use on that class of fire could be hazardous Signup and view all the answers

What expels the extinguishing agent from a pump tank water extinguisher?

manual effort Signup and view all the answers

What is a correct use for a portable fire extinguisher?

Situations in which the use of water is not recommended Signup and view all the answers

What is a primary factor when determining hazard classification for extinguisher selection and placement?

Amount of combustibles present Signup and view all the answers

What is an advantage of portable fire extinguishers over hose lines?

Faster deployment Signup and view all the answers

What is one disadvantage of CO2 extinguishers?

Short discharge range Signup and view all the answers

What is the best way to extinguish a Class C fire?

Shut off the power and treat it as a Class A or B fire Signup and view all the answers

What is the difference between dry powder and dry chemical extinguishing agents?

Each is rated for a different class of fire Signup and view all the answers

What is the most commonly used extinguishing agent for Class A fires?

Water Signup and view all the answers

What is the primary extinguishing mechanism of dry chemical agent?

Interrupting the chemical chain reaction Signup and view all the answers

What is the term for a water-soluble flammable liquid?

Polar solvent Signup and view all the answers

What is the term for the substance that puts out the fire?

Extinguishing agent Signup and view all the answers

What is used to pressurize a stored-pressure water extinguisher?

Compressed air Signup and view all the answers

What residue does a CO2 fire extinguisher leave when discharged?

None Signup and view all the answers

When approaching a fire with an extinguisher in hand, you should always have a(n)

exit route Signup and view all the answers

Which agent is approved for use in a Class K system?

Wet Chemical Signup and view all the answers

Which agent is rated for use on Class A fires?

Ammonium phosphate Signup and view all the answers

Which class of fire extinguisher includes a number in its classification?

A Signup and view all the answers

Which class of fire includes cloth?

A Signup and view all the answers

Which class of fire includes flammable and combustible liquids?

B Signup and view all the answers

Which class of fire involves combustible cooking oils and fats?

K Signup and view all the answers

Which class of fire involves combustible metals?

D Signup and view all the answers

Which class of fire involves energized electrical equipment?

C Signup and view all the answers

Which class of fire is depicted in the pictograph system by a burning trash can next to a wood fire?

A Signup and view all the answers

Which class of fire is depicted in the pictograph system by a fire in a frying pan?

K Signup and view all the answers

Which class of fire is depicted in the pictograph system by a flame and an electrical plug and socket?

C Signup and view all the answers

Which class of fire is depicted in the pictograph system by a flame and gasoline can?

B Signup and view all the answers

Which compound is added to a water extinguisher to improve penetration of fuel?

A wetting agent Signup and view all the answers

Which extinguishing agent is suitable for use on a Class C fire?

Carbon dioxide Signup and view all the answers

Which extinguishing method is being used when a foam blanket is placed over the surface of a burning liquid?

Cutting off the oxygen supply Signup and view all the answers

Which feature of some carbon dioxide extinguishers makes them dangerous for use on Class C fires?

Metal horn Signup and view all the answers

Which fire extinguishing agent is best for use on sensitive electronic equipment?

Carbon dioxide Signup and view all the answers

Which hazard category includes automotive service or repair facilities?

extra Signup and view all the answers

Which motion best accomplishes the removal of the pin and tamper seal from a portable fire extinguisher?

twisting motion Signup and view all the answers

Which of the following is commonly used as a dry chemical extinguishing agent?

ammonium phosphate Signup and view all the answers

Which of the following is one of the three basic components required for fire?

oxygen Signup and view all the answers

Which statement about dry chemical agents is correct?

dry chemical agents are not subject to freezing Signup and view all the answers

Which statement about foam fire extinguishers is correct?

Class B foam extinguisher may be used to some effect on Class A fires Signup and view all the answers

Which statement about the numerical rating of a Class K is correct?

There is no numerical rating for a Class K extinguisher Signup and view all the answers

Which statement best summarizes when a dry chemical extinguisher should be serviced and recharged?

After any discharge Signup and view all the answers

Which statement is correct regarding Class D extinguishing agents?

The specific agent must be matched to the specific fuel Signup and view all the answers

Study Notes

Fire Extinguisher Classifications and Usage

Class A fire extinguishers combat ordinary combustibles like wood and cloth; a numerical rating of 2 indicates it can hold 2.5 gallons of water.
Class B extinguishers are used for flammable liquids and are ineffective against cooking oil.
Class C extinguishers are specifically designed for energized electrical equipment and must not conduct electricity.
Class K extinguishers target combustible cooking oils and fats; their action is termed saponification.
Class D extinguishers are specialized for combustible metals, bringing unique challenges in firefighting.

Extinguisher Components and Functionality

The extinguishing agent in fire extinguishers is stored within a cylinder and is expelled using pressure.
A loaded stream extinguisher is resistant to freezing temperatures for reliable operation in cold conditions.
CO2 extinguishers typically have a maximum effective range of 8 feet and leave no residue upon discharge.

Extinguisher Placement and Hazard Classification

Proper placement of extinguishers depends on occupancy type, with light hazard environments containing fewer combustibles.
Areas with a lot of combustibles require extra caution, hence possibly needing extra extinguishing equipment.
For safety, a fire extinguisher should be located in the kitchen if found in a private residence.

Fire Chemistry and Safety Measures

Combustion begins when fuel reaches its ignition point, emphasizing the importance of heat management.
In tackling a Class C fire, the recommended approach is to shut off power sources and treat the scene as a Class A or B fire.
Understanding the relationship between occupancy type and hazard classification is crucial; they do not always correlate.

Agent Specifications and Handling

Multipurpose dry chemical agents effectively prevent rekindling Class A fuels by forming a crust over them.
Each extinguishing agent has distinct properties; for example, halogenated agents like Bromochlorodifluoromethane are highly effective yet environmentally harmful.
The hydrostatic testing for certain extinguishers, such as those with stainless steel, occurs every 5 years to ensure integrity.

Extinguisher Operation and Maintenance

The acronym PASS (Pull, Aim, Squeeze, Sweep) is essential for proper extinguisher operation, with "P" representing "pull" for removing the pin.
A dry chemical extinguisher must be serviced after any use, ensuring readiness for future incidents.
Class K extinguishers do not follow a numerical rating system, highlighting their unique safety specifications.

Pictograph Recognition and Chemical Properties

Pictographs indicate fire types represented by symbols: a burning trash can for Class A, a frying pan for Class K, and a flame with a gas can for Class B.
Understanding the correct extinguishing method, such as using foam for liquid fires, is crucial for effective firefighting.
Carbon dioxide extinguishing agents are safe for sensitive electronic equipment due to their non-residuum nature.

Risks and Limitations

The use of CO2 extinguishers can be risky on Class C fires due to the potential hazards posed by their metal horns.
Some dry chemical agents can interrupt the chemical chain reaction necessary for fire, illustrating their effectiveness; however, they may not be suited for all situations.
Advantages of portable extinguishers, including quicker deployment compared to hose lines, should be recognized during selection and training.

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Description

This quiz reviews the classifications and usage of various fire extinguishers. It covers essential details about Class A, B, C, K, and D extinguishers, as well as their components and functionality. Test your knowledge on how to effectively combat different types of fires and the mechanics behind fire extinguishers.