TG20:21 HERALDS THE DAWN OF A NEW DIGITAL AGE FROM THE NASC Nearly seven years ago, the HSE, the UKCG (now Build UK) and the leading players in the UK construction and industrial services sectors looked to the NASC to regulate the scaffolding sector with the specific aim of bringing its guidance into compliance with relevant Eurocodes whilst also aiming to boost levels of safety and reducing the number of accidents, injuries and deaths from work at height. Enter TG20 eGuide developers, CADS – a leading international specialist in structural engineering design, who have been serving the global construction industry with marketleading software solutions for over four decades. Their software systems and Building Information Modelling (BIM) services have been adopted by more than 10,000 customers worldwide with 70,000+ copies of CADS software in use in more than 70 countries. Their solution was TG20:13; developed in close collaboration with an NASC
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working group it was a radical step change in tube and fitting scaffold design, demystifying compliance to scaffolding regulations and making design a simpler, safer and swifter affair. Provide a TG20 compliance sheet, or a bespoke scaffold design… end of story. The TG20:13 books were complemented by a highly innovative and user-friendly eGuide software app that was widely adopted and has been a major factor in helping reduce work at height accidents, injuries and fatalities ever since. CADS have once again been chosen by the NASC to work with a task group of their own members to update, improve and radically overhaul the guidance for tube and fitting scaffolding. So, what can we expect with the new TG20:21 version? The NASC is going ‘online’ according to the President Lynn Way who set out her vision of a digital future for the NASC in her inaugural speech at the NASC AGM last November.
TG20:13 has been a success but there has been a lot of feedback and comment worthy of consideration. In addition to day to day requests from all kinds of users and observers much of it came from a consultation exercise held by the NASC in May 2016 in which it sought feedback from NASC members and non-member purchasers of TG20:13.
automatically for the selected site but using an improved topography factor calculation which test results indicate may result in a reduced wind factors. Further, the wind calculation now automatically detects if the site is in a town and, if so, its distance within the town in each wind direction, resulting in an automatic calculation of the exposure correction factor.
Top of the list was to include a representative illustration of the scaffolds in TG20 compliance sheets.
The TG20:21 eGuide also allows the number of boarded lifts to be specified with optional ladder landings which can be introduced at the unboarded lifts if an external stair tower or ladder-access tower are not provided. Part boarding will not in itself affect the maximum safe height of the scaffold but the number of boarded lifts will be considered in the leg load calculation resulting in less conservative designs than the TG20:13 eGuide.
Schedule 3 (Part 2) of the Work at Height Regulations 2005 requires an “assembly, use and dismantling plan” and for many straightforward scaffolds the TG20:13 compliance sheets, together with a method statement, are often sufficient apart from a representative illustration. The type of drawing that can be produced by the eGuide will never replace the expertise of an Engineer using drawing or design software. The TG20:21 compliance sheet will be double-sided with the illustration and principal compliance criteria on the front side and the detailed compliance criteria listed on the reverse in landscape format. Like the TG20:13 compliance sheet, the signoff section states the contract details, site location, the person who created it and the checker. NASC members can include their membership number. If separated from the front then the back page is still, in effect, a selfcontained compliance sheet. The NASC intends to make the TG20:20 eGuide as simple to use as its TG20:13 predecessor so that anyone with a knowledge of scaffolding, not just designer engineers and technicians, can use it successfully. The resulting compliance sheet thus provides a sufficiently informative illustration that is sufficient for the typical, repetitive work for which a TG20 compliance sheet is ideal but supplemented with bespoke drawings produced by designers and technicians where required.
Cantilever fans can be placed at a specified lift and a new screen is provided to configure the desired tie pattern. A TG20 compliant bridge can be positioned within a scaffold elevation with further screens providing for other add-ons, including loading bays and ladderaccess towers for example. TG20 tie patterns displayed in the illustration will automatically adapt to the position of any add-ons. If the façade is permeable (i.e. with significant openings) the representation will be coloured differently. Façade, ledger, plan bracing and structural transoms will also be displayed in positions calculated automatically.
Being an online app the deployment and licensing models adopted will allow the TG20:21 eGuide to be accessed on any Windows, Mac, iOS or Android device with a modern web browser.
one set of guidance free of charge via free subscriptions and a discounted rate on subsequent licenses. But the NASC digital portal will be available to all – boosting scaffolding safety further still.
There will be no software to download and purchasers of the eGuide will access the service via a link from the NASC website using their unique serial number and login credentials. Crucially, the guidance displayed in the new TG20:21 eGuide will always be the latest, up-to-date version, with the apps auto-updating, without needing to re-install them, just like on your smart phone.
The NASC is acutely concerned that it should deliver the best possible value for money to its membership and as a matter of principle wishes to refresh its technical and safety guidance on a regular basis. Feedback from software specialists CADS also reinforced the view that the current eGuide was getting a bit ‘long in the tooth’ and that the TG20 revamp was also a timely opportunity for a technology refresh. All concerned are confident that TG20:21 will take the NASC’s scaffolding guidance to the next level.
The target publication date is February 2021 and the first launch of the NASC eGuide will include electronic copies of refreshed TG20:21 Operational, Design and User Guides. As with TG20:13, NASC members will receive
By Ian Chambers, International Sales & Marketing Director at CADS
Visual representations of the software only. Numbers may not be accurate.
The site location will again be selected from a map, with options available to search for an address and to automatically read the address for the given map marker location. Then the TG20 wind factor will be calculated
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