How does friction loss influence the choice of hose diameter?

How does friction loss influence the choice of hose diameter?

• A. Larger diameter hoses reduce friction loss and deliver required flow with less pressure loss over distance.
• B. Smaller diameter hoses reduce friction loss.
• C. Friction loss is not affected by hose diameter.
• D. Friction loss only affects pump discharge pressure in hydrant operations.

Answer: (C)

Friction loss is the resistance water experiences as it moves through the hose, and it changes with how large the inside of the hose is. For a given amount of water to be delivered over a certain distance, a larger inside diameter reduces that resistance, so the pressure drop along the hose is lower and the nozzle receives the required flow with less pressure loss. Because of this, the diameter you choose is driven by the need to keep friction losses manageable while still meeting other factors like weight and handling. In practice, crews favor the largest practical diameter that still fits the situation, since it minimizes friction loss and helps maintain adequate pressure at the nozzle over distance. Smaller hoses, while lighter and easier to maneuver, incur higher friction losses for the same flow, demanding more pump pressure.

Friction loss is the resistance water experiences as it moves through the hose, and it changes with how large the inside of the hose is. For a given amount of water to be delivered over a certain distance, a larger inside diameter reduces that resistance, so the pressure drop along the hose is lower and the nozzle receives the required flow with less pressure loss. Because of this, the diameter you choose is driven by the need to keep friction losses manageable while still meeting other factors like weight and handling. In practice, crews favor the largest practical diameter that still fits the situation, since it minimizes friction loss and helps maintain adequate pressure at the nozzle over distance. Smaller hoses, while lighter and easier to maneuver, incur higher friction losses for the same flow, demanding more pump pressure.