When two handlines operate on the same fire, what is the effect on pump discharge requirements?

• A. Total flow increases, raising friction losses and possibly requiring higher discharge pressure to maintain nozzle pressures.
• B. Total flow decreases due to shared flow; lower discharge pressure needed.
• C. Flow remains the same; nozzle pressures unaffected.
• D. Discharge pressure drops due to friction so you need less pressure.

Answer: (A)

Two handlines on the same pump mean the pump has to supply the sum of both flows. Each hose has friction losses that grow with flow, and those losses add for the two lines. Since nozzle pressure = pump discharge pressure minus all losses in the hose run, maintaining the same nozzle pressures on both lines typically requires increasing the pump discharge pressure to overcome the greater friction and any elevation losses. If discharge pressure stayed the same, the higher friction would drop nozzle pressure. So the total flow goes up, friction losses rise, and higher discharge pressure may be needed to keep nozzle pressures at the desired level.