ISO 18453:2004

ISO 18453:2004 specifies a method to provide users with a reliable mathematical relationship between water content and water dew point in natural gas when one of the two is known. The calculation method, developed by GERG; is applicable to both the calculation of the water content and the water dew point.
ISO 18453:2004 gives the uncertainty for the correlation but makes no attempt to quantify the measurement uncertainties.