Questions and Answers
What are portable fire extinguishers classified by?
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?
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What type of metals does Class D fire involve?
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What is Class K fire?
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What are the types of fire extinguishing methods?
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What is the purpose of Aqueous Film Forming Foam (AFFF)?
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What do Clean Agent Extinguishers replace?
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What is the primary use of Carbon Dioxide (CO2) extinguishers?
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What is the difference between Dry Chemical and Dry Powder extinguishers?
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What is the system used for identifying portable fire extinguishers?
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To use a portable fire extinguisher, first you ______.
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The inspection of portable fire extinguishers should occur ______.
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How are Class A ratings determined?
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How is the Class B rating determined?
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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.