This standard describes a method for determining the water vapor transmission rate, water vapor permeability, water vapor diffusion resistance of rigid cellular plastics.

The test method applies to rigid cellular materials with thicknesses of 10 mm or more, which may be an integral part of the material or contain natural leather or adhesive coatings of various materials.

The following sets of conditions are provided for different temperature and humidity levels:

a) Temperature 38°C and humidity gradient across the test sample (0-88%)

b) Temperature 22°C and humidity gradient across the test sample (0-85%)

c) Temperature 23°C and humidity gradient across the test sample (0-50%)

The results obtained using this method are suitable for design, production control, and product specification. This method is suitable for materials with water vapor transmission rates in the range of (3 to 200) natograms/m2.s.