Mm diameter duct drag one hundred meters (N · S 2 / M 8); one hundred meters of air leakage rate,% 300 ≤1728.0 ≤5.0 400 ≤410.0 ≤5.0 500 ≤134.0 ≤5.0 600 ≤54.0 ≤5.0 800 ≤13.0 ≤5.0 Note: Each duct length is 10m. Uses: Suitable for all kinds of positive pressure ventilation of underground mines mining face local fan machine positive pressure ventilation and tunnel project. Features: Compared with rubber duct, with wind resistance, long life, light weight, low cost, flame resistance and good, but can quickly stick up under constant wind conditions. Technical indicators: warp tensile strength: ≥2500 N / 50 mm weft tensile strength: ≥2000 N / 50 mm warp and weft tear strength: ≥190 N adhesion strength:> 22 N / 25 mm surface resistance : ≤300 MΩ alcohol torch flaming combustion time sum: ≤6 one hundred meters in diameter duct drag (N · S 2 / M 8) one hundred meters of air leakage rate (%) 300 ≤811.0 400 ≤196.2 450≤121.6 500 ≤54.0 0.5% 600 ≤23.5 800 ≤6.4 1000 ≤2.0