International Standard ISO 17712, Freight containers - Mechanical seals, published in September 2010, is the third generation of 17712. The first generation was a Publicly Available Specification (PAS) published in 2003; the second generation was a revision to ISO/PAS 17712 published in 2006.  The generations are cumulative except for some fine-tuning of earlier work. 

The International Organization for Standardization (ISO) permits its technical committees to draft and vote on Publicly Available Specifications (PAS) as, in effect, a kind of interim International Standard.  A PAS is faster to approve than a formal standard, but it has a limited shelf-life.

The first generation: ISO Technical Committee (TC) 104, Freight Containers, formed Working Group 8 (WG8), Mechanical Seals late in 2002.  Industry and government experts concluded that an international standard on mechanical security seals would enhance post-9/11 cargo security.  Using ISO's PAS procedures, ISO/PAS 17712 was finished quickly.  The PAS focused on the physical parameters of three classes or levels of seal barrier strength: indicative ("I"), security ("S"), and high security ("H").  The barrier strength of a seal was and still is measured with four tests: impact, shear, bend and tensile strength.  The test values that distinguished between "I", "S" and "H" classes reflected numbers in use by major customs authorities. 

 The quality of seals used in international trade improved as trade-related programs encouraged or required use of ISO-compliant "H" seals. Two of the earliest programs were the US Customs-Trade Partnership Against Terrorism (C-TPAT) and the World Customs Organization's "Framework of Standards to Secure and Facilitate Global Trade."

ISO/PAS 17712:2003's narrow scope reflected the time-urgency of industry stakeholders.  It was clear that the seal suppliers' security-related business practises were at least as important as the physical strength of a seal.  Seal manufacturers and distributors with immature or careless security-related management practises could effectively compromise the security of the best physical seal before it was shipped out of the door.

The major thrust of second-generation activities produced Annex A (normative), "Seal manufacturers' security-related practises."  The purpose of the annex is to raise the quality of security-related practises in the mechanical seal industry and assure a buyer that its supplier conforms to industry best practises.  Annex A defines more than two dozen required practices, such as mantenance of quality assurance programs (ISO 9001), facility risk assessment, seven year data retention programs for all seals, and access control to production and storage areas.  The annex requires a report of a successful audit (often referred to as a certificate) from an independent auditor accredited under ISO-sanctioned procedures.  After a successful international ballot, ISO published the revised PAS 17712 in 2006.

The revision made an important linkage of two features:

• Compliant seals must show a mark to indicate their classification - "H" for high security, "S" for security and "I" for indicative.
• Only manufacturers certified as compliant with the normative annex may put grade marks on seals. 

The linkage means that ISO-compliant seals can come only from ISO compliant sources.

The third generation changes published in ISO 17712: 2010 addressed technical issues, added testing for tamper evidence and established an 18 month transition buffer after publication for critical issues. 

Most of the technical changes that affect accredited testing labs, which must have ISO 17712 included in their scope of competence: the changes clarified test fixture designs and added specificity to the test procedures.  Another technical change, reflecting user experience, established an 18mm minimum widest diameter for bolt seals. ISO/PAS 17712 had addressed seal diameter as a functional requirement and the industry norm tended to be 17mm.  The 18 month transition buffer applied to the 18mm requirement to accomodate manufacturer's tooling requirements and particularly to allow seal inventory adjustment throughout bolt seal supply chains.

Testing for tamper evidence is the most important change since addition of the normative Annex A.  Customs regulators in the European Commission approached ISO and expressed strong interest in tamper testing and vetting of security seals. ISO TC 104 leaders decided that WG8 would work with the EC to address their concerns.  All parties shared a goal: to facilitate maintenance of a common global regime for security seals.  

ISO 17712 gives testing labs unusual flexibility in finalizing their test procedures for evidence of tampering.  Tamper attempts must leave detectable evidence of tampering in each of three tests; three successes earn a "Pass" grade but an "undetectable" result on any test generates a "Fail" grade for the seal.  All classes of seals - "I", "S" and "H" - must earn "Pass" grades to qualify as 17712 compliant. 

Tamper evident testing in ISO 17712 is a compromise to accomodate two valid but conflicting goals: providing specific common test procedures and not providing a public "cookbook" of ways to defeat security seals. The compromise presents a challenge to conscientious testing laboratories.

Annex B (normative) requires and 18 month transition before the tamper evident testing and the 18mm minimum widest diameter become required of all compliant seals. The transition is critical for tamper evident testing; it allows time for suppliers to re-examine and enhance anti-tamper features; for testing labs to define and refine their test methods; for lab accreditation agencies to learn the issues sufficiently to vet labs; and for security seal inventory adjustment throughout supply chains. 

Beginning 1 March 2012, all ISO 17712 compliant seals must be certified as tamper evident.

You may purchase copies of ISO 17712: 2010 from ISO itself or from any national standards bodies, such as AFNOR (France), ANSI (US), or BSI (UK).