T4-72 centrifugal fan ventilation for general use. As a general indoor ventilation factories and large buildings can be used as the input gas, also used as output gas. Gas and other air transport should not spontaneous combustion, harmless, non-corrosive gases for steel materials for. Allowed sticky substances gases contained in the dust and hard particles is not greater than 150mg / m3. Gas temperature must not exceed 80 ℃.