Final report on regional key comparison COOMET.M.P-K2: Hydraulic gauge pressure in the range 10 MPa to 100 MPa

Abstract

This report describes a COOMET key comparison of hydraulic pressure standards of seven national metrology institutes that was carried out in the period from June 2005 to July 2008 in order to determine their degrees of equivalence in the range 10 MPa to 100 MPa of the gauge pressure. The pilot laboratory was VMT/VMC. The pressure standards of the participating NMIs were pressure balances of different design, equipped with piston–cylinder assemblies. The transfer standard was a pressure balance, equipped with a 9.8 mm2 piston–cylinder assembly, manufactured by SMU. The participants reported the pressure-dependent effective areas of the transfer standard at specified pressures. The reference values were calculated as the weighted means of PTB, NPL, SMU and VNIIM, which have primary pressure standards. The results by all participants agree with the reference values and with each other within the expanded uncertainties calculated with a coverage factor (k = 2). At the level of standard uncertainties there is a full agreement between 10 MPa and 100 MPa. The results of this comparison were linked to those of key comparison CCM.P-K7. Degrees of equivalence and expanded (k = 2) uncertainties between the COOMET and laboratories having participated in other KCs: CCM.P-K7, APMP.M.P-K7, EUROMET.M.P-K4 and APM.M.P-K7.1 at measured pressure points are presented in the final report. The results of the comparison demonstrate equivalence of the laboratory standards and, for laboratories the CMCs of which are not yet presented in the KCDB, this comparison provides a basis for submission in the range from 10 MPa to 100 MPa of hydraulic gauge pressure.Main text.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 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 (MRA).