Mutual recognition arrangement

Abstract This paper reviews the current state of play of the Mutual Recognition Arrangement created by the International Committee for Weights and Measures in 1999. The aim of the MRA is to provide a framework within which National Metrology Institutes can demonstrate the equivalence of their realisations of the units and quantities of the SI system to which accredited laboratories are traceable. The article offers some views on the need for traceable... 

National traceability or dissemination structures, internationally linked via comparison measurements under the CIPM Mutual Recognition Arrangement, are beginning to play a central role in establishing trace-ability of chemical measurements in practice. Reference materials are the most important transfer standards for disseminating traceability (more precisely the units of measurement) to the user level. Availability of certified reference materials with evidence of their metrological quality is, however, very limited. Great efforts are necessary to improve this situation. 

In October 1999, the directors of the NMIs of the industrialized states of the world signed a Mutual Recognition Arrangement (MRA) for national measurement standards and for calibration and measurement certificates issued by their institutes. This arrangement was drawn up by the International Committee of Weights and Measures (CIPM), under the authority given to it in the Metre Convention. 

Figure 2 The organization of the BIPM Mutual Recognition Arrangement (MRA), agreed in 1999 between the directors of the national measurement institutes of 38 Member States and representatives of two international organizations. (Reproduced with...

---