When calculating friction loss for a practice scenario, which factors must be included?

When calculating friction loss for a practice scenario, which factors must be included?

• A. Hose color, outdoor temperature, time of day, and operator experience.
• B. The brand of nozzle, the water source type, and the weather.
• C. Hose size, GPM, number of 100-foot sections, and number of fittings.
• D. The make and model of the pump, the color of hoses, and the diesel octane rating.

Answer: (C)

Friction loss in a hose is driven by how much water you’re moving, through what size opening, and how far it has to travel, plus the added losses from fittings and valves. The factors used in the calculation are the hose size (diameter), the flow rate (GPM), the total length of hose, and the number of fittings in the line. Hose size matters because larger diameters reduce resistance to flow, while smaller diameters increase it. Higher GPM increases friction losses because more water and energy are being pushed through the pipe, and the relationship isn’t linear. Length matters because the longer the hose, the more distance water travels and more friction it experiences; using 100-foot sections is a standard way to scale the total length. Fittings add discrete loss for each elbow, coupling, or valve, so counting how many fittings are in the run is essential for an accurate total. The other factors listed—hose color, outdoor temperature, time of day, operator experience, nozzle brand, water source type, weather, pump make/model, hose color again, or diesel octane rating—do not change the friction loss calculation in the typical practice scenario. They don’t affect the hydraulic resistance of the water flow through the hose and fittings, so they aren’t included in the friction loss computation.

Friction loss in a hose is driven by how much water you’re moving, through what size opening, and how far it has to travel, plus the added losses from fittings and valves. The factors used in the calculation are the hose size (diameter), the flow rate (GPM), the total length of hose, and the number of fittings in the line. Hose size matters because larger diameters reduce resistance to flow, while smaller diameters increase it. Higher GPM increases friction losses because more water and energy are being pushed through the pipe, and the relationship isn’t linear. Length matters because the longer the hose, the more distance water travels and more friction it experiences; using 100-foot sections is a standard way to scale the total length. Fittings add discrete loss for each elbow, coupling, or valve, so counting how many fittings are in the run is essential for an accurate total.

The other factors listed—hose color, outdoor temperature, time of day, operator experience, nozzle brand, water source type, weather, pump make/model, hose color again, or diesel octane rating—do not change the friction loss calculation in the typical practice scenario. They don’t affect the hydraulic resistance of the water flow through the hose and fittings, so they aren’t included in the friction loss computation.