Which term refers to the decrease of pressure that occurs when water moves through a pipe or hose?

The term that refers to the decrease of pressure occurring when water flows through a pipe or hose is known as friction loss. This phenomenon arises due to the resistance that water encounters as it moves over the internal surfaces of the piping. The friction between the water and the walls of the pipe or hose leads to a loss of pressure, which can affect the flow rate and overall efficiency of water delivery for firefighting or other purposes.

Friction loss is influenced by several factors, including the length and diameter of the pipe, the flow rate of the water, and the roughness of the pipe's interior surface. Understanding this concept is crucial for firefighters as it allows them to calculate the pressure needed at the source to ensure adequate flow at the nozzle, especially when dealing with long hose lines or complex water delivery systems.

The other terms relate to different pressure contexts within firefighting but do not specifically denote the decrease in pressure due to water flow. Residual pressure refers to the pressure that remains in the water delivery system after a certain volume of water has been withdrawn or used. Dynamic pressure is the pressure of water in motion, reflecting the speed and flow. Head pressure refers to the pressure exerted by a column of water due to gravity, often seen in static situations rather