The National Metrology Institute of South Africa (NMISA) Gas Flow Laboratory provides
traceability to the South African Industry for gas flow measurements. A new primary
standard for gas flow calibrations was purchased and commissioned. With three flow cells,
a flow range of 0.5 mL/min to 50 000 mL/min is covered. The main features of this standard
are accuracy, speed and convenience. This paper describes the activities of the NMISA Gas
Flow Laboratory – a discussion of the primary standard, the validation thereof,
calibration methods for client instrumentation, analysis of measurement results and the
calculation of measurement uncertainties.