To prevent unauthorised access to the contents, intermodal containers and trailer doors are fastened with bolt seals. Bolt seals typically need to be opened with a pulling power considerably above 1 tonne.
Bolt seals are simple to use, and the best ones are marked with an auditable serial number on both the bolt and the bush to avoid component part replacement. The seals ought to be tamper-evident, leaving no doubt as to what has been tampered with.
Many bolt seals now have anti-spin features and the best seals align the serial numbers on bolt and bush for ease of checking.
It can be difficult to confirm that the seal that set out on the voyage is the same one that arrives with the client because intermodal shipments are carried over great distances and periods.
Controlling the numbering alone is often insufficient, as seals can be removed and replaced with one that is numbered alike.
The seal should be photographed, and a printed copy should be stuck to the inside of the container door, advises Unisto. In order to allow the seal to be examined in-situ before removal to ensure that it is the same seal that the consignee fitted, the seal image should also be transmitted with the manifest to the consignee.
Towards the fight against global terrorism The ISO 17712:2013 bolt seal quality standard has been promoted by the US Department of Homeland Security for use by organisations that produce and provide bolt seals.
All shipments to the United States should be sealed using a "H" grade, ISO 17712:2013 standard barrier seal to prevent lengthy inspections of the container and its contents. Otherwise, there will be significant delays.
