In fire attack, what does "friction loss" refer to?

Friction loss refers to the decrease in water flow that occurs as water travels through hoses. This phenomenon is due to the internal resistance generated by the hose material and the size of the hose itself. When water flows through a hose, it encounters friction against the sides, which leads to a reduction in pressure and flow rate. The longer and narrower the hose, the greater the friction loss. Understanding friction loss is critical for firefighters, as it impacts the effective pressure and availability of water at the nozzle, which is essential for effectively attacking a fire. Recognizing how friction affects water delivery enables firefighters to calculate required pressures and choose appropriate hose lengths and diameters for their operations.