What are the guidlines for using a mobile access tower in bad weather?
The general guidance given by PASMA and many manufacturers is that mobile access towers (tower scaffolds) certified as conforming with the product standard EN1004 should be stable in a freestanding condition in wind speeds up to 28mph (Beaufort 6).
If the wind speed should exceed 17 mph you must STOP any work on the mobile access tower. The wind speeds on the mobile access tower during work may be monitored using hand held anemometers which are readily available
If the wind speed is likely to reach 25 mph then the mobile access tower must be properly tied to a suitable adjacent rigid supporting structure capable of supporting the additional loads imposed by the mobile access tower. The connections (ties) between the tower and the supporting structure must be rigid in compression and tension i.e. you should NOT use rope, webbing, wire etc. You could use an arrangement of suitable aluminium or steel tubes and couplers.
As the tower must be tied if the wind speed is likely to reach 25mph, you will need to consider this point and take appropriate measures in your planning for the task. Potential wind speeds may 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 likely to reach 40mph, then the mobile access tower must 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.