A two-temperature humidity generator has been developed at the Centre for Metrology and Accreditation (CMA) in order to have a reliable humidity standard. The system has been tested and the analysis of uncertainty has been carried out. The disturbance of the saturation equilibrium, the accuracy of temperature measurements, pressure differences, leaks, desorption and contamination have been investigated. The measurement range of the system is from -40 to +60°C with an uncertainty of less than ±0.25°C (k = 2). The system was found suitable to be used as the CMA humidity standard.
- Analysis of uncertainty
- Humidity standard