Water Penetration Resistance - Very Low Range
The ability of coated fabrics to successfully resist penetration of water through their coatings is an important criterion for determining their suitability for a variety of applications. This determination may be carried out either by applying a gradually increasing hydraulic pressure on the coated side and finding the pressure at which the first drop of water penetrates through the test specimen, or by applying a fixed known hydraulic pressure on the coated face for a specified duration of time and finding the time taken by the first drop of water to penetrate through. Depending on the final use the test specimen is to be put to, the above determination may be carried out either under a low pressure or under a high pressure.
In the low pressure method, the test specimen is held over an open well having a circular opening of 100 cmÂ² area and the pressure is either increased at a specified rate, or is kept constant at a specified value.