[12p-B408-1~10] 1.5 Instrumentation, measurement and Metrology

△ [12p-B408-4] Uncertainty in the Relative Humidity Generation using the Two-Pressure Two-Temperature Humidity Generator

〇Naoya Ishiwata¹, Tamio Niwa¹, Hisashi Abe¹ (1.National Metrology Institute of Japan (NMIJ), AIST)

Keywords:relative humidity, uncertainty, humidity generation

The high accuracy and good long-term stability become required for relative humidity sensors as the use of relative humidity measurements expands in various industries. In this study, the uncertainty in the relative humidity generation with the NMIJ two-pressure two-temperature humidity generator was estimated in detail for the purpose of improvement in the reliability of relative humidity calibration and performance evaluation. Relative humidity in a test chamber for relative humidity calibration is calculated from dew point and temperature of the moist air. The uncertainty of the temperature distribution in the chamber, which is one of the main uncertainty components of relative humidity generation, was estimated accurately with correction for the self-heating of all thermometers used for the measurements. Other uncertainty factors were also evaluated and the total uncertainty was estimated for the generation of relative humidity between 10 %rh and 98 %rh at 23 °C.