Working Load Limit

Working Load Limit(WLL):
 

The maximum load that may be applied to a component of a cargo securement system during normal service, usually assigned by the manufacturer of the component, for different kind of tie down devices, the ways to apply load are different, for instance, the WLL of grade 70 transport chain is the maximum load shall be applied in direct tension to an undamaged  straight length of chain. WLL sometimes is called safe working load.

Working Load Limit determined by Design Factor(DF) and Minimum Breaking Strength(MBS) of specific tie downs, MBS divided by DF is the WLL of the tie downs:

WLL = MBS/DF

For 3/8'' grade 70 chains, the DF is 4:1, MBS is 26400LBS, thus the WLL is 6600LBS.

Sometimes people use Safe Load Limit in place of WLL.

The typical working load limit of tie downs:

1'' tie down straps have the most variations, because people use 1'' straps in all kinds of applications;

2'' tie down straps have typical working load limit of 733lbs, 1000lbs and 3333lbs;

3'' tie down straps have typical WLL 5400lbs;

4'' tie down straps have typical WLL 5400lbs;