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International Organization of  Legal Metrology (OIML)

OIML - Organisation Internationale de Métrologie Légale,  is an inter-governmental organization which was established in 1955 with the goal to foster a global harmonization of legal metrology regulations. In September 2014 it had  60 full members and  67 members, so called observers. The membership fee of the CR amounts to 14 000 EUR. The organization has the following bodies:

  • International Conference of Legal Metrology (CGML) – is the supreme body of the organization and it convenes every 4 years
  • International Committee of Legal Metrology (CIML) – manages the organization in-between the conferences, the CR is represented here since 1993 by the General Director of CMI
  • International Bureau of Legal Metrology (BIML) – an executive body of the organization with a seat in Paris
  • Technical Committees and Sub-committees – proper technical work is concentrated in these groups, a list of  TC members for the CR is here, CR is represented in 59 out of 63 committees.

This global infrastructure generates for its members harmonized metrological regulations (non-binding paper standards of its kind - recommendations) which should be used for preparation of national or regional regulations for metrological and technical requirements and testing methods used in the so called regulated area (in the CR legally controlled measuring instruments). Drafts of OIML recommendation and documents are prepared by technical Committees and Sub-committees consisting of representatives of member states.  OIML has agreements with other normalization bodies like ISO and IEC to prevent any duplications in their work on international normative documents. In preparatory stages for EU Directive  2004/22/ES on measuring instruments (Measuring Instruments Directive, MID) the European Commission has decided that  OIML recommendations can be used in the framework of this directive as so called harmonized documents with the aim to achieve a maximum compatibility of the European legislation with the rest of the world. 

OIML Basic certification system.

OIML (Basic) certification system gives a chance to manufacturers of measuring instruments in the regulated area to obtain the so called a (basic) OIML certificate  (on the basis of a normalized test format) which certifies that a given type of a measuring instrument complies with the corresponding international OIML recommendations. Such test certificates issued by OIML member states which established one or more certification bodies of this kind can be recognized by national authorities of legal metrology on the basis of their voluntary decision. This voluntary character is normally considered to be a weak point of this OIML certification system  - therefore, so called Mutual Recognition Arrangement (the acronym MAA) has been drafted and approved to guarantee an automatic recognition of the test results in the form of prescribed protocols. These test results are subsequently used to issue  national type approval certificates – for details see

Following requirements from manufacturers CMI is active in a limited range in the basic  certification system to serve non-European manufacturers (watermeters, flow measuring instruments for liquids other than water, non-automatic and automatic weighing instruments,  flowmeters for cryogenic liquids) or for measuring instruments outside MID (level guages, dynamic road vehicles weighing instruments).