Rigging is only as strong as its weakest link.
No matter what safe working load is stamped on a hook, if one is cracked, twisted or opening up at the throat, it can’t deliver its full rated capacity.
That’s why inspection is vital in rigging and hoisting. Although an important task of the rigger/signaller is to check all ropes, chains, slings or other attachments before the lift, a more thorough inspection must be performed before use at the start of each shift.
Rigging hardware must have enough capacity for the job. Only load-rated hardware of forged alloy steel should be used for overhead lifting. Load-rated hardware is stamped with its safe working load (SWL).
Once the right hardware has been chosen for a job, it has to be inspected regularly as long as it is in service.
There are warning signs that hardware has been weakened and should be replaced:
Cracks: Inspect closely − some cracks are very fine.
Missing parts: Ensure that parts such as catches on hooks, nuts on cable clips and cotter pins in shackle pins are still in place.
Stretching: Check hooks, shackles, and chain links for signs of opening up, elongation and distortion.
Stripped threads: Inspect turnbuckles, shackles and cable clips.
Inspect the different parts of rigging hardware carefully:
[Using samples of hardware on site, instructor to review the following points.]
[With the crew, instructor to inspect rigging hardware in use or stored on site and arrange for repairs or replacement.]
In New Brunswick, the main provisions on hoisting apparatus and mobile cranes can be found in General Regulation 91-191 under the Occupational Health and Safety Act, sections 207 – 215.