ASTM D 2029:1997

1.1 These test methods describe the determination of the water vapor content of electrical insulating gases by direct or indirect measurement of the dew point and the calculation of the water vapor content. 1.2 The following four test methods are provided: 1.2.1 Method A describes the automatic chilled mirror method for measurement of dew point as low as - 73°C (-99°F). 1.2.2 Method B describes the manual chilled mirror or dew cup method for measurement of dew point as low as - 73°C (-99°F). 1.2.3 Method C describes the adiabatic expansion method for measurement of dew point as low as - 62°C (-80°F). 1.2.4 Method D describes the capacitance method for measurement of dew point as low as - 110°C (-166°F). 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warnings, see 8.1.1, 9.2, 10.1.2 and 10.2.5.