Hydraulic Calculator for Pressure Pipe

This calculator determines the friction head-loss in PVC and PVCO pipe using the Hazen-Williams formula (in U.S. Customary units):

where:

• f = friction loss, ft of H₂O
• C = Hazen-Williams flow coefficient, dimensionless
• Q_gpm = volumetric flow rate, gpm
• D_i = pipe inside diameter, in.
• L = pipe length, ft

Minor losses can be included in the calculation by checking the “Minor Losses” box. If the box is checked, minor losses can be included by using an equivalent length, a minor loss value, or minor loss coefficients for different types of valves or fittings.

Once head loss is calculated, the user can add a “static elevation” value, which is input into a spreadsheet that can be downloaded. The spreadsheet provides head vs. flow rate for a range of flow rates.

Laboratory testing of new pipe and field testing of in-service pipe have both confirmed a Hazen-Williams flow coefficient of 150 is conservative for PVC and PVCO pipe. This value is recommended for hydraulic design. Click here for more information.