Standpipe friction loss calculations include which components?

• A. Horizontal hose layout, vertical standpipe riser, fire department connection, and internal valves or pressure-reducing devices
• B. Friction in the nozzle only
• C. Only the vertical standpipe riser
• D. Only horizontal standpipes with no riser

Answer: (A)

Standpipe friction loss calculations must account for every place water encounters resistance from the source to the nozzle. That means you include the friction losses in the horizontal hose layout, the friction in the vertical standpipe riser as water is pumped upward, the losses introduced by the fire department connection where water enters the system, and the losses caused by internal valves or pressure-reducing devices that restrict flow. All of these contribute to the total head loss and determine the pump pressure needed at discharge.

Friction in the nozzle itself isn’t the only factor; it’s part of the total, but ignoring the upstream and entry losses would lead to underestimating the required pressure. Likewise, focusing only on the vertical riser or only on horizontal portions omits other significant losses. Including all four components gives an accurate assessment of the system’s friction loss.