Randy, an Instrument Technician in the energy industry and recent safety webinar attendee, asks:
“Why do only 3 of 4 chain sling legs take the load?”
Peter Cooke, Columbus McKinnon Training Manager and Safety Webinar Presenter, answers:
When using a chain to build a sling, tolerances for chain can make the legs slightly longer or shorter than one another. Because of this, the National Association of Chain Manufacturers (NACM) agreed to only count 3 of the 4 legs of a quad sling to be rated the same. When you first lift the load off the ground the legs that are under tension will stay under tension, so it is important for the rigger to visually see how many legs are loaded before lifting the load off the ground.
To do this, tension up the legs, but do not let the load leave the ground. Safely approach the sling being sure to stay out of the path of tension. You can then quickly check the legs by shacking them slightly. Although you may find all four legs are taking the load, only three are used for calculating the max working load limit of the sling.
It is important to always check the manufacturer’s load charts and safety information prior to making any lift. You must be qualified to lift the load you are rigging.
Want to learn more? View our Safety Webinar on How to Size Your Chain Slings.