27 Oct 2013
The Story
With high winds forecast over the coming days, now is the perfect time to consider the dangers of high wind, and the precautions that should be taken at times like this. Safety, as always, begins with preparation before the event, but there are important things to consider (and actions to be taken) both during and after periods of stormy weather.
Before the wind starts (hopefully this has all been done before now) it is of course imperative that all scaffolds are erected in accordance with guidance from manufacturers' user guides, technical guidance such as the NASC's TG20, and / or with the appropriate scaffold design. Of particular concern during periods of strong wind are bracing and tie arrangements. When ties are properly installed (correct tie pattern, sufficient coupler connections to scaffold, adequately tested) the chances of failure are massively reduced. This is because scaffold designs account for high wind speeds in the calculation of tie loads - even 70-80 mph wind or greater is usually allowed for as it is known that this sort of weather can and does occur. So the next time you hear a scaffold failure referred to as an 'Act of God' you may ask yourself whether the wind on the scaffold was actually unforeseeable, or if it falls within the expected range for a '1 in 50 year' wind, which is the typical calculation criterion for wind loading.
Other factors to consider in preparation for high winds are scaffold inspections, tying down boards where appropriate (e.g. with board retaining couplers or other proprietary systems) and ensuring that sheeting / netting is adequately secured or even removed if necessary. It is also important that loose materials, e.g. on unfinished scaffolds, are not left exposed to the wind.
Once the stormy weather begins there is little that can be done other than wait for the wind to subside. It should go without saying that scaffolds should not be used (18 m/s or 40 mph being the usual maximum speed before work is stopped completely).
Finally, when the winds have abated, scaffold inspections should pay particular attention to tie locations, ensuring that nothing has failed or worked loose. Sheeting may well have to be reinstated (given that sheeting is often designed to come loose in such circumstances as a safety measure to ensure the integrity of the scaffold itself).
Keep safe everyone, if all of the above has had due consideration then none of us should be relying on luck over the next few days!
