Water repellency tests rain test

Table 12.4 Water-Repellency Tests Simulating Exposure to Rain...

ISO 9865 1991, Textiles, Determination of Water Repellency of Fabrics by the Bundesmann Rain Shower Test, International Standards Organization, Geneva, 1991. 

Four samples of treated fabric are subjected to simulated rain for 10 min. The fabrics (placed on inclined cups and sealed at the edges) are in constant motion and the side of the fabric not exposed to the rain is subjected to a rubbing action. The repellency of the fabric is determined by the appearance of the wetted side, the amount of water absorbed by the fabric and the amount of water passing through the fabric. This test requires an elaborate special apparatus. 

A more severe simulation of a rain event is provided by ISO 9865. This test method is similar to AATCC Test Method 35 except that the water is sprayed for 10 min and the undersides of the fabric samples are rubbed while the spraying takes place. A rather elaborate apparatus is required. The appearance of the fabric face, the amount of water absorbed by the fabric and the amount of water passing through the fabric are all factors in determining the repellency rating of the fabric. 

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