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Mannings N: closed conduits
Unfinished, rough wood form to Vitrified sewer with manholes, inlet, etc.
Manning's n roughness coefficients for open channels and closed conduits — used in hydraulic flow calculations
| section | description | n max (dimensionless) | n min (dimensionless) | n normal (dimensionless) | subcategory |
|---|---|---|---|---|---|
| closed conduits | Unfinished, rough wood form | 0.02 | 0.015 | 0.017 | 7. Concrete: |
| closed conduits | Unfinished, smooth wood form | 0.016 | 0.012 | 0.014 | 7. Concrete: |
| closed conduits | Unfinished, steel form | 0.014 | 0.012 | 0.013 | 7. Concrete: |
| closed conduits | Unlined | 0.015 | 0.011 | 0.013 | Ductile Iron: |
| closed conduits | Vitrified Subdrain with open joint | 0.018 | 0.014 | 0.016 | 9. Clay: |
| closed conduits | Vitrified sewer | 0.017 | 0.011 | 0.014 | 9. Clay: |
| closed conduits | Vitrified sewer with manholes, inlet, etc. | 0.017 | 0.013 | 0.015 | 9. Clay: |
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