Saturator Efficiency and Uncertainty of NIS Primary Standard for Relative Humidity Calibration

In the last ten years, there has been associate interest of makers and laboratories in having more accurate humidity measurements. Electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated, and therefore the uncertainty measurement of these sensors has become a major concern. This paper describes the relative humidity uncertainty analysis and uncertainty contribution from saturator efficiency for the National Institute of Standards' (NIS-Egypt) two-pressure humidity generator. Efficiency tests were administrated. The saturator efficiency test results showed smart performance of the generator, as described below. Uncertainty analysis was also represented for all the sources that touch measurements. The expanded uncertainty of a coverage factor k=2 was found to be from ± 0.1% to ± 0.45% for relative humidity.