Compliance & standards
What is TG20?
TG20 is NASC's technical guidance for tube and fitting scaffolds. The current edition is TG20:21, and its eGuide produces a compliance sheet confirming that a specific scaffold configuration sits within the guidance.
TG20 answers one question: can this scaffold be built without a bespoke design behind it? If the configuration you intend to build — the bay lengths, lift heights, tie pattern, cladding and duty — falls inside the guidance, the eGuide produces a compliance sheet for it, and that sheet is the evidence.
The word that matters is configuration. TG20 does not approve a scaffold in general; it confirms that one particular arrangement has been assessed. Change the arrangement and the sheet no longer describes what is standing.
Where a structure falls outside the guidance, it needs a bespoke design from a competent person — calculations and drawings for that structure. TG20 is not a substitute for that and does not claim to be.
What goes wrong on site
- A compliance sheet generated for the scaffold as planned, then the scaffold built differently, so the sheet describes a structure that was never erected.
- An adaptation during the hire that takes the structure outside the configuration, with nobody going back to check.
- Treating the compliance sheet as a one-off piece of paperwork rather than as the description of what is supposed to be standing.