Roughness Values-Darcy-Weisbach Equation (Colebrook-White)
Commonly used roughness values for different materials are:
Darcy-Weisbach Roughness Heights e for Closed Conduits
| Pipe Material | e (mm) | e (ft) |
|---|---|---|
| Glass, drawn brass, copper (new) | 0.0015 | 0.000005 |
| Seamless commercial steel (new) | 0.004 | 0.000013 |
| Commercial steel (enamel coated) | 0.0048 | 0.000016 |
| Commercial steel (new) | 0.045 | 0.00015 |
| Wrought iron (new) | 0.045 | 0.00015 |
| Asphalted cast iron (new) | 0.12 | 0.0004 |
| Galvanized iron | 0.15 | 0.0005 |
| Cast iron (new) | 0.26 | 0.00085 |
| Concrete (steel forms, smooth) | 0.18 | 0.0006 |
| Concrete (good joints, average) | 0.36 | 0.0012 |
| Concrete (rough, visible, form marks) | 0.60 | 0.002 |
| Riveted steel (new) | 0.9 - 9.0 | 0.003 - 0.03 |
| Corrugated metal | 45 | 0.15 |