AATCC 35-2000 Water Resistance: Rain 1 Test.
1.1 This test method is applicable to any textile fabric, which may or may not have been given a waterresistant or waterrepellent 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 intensities (see 11.1) of water impact to give a complete overall picture of the penetration 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 fbers and yarns, and on the con- struction of the fabric.
2. Principle
2.1 A test specimen, backed by a weighed blotter, is sprayed with water for 5 min under controlled conditions. The blotter is then reweighed to determine the amount of water which has leaked through the specimen during the test.
3. Terminology
3.1 water resistance, n. of fabric, the characteristic to resist wetting and penetration by water. (See also water repel- lency)
4. Safety Precautions NOTE: These safety precautions are for information purposes only. The pre- cautions are ancillary to the testing proce- dures and are not intended to be all inclu- sive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manufac- turers MUST be consulted for specific details such as material safety data sheets and other manufacturer’s recommenda- tions. All OSHA standards and rules must also be consulted and followed. 4.1 Good laboratory practices should be followed. Wear safety glasses in all laboratory areas. 5. Apparatus and Materials
5.1 AATCC Rain Tester (see Figs. 1 and 2 and 11.3).
5.2 White AATCC Textile Blotting Pat per (see 11.4).
6. Test Specimens
6.1 A minimum of three specimens of 20x 20 cm is cut from the test fabric. The fabric samples and the blotting paper should be conditioned in an atmosphere of65士2% RH and 21士I°C for at least 4 h before testing.
7. Procedure
7.1 The test specimen (see 11.5), backed by a 15.2 X 15.2 cm standard pa- per blotter weighed to the nearest 0.1 g is clamped in the specimen holder and the assembly is mounted in a vertical rigid support frame. 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 horizontal water spray at27土1°C (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 nearest0.1 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 determinations or average values of over 5.0 g may be simply reported to5+gor> 5g.
8.2 In order to obtain a complete overall picture of the penetration resistance of a fabric or fabric combination the average penetration with different pressure heads on the nozzle should be obtained. AATCC 35 pdf download.