IFSTA ESSENTIALS OF FIRE FIGHTING
- CHAPTER 7: PORTABLE FIRE
EXTINGUISHERS QUESTIONS WITH
VERIFIED ANSWERS 2026/2027
1. Which class of fire involves energized electrical equipment where the electrical
nonconductivity of the extinguishing agent is of importance?
A. Class A
B. Class C
C. Class B
D. Class D
Answer: B
Conceptual Explanation: Class C fires involve energized electrical equipment. If the
electricity is disconnected, the fire can often be treated as a Class A or B fire.
2. What is the primary mechanism by which carbon dioxide (CO2) extinguishes a fire?
A. Oxygen exclusion (smothering)
B. Chemical chain reaction inhibition
,C. Cooling the fuel below its ignition temperature
D. Saponification
Answer: A
Conceptual Explanation: CO2 extinguishes fire primarily by displacing oxygen, thereby
smothering the fire.
3. Which extinguishing agent is specifically designed for use on Class K fires involving
vegetable oils and fats?
A. Wet Chemical
B. Aqueous Film Forming Foam (AFFF)
C. Dry Powder
D. Multi-purpose Dry Chemical
Answer: A
Conceptual Explanation: Wet chemical agents are designed for Class K fires and work
through saponification, creating a soapy foam layer that smothers the fire.
4. According to NFPA 10, how often should portable fire extinguishers be inspected?
A. Weekly
B. Annually
C. Every six months
, D. Monthly
Answer: D
Conceptual Explanation: NFPA 10 requires at least a monthly inspection to ensure the
extinguisher is in its designated place and hasn’t been tampered with.
5. A Class B rating of ‘20-B’ indicates that a non-expert operator should be able to extinguish
how much area of a deep-layer flammable liquid fire?
A. 10 square feet
B. 20 square feet
C. 40 square feet
D. 5 square feet
Answer: B
Conceptual Explanation: The numerical rating for Class B extinguishers reflects the
approximate square footage of a deep-layer flammable liquid fire that an untrained person
can extinguish.
6. Which process involves the alkaline agent reacting with fats to create a soapy film that
excludes oxygen?
A. Sublimation
B. Polymerization
C. Saponification
- CHAPTER 7: PORTABLE FIRE
EXTINGUISHERS QUESTIONS WITH
VERIFIED ANSWERS 2026/2027
1. Which class of fire involves energized electrical equipment where the electrical
nonconductivity of the extinguishing agent is of importance?
A. Class A
B. Class C
C. Class B
D. Class D
Answer: B
Conceptual Explanation: Class C fires involve energized electrical equipment. If the
electricity is disconnected, the fire can often be treated as a Class A or B fire.
2. What is the primary mechanism by which carbon dioxide (CO2) extinguishes a fire?
A. Oxygen exclusion (smothering)
B. Chemical chain reaction inhibition
,C. Cooling the fuel below its ignition temperature
D. Saponification
Answer: A
Conceptual Explanation: CO2 extinguishes fire primarily by displacing oxygen, thereby
smothering the fire.
3. Which extinguishing agent is specifically designed for use on Class K fires involving
vegetable oils and fats?
A. Wet Chemical
B. Aqueous Film Forming Foam (AFFF)
C. Dry Powder
D. Multi-purpose Dry Chemical
Answer: A
Conceptual Explanation: Wet chemical agents are designed for Class K fires and work
through saponification, creating a soapy foam layer that smothers the fire.
4. According to NFPA 10, how often should portable fire extinguishers be inspected?
A. Weekly
B. Annually
C. Every six months
, D. Monthly
Answer: D
Conceptual Explanation: NFPA 10 requires at least a monthly inspection to ensure the
extinguisher is in its designated place and hasn’t been tampered with.
5. A Class B rating of ‘20-B’ indicates that a non-expert operator should be able to extinguish
how much area of a deep-layer flammable liquid fire?
A. 10 square feet
B. 20 square feet
C. 40 square feet
D. 5 square feet
Answer: B
Conceptual Explanation: The numerical rating for Class B extinguishers reflects the
approximate square footage of a deep-layer flammable liquid fire that an untrained person
can extinguish.
6. Which process involves the alkaline agent reacting with fats to create a soapy film that
excludes oxygen?
A. Sublimation
B. Polymerization
C. Saponification
