What is the minimum WLL required for tie-downs securing loaded intermodal containers on non-chassis vehicles?

Secure each container to the vehicle by: Either chains, wire ropes, or integral devices that are fixed to all lower corners. Or crossed chains that are fixed to all upper corners. Or both. Secure the front and rear of the loaded container independently. Secure the four corners using tiedowns that are attached to the loaded container. The tiedowns must have an aggregate working load limit of at least 50% of the loaded weight of the loaded container. Attach each chain, wire rope, or integral locking device to the container in a manner that prevents it from becoming unfastened while in transit.