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Engineering ToolBox > Mannings Roughness Coefficient
Manning's roughness coefficient values are used in the Manning's formula for flow calculation in open flow channels. Coefficients for some common used surface materials can be found in the table below:
| Surface Material | Manning's Roughness Coefficient - n - |
| Asbestos cement | 0.011 |
| Brass | 0.011 |
| Brick | 0.015 |
| Cast-iron, new | 0.012 |
| Concrete - Steel forms | 0.011 |
| Concrete - Wooden forms | 0.015 |
| Concrete - Centrifugally spun | 0.013 |
| Copper | 0.011 |
| Corrugated metal | 0.022 |
| Galvanized iron | 0.016 |
| Lead | 0.011 |
| Plastic | 0.009 |
| Steel - Coal-tar enamel | 0.010 |
| Steel - New unlined | 0.011 |
| Steel - Riveted | 0.019 |
| Wood stave | 0.012 |