The inter-laboratory comparison has been carried out in the flow rate range between 10 L/h and 300 L/h with light oil in order to assess the calibration uncertainties of the small calibration facilities for hydrocarbon flow at two laborites, NMIJ and ONOSOKKI. A piston type positive flow meter was selected as a travelling meter and the effect of the flow meter due to flow rate, temperature, pressure, viscosity and between-day variability has been investigated by using the NMIJ calibration facility in detailed in order to evaluate the uncertainties due to different calibration condition between the two laboratories. Resulting that the uncertainty due to the flow meter at 20 L/h to 300 L/h is less than the calibration uncertainties at both labs, the selected flow meter is suitable. However, the comparison at 10 L/h is inappropriate, since the uncertainty due to the flow meter is larger than the uncertainty at each lab. Furthermore the two calibration facilities between 20 L/h and 300 L/h at the two labs agree within the quoted expanded uncertainties.
