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Container seal
A container seal is a numbered locking device fixed to a container's doors after packing, so any opening on the way shows. ISO 17712 grades seals H (high-security), S (security) and I (indicative). For containers bound for US importers in CTPAT, the shipper fits a high-security seal at stuffing and records its number on the bill of lading.
Three classes
| Mark | Class | What it takes to remove |
|---|---|---|
| H | High-security | Metal or metal cable, made to delay intrusion |
| S | Security | Lightweight tools |
| I | Indicative | It can be broken by hand; it only shows tampering |
The US importer's rules
CBP's minimum security criteria for CTPAT importers require the container to be sealed immediately after stuffing, by the party responsible or on its behalf, with a high-security seal meeting the current ISO 17712 standard. Cable and bolt seals both qualify.
Worked example: checking a seal with VVTT
- View the seal and the container locking mechanisms, and check them for tampering.
- Verify the seal number against the shipment documents — the bill of lading and the packing list.
- Tug the seal to make sure it is fixed properly.
- Twist and turn the bolt seal to make sure its parts do not unscrew or separate.
CTPAT asks for the seal at the bottom of the secure cam position on the doors, if there is one, rather than on the right door handle, and for the seal number to be printed electronically on the bill of lading. Seal numbers assigned to a shipment should also be sent to the consignee before departure, so it knows which number to expect.
The mistake people make
Sealing the handle. A seal on the right door handle can leave the doors openable without breaking it; the cam position is the one that holds. And a seal number written by hand, or missing from the bill of lading, gives the consignee nothing to check against.
FAQ
Container seal: common questions
- What is a container seal number?
- The unique number stamped on a seal fixed to a container's doors. It is recorded on the bill of lading so the consignee can check, on arrival, that the same seal is intact.
- What is an ISO 17712 seal?
- A seal tested and classed under the ISO 17712 standard: H for high-security, S for security, I for indicative. High-security seals are metal or metal cable, made to delay intrusion.
- What does VVTT mean?
- View, verify, tug, twist — CBP's CTPAT steps for inspecting a container seal: look at it, check its number against the documents, pull on it, and twist the bolt.