In short, if the wind speed exceeds 17mph you must STOP any work on the tower. However, you don’t necessarily need to dismantle it unless the wind is forecast to reach 28mph.
What are the guidelines for using a mobile access tower when it is windy?
If the wind speed should exceed 17mph you must STOP any work on the mobile access tower (tower scaffold). The wind speeds on the mobile access tower during work may be monitored using handheld anemometers which are readily available.
However, you don’t necessarily need to dismantle the tower unless the wind speed is forecast to reach 28mph. This is because the general guidance given by PASMA and many manufacturers is that mobile access towers certified as conforming with the product standard EN1004 should be stable in a freestanding condition in wind speeds up to 28mph (Beaufort 6).
Potential wind speeds should be established by reference to weather forecasts for the duration of the time that the mobile access tower will be standing and also by reference to metrological data for the geographical area where it will be located. If the wind speed is forecast to reach 28mph, then the mobile access tower should not be built or, if it is already built then it should be dismantled. Again, you will need to consider this point and take appropriate measures in your planning for the task.
The location of the site and the surrounding terrain will affect potential wind speeds e.g. on the top of a slope, hill, escarpment or cliff, close to the sea or estuaries, near woodland, in open country or near buildings. All of these terrains have an effect on wind speeds.
If the mobile access tower is to be placed on a high structure where it will be exposed to wind (e.g. on a tall building) then wind speeds at the top of that structure may be considerably higher compared to those experienced at ground level. Therefore you must consider wind speed data which takes this point into account.