Pipe Head Loss

Pressure-pipe head loss — Darcy-Weisbach (Swamee-Jain) or Hazen-Williams plus minor losses.

US customary units. Pipe roughness ε (Darcy-Weisbach) or the Hazen-Williams C, and the minor-loss ΣK, come from the pipe material and a fitting-loss table.

Design diagram — updates live with your inputs

Method & Flow

Methodi

Flow Q (cfs)i

Pipe

Pipe diameter (in)i Inside diameter

Pipe length L (ft)i

Roughness eps (in)i Darcy-Weisbach; ~0.01 cast iron, 0.00006 PVC

Hazen-Williams Ci 120 steel, 130-140 PVC/copper

Losses & Fluid

Sum of minor Ki Fitting loss coefficients

Kinematic viscosity (ft^2/s)i Water ~60F

Available head (ft)i Optional — checks h_L vs available

US customary (ft, cfs)

Validation, assumptions & limitations Download validation report (PDF) ↗

This calculator is verified by 4 independent tests comparing its output against closed-form statics, NDS/SDPWS design-standard values and published worked examples. Full case-by-case results are in the PDF report.

Assumptions

Full-flowing circular pipe, steady incompressible flow.
Swamee-Jain explicit f (turbulent); roughness eps is an input.
Minor losses lumped as sum(K) V^2/2g.

Limitations

Roughness eps / Hazen-Williams C and sum K are design inputs.
Single pipe segment; no pump/elevation energy here (see Bernoulli).

Results are for preliminary design and must be confirmed by a licensed engineer against the current adopted code and project-specific conditions.