What is the best definition of friction loss in fire apparatus engineering?

Friction loss in fire apparatus engineering specifically refers to the pressure loss that occurs when water flows through hoses and fittings. This phenomenon is primarily caused by the internal resistance of the hose material and the fittings that the water must pass through, which can impede flow and result in a decrease in pressure.

The factors that contribute to friction loss include the length and diameter of the hose, the type of material of the hose, and the speed of the water moving through it. As water flows, its contact with the walls of the hose generates resistance, which is quantified as friction loss. Understanding and calculating this loss is critical for fire apparatus engineers to ensure effective water delivery in firefighting operations.

While energy lost due to hose connections, leaks in the system, and resistance from uphill pumping can impact overall system efficiency, they do not specifically define friction loss as it applies to the flow of water in hose lines and fittings. Thus, the focus of friction loss is uniquely tied to the interaction between water and the internal structures through which it flows.