Rigging Hardware Rating
Rigging hardware rating is the maximum safe load-carrying capacity assigned to a rigging component or assembly, expressed as the Working Load Limit (WLL) or rated load, which must not be exceeded in service. It is distinct from the design factor, which is the reserve strength ratio between breaking strength and WLL. Under WorkSafeBC OHS Regulation Part 15, rigging includes ropes, chains, slings, and fittings, all requiring clear WLL markings.
On a shop floor, rigging hardware rating is applied by matching the tagged capacity of hooks, shackles, slings, master links, and chain to the actual lift geometry, load weight, and hitch configuration before a lift starts. Riggers verify component markings, confirm total lifted load including rigging gear, account for sling angles and multi-leg bridle distribution, and reject any item with unknown, unreadable, damaged, or insufficient rating. For suspended work platforms and worker-support applications, stricter requirements apply, including a minimum design factor of 10 and specific component rules like secured hooks and properly fabricated sling eyes.
If a shackle has a 4.75 t WLL, can the lift use the 4.75 t plus a small margin?
No. WorkSafeBC requires that the load applied to rigging not exceed the WLL; the margin is already built into the design factor.
Can a professional engineer reduce the design factor on a dedicated lift assembly?
Yes, but only for a specific lift and only if the assembly is engineered and certified for that purpose; if later used for continued or general service, it must be re-rated to standard requirements.
What happens when rigging supports workers rather than just material?
The design factor must be at least 10, which is stricter than ordinary material-handling rigging because failure consequences are higher.
Is a visible tag enough if the hardware itself is worn or damaged?
No. Marking proves identity and rating, but the component must also remain suitable and free from damage; if condition compromises capacity, it must be removed from service even if the tag is intact.
Does a multi-leg bridle automatically get the sum of all leg WLLs?
Not necessarily. WorkSafeBC standards include system-specific limits and require load sharing through proper master links/shackles and correct assembly; the usable rating depends on configuration, angle, and applicable standard.