What is referred to as the part of total pressure loss while forcing water through fittings and hoses?

Friction loss is the term used to describe the portion of total pressure loss that occurs when water flows through fittings, hoses, and other components of a fire hose system. This loss is primarily due to the resistance the water encounters as it moves through these various elements, which can include bends, twists, and restrictions in the hose and fittings.

The calculation of friction loss is critical for firefighters to ensure they maintain adequate pressure at the nozzle for effective firefighting operations. Understanding this concept helps in calculating the necessary pressures required to overcome the losses and deliver water effectively to the fire scene.

In contrast, flow pressure refers to the pressure available for flow at the discharge of a nozzle or hydrant, static pressure represents the pressure in the system when the water is not flowing, and residual pressure is the pressure remaining in the system when water is flowing. These other pressures are important but do not specifically address the pressure loss incurred during the flow through hoses and fittings.