National Measurement Laboratories R.O.C. (NML), entrusted by BSMI, MOEA, is responsible for establishing and maintaining the national primary standards for the traceability for domestic industry.  With its accumulated capability, NML has volunteered to act as a pilot and coordinate a CIPM low-pressure gas flow key comparison this year on, registered as CCM.FF-K6.2017.  The comparison is organized for the purpose of determining the degrees of equivalence of the participating laboratories spanning the gas flow range from 2 mL/min of nitrogen to 10 L/min of nitrogen; standard volumetric flow reference conditions are 101.325 kPa and 0 °C.  Ten laboratories from four RMOs (Regional Metrology Organizations) are participating in the comparison, including: CMI (Czech), NML (Chinese Taipei), INRIM (Italy), KRISS (Republic of Korea), LNE (France), METAS (Switzerland), NIST (the United States), NMIA (Australia), NMIJ (Japan), and PTB (Germany).

Key comparison is an essential activity of national metrology institutes, with the purpose of determination of the degree of equivalence of the national standards.  The comparison is accomplished by each laboratory calibrating a transfer standard that is circulated among the participating labs.  The comparison results and CMCs (Calibration and Measurement Capabilities) are publicly available in the KCDB (key comparison database) kept by BIPM.  Certificates supported by CMCs published in the KCDB are accepted worldwide at whatever accuracy is stated in the database. 

The measurement of low-pressure gas flow is vital to economic growth and high-tech competitiveness, and has wide applications such as in oil and natural gas transactions and in flow control in the manufacturing process of high-tech factories.  Taking home gas meters as an example, the standard of low-pressure gas flow established by NML supports Government’s credibility, via traceability, to guarantee the fairness of a trade that amounts to more than 50 billion NT dollars each year.  Other applications include dilution gas standards for PM2.5 environmental monitoring, and gas control or measurement in optical communication/semiconductor industries.

For the comparison, NML has completed the technical protocol and is preparing the pre-test for the transfer standard - a high precision transfer standard based on four molbloc-L flow elements and a molbox1+.  We plan to send out the transfer standard to participants one by one starting in October 2017 and expect to complete the circulation before July 2019.  

BSMI, MOEA: Bureau of Standards, Metrology & Inspection, Ministry of Economic Affaris

CIPM: International Committee for Weights and Measures