AATCC 42-2007
1.1 This test method is applicable to any textile fabric, which may or may not have been given a water-repellent finish. It measures the resistance of fabrics to the penetration of water by impact, and thus can be used to predict the probable resistance of fabrics to rain penetration resistance of garment fabrics.
1.2 The results obtained with this test method depend on the water repellency of the fibers and yarns and on the construction of the fabric.