1. Scope

1.1 These test methods cover the determination of water vapor transmission (WVT) of materials through which the passage of water vapor may be of importance, such as paper, plastic films, other sheet materials, fiberboards, gypsum and plaster products, wood products, and plastics. The test methods are limited to specimens not over 11/ 4 in. (32 mm) in thickness except as provided in Section . Two basic methods, the Desiccant Method and the Water Method, are provided for the measurement of permeance, and two variations include service conditions with one side wetted and service conditions with low humidity on one side and high humidity on the other. Agreement should not be expected between results obtained by different methods. The method should be selected that more nearly approaches the conditions of use.

1.2 The values stated in inch-pound units are to be regarded separately as the standard. Within the text, the SI units are shown in parentheses. The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. Combining values from two systems will result in non-conformance with the standard. However derived results can be converted from one system to other using appropriate conversion factors (see Table 1).

1.3 This standard does not purport to address all of the safety problems, 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

C168 Terminology Relating to Thermal Insulation

D449 Specification for Asphalt Used in Dampproofing and Waterproofing

D2301 Specification for Vinyl Chloride Plastic Pressure-Sensitive Electrical Insulating Tape

E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Keywords

permeability; plastics (general); plastic sheet and film; sheet material; thermal-insulating materials; thermal insulation permeability films; water vapor transmission (WVT);

ICS Code

ICS Number Code 77.040.99 (Other methods of testing metals)

DOI: 10.1520/E0096_E0096M-05

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