Centrifugal pumps are ubiquitous at process plants but many
users don't understand how to select and install them. Some
strict rules apply and the devil is in the details. So, this
article presents some pointers I've gleaned over the years. Pump
selection should start with the system curve. Plants that supply
vendors with a system curve have addressed 80% of the pump
selection process. Unfortunately, plant-supplied system curves
are rare and this leads to excessive costs. Developing the curve
first requires establishing the piping lay out, allowable system
pressures and flow rates. Once isometrics are drawn, you can
calculate and graph the system curve. The pressure/flow rate
plot should represent the changes that flow will experience over
the life of the process. This plot is essential for the pump
vendor to make a valid recommendation. The only other plot
needed is the range of Net Positive Suction Head Available
(NPSHA) the pump can experience. Determining the total NPSHA
requires calculating suction-side