Calculation of Required Pipe Diameter
The Excel spreadsheet template shown in this section will calculate the pipe diameter needed to carry a specified flow rate of fluid with known density and viscosity, with a specified maximum head loss. The same iterative procedure is used to calculate the friction factor, f, however an assumed value of pipe diameter, D, is needed to start the process, because a value for D is needed to determine a value for f. After a value for f is found using the assumed D, then another set of iterative calculations are needed to find the required minimum pipe diameter, D.
Click here to download this Excel Template with U.S. units.
Click here to download this Excel Template with S.I. units.
As noted on the Excel spreadsheet template, the iterative calculation for D, doesn't converge very smoothly. The best way to proceed with it is to try standard pipe diameters until you find the smallest standard diameter for which the calculated required diameter is less than the assumed value.
U.S. standard pipe diameters for most types of pipe material are as follows (in inches):
1/2, 3/4, 1, 2, 3, 4, 6, 8, 10, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 54, 60, (then 6" increments up to 180")