FCTC Fire Behavior and Service Terminology 4 — Questions and Answers
Question 1: What term describes the minimum temperature at which a liquid produces enough vapor to form an ignitable mixture near its surface?
- Ignition temperature
- Flash point (Correct answer)
- Fire point
- Boiling point
Correct answer: Flash point
Flash point is the lowest temperature at which a liquid gives off sufficient vapor to form an ignitable mixture with air near the surface.
Question 2: Which phenomenon occurs when a fire in a compartment suddenly and simultaneously ignites all exposed combustible surfaces?
- Backdraft
- Flashover (Correct answer)
- Smoke explosion
- Rollover
Correct answer: Flashover
Flashover is the near-simultaneous ignition of all combustible materials in an enclosed area when they reach their ignition temperature.
Question 3: In fire service terminology, what does the acronym 'BLEVE' stand for?
- Burning Liquid Explosive Vapor Event
- Boiling Liquid Expanding Vapor Explosion (Correct answer)
- Bulk Liquid Emergency Venting Escape
- Burning Liquid Energy Vent Explosion
Correct answer: Boiling Liquid Expanding Vapor Explosion
BLEVE stands for Boiling Liquid Expanding Vapor Explosion, which occurs when a pressurized container holding liquid fails catastrophically.
Question 4: What is the term for the layer of hot gases and smoke that accumulates at the ceiling level of a burning room?
- Thermal column
- Smoke layer (Correct answer)
- Heat stratum
- Convective plume
Correct answer: Smoke layer
The smoke layer or hot gas layer forms at ceiling level as buoyant combustion products rise and collect, creating a stratified zone.
Question 5: Which class of fire involves energized electrical equipment?
- Class A
- Class B
- Class C (Correct answer)
- Class D
Correct answer: Class C
Class C fires involve energized electrical equipment, and water-based extinguishers should not be used due to electrocution risk.
Question 6: What fire behavior term describes the visible flames rolling along the ceiling ahead of the main fire front?
- Flashover
- Rollover (Correct answer)
- Backdraft
- Thermal layering
Correct answer: Rollover
Rollover, also called flameover, occurs when unburned gases ignite and flames roll along the ceiling ahead of the main fire body.
Question 7: What is the term for the rapid, explosive burning of accumulated hot gases when oxygen is suddenly introduced into an oxygen-depleted burning compartment?
- Flashover
- Rollover
- Backdraft (Correct answer)
- Fire point
Correct answer: Backdraft
Backdraft is a dangerous explosion caused by the sudden introduction of air into a superheated, oxygen-deficient compartment filled with combustible gases.
FCTC Fire Behavior and Service Terminology 4
What term describes the minimum temperature at which a liquid produces enough vapor to form an ignitable mixture near its surface?