ISO 17712

ISO 17712 is the standard for mechanical seals used to secure freight containers in international trade, setting uniform rules for classifying, accepting, and withdrawing seals. It defines three strength classes: I for indicative, S for security, and H for high security. Indicative seals provide tamper evidence only and fall below the 231 kg (2.27 kN) tensile threshold; security and high-security seals meet or exceed it, with the H class built from metal or metal cable and subjected to the full barrier and tamper-evidence testing. C-TPAT and most customs security programs require an H-class seal. The standard also tests resistance to undetected tampering and mandates manufacturer audit.