5.1 The purpose of this test method is to obtain values for the water vapor transmission rate of barrier materials.

5.2 Water vapor transmission rate is an important property of materials and can be related to shelf life; product stability, breath-ability, and wearing comfort.

5.3 Data from this test method is suitable as a referee method of testing, provided that the purchaser and seller have agreed on sampling procedures, test conditions, and acceptance criteria.

1.1 This test method covers a procedure for determining the rate of water vapor transmission ranging between 500 to 100,000 g/m²day through nonwoven and plastic barrier materials. The method is applicable to films, barriers consisting of single or multilayer synthetic or natural polymers, nonwoven fabric, and nonwoven fabrics coated with films up to 3 mm (0.1 in.) in thickness.

1.2 This test method provides for the determination of (1) water vapor transmission rate (WVTR), and (2) the permeance to water vapor.

1.3 The values stated in metric units are to be regarded as the standard. The acceptable units for water vapor transmission rate are usually g/m²day.

1.4 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.