UNI 4920: 2013, AATCC Test Method 22: 2014
It is especially suitable for measuring the water-repellent efficacy of finishes applied to the fabrics.The exact definition of the test method is therefore "resistance to wetting."
The distance between the center of the sprayer and the center of the support is fixed as defined by the Standard.
The test is carried out by fixing the tube to the frame so that it is not bent, and then pour 250 mL of water at (20 ± 5) °C in the funnel; so you will have a splash in the average length of 25-30 seconds. It then rotates the frame 180 ° and the test repeated.
For test pieces of ribbed fabrics, such as velvets, please also place the tube on the frame so that it presents the coasts tilted 45° with respect to the flow of water coming down along the fabric itself.