Waterproof breathable fabric waterproof principle
         Fabric waterproof refers to the fabric of liquid water through the barrier resistance performance of hate. Traditionally, "Waterproof fabrics Waterproof fabric)" (the term is used to describe a fabric in hydraulic circumstance also can not finish, Waterproof fabrics of gaseous or liquid water, the water is not always keep this period. Water, but not through the fabric surface fabric can be moist. Often, in the fabric surface besmear or a layer of fabric is close-grained cannot through water film can make the fabric has waterproof fabrics.
 
        The fabric (Waterepellent fabric) refers to any external forces in not undergo fabric effect under the condition of static, against water permeability of fabric. The fabric fabric can allow the water and gas by static condition and not allow liquid water permeability, its essence is not allow water to wet fabric. This requires fabrics with low surface fabric.
 
        Waterproof breathable fabric Moisture Permeable Waterproof fabric (and) refers to exert pressure on the fabric are completely Waterproof, daily use of water vapor, and through the use of remained in the period of the ability. Its essence is a molecular and water vapor great differences between the volume. To improve the waterproof, normally required the fabric surface is not wet. American association of home textile and dyeing chemist AATCC () and American material experiment society (ASTM) put out of the penetration resistance defined for fabric or both.
 
        Liquid water through the garment fabric into clothing inside there are two ways:
        1 the water like rain or outside, snow contact fabric by wetting, fabric, through the fabric of capillary effect of aperture fabric is transferred to the water holes inside and other parts of the fabric surface, this kind of circumstance is main with the fabric surface and surface roughness, as a kind of spontaneous process.
        2 water in certain outside pressure or under their kinetic energy within the aperture fabric directly through the holes and enter the inside of the fabric, this kind of situation and surface and surface roughness can depends largely on the outside, inside the large aperture fabric, the size of the hole. Therefore, the fabric is also includes prevent leakage problems by water flowed wetting, fabric and penetrate into.