This test method is suitable for use under actual or simulated in-service conditions; that is, one side of the unit is exposed to room temperature, while the other side is exposed to natural or simulated weather conditions. Where the glazing conditions and the 24-h history are different or changed from previous conditions, the frost/dew point may not be comparable to a previous measurement.

This test method is applicable for the uncoated or unfilmed clear (transparent) glass pane of sealed insulating glass units. If this apparatus is used with coated or filmed glass pane, the coating or film on the surface of glass pane may be damaged.

This test method may require minor modifications to keep the measuring surface of the frost/dew-point apparatus in contact with the glass if the insulating glass unit is not in the true vertical position.

1.1 This test method describes a field or laboratory procedure for determining the frost/dew point within the air space(s) of sealed insulating glass units and establishes the criteria for determining whether that point is below or above a given or specified temperature.

1.2 This test method also describes the apparatus to be used for these determinations.

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 hazard statements, see 9.1.3 and 9.3.7.