This International Standard describes hygrometers used for the determination of the water dew point of natural gases by detecting water vapour condensation occuring on a cooled surface or by checking the stability of the condensation on this surface.
DS/EN ISO 6327:2008 history
2008DS/EN ISO 6327:2008 Gas analysis - Determination of the water dew point of natural gas - Cooled surface condensation hygrometers