EURAMET.M.P-S9: comparison in the negative gauge pressure range −950 to 0 hPa

A comparison in the negative gauge pressure range was arranged in the period 2011 - 2012. A total of 14 laboratories participated in this comparison: BEV (Austria), CMI (Czech Republic), DANIAmet-FORCE (Denmark), EIM (Greece), HMI/FSB-LPM (Croatia), INM (Romania), IPQ (Portugal), LNE (France), MCCAA (Malta), METROSERT (Estonia), MIKES (Finland), MIRS/IMT/LMT (Slovenia), NSAI (Ireland) and UME (Turkey). The project was divided into two loops: Loop1, piloted by MIKES, and Loop2, piloted by LNE. The results of the two loops are reported separately: Loop1 results are presented in this paper. The transfer standard was Beamex MC5 no. 25516865 with internal pressure module INT1C, resolution 0.01 hPa. The nominal pressure range of the INT1C is −1000 hPa to +1000 hPa. The nominal pressure points for the comparison were 0 hPa, −200 hPa, −400 hPa, −600 hPa, −800 hPa and −950 hPa. The reference values and their uncertainties as well as the difference uncertainty between the laboratory results and the reference values were determined from the measurement data by Monte Carlo simulations. Stability uncertainty of the transfer standard was included in the final difference uncertainty. Degrees of equivalences and mutual equivalences between the laboratories were calculated. Each laboratory reported results for all twelve measurement points, which means that there were 168 reported values in total. Some 163 of the 168 values (97 %) agree with the reference values within the expanded uncertainties, with a coverage factor k = 2. Among the laboratories, four different methods were used to determine negative gauge pressure. It is concluded that special attention must be paid to the measurements and methods when measuring negative gauge pressures. There might be a need for a technical guide or a workshop that provides information about details and practices related to the measurements of negative gauge pressure, as well as differences between the different methods. The comparison is registered as EURAMET project no. 1170 and as a supplementary comparison EURAMET.M.P-S9 in the BIPM key comparison database. 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 (CIPM MRA).</jats:p

Comparison in gas media (absolute and gauge mode) in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow a link to the CCM.P-K6 and CCM.P-K2 comparisons to be established. This project interested a lot of laboratories from the beginning with 23 participants, 22 of which have submitted results. The circulation of the transfer standard began in July 2009 and lasted until January 2012. No major problems occurred during the transport. The measurand of the comparison is the effective area of a piston-cylinder determined in gauge and absolute pressure from 25 kPa to 200 kPa with pressure steps of 25 kPa. The transfer standard is a gas lubricated tungsten carbide piston-cylinder with an effective area of ~9.8 cm2, fabricated by DH Instruments and compatible with a PG-7601 pressure balance. Some participants used their own pressure balance while a pressure balance with a reference vacuum sensor has been circulated for the participants not equipped with this system. One participant (SMU, Slovakia) has never provided the measurement results and another participant (FORCE Technology, Denmark) submitted a revised set of measurement results after the pilot laboratory mentioned that the equivalence was not met. After the determination of the reference value, all the 22 participants who delivered the results in gauge pressure demonstrated equivalence respective to the reference value on most of the range. In absolute pressure the equivalence is demonstrated, for all nominal pressures, by all 17 participants who submitted results. The comparison is linked to the CCM.P-K6 for gauge pressure and to CCM.P-K2 for absolute pressure. The link does not strongly affect the equivalence of the results and an excellent degree of equivalence is achieved in gauge and absolute pressure