share more. 1. The smoke exhaust duct should not cross the fire zone. The air duct that vertically passes through each floor should be made of refractory materials, and should be located in the pipeline well or adopt concrete air duct. Second, the smoke exhaust duct should be made of nonmetallic incombustible materials such as metal plate and concrete, because the smoke temperature is high when it is discharged from a fire. It should also be installed firmly, and the smoke exhaust duct will not fall off when the temperature rises, and it should have good air tightness. 3. The air volume passing through the smoke exhaust duct shall be calculated as twice the maximum smoke exhaust day in all the smoke exhaust outlets of each branch duct of the smoke exhaust system. 4. Structural requirements of smoke exhaust duct: 1. The distance between the outer surface of smoke exhaust duct and combustible components such as wood should not be less than 1.5 ㎝, or the outer surface of smoke exhaust duct should be covered with thermal insulation material with a thickness of not less than 1.11 ㎝. 2. When the smoke exhaust duct passes through the smoke barrier, the gap between the duct and the smoke barrier should be tightly filled with incombustible materials such as cement mortar. 3, smoke exhaust duct and smoke exhaust fan connection, appropriate USES flange connection, or use non-combustible soft connection. 4. Metal smoke exhaust pipes that need heat insulation. Non-combustible thermal insulation materials must be used, such as mineral wool, glass wool, rock wool, aluminum silicate and other materials. 5, flue gas outlet material should be made of materials with good fire resistance; The location of the outlet should be determined according to the conditions of the building, and the parts with burning danger must be avoided.