Episode 13: Container door lock

Opening a container is always an exciting experience for everyone. The inspection authorities know from experience that opening can sometimes have unpleasant consequences.

To prevent this, they always take precautions to ensure that the door can be opened safely. In my experience, there are two types of shippers.

Some create a danger for those who open the doors because they don’t know any better and others consciously accept this danger. For example, if the container is fumigated and not labeled. My focus is on the shipper group, which doesn’t know any better, and I want to change that.

The CTU code stipulates that the door must always be safe to open. This principle must run through all considerations.

The load securing to the container door may have to fulfill two tasks

• firstly, secure the load against falling out and
• secondly, secure the load against transportation loads .

What is the difference?

If the distance between the load and the door is more than 15 cm, the securing method (e.g. lashings) must secure the load against the usual transportation loads (sea transport 0.4 g). At the same time, this provides protection against falling out.

If the distance is less than 15 cm, the door secures the load against the usual transportation loads (sea transport 0.4 g) and only securing the load against falling out is required.

Backup methods

What methods are there to secure the load if the distance to the door is greater than 15 cm and this distance cannot be reduced in any other way?

The classic method is bracing. The forces should not, as in this example, be applied to the corrugations, but to the corner posts. Fixing the crosspieces in the beads is an indeterminate method because there is no reliable information on the forces that can be transmitted.

If there are tests with repeatable results for a specific case, that would be acceptable. Otherwise avoid this method.

The H or double H fuse used to be a common method because it could be produced with running belt material.
However, its effectiveness is rather controversial today because it is difficult to produce correctly and requires a lot of practice.

Professionally produced lashings with up to 4 cross bands are the most common method today.
In the variant shown in the picture, the height of the cross belts can be variably adjusted to the load.

Protection against falling out

There are also a number of now standardized methods for securing against falling out.

Safety tarpaulin, combined with a flat stowage cushion. The crossed hinges prevent the stowage cushion from exerting pressure against the door.

The S.A.M. system consists of two stowage cushions connected by a tarpaulin. The outer sides of the pads can have an anti-slip coating to provide greater frictional force. This system has proved particularly effective for refrigerated containers.

The TyPatch system is a method that is suitable for uniform and dimensionally stable load units. As this is a system that works like an adhesive tape, it is important to pay particular attention to the manufacturer’s instructions for use and application. In particular, the bonding surfaces must be dust-free and dry.

Conclusion

The above examples are not final and conclusive; there are certainly many company-specific variants.

The responsible stevedore must in any case ensure that the general requirements of the CTU Code are implemented correctly and sufficiently so that there are no complaints, delays or fines during inspections.

Yours, Sigurd Ehringer

Tobias Kreft