Coal mining ventilation ducting is a kind of flexible ventilation hose duct guiding wind flow along a certain direction undermine. There are two kinds of ventilation hose duct in domestic market, the first generation of rubber coated seamed ventilation hose duct and the second generation of PVC flexible ventilation duct hose. It can be divided into Lay Flat Ventilation Duct and Spiral Ventilation Duct. Lay flat ventilation duct is applied for ventilation of whole coal mine and some part ventilation. Spiral ventilation duct is mainly used for ventilation of tunneling face and coal face.
Because the friction will produce the static electricity that will make combustible gases (methane) burn. When the wind reaches 40 m3/min, there will be 28 MJ electric charge through the friction of air and ventilation ducting. When the gas concentration reach 5%, it will make gas detonation.
Through measuring by expert, when surface electrical resistance of ventilation ducting materials has less than 3×108 Ω, there will be less static electricity. When it has more than 3×108 Ω, surface will be easy to accumulate a lot of charges and easy to reach 28 MJ. So 3×108 Ω is the important indicator when testing anti-static function.