NMIJ Newsletter

CIPM Mutual Recognition Arrangement

In response to economic globalization, the Mutual Recognition Arrangement (MRA) was drawn up by the International Committee of Weights and Measures (CIPM), under the authority given to it in the Metre Convention. The CIPM MRA was signed in 1999 at the 21st meeting of the General Conference on Weights and Measures (CGPM) by the National Metrology Institutes (NMIs) from 38 Member States of the Metre Convention and two international organizations. The arrangement was enforced in Jan. 2005. As of Jan. 2021, the arrangement covers institutes from 63 Member States, 39 Associate States and Economies of the CGPM and four international organizations. The list of participants is available at https://www.bipm.org/en/cipm-mra/participation.

The objectives of the CIPM MRA is to establish the degree of equivalence of national measruement standards maintained by NMIs and to provide for the mutual recognition of calibration and measurement certificates, thereby to provide governments and other parties with a secure technical foundation for wider agreements related to international trade, commerce and regulatory affairs.

Calibration Measurement Capabilities (CMCs)

To achieve the goal of the CIPM MRA mentioned above, NMIs and Designated Institutes (DIs) in individual countries develop and maintain their national measurement standards and declare their CMCs by establishing quality systems, receiving peer reviews by signatory NMIs and DIs, and participating in the related international comparisons for each each measurand. Approved CMCs are registered in the database (KCDB Appendix-C) maintained by the International Bureau of Weights and Measures (BIPM), and are publicly available on the Web. The total number of registered CMCs is 25717 as of April 2022.

KCDB searching system: https://www.bipm.org/kcdb/

International Comparison

The results of the international comparisons provide vital evidence for NMIs and DIs to declare their CMCs. Consultative Committees, set up for each metrology field under the CIPM, execute CIPM key comparisons to test the principal techniques and method of the field. In principle, these comparisons are conducted by the institutes having the highest technical competence and experience, normally by the member NMIs and DIs of the CCs. When a Regional Metrology Organization (RMO) conducts key comparisons, one of the institutes which participated in the preceding key comparison serve as the pilot institute in many cases. RMO key comparisons are open to all RMO members and other institutes, subject to decision by the organizing RMO.

figure1

The results of RMO key comparisons are linked to the corresponding CIPM key comparisons through the NMIs participated in the CIPM key comparisons, providing vital evidence to declare CMCs as well as the result of the CIPM key comparison. Meanwhile, supplementary comparisons are individually conducted by RMOs to cover areas or techniques not addressed by the CIPM and RMO key comparisons.

The results of international comparisons are registered in the database (KCDB Appendix-B) and updated on the Web. A total of 1767 international comparisons are registered in the KCDB as of April 2022. Japan is ranked 2nd in the world with participation in 563 international comparisons.

The number of participation in the international comparisons

(as of April 2022, KCDB searching system: https://www.bipm.org/kcdb/)

  Country May 2011 Apr. 2012 May 2013 May 2014 Nov. 2015 Dec. 2016 Aug. 2017 Feb.
2018
Mar. 2019 Oct. 2020 Oct. 2021 Apr. 2022
1 Germany 547 575 600 627 683 698 719 730 753 612 791 798
2 Japan
(NMIJ)*
361
(353)
390
(381)
407
(396)
427
(420)
462 476
(450)
491 496
(485)
508
(501)
538
(526)
555
(533)
563
(545)
3 United States 400 417 432 450 481 485 501 505 515 527 543 543
4 United Kingdom 403 422 432 448 478 479 488 492 502 523 538 542
5 France 369 389 406 430 451 465 475 483 496 521 534 539
6 Russia 301 322 340 360 392 408 422 431 450 471 507 515
7 Korea 303 332 354 378 395 410 423 428 450 479 498 501
8 China 253 277 302 323 352 366 381 387 410 456 477 486
9 Italy 244 257 272 282 293 299 302 308 316 329 338 341
10 Australia 233 249 257 269 281 286 299 301 307 319 332 334
Grand Total** of
International Comparisons
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
1003 1081 1188 1278 1343 1453 1499 1529 1588 1673 1745 1767

*The figures in the brackets show the number of NMIJ's participation in the international comparisons.

**The grand total shows the sum of key and supplementary comparisons registerd in the KCDB.