USCG Fire Fighting Exam 2026 |
Questions & Answers with Detailed
Explanations | Comprehensive United
States Coast Guard Training
fire triangle
Answer: fuel, oxygen, heat (removal of one extinguishes fire)
fire tetrahedron
Answer: Heat, Fuel, Oxygen, Chemical Chain Reaction
explosive limits
Answer: % of gas mixed with air above/below where ignition will NOT take place:
lower = mix is too lean to burn, upper = mix is too rich to burn
thermal layering
Answer: gases forming in layers according to temperature
solids
Answer: definite rigid shape and volume, motion is restricted to vibrations
liquids
Answer: definite volume, indefinite shape, less dense than solid but denser than
gases
gases
Answer: no definite shape or volume, expand quickly in increased temperatures
boiling point
Answer: the temperature at which the vapor pressure of a liquid is just equal to
the external pressure on the liquid
flash point
Answer: the minimum temperature at which a substance when mixed with air will
flash but not sustain combustion
,freezing point
Answer: the temperature at which a liquid changes to a solid
sublimation
Answer: the process in which a solid changes directly into a gas
vapor density
Answer: weight of a gas compared to the weight of an equivalent amount of dry
air
specific gravity
Answer: ratio of the weight of a liquid to the weight of an equal volume of fresh
water
Class A fire
Answer: ordinary combustibles (wood, paper, cloth, plastics) – extinguish with
water or Class A extinguisher
Class B fire
Answer: flammable liquids (oil, gasoline, paint, grease) – extinguish by smothering
(foam, CO₂, dry chemical)
Class C fire
Answer: energized electrical equipment – extinguish with non-conductive agent
(CO₂, dry chemical)
Class D fire
Answer: combustible metals (magnesium, titanium, sodium) – extinguish with
specialized dry powder
Class K fire
Answer: cooking oils and fats (kitchen fires) – extinguish with wet chemical
extinguisher
the most common cause of shipboard fires
Answer: improper disposal of smoking materials
primary hazard of a class B fire
Answer: rapid spread, vapor explosion, reignition
, primary hazard of a class C fire
Answer: electric shock, arcing, fire spreading through wiring
the most effective extinguishing agent for class A fires
Answer: water (cooling)
smothering effect
Answer: removing oxygen from the fire by covering with foam, CO₂, or a fire
blanket
cooling effect
Answer: removing heat from the fire by applying water or other cooling agents
chain reaction breaking
Answer: interrupting the chemical reaction using dry chemical or
halon-replacement agents
minimum oxygen concentration required to sustain combustion
Answer: approximately 15% – 16% by volume
portable CO₂ extinguisher discharge range
Answer: approximately 3 to 8 feet depending on size
dry chemical extinguisher advantage
Answer: fast knockdown, effective on B and C fires, leaves residue
dry chemical extinguisher disadvantage
Answer: messy, limited visibility, potential damage to electronics
CO₂ extinguisher advantage
Answer: clean, no residue, effective on B and C fires, does not damage equipment
CO₂ extinguisher disadvantage
Answer: limited range, short duration, asphyxiation hazard in enclosed spaces
foam extinguisher advantage
Answer: forms a blanket to smother, cools, effective on A and B fires
wet chemical extinguisher primary use
Answer: class K fires (cooking oils and fats)
Questions & Answers with Detailed
Explanations | Comprehensive United
States Coast Guard Training
fire triangle
Answer: fuel, oxygen, heat (removal of one extinguishes fire)
fire tetrahedron
Answer: Heat, Fuel, Oxygen, Chemical Chain Reaction
explosive limits
Answer: % of gas mixed with air above/below where ignition will NOT take place:
lower = mix is too lean to burn, upper = mix is too rich to burn
thermal layering
Answer: gases forming in layers according to temperature
solids
Answer: definite rigid shape and volume, motion is restricted to vibrations
liquids
Answer: definite volume, indefinite shape, less dense than solid but denser than
gases
gases
Answer: no definite shape or volume, expand quickly in increased temperatures
boiling point
Answer: the temperature at which the vapor pressure of a liquid is just equal to
the external pressure on the liquid
flash point
Answer: the minimum temperature at which a substance when mixed with air will
flash but not sustain combustion
,freezing point
Answer: the temperature at which a liquid changes to a solid
sublimation
Answer: the process in which a solid changes directly into a gas
vapor density
Answer: weight of a gas compared to the weight of an equivalent amount of dry
air
specific gravity
Answer: ratio of the weight of a liquid to the weight of an equal volume of fresh
water
Class A fire
Answer: ordinary combustibles (wood, paper, cloth, plastics) – extinguish with
water or Class A extinguisher
Class B fire
Answer: flammable liquids (oil, gasoline, paint, grease) – extinguish by smothering
(foam, CO₂, dry chemical)
Class C fire
Answer: energized electrical equipment – extinguish with non-conductive agent
(CO₂, dry chemical)
Class D fire
Answer: combustible metals (magnesium, titanium, sodium) – extinguish with
specialized dry powder
Class K fire
Answer: cooking oils and fats (kitchen fires) – extinguish with wet chemical
extinguisher
the most common cause of shipboard fires
Answer: improper disposal of smoking materials
primary hazard of a class B fire
Answer: rapid spread, vapor explosion, reignition
, primary hazard of a class C fire
Answer: electric shock, arcing, fire spreading through wiring
the most effective extinguishing agent for class A fires
Answer: water (cooling)
smothering effect
Answer: removing oxygen from the fire by covering with foam, CO₂, or a fire
blanket
cooling effect
Answer: removing heat from the fire by applying water or other cooling agents
chain reaction breaking
Answer: interrupting the chemical reaction using dry chemical or
halon-replacement agents
minimum oxygen concentration required to sustain combustion
Answer: approximately 15% – 16% by volume
portable CO₂ extinguisher discharge range
Answer: approximately 3 to 8 feet depending on size
dry chemical extinguisher advantage
Answer: fast knockdown, effective on B and C fires, leaves residue
dry chemical extinguisher disadvantage
Answer: messy, limited visibility, potential damage to electronics
CO₂ extinguisher advantage
Answer: clean, no residue, effective on B and C fires, does not damage equipment
CO₂ extinguisher disadvantage
Answer: limited range, short duration, asphyxiation hazard in enclosed spaces
foam extinguisher advantage
Answer: forms a blanket to smother, cools, effective on A and B fires
wet chemical extinguisher primary use
Answer: class K fires (cooking oils and fats)
