The purpose of this guideline is to define minimum requirements for the reference standard, calibration equipment, calibration procedure and the estimation of the measurement uncertainty in the calibration of hygrometers. It applies to calibration devices with direct measurement of relative humidity by means of resistive, capacitive, resistive-electrolytic as well as mechanical sensor elements. In this guideline, the term gas humidity refers to gaseous substance systems consisting of the components water and carrier gas. The guideline applies to the carrier gases air and nitrogen. For other carrier gases, the application of the guideline still is to be assessed.
If the calibration of the gas temperature is desired in addition to the humidity calibration, the guidelines DKD-R 5-1 or DKD-R 5-3 apply to the temperature calibrations. The selection of the guideline depends on the sensor element.