Firefighter Knowledge and Safety: Behavior, PPE, SCBA, Tools, Hose, Water, Ventilation, Rescue
Domain 3 tests fire behavior, PPE and SCBA, tools, ladders, hose, water supply, ventilation, and rescue. The exam favors safe sequence and cause–effect over trivia.
Fire behavior
- The fire tetrahedron: fuel, oxygen, heat, and chemical chain reaction. Remove one side and combustion stops.
- Stages: incipient, growth, fully developed, decay. Flashover is the transition from growth to full room involvement; backdraft is a smoke explosion when oxygen enters a hot, fuel-rich space.
- Read smoke: velocity, density, and color indicate heat and location.
PPE, SCBA, and safety
- Don all PPE before entry; check the SCBA facepiece seal and cylinder pressure.
- Know your low-air alarm and exit point before you enter. Never work past your exit threshold.
- Use the buddy system and maintain radio contact.
Tools, ladders, hose, and water
- Halligan and flathead axe are forcible-entry tools; pike poles pull ceilings.
- Ground ladders: place at about a 75-degree angle, secure the base, and extend above the sill or roof as taught.
- Attack lines move water at the nozzle; supply lines feed the pump. Establish water supply before deep interior work.
Worked example
Nozzle pressure is 100 psi; 200 ft of hose has 35 psi friction loss per 100 ft; the nozzle is 10 ft above the pump. Friction loss = 2 × 35 = 70 psi. Elevation = 10 ft × 0.5 psi/ft = 5 psi. Pump pressure = 100 + 70 + 5 = 175 psi.
Traps
- Confusing flashover with backdraft.
- Forgetting elevation or multiplying friction loss for only one 100-ft section.
- Charging a line before the officer’s order or before the nozzle is ready.
- Treating a supply line as an attack line.