For a given hose size, what impact does doubling the length of the hose have on friction loss?

Doubling the length of a hose significantly impacts friction loss due to the principles of fluid dynamics. Friction loss in a hose is influenced by its length and diameter, as well as the flow rate of the water through it. The relationship between length and friction loss is linear, but with respect to the square of the flow velocity, it can also be expressed in terms of proportional increase.

When the length of the hose is doubled, the friction loss does not merely increase proportionately; it increases according to the square of the length increase. This means that if you double the length of the hose, the friction loss increases by a factor of four. This quadratic relationship can be expressed mathematically, where friction loss is proportional to the length of the hose times the square of the velocity. Therefore, when the length is doubled, the total impact on friction loss results in a fourfold increase.

This understanding is crucial for fire apparatus operators, as failing to account for the surge in friction loss when extending hose lines can lead to inadequate pressure at the nozzle and potentially hinder firefighting operations.