Equipment Wind Speed Limits
All lifting operations must cease when wind speeds exceed the limits below. These are general industry limits — always check the manufacturer's operating manual for your specific machine, as limits may be lower depending on load, configuration, and sail area.
| Equipment | Max Wind Speed (mph) | Max Wind Speed (m/s) | Reference |
|---|---|---|---|
| Tower Crane | 38 | 17.0 | BS 7121-5 |
| Mobile Crane | 31 | 13.9 | Manufacturer |
| MEWP (Boom) | 28 | 12.5 | BS 8460 |
| MEWP (Scissor) | 28 | 12.5 | BS 8460 |
| Lorry Loader | 31 | 13.9 | BS 7121-4 |
| Crawler Crane | 31 | 13.9 | Manufacturer |
Important: These are maximum limits in open terrain at ground level. Actual safe operating limits may be significantly lower when considering height, load sail area, and local conditions such as funnelling between buildings.
Beaufort Scale
The Beaufort Scale provides a practical way to estimate wind speed from visible signs on site without instrumentation.
| Force | Speed (mph) | Description | Visible Signs |
|---|---|---|---|
| 0 | 0-1 | Calm | Smoke rises vertically |
| 1 | 1-3 | Light air | Smoke drifts slowly |
| 2 | 4-7 | Light breeze | Leaves rustle, wind felt on face |
| 3 | 8-12 | Gentle breeze | Leaves and small twigs move constantly |
| 4 | 13-18 | Moderate breeze | Dust and loose paper raised, small branches move |
| 5 | 19-24 | Fresh breeze | Small trees sway, crested wavelets on inland water |
| 6 | 25-31 | Strong breeze | Large branches move, whistling in wires, umbrellas difficult |
| 7 | 32-38 | Near gale | Whole trees in motion, difficulty walking against wind |
| 8 | 39-46 | Gale | Twigs break off trees, progress generally impeded |
| 9 | 47-54 | Strong gale | Slight structural damage, chimney pots and slates removed |
| 10 | 55-63 | Storm | Trees uprooted, considerable structural damage |
| 11 | 64-73 | Violent storm | Widespread damage |
| 12 | 74+ | Hurricane | Devastation |
Height Correction Factors
Wind speed increases with height above ground level. If you measure wind speed at ground level, apply the correction factor below to estimate the wind speed at the working height of your equipment.
| Height Above Ground | Correction Factor | Example (20 mph at 10 m) |
|---|---|---|
| 10 m (baseline) | 1.00 | 20.0 mph |
| 20 m | 1.10 | 22.0 mph |
| 30 m | 1.17 | 23.4 mph |
| 50 m | 1.27 | 25.4 mph |
| 100 m | 1.40 | 28.0 mph |
Note: These factors assume open, flat terrain (Category 2). In urban areas with surrounding buildings, the wind profile may differ. Always use an anemometer at the actual working height where possible.
Wind Speed Calculator
Convert between mph, m/s, km/h, and knots. Check against equipment limits instantly.
