TG20:21 scaffold checks

01What TG20:21 is

TG20:21 is the NASC's good-practice guidance for tube-and-fitting scaffolds, widely specified on Saudi projects. A scaffold that matches one of its compliant set-ups can be built from the guidance alone. Heavy loading bays, tall sheeted scaffolds and cantilevers need a design from a competent scaffold designer before they go up.

02When to inspect

• Before first use, once the erector hands it over.
• At least every seven days while it is in use.
• After any change, such as an alteration, a removed tie or an impact.
• After strong wind or anything else that could affect its stability.

If your client's site rules ask for more frequent checks, theirs apply.

03What we check

• Foundations. Sole boards and base plates on firm, level ground, with nothing undermining them.
• Standards, ledgers and transoms. Plumb, level and correctly spaced, with all couplers tight.
• Bracing. Façade and ledger bracing complete and in the right places.
• Ties. The tie pattern matches the design or compliance sheet, and ties are tested where the design requires.
• Platforms. Fully boarded, boards supported and secured, with no gaps or trip hazards.
• Edge protection. Guardrail at least 950 mm high, an intermediate rail leaving no gap over 470 mm, and 150 mm toe boards.
• Access. Ladders tied and rising about 1 m above the landing, or a stair tower.
• Loading and sheeting. Only where the design allows for the extra load and wind.

04Tags at access points

Each inspected scaffold gets a SMAT tag at its access points showing who inspected it, when, and when the next inspection is due. A scaffold that fails is tagged "Do not use" until the defects are fixed.