Duct Diameter Calculator
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Calculate duct sizes, velocities, and equivalent dimensions for Circular and Rectangular systems.
Circular Calculator
Recommended Minimum Velocities
Based on Health and Safety Executive (HSE) guidance for contaminant transport.
| Velocity (m/s) | Typical Contaminants |
|---|---|
| ~5 | Clean Air, Hot Air, Steam, Non-toxic Vapours |
| ~10 | Solvent Vapours, Light Fumes, Acid Fumes, Oil Mist |
| ~12.5 | Welding Fume, Paint Spray, Cotton Lint, Wood Flour |
| ~15 | Fine Dry Dust (Flour), Sawdust, Plastic Dust, Leather Dust |
| ~17.5 | Medium Dust (Cement), Limestone, Foundry Shakeout |
| ~20 | Coarse Dust, Wood Shavings, Metal Filings, Grinding Dust |
| ~22.5 | Heavy/Abrasive (Sandblasting), Lead Dust, Cast Iron Boring |
| 25+ | Damp/Sticky Materials, Moist Powders, Wood Chips |