AATCC 35-2018 is applicable to any textile fabric, which may or may not have been given a water-resistant or 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 rain penetration resistance of fabrics. It is especially suitable for measuring the penetration resistance of garment fabrics. With the instrument, tests may be made at different intensities of water impact to give a complete picture of the penetration resistance of a single fabric or combination of fabrics. The results obtained with this test method depend on the water repellency of the fibers and yarns, and on the construction of the fabrics. A test specimen, backed by a weighed blotter, is sprayed with water for 5 minutes under controlled conditions. The blotter is then reweighed to determine the amount of water which has leaked through the specimen during the test.