Measurement results and drift analysis of a relative humidity meter used for temperature range, 5 °C to 55 °C, at the NMISA

摘要

The National Metrology Institute of South Africa (NMISA) humidity laboratory maintains and disseminates the measurement traceability of relative humidify and dewpoint temperature. For relative humidity (5 %rh to 95 %rh), NMISA humidity laboratory had only the capability to provide traceability at the temperature range of 15 °C to 30 °C. However the industry required the traceability of measurements outside of the accredited scope of NMISA. The capacitive relative humidity meter was purchased for the purpose of extending the accreditation scope to the temperature range 5 °C to 55 °C. To support the accreditation and quality assurance of the extended capabilities, the laboratory participated in two bilateral inter-laboratory comparisons using this meter as the transfer standard. The comparison was for the relative humidity range 5 %rh to 95 %rh at the temperature range of 5 °C to 55 °C. The measurement results of the comparisons and the drift analysis of the meter since commissioned are presented in this paper.