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Research paper : Improvement of reliability in pressure measurements and international mutual recognition (T. Kobata et al.)−223−Synthesiology - English edition Vol.4 No.4 (2012) related technologies for the pressure gauge calibration at the industrial sites by the calibration labs. 7.2 International mutual recognition of pressure measurementAIST participated in the international comparison of the national standards for pressure conducted by the Comité Consultatif pour la Masse et les Grandeurs Apparentées (CCM) of CIPM, as well as the Consultative Committee for Mass of the Asia Pacific Metrology Program (APMP)[19]-[23][25]. Table 3 shows the international comparisons in which AIST had participated and the ones in progress. AIST organized the international comparison as the pilot institute in the majority of the APMP international comparisons, and engaged in the creation of the execution schedule, drafting of the measurement manual, preparation of the transfer device and the property evaluation, organization of the comparison results, and the write-up of the final report[19]-[22]. In the international comparisons organized by AIST, the digital pressure gauge was used actively as the transfer device to enhance efficiency, as mentioned in subchapter 6.2.The international equivalence of the AIST national standard was confirmed according to the results of the international comparisons of several pressure ranges[19]-[23][25]. AIST is planning to participate actively in the future international comparisons, and will continue to ensure the international equivalence of the Japanese national standards.The results of the international comparisons conducted by AIST as the pilot institute are registered in the Appendix B of the international Mutual Recognition Arrangement, CIPM, as mentioned in subchapter 2.2. The calibration and measurement capabilities that the participating national metrology institutes claimed based on the results of the international comparison are registered in the Appendix C of the Mutual Recognition Arrangement after international recognition. By actively participating in the international comparison activities, we believe we were able to support the smooth accreditation of the calibration and measurement activities of several countries, mainly of Asia, as well as Japan.By utilizing the digital pressure gauge, we were able to reduce the size and weight of the transfer device, hence reducing the problems during transportation. We were also able to obtain sufficient comparative precision by evaluating the long-term stability using multiple digital pressure gauges for redundancy in each transfer device. Also, the international comparison could be done in short periods by preparing multiple transfer devices and circulating them simultaneously. By using the transfer device comprised of the digital pressure gauge in the international comparison, we were able to efficiently confirm the international equivalence of the national standard necessary for international mutual recognition. 8 ConclusionThe R&D was conducted to confirm the international equivalence of the national standard for the international mutual recognition and to maintain the reliability of the pressure measurement at the industrial site, using the digital pressure gauge. As the pressure standard at the industrial site, the pressure balance and the liquid column manometer that have excellent long-term stability were traditionally used, but the use of the digital pressure gauge and various pressure generators are now increasing. The technologies for property evaluation and calibration of the digital pressure gauge described in this paper are used effectively in the pressure standard system, and the practical application of the effective standard provision system using the digital pressure gauge as the standard or transfer device is progressing. With the diffusion of JCSS, the calibration of the digital pressure gauge traceable to the national standard for pressure for a wide pressure range is now available to the general user through accredited pressure calibration labs, and this contributes to the increased reliability of on-site pressure measurement.Table 3. International comparison for pressure in which AIST participated (since 2001)2007-2010100 MPa - 1000 MPaAPMP.M.P-S8**International comparison with AIST as the pilot institute2010-50 MPa - 500 MPaAPMP.M.P-K13*2008-201150 MPa - 500 MPaCCM.P-K13200140 MPa - 200 MPaAPMP.M.P-K7.TRI*2007-200910 MPa - 100 MPaAPMP.M.P-K7.1*2002-200510 MPa - 100 MPaHydraulic gauge pressureAPMP.M.P-K7*2003-200510 MPa - 100 MPaHydraulic gauge pressureHydraulic gauge pressureHydraulic gauge pressureHydraulic gauge pressureHydraulic gauge pressureHydraulic gauge pressureCCM.P-K72005-20061 Pa - 5 kPaGas differential pressureAPMP.M.P-K5*2009-10 kPa - 110 kPaGas absolute pressureAPMP.M.P-K91998-20010.4 MPa - 4 MPaGas gauge pressureAPMP.M.P-K1.c1998-200120 kPa - 105 kPaGas gauge pressureAPMP.M.P-K6Year executedPressure rangeKindIdentifier

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