Fabric Breathability Tester Principles and Standards

　　The fabric breathability tester is used to quickly determine the breathability of various sheet-like materials such as coated fabrics, filter paper, filter materials, plastics, etc.

　　Breathability testing principle:

　　Air passes through the fabric vertically, forming a certain pressure difference between the front and back of the fabric. The amount of air passing through the fabric per unit time under a certain pressure difference is measured, which is the breathability of the fabric. Compare existing testing standards for textile breathability and study various factors that affect fabric breathability.

　　Breathability testing standards:

　　The comparison of air permeability testing standards, commonly used air permeability testing standards include ASTMD737-1996 "Test Method for Air Permeability of Textiles", ISO9237-1995 "Determination of Air Permeability of Textile Fabrics", GB/T 5453-1997 "Determination of Air Permeability of Textile Fabrics" and JIS L1096-1999 "Test Method for Air Permeability of Textiles". Among them, GB/T 5453-1997 is equivalent to ISO9237-1995. JISL1096-1999 is divided into Method A and Method B. Method A uses a Frazir permeability tester with a pressure difference of 125Pa, and measures 5 times to obtain the average value; The B method uses a Gurley air permeability tester to measure the time it takes for 300mL of air to pass through the fabric at a specific pressure difference. The air permeability is expressed in seconds and is suitable for woolen fabrics. Due to the requirement of using specific instruments in JISL1096, it is not commonly used in daily quality testing.

　　The commonly used methods for testing the breathability of textiles are ASTMD737-1996 and GB/T5453-1997. Because air leakage can affect the test results of fabric permeability, measures to prevent air leakage are mentioned in each test standard, requiring the use of sample fixtures and rubber washers. Rubber gaskets are prone to aging and deformation after multiple uses, which can affect the test results and should be discarded. The sample fixture is suitable for knitted fabrics or fabrics that are prone to sticking to the test head, and is not suitable for heavy or stiff fabrics. When there is a difference in breathability between the front and back of the tested fabric, the side with lower pressure should face downwards to prevent air leakage. If you want to obtain the breathability of the fabric, you can cover the sample with a non breathable cover and measure the air leakage and air flow rate through the fabric separately.