Worldwide metrology

International co-operation in action

The Metre Convention (Convention du Mètre), signed in Paris on 20 May 1875 by representatives of 17 nations and modified slightly in 1921, remains the basis of international agreement on units of measurement. Today, there are 64 Member States of the Metre Convention and 36 Associate States and Economies. The Convention created an intergovernmental organisation, known as the International Bureau of Weights and Measures (Bureau International des Poids et Mesures, BIPM), that co-ordinates international metrology and the development of the metric measurement system. Its work is supervised by the International Committee for Weights and Measures (Comité International des Poids et Mesures or CIPM). The BIPM and CIPM guided the development of the international metrology system in operation today, the introduction of the SI system in 1960 and the establishment of the CIPM Mutual Recognition Arrangement in 1999. 

The CIPM is responsible for oversight of the CIPM Mutual Recognition Arrangement (CIPM MRA). Through its system of peer review, intercomparisons and Calibration and Measurement Capabilities (CMCs) this arrangement provides the basis for recognising the degree of equivalence of the standards maintained by NMIs and mutual recognition of the calibration and measurement certificates that they issue. This provides the basis for recognition of equivalence of other measurements made in society provided that they are traceable to an NMI. The Arrangement is supported by 10 CIPM Consultative Committees made up of technical experts from NMIs, DIs and appropriate scientific bodies. 

Regional Metrology Organisations (RMOs) are made up of NMIs from the same part of the world. RMOs coordinate activities between its members and also between other RMOs. The RMO for European NMIs is EURAMET and NPL is an active member of this organisation. NPL is also an Associate Member of the Asia-Pacific Metrology Programme (APMP), which is a reflection of its growing interests in that region.

EURAMET’s mission is to develop and disseminate an integrated, cost-effective and internationally competitive measurement infrastructure for Europe, taking into account the needs of industry, business and governments. Bringing European NMIs and DIs together, the organisation supports members to meet their national requirements and to establish a balanced European measurement infrastructure. As one of 6 Regional Metrology Organisations EURAMET has a role in implementing the CIPM MRA. This is done through several Technical Committees, most of which include an NPL representative. There are two other main tools that EURAMET uses to achieve its goals. The first is a series of European metrology research programmes funding collaborative research projects (EMRP, EMPIR and now The Partnership on Metrology). The second tool is a number of European Metrology Networks (EMN) which provide an interface between the metrology community and stakeholders in academia, regulatory bodies and business. NPL is the UK member of EURAMET and an active participant in European research projects and EMN. The Management Support Unit for EURAMET/EU funded metrology research programmes is hosted at NPL.