Response time measurement of hygrometers at LNE-CETIAT

LNE-CETIAT has been involved in European project JRP HIT – EMPIR (www.empir-hit.eu). The objectives of this project were to improve the accuracy of industrial humidity measurements, to provide new traceability capabilities and to develop new calibration techniques at high temperatures up to 180 °C and under transient conditions. Considering the last aspect, LNE-CETIAT has worked on the development of a humidity step generator for studying response time of hygrometers. Indeed, classical calibrations are performed under quasi-static conditions whilst the end users measurement conditions are, most of the time, non-static or dynamic. In order to tackle this situation, LNE-CETIAT has started to developed dynamic humidity generator which enables response time measurement by applying humidity step to the device under test. In this article the test rig is presented as well as results obtained with chilled mirror hygrometers. A discussion about response time of chilled mirror concludes this work.