The new OIML certificate system, a practical approach

On 1 January 2018 a new OIML certificate system will be in place. It replaces the Basic and MAA certificate system. The new certificate system is designed to establish a single certification system with improved structures, rules and procedures and with further involvement of stakeholders. The new certificate system is called the OIML‑CS.


The OIML Basic certification system was established in 1991 and was a voluntary recognition and acceptance of Test Reports. The competence for participation in the system of the Issuing Authority and Test Laboratory was based on self-declaration. In 2005 a number of OIML member states signed a Declaration of Mutual Confidence to recognise OIML Test Reports based on a Mutual Acceptance Arrangement (MAA). Prove of competence on basis of the ISO/IEC 17025 was demonstrated for the participating Test Laboratories.

However, there was an unsatisfactory level of acceptance of OIML certificates, unsatisfactory level of participants, unsatisfactory number of category of measuring instruments and unsatisfactory management structures to operate both systems. To improve the system a single certification system is established with two schemes:

  • Scheme A:
    For this scheme the Issuing Authorities and Test Laboratories have provided proof of competence, either by an accreditation or peer assessment. Participants in scheme A are obliged to accept each other’s certificates and test reports.
  • Scheme B:
    For this scheme the issuing authorities self-declare competence and accept certificates and test reports on voluntarily basis.

The Scheme A is more or less a successor of the MAA certificate system, Scheme B of the Basic certificate system. Where the Basic and MAA system allowed to issue certificated under the Basic or MAA system simultaneously, the OIML-CS allows certificated to be issued under scheme A or B only.

What changes for the customer?

The main impact is for the Issuing Authorities and appertaining Testing Laboratories to comply with the requirements for demonstrating competence. The technical requirements for all categories of measuring instruments remain unchanged. All current OIML recommendations and all issued OIML certificates remain valid. However, no Basic or MAA certificates may be issued after 1 January 2018. Test data obtained for these certificates may be used, under specific conditions, to establish new certificates under the OIML-CS.

NMi will guide clients in obtaining OIML-CS certificates. We created a white paper with detailed information that you can download for free by filling in the webform. Do you still have questions after reading its content? Don’t hesitate to contact us by sending us an email to

Request form White Paper "The new OIML Certification System"

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