Calculating Sling WLL vs. Crane WLL #construction #materialhandling #rigging

What is the core difference in calculating the sling Working Load Limit and the crane Working Load Limit (Rated Capacity)?

The working load limit or capacity of a lifting product is determined by the manufacturer of that product. The WLL limit is calculated by dividing the MBL, or Minimum Breaking Load, by the safety factor applied to that particular product. Most, but not all, slings have a design factor of 5-1. Chain slings often have a design factor of 4-1. Most overhead and mobile cranes are somewhat lower and can have a design factor in the 3-1 range.

Remember that the lowest working load limit, whether it be on your crane or your rigging, is not to be exceeded. If the rated capacity of your crane is 1 ton, you can put a shackle with a WLL of 30 tons on the hook, but you still can’t lift anything more than 1 ton, rigging included.

SME B30.26-2015 Rigging Hardware: working load limit (WLL): see rated load.

ASME B30.26-2015 Rigging Hardware: rated load: the maximum allowable working load established by the rigging hardware manufacturer. The terms rated capacity and working load limit are commonly used to describe rated load.

ASME B30.5-2021 Mobile and Locomotive Cranes: rated capacity: the maximum allowable load the equipment can lift at any given radius.

ASME B30.2-2022 Overhead and Gantry Cranes: rated load (capacity): the maximum load designated by the manufacturer for which a crane or individual hoist is designed and built.

ASME B30.26-2015 Rigging Hardware: design factor: ratio between nominal or minimum breaking strength and rated load of the rigging hardware.

ASME BTH-1–2023 Design of
Below-the-Hook Lifting Devices: design factor: the ratio of the limit state stress(es) or strength of an element to the permissible internal stress(es) or forces created by the external force(s) that act upon the element
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[MasterArkannor]

I love the thought of some salesman styling better rigging to someone whose equipment already exceeds their machinery's load limit 😆

[Aterhallsam]

It’s ridiculous it even has to be explained but I know why you are explaining it. I have seen stuff lol.