3 basics symbol You Must Know on your lifting rigging hardware

Do you know random numbers or symbols on your lifting equipment? We’d like to reveal 3 “basic” customers MUST be aware of when using rigging hardware, chain, and lifting slings.

What Does Working Load Limit Mean?

Working load limit is also known as safety working load, abbreviated as W.L.L, it is the maximum safe working load that a piece of lifting equipment, without fear of breaking. It usually varies based on what type of rigging or safety equipment and are identified by manufacturers.

Working Load Limit (WLL)

Minimum Breaking Strength

The minimum break strength aka Minimum Breaking Load (MBL) refers to the required force at which your load equipment will fail. It is expressed in pounds, and/or tonnes, and will actually fail if you go over the guaranteed strength.

Minimum Breaking Strength(MBS)

Safety Factor

The safety factor is the ratio between the minimum breaking strength and the working load limit.
It is a calculation of the Minimum Breaking Strength (MBS) aka Minimum Breaking Load (MBL) divided by Working Load Limit (WLL)

As such:


So if a shackle has a WLL of 1 ton, would have a SWL or MBS of 4 tons if a safety factor of 4 (4:1, 4 to 1, or 1/4) is used, usually the safety factor ranging from 4 to 6 on lifting equipment.

Safety Factor(S.F)

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