Free Pipe Friction Loss Calculator
Calculate head loss due to pipe friction using the Hazen-Williams equation for water supply systems.
GPM
in
ft
Total Head Loss
0.00 ft
Head Loss per 100 ft0.00 ft/100ft
Pressure Loss0.00 psi
Total Head Loss vs Flow Rate
Hazen-Williams Formula
h_f = 10.67 x (Q / C)^1.852 / D^4.8655 x L
This empirical formula is widely used for water distribution systems. C is the roughness coefficient (150 for new PVC, 130 for copper, 100 for old steel). Results are in feet of head; multiply by 0.4333 for psi.
Example Calculation
15 GPM through 1-inch copper (C=130) for 100 feet.
- 01h_f/100ft = 10.67 x (15/130)^1.852 / (1/12)^4.8655
- 02Compute numerator and denominator using the formula
- 03Total head loss for 100 ft is approximately 12.5 ft
- 04Pressure loss = 12.5 x 0.4333 = 5.42 psi
Frequently Asked Questions
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