10-minute drill
Friction loss drill
A driver/operator friction loss drill for practicing hose size, length, flow, and the C × Q² × L formula.
Drill plan
ObjectiveHelp firefighters see how flow and hose length change pressure loss.
Setup
- Compare 150, 185, and 250 GPM flows
- Use 100-foot and 200-foot hose lengths
- Use department friction-loss chart or FireOps Calc quick calculator
- Discuss why doubling flow more than doubles loss
Student taskGive each crew two hose layouts and have them estimate friction loss before checking the calculator.
Expected answer pathFriction loss increases with the square of flow. The exact answer depends on hose coefficient, hose length, and GPM.
Common mistakes
- Forgetting to state nozzle pressure or required appliance/device pressure.
- Using GPM where PSI is needed, or PSI where GPM is needed.
- Adding elevation or appliance loss twice.
- Ignoring department SOPs, apparatus pump chart, or manufacturer data.
Instructor note: After the first answer, change one variable and repeat the calculation.
Print notes
This page is designed to print as a simple station drill handout. Use it with the calculator/tool link above to check student answers live.