Recognition Arrangement: the MRA and its implementation
The Mutual Recognition Arrangement or MRA, was drawn up by the International Committee of Weights and Measures (CIPM) under the authority given to it by the Member States of the Metre Convention, and signed in October 1999 by the directors of the NMIs
The MRA establishes mutual recognition of the national measurement standards and of the calibration and measurement certificates (Calibration Measurement Capabilities - CMC) issued by the NMIs.
To establish the mutual recognition criteria on an objective basis, this arrangement rests on :
- The results of a series of key comparisons based on specific processes that lead to quantitative estimation of the degree of equivalence of the national measurement standards ;
- The implementation by each NMI of the suitable means in order to ensure measurements quality ;
- The effective participation of each NMI in the appropriate supplementary comparisons.
This arrangement includes two sections: in the first one, signatories recognize the degree of equivalence of the national measurement standards of the participating NMIs; in the second section, signatories recognize the validity of the calibration and measurement certificates issued by the participating NMIs. A specific logo has been created, said logo can be applied to the calibration certificates issued by the NMIs, for CMCs published in the KCDB (Key Comparison DataBase du BIPM).
The Laboratoire national de métrologie et d'essais (LNE) is the metrology institute which mission is to implement the national metrological policy in France. As such, and as signatory of the MRA, LNE must meet its criteria for an effective recognition of the calibration possibilities in the French NMIs and the laboratories associated with the LNE.
The key points of the MRA
- The degree of equivalence of the national measurement standards maintained by the NMIs ;
- Provide for the mutual recognition of the calibration and measurement certificates issued by the NMIs ;
- Provide thus to the Governments and other parties solid technical foundation for other more extended agreements in connection with international trade, and regulation activities.
- Global coordination is performed by the BIPM under the patronage of the CIPM ;
- The CIPM’s Consultative Committees (CCs), the Regional Metrology Organisations (RMOs) and the BIPM are responsible for the organisation and the realisation of the key and supplementary comparisons and for validation of their results ;
- A Joint Committee for RMOs and BIPM (JCRB) is responsible for reviewing the possibilities regarding measurements and calibrations declared by the NMIs, in order for these to be listed in the BIPM’s database.
A database containing the result of the key comparisons of the national measurement standards and the lists of the NMIs’ calibration and measurement capabilities is available on the BIPM site.
- International comparisons of measurements, indicated as Key Comparisons ;
- International comparisons of supplementary measurements ;
- Implementation by the NMIs of quality systems and demonstration of their competencies ;
- Assessment of the calibration capabilities of all the NMIs. Such assessment is done at a first stage within each RMO, then by the others RMOs and validated by the JCRB.
- Declaration of the possibilities regarding measurements for each institute, listed in the database managed by the BIPM and accessible to the public via the Web.
The NMIs’ directors signing the Mutual Recognition Arrangement are doing so with the consent of the appropriate authorities of their respective countries. And in so doing, they :
- Accept the procedures written in the Arrangement and aimed at establishing the database ;
- Recognise the results of the key comparisons listed in the database ;
- Recognise the possibiliies regarding measurement and calibration of other institutes participating in the Arrangement and listed in the BIPM’s database.
A database containing the result of the key comparisons of the national measurement standards and the lists of the possibilities for calibration and measurement in the NMIs, is available on the BIPM site.
Schematic of the international metrology organization under the MRA