ASTM E96 Standard Test Methods for Water Vapor Transmission of Materials

The ASTM E96 test covers the determination of the water vapor transmission (WVT) of materials where the passage of water vapor may be important, such as paper, plastic films, other sheet materials, fiberboards, gypsum and gypsum products, wood products, and plastics.

Test methods are limited to specimens not greater than 11/4 in thickness, except as specified. Two basic methods are provided for the measurement of permeability, the Desiccant Method and the Water Method, and two variations include service conditions with wetted service conditions on one side and service conditions with low humidity on one side and high humidity on the other. Consensus should not be expected between the results obtained by different methods. The method that is closer to the conditions of use should be chosen.

The purpose of these tests is to obtain reliable water vapor transfer values ​​through permeable and semipermeable materials, expressed in appropriate units, by means of simple apparatus. These values ​​are for use in design, manufacture and marketing.

The permeability value obtained under one set of test conditions may not show under a different set of conditions. For this reason, test conditions that closely approximate the conditions of use should be selected. Any set of conditions can be used and these conditions can be reported, while useful standard conditions are additionally displayed.

Values ​​stated in SI units or inch-pound units should be considered separately as standard. Values ​​specified in each system may not be exactly equivalent; therefore, each system will be used independently of the other system. Combining values ​​from the two systems may result in non-compliance with the standard. However, the derived results can be converted from one system to another using appropriate conversion factors.

These units are used in the construction trade. Other units can be used in other standards. All conversions from mmHg to Pa are done at 0°C.

This standard is not intended to address all security issues, if any, associated with its use. It is the responsibility of the user of this standard to determine appropriate safety and health practices prior to use and to determine the applicability of regulatory restrictions.

Our organization also provides testing services to businesses within the framework of laboratory testing services, within the scope of ASTM E96 Standard Test Methods for Water Vapor Transmission of Materials.