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Manning's Roughness Coefficient
Manning's roughness coefficient values for some common materials
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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 |
| Asphalt | 0.016 |
| Brass | 0.011 |
| Brickwork | 0.015 |
| Cast-iron, new | 0.012 |
| Clay tile | 0.014 |
| Concrete - steel forms | 0.011 |
| Concrete - finished | 0.012 |
| Concrete - wooden forms | 0.015 |
| Concrete - centrifugally spun | 0.013 |
| Copper | 0.011 |
| Corrugated metal | 0.022 |
| Earth | 0.025 |
| Earth channel - clean | 0.022 |
| Earth channel - gravelly | 0.025 |
| Earth channel - weedy | 0.030 |
| Earth channel - stony, cobbles | 0.035 |
| Floodplains - pasture, farmland | 0.035 |
| Floodplains - light brush | 0.050 |
| Floodplains - heavy brush | 0.075 |
| Floodplains - trees | 0.15 |
| Galvanized iron | 0.016 |
| Glass | 0.010 |
| Gravel | 0.029 |
| Lead | 0.011 |
| Masonry | 0.025 |
| Metal - corrugated | 0.022 |
| Natural streams - clean and straight | 0.030 |
| Natural streams - major rivers | 0.035 |
| Natural streams - sluggish with deep pools | 0.040 |
| Plastic | 0.009 |
| Polyethylene PE - Corrugated with smooth inner walls | 0.009 - 0.015 |
| Polyethylene PE - Corrugated with corrugated inner walls | 0.018 - 0.025 |
| Polyvinyl Chloride PVC - with smooth inner walls | 0.009 - 0.011 |
| Steel - Coal-tar enamel | 0.010 |
| Steel - smooth | 0.012 |
| Steel - New unlined | 0.011 |
| Steel - Riveted | 0.019 |
| Wood - planed | 0.012 |
| Wood - unplaned | 0.013 |
| Wood stave | 0.012 |
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Related Topics
- Fluid Mechanics - The study of fluids - liquids and gases. Involves various properties of the fluid, such as velocity, pressure, density and temperature, as functions of space and time.
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Related Documents
- Imperial and SI Fluid Mechanics Dimensions and Units - Imperial (USCS) and SI dimensions and units terminology
- Manning's Formula for Gravity Flow - Manning's equation for calculating gravity flow in open channels
- Roughness & Surface Coefficients of Ventilation Ducts - Surface coefficients to calculate friction and major pressure loss in ventilation ducts - concrete, galvanized steel, corroded steel and more
