Final report on supplementary comparison APMP.M.P-S9 in gas gauge pressure from 2 MPa to 20 MPa

Abstract

This report describes the results of a supplementary comparison of gas pressure standards at three National Metrology Institutes - National Institute of Metrology (Thailand) (NIMT), Physikalisch-Technische Bundesanstalt (PTB) and National Metrology Laboratory of the Philippines (NMLPHIL) - carried out within the framework of Asia-Pacific Metrology Programme (APMP) in order to determine their degrees of equivalence at pressures in the range from 2 MPa to 20 MPa for gauge mode. The pilot institute was NIMT. The measurements were carried out from February 2016 to July 2016. All participating institutes used pressure balances as their pressure standards. A reference pressure monitor was used as a transfer standard. Characteristics of the transfer standard were evaluated at the pilot institute and then used for uncertainty estimations. After completing the comparison measurements, the transfer standard showed a less stable behaviour than expected, resulting in a significant contribution to the uncertainties of the results. The degrees of equivalence that were evaluated in terms of differences of the participant's results and the comparison reference values divided by their expanded uncertainties (k=2) are all within the unity. This demonstrates equivalence of the compared standards on the uncertainty level, which is unfortunately dominated by the uncertainty of the transfer standard.Main textTo 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 kcdb.bipm.org/.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).