Checking anchors during a long scaffold job

Scaffold tie anchors should be checked every time the scaffold has its statutory inspection. NASC TG4:25 makes the anchors part of that regular examination, not a separate check done only at the start of the job.

Look for new cracks in the brick, block or concrete or in the joints round the anchor, rust running out of the hole, and a bent or damaged ring bolt, eye or tie.

A bent anchor or tie has been loaded in a way it was not meant to take: find the cause before you refit.

Tie anchors may need proof testing again after severe weather, or if the scaffold has been undermined. TG4:25 does not say how many anchors to retest or who decides, so agree it with the scaffold designer or responsible engineer.

When anchors are retested:

• choose anchors that were not tested at an earlier examination, where possible;
• test to 1.25 × the tie duty, as for the first proof tests;
• tag each anchor examined with the date and the test load, and tag any that fail;
• if a retest fails, using the Section 9.7 rates (1 in 10, then 1 in 5, then every anchor) is a sensible default, although TG4:25 does not state it for retests. See proof testing scaffold ties.

Ask whether the change puts more load on the anchors, or load in a new direction. If it might, stop and ask the scaffold designer before carrying on. The usual culprits:

• Push loads move onto the anchors when other trades take out props such as butted transoms. Whether the anchor can take compression is a question for its maker; see the load table in working out the tie load.
• The scaffold catches more wind when sheeting or cladding goes on. TG4:25 §9.3 counts swapping sheeting for netting, or taking cladding off, as ways to cut the tie duty, so the reverse can raise it.
• Ties move to new positions, and each new anchor has to meet the same placing rules as the first. See scaffold anchor types.

If a job is respecified to BS 8539, our test-load calculator works out its preliminary test loads.

Choose stainless or removable anchors for long jobs, cap drop-ins that aren't stainless, and look for rust at every inspection. Drop-in anchors stay in the wall for good, which is why the cap matters. Removable anchors avoid the problem altogether: a nylon plug leaves nothing to rust once its eye is unscrewed.

Treat anchors carried over from an earlier scaffold as part of this job: they need proof testing like any others, because TG4:25 asks for proof tests on every project, including those using anchors already in place.

• Nylon plugs that were capped in the wall can serve again, at double the usual proof-testing rate.
• Screw-in eyes usually go back into service once you have checked they are straight, undamaged and free of rust.
• Other anchors: bin any that are bent, rusty or in doubt; otherwise reuse only what the maker allows, inspect every one, and keep a count so none goes back more often than the maker permits.
• Maintenance anchor points fitted under the CDM Regulations, in buildings from after 1994, are not automatically fit for a scaffold. Settle early who answers for them and what they can take, and test them if the anchor or the wall may have deteriorated.

Record each retest as a test report: where each anchor was, the test load, the result and the tag details. The report records facts and does not approve the anchors; the person responsible for the scaffold decides what happens next. See what goes in a site test report.