Comparison of the primary low gas flow standards between MIKES and METAS

At Centre for Metrology and Accreditation (MIKES), a primary calibration system for gas mass flows between 0.42 mg/s and 625 mg/s is based on dynamic weighing providing traceability directly to the national mass and time standards. To evaluate the agreement of the system with a volumetric primary calibrator, the international comparison between MIKES and the Swiss Federal Office of Metrology and Accreditation (METAS, Switzerland) was carried out. At METAS, the primary low gas flow standard provides traceability to the Swiss national measurement standards for length and time. The results of the comparison showed that the two systems do not deviate more than ±0.15% in the mass flow range 0.42–625 mg/s.