Fire Fighting Chapter 7 Flashcards

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Questions and Answers

At what stage of fire growth are portable fire extinguishers primarily designed to function?

incipient stage

What class of fires involves ordinary combustibles such as wood, paper, cloth, and rubber?

Class A

Which class of fires involves flammable liquids such as gasoline, oil, grease, tar, and oil-based paints?

Class B

What is the standard shape used to identify a portable fire extinguisher used for flammable liquid fires?

Red square Signup and view all the answers

Which extinguishing agent is combined with alkali metal salt in a loaded-stream fire extinguisher to combat freezing of the agent?

Water Signup and view all the answers

Which extinguishing agent is used for Class B and C fires and is not subject to freezing?

Dry chemical Signup and view all the answers

What class of foam concentrate extinguisher discharges a foam solution that floats across the surface and separates fuel from oxygen?

Class B foam Signup and view all the answers

Which agent is formulated from finely ground sodium chloride and forms a solid crust over the material on fire?

Dry powder Signup and view all the answers

What is the acronym for activating a fire extinguisher to apply the extinguishing agent in four simple steps?

PASS Signup and view all the answers

Which type of fire extinguisher requires hydrostatic testing every 12 years?

Halogenated agent Signup and view all the answers

A Class A fire extinguisher with a numerical rating of 2 contains ______ of water.

2.5 gal (9.5 L) Signup and view all the answers

A Class B foam extinguisher is effective on all of the following fuels except one.

Cooking oil Signup and view all the answers

A Class C agent must:

not conduct electricity 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 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 the application of a multipurpose dry chemical agent to a Class K fire is:

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

According to NFPA standards, the maximum floor area that can be protected by each extinguisher is specified according to:

occupancy type Signup and view all the answers

All fire extinguishers are classified according to:

the classes of fire on which they are safe and 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.

halon Signup and view all the answers

Class B foam fire extinguishers are also effective on:

Class A fires Signup and view all the answers

Class D agents work primarily by:

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

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

arranged so that a fire is unlikely to spread 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 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

In general, the maximum discharge range of a CO2 extinguisher is:

8 ft (2.5 m) 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 production and use of Halon extinguishing agents is limited because they are:

harmful to the earth's ozone layer Signup and view all the answers

The weight of carbon dioxide is about ___________ times the weight of air.

1.5 Signup and view all the answers

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

Sufficient extinguishing power for 40 ft² (4.7 m²) of burning fuel 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 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 primary extinguishing mechanism of halogenated agents?

Disrupting the molecular 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 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 rated for use on Class A fires?

Ammonium phosphate Signup and view all the answers

Which class of fire includes combustible cooking oils and fats?

K Signup and view all the answers

Which class of fire includes combustible metals?

D 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 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 a 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 approved for use in a Class K system?

Wet chemical 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 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 is a common dry chemical extinguishing agent?

Potassium chloride Signup and view all the answers

Which is a disadvantage of CO2 extinguishers?

Short discharge range Signup and view all the answers

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

Air 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 part of a fire extinguisher contains the extinguishing agent?

Cylinder 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 the numerical rating of a Class K extinguisher 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

Which test is required to measure the ability of an extinguisher cylinder to withstand steady internal pressure?

Hydrostatic Signup and view all the answers

Study Notes

Fire Extinguisher Basics

Portable fire extinguishers are primarily designed to function during the incipient stage of fire growth.
All extinguishers are classified according to the types of fires they can effectively combat.

Fire Classes

Class A fires involve ordinary combustibles, including wood, paper, cloth, and rubber.
Class B fires involve flammable liquids such as gasoline, oil, grease, tar, and oil-based paints.
Class C fires consist of energized electrical equipment, which must not conduct electricity.
Class K fires include combustible cooking oils and fats, while Class D fires involve combustible metals.

Extinguishing Agents

Common Class A extinguishing agents include water and ammonium phosphate.
Dry chemical agents are effective for Class B and C fires and typically do not freeze.
Halogenated agents, such as bromochlorodifluoromethane (halon), disrupt molecular chain reactions to extinguish fires.
CO2 extinguishers leave no residue upon discharge and are suitable for sensitive electronic equipment.
Wet chemical agents are specifically approved for Class K systems.

Fire Extinguisher Usage

The acronym PASS stands for Pull, Aim, Squeeze, and Sweep, representing the steps for operating a fire extinguisher.
A loaded stream extinguisher is designed to resist freezing, typically using water as an extinguishing agent.
To combat cooking oil fires, using the proper Class K agents is crucial as cooking oil is ineffective against Class B foam extinguishers.

Extinguisher Maintenance

Halogenated agent extinguishers require hydrostatic testing every 12 years, while dry chemical extinguishers with stainless-steel shells need testing every 5 years.
Extinguishers should be serviced and recharged after any discharge to ensure readiness.
The maximum discharge range of a CO2 extinguisher is approximately 8 feet (2.5 m).

Important Considerations

Situations best suited for portable extinguishers include small fires such as those in wastebaskets.
The effectiveness of a Class A extinguisher with a numerical rating of 2 corresponds to 2.5 gallons (9.5 L) of water.
Each Class B extinguisher’s rating reflects its extinguishing power over a specified area, e.g., a rating of 40 means it can handle 40 ft² (4.7 m²) of burning fuel.

Fire Safety Standards

According to NFPA standards, extinguisher placement and the maximum floor area protected are dependent on occupancy type.
The placement of extinguishers does not necessarily correlate with the occupancy use category.
Class D extinguishing agents must be specifically matched to the fuel type of the fire for effective suppression.

Other Relevant Facts

Dry powder agents form a solid crust over burning materials, effectively suffocating the fire.
The weight of carbon dioxide is about 1.5 times that of air, which helps in suppression by displacing oxygen.
A water-soluble flammable liquid is referred to as a polar solvent, which poses particular hazards.

Summary of Extinguisher Components

The cylinder of a fire extinguisher contains the extinguishing agent, while air is used to pressurize a stored-pressure water extinguisher.
The extinguishing action provided by foam blankets involves cutting off the oxygen supply from the burning liquid's surface.

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Test your knowledge with these flashcards on fire fighting concepts from Chapter 7. Focus on different classes of fires, their characteristics, and effective extinguishing methods. Ideal for students and professionals looking to reinforce their understanding of fire safety.