Compliance · 9 min read

TG20:21 compliance sheet: what it is and how to produce one

Ask most scaffolders what a TG20:21 compliance sheet actually is and you'll get "the eGuide printout", true, but not much use if a client or principal contractor asks what it proves. This is the plain-English answer: what it demonstrates, when you need one, what it must contain, how it's produced, and who's meant to hold onto it.

If you want the wider picture on load classes and tie patterns, our TG20:21 compliance guide covers those in full; this article stays on the sheet itself.

What a compliance sheet actually proves

A TG20:21 compliance sheet is evidence that a specific scaffold configuration. The exact height, length, load class, tie pattern, bracing and boarding you're proposing, falls within the range the NASC's Good Practice Guidance has already assessed as structurally sound. It is not a design in the engineering sense; nobody has done a bespoke calculation for your job. Instead, the eGuide software checks your inputs against the pre-validated envelope in TG20:21 and, if they fit, generates a sheet confirming the configuration is compliant.

In practical terms it proves three things to anyone who asks: that the scaffold was checked against a recognised industry standard before it went up, that the person producing the sheet input real dimensions and loadings rather than guessing, and that what's on site matches what the sheet describes (which is why inspectors cross-check the two).

When you need one

In practice, a compliance sheet (or a bespoke design where the configuration doesn't fit the eGuide) is expected on every scaffold that a principal contractor, client or your own insurer would reasonably ask about, which today means almost every job beyond the smallest domestic tower. Specific triggers:

• Any commercial site. Most principal contractors won't let a scaffold go up without one on file before CDM sign-off.
• Any domestic job where the scaffold is tied, sheeted, or supports a loading bay.
• Any scaffold your own insurer or NASC membership terms require documentation for.
• Any job where the client specifically asks for TG20:21 evidence, increasingly common even on smaller works.

The one case a sheet won't cover you: if the scaffold falls outside the eGuide's compliant envelope, long spans, unusual heights, bridging, truss-outs, non-standard ground. Then you need a bespoke design instead; see when a scaffold needs bespoke design for where that line sits.

What the sheet must carry

The sheet is only as good as the inputs. Feed the eGuide the wrong height or the wrong load class and you'll get a confident-looking printout for a scaffold that doesn't match what's actually going up, which protects nobody.

How it's produced

The standard route is the NASC's TG20:21 eGuide software: you (or your supervisor) enter the scaffold's dimensions, intended load class, location and sheeting status, and the software checks the combination against the pre-calculated compliant range in the Design Guide. If it fits, it outputs a compliance sheet you can print or save as a PDF. If it doesn't fit, the software will tell you it's outside scope, that's your signal to bring in a scaffold designer.

A growing number of scaffolders now generate this alongside their quote rather than as an afterthought once the job's won, because it's far easier to catch a configuration that needs bespoke design before you've priced and booked the job than after the first lift is up.

Who keeps it, and for how long

• The scaffolding contractor keeps the master copy on file as part of the job pack, alongside the quote and handover certificate.
• The client or principal contractor receives a copy at handover, see our guide to handover certificates and inspection records for how the two documents fit together.
• Retention period, most contractors keep the compliance sheet with the rest of the job pack for at least six years to match typical insurance and contract limitation periods.

If the scaffold is later altered, an extra lift added, sheeting introduced part-way through the hire, the original sheet no longer describes what's on site. A new sheet (or design check) should be produced for the altered configuration, and the old one superseded rather than left as if it still applies.

Worked example

A contractor quotes a two-lift independent tied scaffold, 18 m run, 6 m working height, Class 3 loading, unsheeted, on a moderately exposed suburban site. Inputting these into the eGuide confirms the configuration is compliant on a standard tie pattern at 4 m centres along both lifts. The sheet is generated, attached to the quote, and a copy handed over with the handover certificate on erection day. Total time from input to printed sheet: under ten minutes, far quicker than the half-day-plus turnaround a bespoke design would need if the job had fallen outside scope.

Common questions

Is a compliance sheet the same as a design?

No. A compliance sheet confirms your configuration matches a pre-assessed compliant scaffold in TG20:21. A design is bespoke engineering calculation for a configuration that doesn't fit that envelope, produced by a qualified scaffold designer.

Do I need a new sheet for every job, even similar ones?

Yes. Even a scaffold that looks identical to last week's job on a different street can differ in exposure, ground, or exact dimensions enough to change the compliant tie pattern or load class, each job needs its own sheet.

What if the eGuide says the configuration is out of scope?

Stop and get a bespoke design rather than trying to force the numbers to fit. Working outside a compliance sheet's scope without a design leaves you with no valid evidence the scaffold is sound.

Can a client refuse to accept a scaffold without a compliance sheet?

Yes, and increasingly they do, most principal contractors now build it into their CDM paperwork requirements before allowing access, so it's worth having ready at handover rather than producing it under pressure afterwards.

TG20:21 is a trademark of the National Access & Scaffolding Confederation (NASC). Figures given are illustrative and typical, always confirm the exact output for your configuration using the current eGuide.