ISO 18696:2006 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 wetting by water by the tumble-jar absorption test. It is particularly suitable for measuring the water-repellent efficacy of finishes applied to fabrics, because it subjects the treated fabrics to dynamic conditions similar to those often encountered during actual use.
The test is not intended for use in predicting rain-penetration resistance of fabrics, since it measures absorption of water into, but not through, the fabric. It is intended to determine a fabric's ability to resist water absorption and can be used to predict the probable weight gain of a garment in actual use. The test is best suited for fabrics used in garments for severe wet environmental conditions over an extended time.