FE Fire Extinguisher Types & Classification 1 — Questions and Answers

Question 1: Which of the following is the correct classification for a fire extinguisher used on electrical fires?

Class A
Class B
Class C (Correct answer)
Class D

Correct answer: Class C

Class C fires involve energized electrical equipment. Class C fire extinguishers are specifically designed to be non-conductive, meaning they will not transmit electricity. This makes them safe and effective for extinguishing electrical fires without posing a risk of electrocution to the user.

Question 2: What type of fire extinguisher is most suitable for fires involving flammable liquids?

Class A
Class B (Correct answer)
Class C
Class D

Correct answer: Class B

Class B fires involve flammable liquids such as gasoline, oil, or grease. Class B fire extinguishers are formulated to smother these types of fires by cutting off the oxygen supply or inhibiting the chemical chain reaction. This prevents the fire from reigniting and effectively extinguishes it.

Question 3: Which of the following extinguishing agents is commonly used in Class D fire extinguishers?

Water
Foam
Dry Powder (Correct answer)
CO2

Correct answer: Dry Powder

Class D fires involve combustible metals like magnesium, titanium, or sodium, which burn at extremely high temperatures. These fires require specialized dry powder agents that work by smothering the fire and absorbing heat. Using water or other common extinguishing agents can react violently with burning metals, making the fire worse.

Question 4: What type of fire extinguisher is best suited for a wood or paper fire?

Class A (Correct answer)
Class B
Class C
Class D

Correct answer: Class A

Class A fires involve ordinary combustible materials such as wood, paper, cloth, and trash. Class A fire extinguishers typically use water or water-based agents to cool the fuel below its ignition temperature. This method effectively removes the heat element from the fire triangle, extinguishing the blaze.

Question 5: Which of the following best describes the use of a CO2 fire extinguisher?

For cooking fires
For electrical and liquid fires (Correct answer)
For wood and paper fires
For metal fires

Correct answer: For electrical and liquid fires

CO2 (carbon dioxide) fire extinguishers are highly effective on Class B fires (flammable liquids) and Class C fires (electrical equipment). They work by displacing oxygen around the fire and cooling the fuel, interrupting the combustion process. Their non-conductive nature makes them safe for use on electrical fires without damaging sensitive equipment.

Question 6: Which fire extinguisher type is suitable for a fire involving combustible metals?

Class A
Class B
Class C
Class D (Correct answer)

Correct answer: Class D

Class D fires are unique to combustible metals, such as magnesium, titanium, or sodium. These fires require specialized Class D extinguishers that contain specific dry powder agents. These agents are designed to smother and cool the burning metal without causing a dangerous reaction, which can occur with other extinguishing agents.

Question 7: What is the primary advantage of using a Class K fire extinguisher?

They are ideal for electrical fires.
They are effective on grease fires (Correct answer)
They are used for wood and paper fires.
They are suitable for metal fires.

Correct answer: They are effective on grease fires

Class K fire extinguishers are specifically designed for fires involving cooking oils and fats (grease fires) commonly found in commercial kitchens. They use a wet chemical agent that creates a foam blanket, cooling the fuel and preventing reignition. This makes them highly effective and safe for these specific types of fires.

Question 8: What does a fire extinguisher's pressure gauge indicate?

The weight of the fire extinguisher
The amount of fire retardant left
The pressure level of the extinguisher (Correct answer)
The time needed to discharge the extinguisher

Correct answer: The pressure level of the extinguisher

The pressure gauge on a fire extinguisher indicates the internal pressure of the propellant gas, which is crucial for expelling the extinguishing agent effectively. A gauge needle pointing to the green zone signifies that the extinguisher is properly charged and ready for immediate use. Regular checks of this gauge are vital for ensuring operational readiness.

Question 9: Which fire extinguisher type should never be used on a liquid fire?

Class A
Class B
Class C
Class A (water-based) (Correct answer)

Correct answer: Class A (water-based)

Class A (water-based) fire extinguishers are designed for ordinary combustibles like wood and paper. Using water on a Class B (liquid) fire can be extremely dangerous as it can spread the flammable liquid, making the fire larger and more difficult to control. Water can also cause a violent reaction if the liquid is superheated.

FE Fire Extinguisher Types & Classification 1

Which of the following is the correct classification for a fire extinguisher used on electrical fires?