Firefighting Practice Questions

1. Why is water the preferred agent for a Class A fire?

• A.It smothers the oxygen instantly
• B.It is non-conductive
• C.It chemically breaks the fuel down
• D.Its cooling effect removes heat from the fire✓

Why: Water's great heat-absorbing capacity cools burning solids below their ignition temperature, attacking the heat side of the fire triangle. It is ideal for Class A combustibles but must not be used on live electrical (Class C) or most flammable-liquid (Class B) fires.

2. A fixed CO2 flooding system extinguishes a fire in an engine room primarily by:

• A.Displacing oxygen and smothering the fire✓
• B.Cooling the space with cold gas
• C.Coating surfaces with foam
• D.Absorbing the smoke

Why: CO2 works mainly by displacing oxygen and smothering the fire. Because it makes the space immediately lethal to anyone inside, the crew must be evacuated and accounted for, and the space sealed, before the system is released.

3. Foam is especially effective on a Class B (flammable liquid) fire because it:

• A.Conducts electricity away from the fire
• B.Cools the metal structure only
• C.Forms a blanket that separates the fuel from oxygen and suppresses vapors✓
• D.Adds oxygen to complete combustion

Why: Foam floats on the liquid surface, smothering the fire by sealing the fuel away from oxygen and suppressing flammable vapors, while its water content cools. It is the agent of choice for spill and tank fires but must not be used on live electrical equipment.

4. When advancing a fire hose toward a fire, the team should:

• A.Stand fully upright for a better view
• B.Run directly into the smoke
• C.Spray water on the smoke above their heads
• D.Stay low, below the heat and smoke layer, and approach from upwind✓

Why: Heat and toxic smoke rise, so staying low keeps the team in cooler, more breathable air. Approaching from upwind (or up-current) keeps smoke and heat blowing away from the attack team. A wide fog pattern can also shield advancing firefighters.

5. The acronym for operating most portable fire extinguishers, 'PASS,' stands for:

• A.Push, Aim, Spray, Stop
• B.Pull the pin, Aim at the base, Squeeze the handle, Sweep side to side✓
• C.Prepare, Alert, Suppress, Secure
• D.Point, Activate, Soak, Stand by

Why: PASS = Pull the pin, Aim at the base of the fire, Squeeze the handle, and Sweep side to side. Aiming at the base attacks the burning fuel rather than the flames, and sweeping covers the whole burning area.