Fire Safety Chapter 7: Extinguishers

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Questions and Answers

What are portable fire extinguishers classified by?

The color of the label

The brand of the extinguisher

The type of fire they extinguish (correct)

The size of the extinguisher

What is Class A fire?

Ordinary combustibles such as textiles, paper, plastics, rubber, and wood.

What does Class B fire involve?

Flammable and combustible liquids and gases such as alcohol, gasoline, oils, and petroleum gas.

What is special about Class C fire extinguishers?

They involve energized electrical equipment and water cannot be used. Signup and view all the answers

What type of metals does Class D fire involve?

Combustible metals and alloys such as lithium, magnesium, potassium, and sodium. Signup and view all the answers

What is Class K fire?

Involves combustible cooking oils such as vegetable or animal fats. Signup and view all the answers

What are the types of fire extinguishing methods?

Cooling Signup and view all the answers

What is the purpose of Aqueous Film Forming Foam (AFFF)?

To combat Class B fires and suppress vapors from liquid fuel spills. Signup and view all the answers

What do Clean Agent Extinguishers replace?

Halon. Signup and view all the answers

What is the primary use of Carbon Dioxide (CO2) extinguishers?

To extinguish Class B and C fires. Signup and view all the answers

What is the difference between Dry Chemical and Dry Powder extinguishers?

Dry Chemical extinguishers are commonly used for Classes A, B, and C, while Dry Powder extinguishers are specifically for Class D fires. Signup and view all the answers

What is the system used for identifying portable fire extinguishers?

Geometric shapes of specific color with the class letter or pictographs. Signup and view all the answers

To use a portable fire extinguisher, first you ______.

Pull the pin Signup and view all the answers

The inspection of portable fire extinguishers should occur ______.

once a month Signup and view all the answers

How are Class A ratings determined?

From 1-A through 40-A based on the amount of extinguishing agent and the duration and range of the discharge. Signup and view all the answers

How is the Class B rating determined?

Rated from 1-B to 640-B based on the approximate square footage of a flammable liquid fire it can extinguish with one full extinguisher. Signup and view all the answers

Study Notes

Classification of Portable Fire Extinguishers

Five classes: A, B, C, D, and K correspond to different fire types.
Each class targets specific materials for effective extinguishment.

Class A

Designed for ordinary combustibles: textiles, paper, plastic, rubber, and wood.
Effective extinguishing agents include water and dry chemicals.

Class B

Targets flammable liquids and gases like alcohol, gasoline, oils, and petroleum gas.

Class C

Specifically for energized electrical equipment.
Water is not suitable; extinguishers will not conduct electricity.

Class D

Involves combustible metals: lithium, magnesium, potassium, and sodium.
Best extinguished using dry powder extinguishers.

Class K

Focuses on combustible cooking oils: vegetable and animal fats.
Extinguishment primarily in kitchens using wet chemical systems.

Types of Fire Extinguishers

Smothering: Eliminates oxygen from the fire.
Cooling: Lowers burning material temperature.
Chain breaking: Disrupts chemical reactions in the fire.
Saponification: Creates a soapy foam that excludes oxygen.

Saponification

Occurs when alkaline-based chemicals mix with cooking oils, forming a soapy foam.

Aqueous Film Forming Foam (AFFF)

Designed for Class B fires.
Useful for controlling small liquid fuel spills.

Clean Agent Extinguishers

Replace Halon; non-conductive and safe for Class C fires.
Evaporates quickly, leaving no residue.

Carbon Dioxide (CO2) Extinguisher

Most effective for Class B and C fires.
Dispersed gas, limited reach, and can be affected by wind.

Dry Chemical Extinguisher

Suitable for Class A, B, and C fires.
Available in regular B or C rated and multipurpose A, B, C rated types.

Dry Powder Extinguisher

Specifically used for controlling Class D fires involving combustible metals.

Identifying Portable Fire Extinguishers

Uses geometric shapes in specific colors with class letters or pictographs for selection.

Using Portable Fire Extinguishers

Follow the PASS technique:
- Pull the pin,
- Aim at the base of the fire,
- Squeeze handles,
- Sweep nozzle back and forth.

Inspecting and Maintaining Portable Fire Extinguishers

Monthly inspections ensure accessibility and operability.
Hydrostatic testing recommended every 6 or 12 years, depending on the extinguisher.

Class A Ratings

Rated from 1-A to 40-A; based on extinguishing agent amount, duration, and discharge range.

Class B Ratings

Rated from 1-B to 640-B; indicates the flammable liquid area a single extinguisher can manage.

Class C Ratings

Matches Class A or B fires involving energized equipment; confirms non-conductivity of the agent.

Class D Ratings

Variability based on the specific metal; factors include reaction with the extinguishing agent and toxicity considerations.

Class K Ratings

Must meet specific extinguishing requirements for cooking oils; designed for higher temperature fires.

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Description

Explore the classification of portable fire extinguishers in Chapter 7. This quiz covers the different classes of extinguishers, including Class A, B, C, D, and K. Learn how each extinguisher is designed to tackle specific types of fires effectively.