Typical Roughness Values for Pressure Pipes
Typical pipe roughness values are shown below. These values may vary depending on the manufacturer, workmanship, age, and many other factors.
Comparative Pipe Roughness Values | ||||
Material | Manning's Coefficient n | Hazen-Williams C | Darcy-Weisbach Roughness Height | |
k (mm) | k (0.001 ft.) | |||
Asbestos cement | 0.011 | 140 | 0.0015 | 0.005 |
Brass | 0.011 | 135 | 0.0015 | 0.005 |
Brick | 0.015 | 100 | 0.6 | 2 |
Cast-iron, new | 0.012 | 130 | 0.26 | 0.85 |
Concrete: | ||||
Steel forms | 0.011 | 140 | 0.18 | 0.6 |
Wooden forms | 0.015 | 120 | 0.6 | 2 |
Centrifugally spun | 0.013 | 135 | 0.36 | 1.2 |
Copper | 0.011 | 135 | 0.0015 | 0.005 |
Corrugated metal | 0.022 | - | 45 | 150 |
Galvanized iron | 0.016 | 120 | 0.15 | 0.5 |
Glass | 0.011 | 140 | 0.0015 | 0.005 |
Lead | 0.011 | 135 | 0.0015 | 0.005 |
Plastic | 0.009 | 150 | 0.0015 | 0.005 |
Steel | ||||
Coal-tar enamel | 0.010 | 148 | 0.0048 | 0.016 |
New unlined | 0.011 | 145 | 0.045 | 0.15 |
Riveted | 0.019 | 110 | 0.9 | 3 |
Wood stave | 0.012 | 120 | 0.18 | 0.6S |