What is the decrease in pressure that occurs as water moves through a hose?

Friction loss is the term used to describe the decrease in pressure that occurs as water travels through a hose. This phenomenon is primarily due to the resistance caused by the inner surface of the hose material, which creates friction as the water flows. The longer the hose and the smaller its diameter, the greater the friction loss will be.

In practical firefighting scenarios, understanding friction loss is crucial for calculating the necessary pressure to effectively deliver water to the fire, ensuring that firefighters can maintain adequate flow and pressure at the nozzle.

Velocity loss, static loss, and dynamic loss refer to other factors affecting water flow but do not specifically denote the pressure drop resulting from friction within the hose. Velocity loss relates to how speed changes, static loss deals with pressure loss due to elevation or gravity, and dynamic loss accounts for pressure lost due to changes in flow patterns or restrictions. Therefore, friction loss is the specific term that accurately describes the pressure decrease occurring from the hose's internal resistance during water flow.