Quantitative leak tests with vacuum technology have become an important tool in industry for safety and operational reasons and to meet environmental regulations. In the absence of a relevant key comparison, so far, there are no calibration measurement capabilities published in the BIPM data base. To enable national metrology institutes providing service for leak rate calibrations to apply for these entries in the data base and to ensure international equivalence in this field, key comparison CCM.P-K12 was organized. The goal of this comparison was to compare the national calibration standards and procedures for helium leak rates. Two helium permeation leak elements of 4×10−11 mol/s (L1) and 8×10−14 mol/s (L2) served as transfer standards and were measured by 11 national metrology institutes for L1 and 6 national metrology institutes for L2. Equivalence could be shown for 8 laboratories in the case of L1 and for all 6 in the case of L2. Three different evaluation methods were applied and are presented in this report, but the random effects model was accepted as most suitable in our case.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).

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A comparison between the D. I. Mendeleyev Institute for Metrology (VNIIM, Russian Federation), the Physikalisch-Technische Bundesanstalt (PTB, Germany) and the Slovak Institute of Metrology (SMU, Slovakia) was organized by the VNIIM as the coordinator and pilot laboratory of a COOMET project that started in 1995 and finished in 1998. The comparison was realized on the basis of cross-float experiments with two transfer standards -5 cm 2 piston-cylinder assemblies for pressure balances -manufactured by, and belonging to, the VNIIM. The transfer standards and the methods applied to determine their effective areas, , are described and the comparison results presented. With the equivalence criterion for the agreement between any two participants taken to be ( being the standard uncertainty of the effective area of the transfer standard used), the national standards of the participants for the pressure range covered by the comparison experiments may be considered to be equivalent. As one of the participants in the present comparison (PTB) used the same primary standards in comparisons organized by EUROMET* and by the Consultative Committee for Mass and Related Quantities (CCM), the participants in this COOMET project can indirectly compare their pressure standards with those of other European countries, Japan, and the United States.

This article is devoted to development and research of sensitive elements, transducers and vacuum gauges created by resonant method and intended for measuring absolute pressure in a wide range from 10 to 104 Pa.