Final Report on Supplementary Comparison EURAMETMP-S14 of Hydraulic Gauge Pressure Standards from 50 MPa to 1000 MPa

The EURAMET.M.P-S14 supplementary comparison was organized for the purpose of determination of the degree of equivalence of the national standards for static high-pressure measurement over the range 0.05 GPa to 1 GPa. A collection of eight selected high-pressure transducers with different ranges was used as a transfer standard. Five National Metrology Institutes (NMIs) from EURAMET participated in this comparison - PTB (Germany), SMU5 (Slovakia), CMI (Czech Republic), LNE (France), METAS (Switzerland), and all participants reported independent traceability chains to the SI. The measurements were provided at prescribed reference pressure and temperature conditions. The comparison reference value (CRV) and its uncertainty were determined separately at each pressure point, pressure transducer and particular conditions (up- and downward pressure measurement and pressure range). All the CRV results were summarised to determine the degree of equivalence for each laboratory at each pressure. The calculated degrees of equivalence show all the laboratories to be consistent at all pressures (see Appendix A6). METAS has measured, but withdrawn its results at (600, 700 and 800) MPa. Moreover, SMU withdrew their results as well. The uncertainties of the laboratories' measurements were, in many cases, much higher than the uncertainties of the laboratories' standards, which indicate problems in calibration of high pressure transducers at high pressures. [GRAPHICS]