Tag: number

All too often our trainers visit work sites only to find people working at height making the same mistake again and again. Is it a minor mistake? No! It is one that would be catastrophic if the worker should fall. Some people think that the number one mistake as a worker operating without safety equipment. Not so!
The number one mistake I see is where companies have incurred the cost of providing safety equipment, however through lack of the required knowledge the worker is using it incorrectly. The worker feels safe but doesn’t know that if he falls his protective equipment will fail.
It would be a tragedy, worse it would be unnecessary.
The number 1 mistake is connector misuse by the site worker.
What does misuse mean?
1. Choking – tying off incorrectly
2. Connecting to an unsuitable anchor point
3. Incorrect directional loading
1. Choking
This is where a site worker is supplied a lanyard, often with a small karabiner at the end. The site worker instinctively passes the lanyard around an anchor point e.g. a column or a beam, using the karabiner to choke i.e. tighten the lanyard around the anchor point.
The problem arises should the worker fall, further tightening the choked lanyard and subsequently applying a shock load inappropriately to the karabiner gate most likely causing the barrel of the karabiner to fail. Karabiners are designed to accommodate tensile (pull) forces along their length and are at their weakest when the load forces are across the minor axis (width) or against the gate.
  It is generally accepted that to engineer a connector to withstand the directional loading across the gate of the Karabiner which has been choked during a fall would require a gate strength of 5,000 lbs.
 Note that this dynamic loading failure across the gate of the connector applies to all styles of connector i.e. scaffold hook, snap hook, and karabiner.
2. Connecting to an unsuitable anchor point
For example, a roof worker may instinctively connect to an handrail believing this to be a suitable fixing point.
Note! All temporary anchorage points must be able to withstand a 12 kN Load. If in doubt the anchor point should be approved by a structural engineer.
3. Scaffold Hooks
Scaffold hooks are often placed around scaffolding resting on a horizontal member, i.e. the gate of the scaffold hook will be forced open subject to the loading that would be imposed by the horizontal member in the event of a fall. This occurs because the downward direction or loading imposed by the cross-member is across the axis of the gate on the scaffold hook and will result in complete hook failure as the hook gate will subsequently bend open, or in worst-case scenario, will explode.
Summary of connector misuse
Often a lack of understanding of equipment performance and its limitations can result in site workers being issued with inappropriate safety equipment which is not suitable for its intended use.
For example the scaffold hooks are often used …