scope:

Specifies the method to determine the mass of the water vapour transmitted through the adhesive tape under specific test conditions. Details of the test method depend upon the width of the adhesive tape under test. For adhesive tapes less than 50 mm width it is necessary to use Annex A (normative). When test pieces below 50 mm wide are used (as will be common) together with the smaller dry box the precision of this test may be reduced due to undesired moisture transmission at the adhesive seal. This part of the method should therefore be considered to give only approximate values.