What is the OIML?

The International Organization of Legal Metrology (OIML) is an intergovernmental treaty organization whose membership includes Member States, countries which participate actively in technical activities, and Corresponding Members, countries which join the OIML as observers. It was established in 1955 (see the Convention) in order to promote the global harmonization of legal metrology procedures. Since that time, the OIML has developed a worldwide technical structure that provides its Members with metrological guidelines for the elaboration of national and regional requirements concerning the manufacture and use of measuring instruments for legal metrology applications.

Countries which are not yet Members of the OIML may download a PDF file giving additional information.

Definition of Legal Metrology

Legal Metrology is the entirety of the legislative, administrative and technical procedures established by, or by reference to public authorities, and implemented on their behalf in order to specify and to ensure, in a regulatory or contractual manner, the appropriate quality and credibility of measurements related to official controls, trade, health, safety and the environment.

OIML Publications

The OIML develops model regulations, International Recommendations, which provide Members with an internationally agreed-upon basis for the establishment of national legislation on various categories of measuring instruments. Given the increasing national implementation of OIML guidelines, more and more manufacturers are referring to OIML International Recommendations to ensure that their products meet international specifications for metrological performance and testing.

OIML Draft Recommendations and Documents are developed by Technical Committees or Subcommittees which are formed by the Member States. Certain international and regional institutions also participate on a consultation basis.

Cooperative agreements are established between the OIML and certain institutions, such as ISO and IEC, with the objective of avoiding contradictory requirements; consequently, manufacturers and users of measuring instruments, test laboratories, etc. may simultaneously apply OIML Publications and those of other institutions (See web sites of international and regional organizations in liaison with the OIML).

The main elements of an International Recommendation are Scope, application and terminology; Metrological requirements; Technical requirements; Methods and equipment for testing and verifying conformity to requirements; and the Test report format.

OIML Certificate System
for Measuring Instruments

The OIML Certificate System for Measuring Instruments was introduced in 1991 to facilitate administrative procedures and lower the costs associated with the international trade of measuring instruments subject to legal requirements.

The System provides the possibility for a manufacturer to obtain an OIML Certificate and a Test Report indicating that a given instrument type (pattern) complies with the requirements of the relevant OIML International Recommendations.

Certificates are delivered by OIML Member States that have established one or several Issuing Authorities responsible for processing applications by manufacturers wishing to have their instrument types (patterns) certified.

OIML Certificates are accepted by national metrology services on a voluntary basis, and as the climate for mutual confidence and recognition of test results develops between OIML Members, the System serves to simplify the type (pattern) approval process for manufacturers and metrology authorities by eliminating costly duplication of application and test procedures.

The OIML web site database lists those OIML Certificates registered by the BIML, and gives the list of categories of instruments covered by the System, the addresses of Issuing Authorities in OIML Member States (Issuing Authorities listed here), and those of recipients of Certificates (applicants and manufacturers).

The list of categories gives the references of the applicable Recommendations and specifies the Member States (by their ISO country codes) which have established an Issuing Authority for the relevant category.

In any given OIML Member State, there may be several Issuing Authorities; however, for a given category only one Issuing Authority may exist.

Further information on the System, particularly concerning the rules and conditions for the application, issue, and use of OIML Certificates, may be found in OIML Publication P 1 (Edition 2003) which may be downloaded in English or French from our web site. Printed copies are available from the BIML.

The fee for registering an OIML certificate is currently 150 EUR.