ISO 17712 and security seals for containers

ISO 17712 and security seals for containers


ISO 17712 is a set of rules which establish procedures for the unification and classification of security seals for fitting on mechanical cargo containers. It defines the types of seals that can be used for this purpose, but also establishes the basic general requirements and tests that seals must pass in order to be certified under this standard.

Compliance with these regulations is an essential requirement for security seals to be accepted for domestic and international transport of goods.


General requirements for seals specified by ISO 17712

ISO 17712 requires that all security seals have the following general features:

  • Security seals must be unique, difficult to imitate and be marked with the corresponding information.
  • The design should be easy to inspect and to determine whether it is being used properly or its application is defective. No room must be left for doubt.
  • Security bolt seals must be at least 18 millimetres in diameter.
  • They are single use devices: by removing them, the seals must be destroyed and become unusable. They have to show clear proof in case of inviolability.
  • They must meet the thresholds of strength specified by the standard and pass all the tests to which they are submitted at the accredited bodies.


Three types of seals allowed by ISO 17712

ISO 17712 defines the various types of certified cargo container seals. There are three of these:

1. Indicating seals

They are plastic or metallic seals that are easy to open after they are fitted. As container seals, this type is used on empty containers which have to be moved over short distances, for example, in the same city. These seals ensure that the container is clean and suitable for loading. Of course, the indicating security seals must bear the regulatory marking including the numbering and the logo of the company.


2. Security seals

Security seal with metallic cable F-150Locking this type of seal already provides greater security, in order to prevent the unauthorized opening of cargo containers. The difference between this category of seals and the next is that security in this case is more restricted. In any case, if a seal has been broken, it must be evident during an inspection. They are also marked with numerical information and the logo.


3. High security seals

Clik-Lok high security sealThey are made of extremely strong materials such as metal, or they incorporate steel cable. The ultimate purpose of this type of seals is to prevent and hinder at all costs any attempt to open or tamper with them. In addition, advanced special tools are needed for its removal. The most commonly used type of marking for these seals is by laser, due to its excellent resistance to environmental aggression. The letter “H” (from High Security Seals) defines the classification of this type of seal.


Mechanical strength tests in ISO 17712

Security seals certified in accordance with the standard must comply with specific tests in relation to tensile, cutting and impact strength. These tests must be carried out in institutions accredited by the regulations. Let us see in detail what they consist of:

  • Tensile strength: defines the strength of the security mechanism, which must be greater than 1,000 kg. It consists of pulling the ends until they eventual separate.
  • Cutting: both in security bolt seals and those with metal cables, the cutting strength must be greater than 340 kg.
  • Lateral impact: this test consists of striking the security bolt seal perpendicularly in an attempt to break it. Tests the flexibility of the seal shaft and its ability to bend.
  • Vertical impact: in this case, the impact may come from any angle until the seal is broken.


Responsibility in the handling of security seals for containers


1. Responsibilities of security seal users

The user of security seals should follow the best usage practices of seals as discussed in our article. In summary, these include the obligation to keep a detailed log of the seals (and their breakage where appropriate), the conservation of the seals and monitoring of the application process. Of course, all this must be supervised by a responsible person designated by the company.

Checking container seals

2. Responsibilities of security seal manufacturers

However, security seal manufacturers must also meet the following obligations:

  • Keep a log of all seals manufactured, as well as the numbering and markings in order to prevent duplicates and keep the information at hand.
  • Certify that the manufacturing process complies with the criteria of strength and the materials specified by ISO 17712.
  • Have an adapted customization service.
  • Have a direct contact with specialists to provide solutions to any issues that may arise concerning security seals for containers.

Contacta con Precintia (sector logístico)

Documents that certify compliance with ISO 17712

To prove that security seal manufacturers complies with ISO 17712 regarding the manufacture of seals for containers, they must provide the following documents:

  • Annex A of ISO 17712 which guarantees that it respects best practice.
  • The certificate that the security seals exceed or comply with the minimum tensile strength specified in clause number 5 (in the category of high security seals).
  • The document which accredits the tests that have been carried out in the laboratory to prove the mechanical strength of the seals.
  • The letter of conformity with the requirements relating to evidence of tampering in order to deter counterfeiting attempts.
  • In addition, the manufacturer must also be certified to the ISO 9001 standard that guarantees the quality management system followed throughout the process.


Find the Precintia seals for your containers approved in accordance with ISO 17712. If your company needs to acquire this type of security seal, do not hesitate to contact us.


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