Automatic Air Permeability Tester is used to determine the air permeability of fabric automatically. The wide measuring range covers all kinds of knitted, woven, non-woven, coated fabrics, paper, film, leather, etc.The rate of flow of air passing perpendicularly through a given area of fabric is measured at a given pressure difference across the fabric test area over a given time period, unit (mm/s); Related standards: GB/T 5453, ISO 9237, ASTM D737 etc.