The deadline for the switch over from BS 5973 to TG20:08 was the 1st January 2011. This means that all scaffolding in the UK that was originally built in accordance with BS5973 will have to be built in accordance with TG20:08 (or BS EN 12811-1) from this date onwards.
The situation is clarified by Ian Nicol, Chairman of the NASC Working Group for TG20: "The scope of TG20 only covers scaffolds that are supported by existing buildings and are one bay width. These solutions cover traditional scaffolds that were originally erected in accordance with BS 5973. TG20 provides confirmation of the maximum height that these scaffolds can now be built, together with associated technical data. TG20 only provides guidance for all other structures associated with an independent scaffold including, loading bays, stair towers etc. – no designed solutions are provided."
Is that a good thing? Is that a bad thing? Well it depends which side you are looking from I suppose. The implications for scaffold designers are not as complicated as some people are suggesting in my opinion. Yes there are some significant changes to accommodate and the justification of the design has changed somewhat, but it will not change what actually needs to go into the scaffolds to make them work in calculation.
Ian Nicol went on to say "All other types of scaffold including bridges, façade retention, buttresses, all types of shoring and temporary roofs etc. must be designed using other appropriate standards including BS 5975 (where permissible stress can be used) which covers a large variety of scaffolds. TG20 is not appropriate in these instances". So this means that you can only design independents to TG20, saying you are designing other structures to TG20, or, more importantly maybe, being asked to design other structures to TG20, is not applicable. Maybe then we need to educate our clients that BS 5975 will be the code of practice used for the design of all scaffolding except independents tied to buildings.
There is one thing that is often forgotten when discussing the whole TG20 v 5973 subject. TG20 came about because of the need for the UK to adhere to the new European code of practice BS EN 12811-1. When BS EN 12811-1 was being produced we (as engineers in the UK) had an option to comment and discuss it's content at the draft stage in the same way as we do when new British Standards are written. How many people took the time to read and comment on the draft of BS EN 12811-1? How many people read the draft and raised the alarm for the implications of the UK scaffolding industry? Not many; I know of only two people to attend the consultation meetings. So, in a way, we only have ourselves to blame. Therefore, I would like to commend the NASC for stepping up to the plate to actually give us something that we can work with and ensure that the way we build scaffolding using tube & fittings is acceptable for years to come.
The NASC has created a set of video presentations on TG20:08, one for part one and one for part two. These can be found on their You Tube channel by following the links below:
Presentation on TG20:08 Part One
Presentation on TG20:08 Part Two