Which change would NOT increase friction loss?

• A. Replacing with a larger diameter hose
• B. Adding bends
• C. Increasing hose length
• D. Increasing GPM

Answer: (A)

Friction loss rises with how hard water has to push through the hose: more flow, longer distance, and more turns mean more resistance. A bigger diameter hose lowers friction loss because the water velocity for the same flow decreases and the wall shear is reduced, so there’s less resistance per unit length.

Replacing with a larger diameter hose would not increase friction loss; it actually lowers it for the same flow, helping conserve pressure to the nozzle. Adding bends, increasing hose length, and increasing GPM all increase friction loss: bends add resistance, longer length means more distance for friction to act, and higher flow moves more water through, increasing friction.