IFSTA CHAPTER 18: FOAM FIRE
FIGHTING, LIQUID FIRES, AND GAS
FIRES (LATEST 2026/ 2027 UPDATE)
QUESTIONS AND 100% CORRECT
VERIFIED ANSWERS| GRADE A+
1. Which process involves the cooling of a liquid fuel to prevent the formation of ignitable
vapors?
A. Cooling
B. Separating
C. Smothering
D. Penetrating
Answer: A
Conceptual Explanation: Cooling is the reduction of the temperature of a fuel and
adjacent surfaces to a point where it no longer produces flammable vapors.
2. What is the expansion ratio for high-expansion foam used in confined spaces?
A. 200:1 to 1000:1
B. 20:1 to 200:1
C. 2:1 to 20:1
,D. 1000:1 to 2000:1
Answer: A
Conceptual Explanation: High-expansion foam is defined as having an expansion ratio
from 200:1 up to 1000:1.
3. Which foam application method is most appropriate for a large open pool of hydrocarbon
fuel on the ground?
A. Roll-on method
B. Sub-surface injection
C. Rain-down method
D. Bank-down method
Answer: A
Conceptual Explanation: The roll-on method is used by directing the foam stream onto
the ground in front of the spill, allowing the foam to roll across the surface of the fuel.
4. What occurs when water is trapped under the surface of a burning viscous oil and turns to
steam?
A. Froth-over
B. Slop-over
C. Boil-over
D. Surface tension release
, Answer: C
Conceptual Explanation: Boil-over is the spontaneous violent eruption of hot oil when
water at the bottom of a tank is heated to steam and expands.
5. Which type of foam concentrate is specifically designed to resist breakdown when applied
to polar solvents?
A. Fluoroprotein foam (FP)
B. Class A foam
C. Aqueous film forming foam (AFFF)
D. Alcohol-resistant AFFF (AR-AFFF)
Answer: D
Conceptual Explanation: Alcohol-resistant AFFF forms a membrane over polar solvents
like alcohol or ketones to prevent the solvent from destroying the foam blanket.
6. The Venturi principle is utilized in which type of foam proportioning equipment?
A. Balanced pressure proportioner
B. Batch mixing tank
C. In-line foam eductor
D. Apparatus tank
Answer: C
FIGHTING, LIQUID FIRES, AND GAS
FIRES (LATEST 2026/ 2027 UPDATE)
QUESTIONS AND 100% CORRECT
VERIFIED ANSWERS| GRADE A+
1. Which process involves the cooling of a liquid fuel to prevent the formation of ignitable
vapors?
A. Cooling
B. Separating
C. Smothering
D. Penetrating
Answer: A
Conceptual Explanation: Cooling is the reduction of the temperature of a fuel and
adjacent surfaces to a point where it no longer produces flammable vapors.
2. What is the expansion ratio for high-expansion foam used in confined spaces?
A. 200:1 to 1000:1
B. 20:1 to 200:1
C. 2:1 to 20:1
,D. 1000:1 to 2000:1
Answer: A
Conceptual Explanation: High-expansion foam is defined as having an expansion ratio
from 200:1 up to 1000:1.
3. Which foam application method is most appropriate for a large open pool of hydrocarbon
fuel on the ground?
A. Roll-on method
B. Sub-surface injection
C. Rain-down method
D. Bank-down method
Answer: A
Conceptual Explanation: The roll-on method is used by directing the foam stream onto
the ground in front of the spill, allowing the foam to roll across the surface of the fuel.
4. What occurs when water is trapped under the surface of a burning viscous oil and turns to
steam?
A. Froth-over
B. Slop-over
C. Boil-over
D. Surface tension release
, Answer: C
Conceptual Explanation: Boil-over is the spontaneous violent eruption of hot oil when
water at the bottom of a tank is heated to steam and expands.
5. Which type of foam concentrate is specifically designed to resist breakdown when applied
to polar solvents?
A. Fluoroprotein foam (FP)
B. Class A foam
C. Aqueous film forming foam (AFFF)
D. Alcohol-resistant AFFF (AR-AFFF)
Answer: D
Conceptual Explanation: Alcohol-resistant AFFF forms a membrane over polar solvents
like alcohol or ketones to prevent the solvent from destroying the foam blanket.
6. The Venturi principle is utilized in which type of foam proportioning equipment?
A. Balanced pressure proportioner
B. Batch mixing tank
C. In-line foam eductor
D. Apparatus tank
Answer: C
