The breathability of fabric is one of the important indicators of fabric performance. The breathability of fabric directly affects the insulation and comfort of clothing. The breathability of industrial textiles, such as parachutes, water hoses, and filter fabrics, is closely related to their functionality and impact on usage and filtration efficiency.
Fabric breathability refers to the ability of air to pass through the fabric's pores when there is a pressure difference on both sides of the fabric. This is typically achieved through the interweaving of warp and weft yarns and the gaps between fibers. Therefore, the breathability of fabric is determined by the number and size of pores between fibers, as well as factors such as fiber and yarn characteristics, fabric geometry, and finishing processes.
The indicators for fabric breathability include air permeability and air permeability rate. Air permeability refers to the volume of air passing through a unit area of fabric per unit time under a specified pressure difference, measured in m3/m2s. Air permeability rate, on the other hand, measures the rate at which air flows vertically through a sample fabric under specified conditions of area, pressure drop, and time, with units in mm/s. The fabric's air permeability is positively correlated with the pressure difference between both sides of the fabric. According to the new national standard, air permeability rate is now used to represent fabric breathability, and the numerical values of air permeability rate and air permeability are equivalent.
In accordance with the experimental method specified in the national standard GB5453-85, fabric breathability is measured using a fabric permeability tester under a certain pressure difference, to determine the amount of air passing through the fabric per unit time and thus assess its breathability.
Green air permeability meter is used to test the air permeability of various flat materials such as: knitted fabrics, woven fabrics (including densely coated fabrics), non-woven fabrics, paper, filter paper felt, glass fiber, air filters and foams and other materials.
Applicable Standards:
GB/T5453, GB/T13764, ASTM D737, ASTM D3574, ISO9237, AFNOR G07-111, BS5636, DIN53887, JISL1096-A and other national standards.
Test steps:
1. Prepare the sample as required, cut it to the specified size, and install it on the instrument.
2. Select the orifice plate. (Note: For different tested fabrics, different diameter orifice plates should be used. The better the material's breathability, the larger the selected orifice plate diameter. Testers can choose the orifice plate based on historical data on material breathability or estimate based on experience. If the breathability of the tested material is unclear, the appropriate orifice plate number should be determined through testing.)
3. Turn on the instrument, in test mode, press the "Set" key to enter parameter settings, including sample pressure difference, sample area, nozzle size, and testing unit. After setting the parameters, press the "Zero" key on the test interface to initialize the pressure sensor, press down the sample compression handle, and click the "Test" key to start the test.
4. When the set pressure difference is reached, the instrument will automatically calculate the test results and stop the test. After the test is completed, you can press the "Function" key to perform corresponding operations in the pop-up menu, view the test results by pressing the "Retrieve" key, and print the test results. After the test is finished, turn off the power, clean the instrument and accessories, and remove the fixed value cover.
