TG20 compliance, explained: what a compliance sheet actually tells you

Most disputes about a scaffold start with a simple question that nobody on site can answer quickly: what was this built to? TG20 exists so that question has a short answer for the majority of ordinary scaffolds — a compliance sheet, generated for that structure, saying it matches a configuration that has already been checked.

What TG20 is

TG20 is NASC's technical guidance for tube and fitting scaffolds. The current edition is TG20:21, and it comes with an eGuide — software that takes the details of the scaffold you intend to build and, if that configuration sits inside the guidance, produces a compliance sheet for it. That sheet is the evidence. It names the structure, the configuration, the loading class and the tie pattern it depends on.

The important word is configuration. TG20 does not bless a scaffold in general terms; it confirms that a specific arrangement — these bay lengths, these lift heights, this ties pattern, this cladding, this duty — has been assessed and can be built without a bespoke design behind it.

What a compliance sheet does not do

• –It does not survive a change. Add a lift, sheet it, hang a loading bay off it or reduce the ties, and the sheet you hold describes something that is no longer standing on site.
• –It does not replace inspection. A compliant design says the scaffold can be built safely; only an inspection says it was, and still is.
• –It does not cover every structure. Anything outside the guidance needs a design from a competent person, not a compliance sheet.
• –It is not a handover certificate. Design and handover answer different questions — what it should be, and what was actually handed over.

Keeping the sheet attached to the scaffold

The practical failure is rarely producing the sheet. It is finding it eighteen months later, for the right structure, in a form that matches what was built. Compliance sheets that live in a folder on one machine drift away from the scaffolds they describe the first time someone adapts a structure without going back to the paperwork.

The fix is boring and effective: hold the design against the structure record rather than against the job, and make an adaptation something you log rather than something you remember. Then the question "what was this built to?" has an answer that includes the date it changed.