Comparison of primary gas flow standard spanning the range from 2 mL/min to 10 L/min

Main text The CCM.FF-K6.2017 comparison was organised for the purpose of determination of the degree of equivalence of the national standards for low-pressure gas flow measurement over the range 2 mL/min to 10 L/min. Four molbloc-L flow elements and a molbox1+ were used as the transfer standards. Ten laboratories from three RMOs participated between August 2017 and January 2020 - EURAMET: INRIM (Italy); LNE (France); PTB (Germany); METAS (Switzerland); CMI (Czech Republic); SIM: NIST (USA); APMP: NMIJ/AIST (Japan); KRISS (Korea); NMIA (Australia); CMS (Chinese Taipei). The measurements were provided at prescribed reference pressure and temperature conditions. All results were used in the determination of the key comparison reference value (KCRV) and the uncertainty of the KCRV. The reference value was determined at each flow separately following the procedure presented by M G Cox [1]. The degree of equivalence with the KCRV was calculated for each flow and laboratory. This KCRV can now be used in further regional comparisons. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).