AATCC TM35:2021 pdf download.Test Method for Water Resistance: Rain
1.1 This test method 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 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 intensi- ties (see 11.1) of water impact to give a complete overall picture of the penetra- tion resistance of a single fabric or a combination of fabrics. 1.2 The results obtained with this test method depend on the water repellency of the fibers and yarns, and on the con- struction of the fabric.
The specimen assembly is positioned into the central portion of the spray at a distance of 30.5 cm from the face of the spray nozzle (see 11.6). A hor- izontal water spray at 27 ± 1°C (81 ± 2°F) (see 11.2) is directed against the specimen and is allowed to continue for a period of 5 min. At the end of the spray period the blotter is carefully removed and quickly reweighed to the nearest 0.1 g. 8. Evaluation 8.1 Water penetration as indicated by the increase in mass of the blotting paper during the 5 min test period is calculated, and the average for the three test speci- mens is reported. Individual determina- tions or average values of over 5.0 g may be simply reported to 5 + g or > 5 g. 8.2 In order to obtain a complete over- all picture of the penetration resistance of a fabric or fabric combination the average penetration with different pressure heads on the nozzle should be obtained. The pressure head should be varied by 300 mm increments in order to determine (a) the maximum head at which no penetra- tion occurs, (b) the change in penetration with increasing head and (c) the mini- mum head required to cause “break- down” or the penetration of more than 5 g of water. At each pressure head a mini- mum of three specimens should be tested in order to obtain the average penetration for that head.AATCC TM35 pdf download.