What are the basic requirements for sizing a centrifugal pump?

Centrifugal pump sizing requires: flow rate (normal, maximum, minimum operating ranges), total dynamic head (TDH = discharge pressure - suction pressure + friction losses + elevation), fluid properties (density, viscosity, vapor pressure), and NPSH available vs. required. Process engineer provides: operating conditions, fluid properties, piping arrangement for NPSH calculation, and control scheme. Pump engineer selects: pump type, impeller size, driver power, and materials. Key outputs: pump curve, efficiency, power consumption, and NPSH margin. Always include margin (10-20% on head) for uncertainties and future capacity.