In a long hose lay, how does friction loss affect the required pump discharge pressure if nozzle pressure must be maintained?

• A. It increases the required pump discharge pressure to maintain nozzle pressure.
• B. It decreases the required pump discharge pressure.
• C. It has no impact on nozzle pressure.
• D. It only affects discharge pressure if the hose diameter changes.

Answer: (A)

Friction loss is the pressure drop that occurs as water moves through hose. When nozzle pressure must stay the same, the pump must supply enough discharge pressure to overcome that loss along the entire hose length. In a long hose lay, friction losses accumulate, so the longer the run, the more pressure must be added at the pump to keep the nozzle at the target pressure. The amount of loss grows with higher flow and with smaller diameter hose, so longer runs or tighter hoses require higher pump discharge pressure to maintain nozzle pressure.