Walk any site with work at height and you will find harness inspection records in good order: dates, serial numbers, the name of the person who checked them. Ask what the lanyard will be clipped to, and how much clear space is beneath the worker, and the answers get noticeably vaguer.
That is the wrong way round. A harness is a way of distributing force across a body. It does not stop a fall. The anchor stops the fall, and the clearance decides whether stopping happens before the ground does.
What an anchor actually has to do
A falling body arrested over a short distance generates forces far beyond its own weight. This is why anchor points for fall arrest are specified in the order of thousands of kilograms of static load, and why the choice of anchor is an engineering question rather than a matter of finding something solid-looking.
The things people clip to that are not anchors: handrails and guardrails, which are designed to resist a lateral push and not a vertical shock load; pipework and cable tray; ductwork; ladder rungs; conduit; scaffold tube that nobody has assessed for this purpose; and any structural member chosen because it was the nearest thing at chest height.
The arithmetic nobody does
Fall clearance is the part that is genuinely counter-intuitive. Beneath the anchor you have to allow for, in order: the length of the lanyard, the full deployment of the energy absorber, the height of the worker below the D-ring, and a safety margin. Add them honestly and a standard shock-absorbing lanyard needs several metres of clear space below the anchor point.
Which means a man working from a platform three metres up, clipped to an anchor at his feet, has a system that will not arrest him before he lands. Everything looks correct. The equipment is certified, the inspection is current, and the arrangement cannot work.
The details that change the answer
- Anchor height relative to the D-ring. An anchor above the shoulder shortens the fall. An anchor at foot level roughly doubles the free-fall distance before the absorber even engages.
- Swing fall. Working to the side of the anchor rather than below it turns a vertical fall into a pendulum, into whatever is in the arc.
- Edges. A lanyard dragged over a sharp structural edge during a fall can be cut through before the absorber does anything. This needs either edge protection or a lanyard rated for it.
- Rescue. Arresting a fall is not the end of the event. Suspension in a harness becomes dangerous within minutes, and “call the fire brigade” is not a rescue plan.
Where this should be settled
Anchor points and clearance belong in the planning, not in the toolbox talk on the morning. They need to be identified, assessed, and — where they are permanent — proof tested and periodically re-certified, with the tested capacity recorded somewhere the crew can find it.
Then hierarchy still applies. Fall arrest is the last resort, below eliminating the work at height, below a physical edge protection, below restraint that stops the person reaching the edge at all. A harness is what is left when all the better answers have been ruled out — not the first thing to reach for.
Are Your Anchor Points Assessed or Assumed?
Our HSE and inspection teams survey work-at-height arrangements, assess and certify anchor points, run fall clearance calculations for each position, and build the rescue plan that has to sit behind them.
Explore HSE Services