Supplementary comparison of gas provers in the gas flow range 0.25 m³/h to 25 m³/h

Main text This report presents the results of an inter-laboratory comparison organized in order to determine the degrees of equivalence of bell and piston prover standards in the gas flow range 0.25 m 3 /h to 25 m 3 /h. The objective of the comparison was to support and prove the Calibration and Measurement Capabilities (CMC) in gas flow of the participating NMIs: BEV (Austria), METAS (Switzerland), GUM (Poland) and INRIM (Italy). The comparison was organized and evaluated by BEV as pilot laboratory. METAS provided the transfer standard a TRIPLE rotary meter G16 and performed the first and last measurement of the loop. The results of the calibrations were used to determination the key comparison reference value (KCRV) and its uncertainty. The reference value was determined at each flow separately following procedure A presented by M G Cox. The degrees of equivalence with the KCRV were calculated. The comparison shows very good agreement between the testing facilities. Only one setup failed the consistence test at three flow rates and had one comparison result in the "warning level". 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).