Which item is not typically part of pump sizing?

• A. Required flow rate
• B. Total dynamic head
• C. Electrical voltage of the supply
• D. Pipe friction losses

Answer: (C)

Sizing a pump focuses on meeting the system’s hydraulic needs: the design flow rate and the total dynamic head the pump must develop. The design flow rate ensures enough water is delivered to the irrigation zones, while the total dynamic head includes static lift and all losses due to friction in pipes, fittings, and valves along the flow path. Pipe friction losses are a fundamental part of this head calculation because they determine how much pressure the pump must generate to push water through the network at the desired flow.

Electrical voltage of the supply is an electrical consideration rather than a hydraulic one. It doesn’t change the water’s flow or the head the system requires; it mainly affects which motor model and electrical setup can be used. You’d select a motor or drive compatible with the available voltage after you’ve sized the pump hydraulically. So the electrical voltage of the supply is not typically part of the pump sizing itself.