Hazen Williams Coefficients

Reference data and engineering information about hazen williams coefficients for miscellaneous applications.

hazenwilliamscoefficientsCalculator

Overview

Engineering reference data for Hazen Williams Coefficients in miscellaneous.

Key Formulas

Unit Conversion

$y = x \cdot k$

Multiply by conversion factor.

Linear Interpolation

$y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}$

Estimate between two known points.

Percentage

$p = \frac{\text{part}}{\text{whole}} \times 100\%$

Part as fraction of whole.

Variables

Symbol	Description	Unit
$x$	Input value	—
$y$	Output value	—
$k$	Conversion factor	—

Hazen-Williams Coefficients Table

The Hazen-Williams coefficient (C) represents the relative smoothness of a pipe's interior surface. Higher values indicate smoother surfaces with less friction loss. These coefficients are empirical values commonly used in hydraulic engineering for water flow calculations.

46 rows

Hazen-Williams Coefficients for Common Pipe and Duct Materials
Material	Hazen-Williams Coefficient (c)
ABS - Acrylonite Butadiene Styrene	130
Aluminum	130 - 150
Asbestos Cement	140
Asphalt Lining	130 - 140
Brass	130 - 140
Brick sewer	90 - 100
Cast-Iron - new unlined (CIP)	130
Cast-Iron - 10 years old	107 - 113
Cast-Iron - 20 years old	89 - 100
Cast-Iron - 30 years old	75 - 90
Cast-Iron - 40 years old	64 - 83
Cast-Iron, asphalt coated	100
Cast-Iron, cement lined	140
Cast-Iron, bituminous lined	140
Cast-Iron, sea-coated	120
Cast-Iron, wrought plain	100
Cement lining	130 - 140
Concrete	100 - 140
Concrete lined, steel forms	140
Concrete lined, wooden forms	120
Concrete, old	100 - 110
Copper	130 - 140
Corrugated Metal	60
Ductile Iron Pipe (DIP)	140
Ductile Iron, cement lined	120
Fiber	140
Fiber Glass Pipe (FRP)	150
Galvanized Iron	120
Glass	130
Lead	130 - 140
Metal Pipes - Very to extremely smooth	130 - 140
Plastic	130 - 150
Polyethylene (PE, PEH)	140
Polyvinyl chloride (PVC, CPVC)	150
Smooth Pipes	140
Steel - new unlined	140 - 150
Steel, corrugated	60
Steel, welded & seamless	100
Steel, interior riveted, no projecting rivets	110
Steel, projecting girth & horizontal rivets	100
Steel, vitrified, spiral-riveted	90 - 110
Tin	130
Vitrified Clay	110
Wrought Iron, plain	100
Wooden or Masonry Pipe - Smooth	120
Wood Stave	110 - 120

Source: engineeringtoolbox.com

Key Observations

Pipe aging significantly affects coefficients: Cast-iron pipe C values decrease from 130 (new) to 64–83 (40 years old) due to corrosion and tuberculation
Lining restores or improves coefficients: Cement-lined and bituminous-lined cast-iron pipes achieve C = 140, matching new smooth pipes
Plastic and modern materials (PVC, CPVC, FRP) consistently show high coefficients (150) due to their smooth interior surfaces
Corrugated metal has the lowest coefficient (60) due to the rough, wavy interior surface
Ranges indicate variability based on manufacturing conditions, age, and installation quality

References

Original Source

Source: engineeringtoolbox.com