Water Vapor
Permeability is a feature that determines the quality and practicality of the application of a given fabric. Clothes or footwear made of materials of inadequate permeability may be unhealthy and uncomfortable. In order to determine water vapor permeability, the RADWAG moisture analyzer has to be equipped with a water vapor permeability determination set.
The developed method of testing water vapor permeability consists in placing the required amount of water in a vessel made of aluminum alloy, inside which a fabric sample, cut using a blanking die, is clamped. Prior to the test, the sample should be left in a room with stable ambient conditions for 24 hours. It is recommended to place the vessel containing water and sample in the moisture analyzer and start the drying process at 40°C. The advantage of this method is a very short drying time. It takes up to 50 minutes to obtain the result. In contrast, measurement carried out using the standard method takes up to 72 hours.
Measurement results are presented in mg H2O / 1000 mm2 / 24h or as the percentage amount of water vapor passed through the material to the amount of water vapor passed without the tested fabric.