FE Fire Extinguisher Types & Classification 2 — Questions and Answers
Question 1: Which extinguisher class is specifically designed for fires involving energized electrical equipment?
- Class A
- Class B
- Class C (Correct answer)
- Class D
Correct answer: Class C
Class C extinguishers are rated for energized electrical equipment fires and use non-conductive agents.
Question 2: A halogenated (clean agent) extinguisher is MOST appropriate for which environment?
- Outdoor lumber storage
- Server room with sensitive electronics (Correct answer)
- Commercial kitchen fryer
- Metal grinding workshop
Correct answer: Server room with sensitive electronics
Clean agents leave no residue and are safe for sensitive electronics, making them ideal for server rooms.
Question 3: What does the numerical rating preceding a Class A designation (e.g., 2-A) indicate?
- The agent's chemical concentration
- The extinguisher's weight in pounds
- The relative firefighting capacity compared to water (Correct answer)
- The maximum distance from which it can be discharged
Correct answer: The relative firefighting capacity compared to water
The number before Class A represents the relative firefighting capacity, with each unit roughly equivalent to 1.25 gallons of water.
Question 4: Which type of extinguisher agent is classified as a 'wet chemical' and is primarily used on Class K fires?
- Potassium acetate solution (Correct answer)
- Monoammonium phosphate powder
- Carbon dioxide gas
- Halon 1211
Correct answer: Potassium acetate solution
Potassium acetate (and similar potassium-based solutions) form a wet chemical agent that saponifies cooking oils for Class K fires.
Question 5: A stored-pressure dry chemical extinguisher differs from a cartridge-operated unit primarily in that it:
- Uses a different chemical agent
- Has the expellant gas stored separately in a cartridge
- Contains both agent and expellant gas in a single cylinder (Correct answer)
- Requires no pressure gauge
Correct answer: Contains both agent and expellant gas in a single cylinder
In stored-pressure units, the propellant gas and dry chemical agent share the same cylinder, unlike cartridge-operated units.
Question 6: Which extinguisher type leaves a white powdery residue that can damage food preparation surfaces and equipment?
- Carbon dioxide (CO2)
- Clean agent (halogenated)
- Dry chemical (ABC powder) (Correct answer)
- Wet chemical
Correct answer: Dry chemical (ABC powder)
Dry chemical extinguishers leave a corrosive, powdery residue that can contaminate food and damage sensitive surfaces.
Question 7: What UL classification would you expect on an extinguisher rated for both ordinary combustibles and flammable liquids but NOT electrical fires?
- A:C
- A:B (Correct answer)
- B:C
- A:B:C
Correct answer: A:B
An A:B rating covers ordinary combustibles (Class A) and flammable liquids (Class B) but excludes energized electrical equipment (Class C).
FE Fire Extinguisher Types & Classification 2
Which extinguisher class is specifically designed for fires involving energized electrical equipment?