机械排烟系统是采取排烟风机进行机械排风。据有关资料介绍，一个设计优良的机械排烟系统在火灾中能排出80%的热量，使火灾现场温度大大降低，对人员安全疏散和灭火有重要作用。机械排烟系统设在建筑物中不具备自然排烟条件的中庭，当安全通道长度超过20m时，应设机械排烟系统，在可燃物较多或经常有人停留的房间，也应设置排烟系统。
The mechanical exhaust system adopts the exhaust fan for mechanical exhaust. According to the relevant data, a well-designed mechanical smoke exhaust system can discharge 80% of the heat in the fire, greatly reducing the temperature of the fire scene, which plays an important role in the safe evacuation and fire fighting of people. The mechanical smoke exhaust system is set in the atrium without natural smoke exhaust conditions in the building. When the length of the safety passage exceeds 20 m, the mechanical smoke exhaust system shall be set. In the room with more combustibles or frequent people staying, the smoke exhaust system shall also be set.