Waterproof/breathable fabrics:

Waterproof/breathable fabrics resist water droplets from passing through while at the same time allowing water vapour through. Their ability to block out rain and snow while allowing vapour from sweat to evaporate lends to their use in outdoor sports clothing and single wall tents.

Shower proof fabric: Shower proof fabric is fabric that resists water. You could pour a glass of water over it and watch the liquid simply form beads and run off. You should find they protect you against all but heavy rain

WATER PROOFING TESTS:

CONE TEST:

This is a test for the water proofness of the fabric that is locally stressed. A circular or rectangular specimen of fabric is folded twice and then opened to obtain a cone with the coated side inward. At the tip of the cone, the material is folded so sharply that the coating is heavily stressed. The cone is then put in a wire cone and , in turn placed into a glass funnel and filled with a specified quantity pf water. There should not be any penetration of liquid, as well as no wetting of the outer surface of the specimen cone after 18 hrs.

BUNDESMANN WATER REPELLENCY TEST

The Bundesmann water repellency tester is used to determine resistance to wetting and resistance to penetration by water of water repellent fabrics which are permeable to air.In this test, four test specimens taken from the fabric under test are simultaneously exposed to a simulated heavy shower of controlled intensity while the lower surface of each specimen is subjected to a rubbing action. The increase in mass of the specimen during exposure to the shower is determined and any water passing through the fabric collected and its volume determined. The Bundesmann Water Repellency Tester consists of a steel structure with a water collection tank. A cup assembly with specimens is rotated at a specified speed in this tank about a vertical axis with the help of an electric motor and worm reduction gearbox placed underneath the tank. A shower is produced by means of nine brass nozzles. Water jets coming from the nozzles impinge on stainless steel screws fitted on an aluminum plate. The nozzles are fitted on aluminum blocks, which are in turn connected to a closed piping system. Water is supplied to the piping system through an electric pump.

HYDROSTATIC HEAD :

This apparatus is used to determine the resistance of textile fabrics to penetration by water at a constant rate of increase of pressure. The hydrostatic pressure supported by a fabric is a measure of the resistance to the passage of water through the fabric. A specimen is subjected to a uniformly increasing pressure of water on one face, under standard conditions, until penetration occurs in three different places. The hydrostatic pressure at which water penetrates the fabric at the third place is noted. The test is suitable for tent cloths, tarpaulins, and fabrics coated with an impermeable film, for example the rubber.

SPRAY TEST FOR WATER REPELLENCY

Purpose and Scope This test method is applicable to any textile fabric, which may or may not have been given a water-repellent finish. It measures the resistance of fabrics to wetting by water. It is especially suitable for measuring the water-repellent efficacy of finishes applied to fabrics, particularly plain woven fabrics

Principle Water sprayed against the taut surface of a test specimen under controlled conditions produces a wetted pattern whose size depends on the relative repellency of the fabric. Evaluation is accomplished by comparing the wetted pattern with pictures on a standard chart.

Test Specimens Three test specimens 180x180 mm (7x7 in.) are needed and should be conditioned at 65 ± 2% relative humidity. Each specimen should contain different groups of lengthwise and widthwise yarns.

Procedure1) Fasten the test specimen securely in the 152 mm metal hoop so that it presents a smooth wrinkle-free surface.

2) Place the hoop on the stand of the tester with the fabric uppermost in such a position that the center of the spray pattern coincides with the center of the hoop

3) Pour 250 ml of distilled water at 27 ± 1°C (80 ± 2°F) into the funnel of the tester and allow it to spray onto the test specimen in 25-30 sec.

4) Avoid touching the funnel with the beaker while pouring the distilled water.

5) Take the hoop by one edge and tap the opposite edge smartly once against a solid object, with the fabric facing the object,then rotate the hoop 180° and tap once more on the point previously held.