HDPE pipe — Hazen-Williams headloss

This page covers headloss calculation for HDPE pipe using the Hazen-Williams equation — the canonical pairing for Trenchless install, gas, slip-line rehab.

Pipe parameters — HDPE

Hazen-Williams C-factor (new)

150

Hazen-Williams C-factor (aged)

145

Absolute roughness (ε)

5e-06 ft

Typical uses

Trenchless install, gas, slip-line rehab

Hazen-Williams method

Water-only, turbulent flow, 40-75°F. The default choice for municipal and irrigation work.

Formula

h_f = 10.67 · L · (Q/C)^1.852 / D^4.87  (SI units)

Limitations

Inaccurate for non-water fluids, very cold or hot temperatures, and laminar flow.