A smoke exhaust fan is a specialized ventilation device designed to remove smoke, hot gases, and harmful fumes from buildings during fire or emergency conditions. It is a key component of modern fire safety and environmental control systems in commercial, industrial, and residential structures. By extracting smoke from escape routes and occupied areas, it helps maintain visibility, reduce toxic gas concentration, and protect the structural integrity of buildings.In normal operation, a smoke exhaust fan can be integrated into the general ventilation system, providing daily air exchange and improving indoor air quality. During a fire, however, it switches to emergency mode. In this mode, the fan operates at high temperature and high speed, quickly discharging smoke and hot gases to the outside. This process slows down the spread of fire, supports safe evacuation, and creates better conditions for firefighting and rescue teams.The construction of a smoke exhaust fan typically includes a robust housing, high‑temperature‑resistant impeller, durable motor, and protective coatings. Materials are selected to withstand elevated temperatures for a specified period, often reaching 250–300°C or higher depending on the application and local standards. The fan can be axial, centrifugal, or mixed‑flow in type. Axial fans are usually used where high air volume and relatively low pressure are required, while centrifugal fans are chosen for higher pressure and complex duct systems.Control and automation play a vital role in the performance of smoke exhaust systems. Smoke exhaust fans are usually connected to the building management system or dedicated fire control panel. When smoke detectors, heat detectors, or sprinkler systems are activated, the control system automatically starts the smoke exhaust fan and opens relevant fire dampers. In some designs, manual overrides allow firefighters to control fan operation directly according to the real‑time situation in the building.Proper design and installation of smoke exhaust fans must follow applicable fire codes and building regulations. Key design considerations include air volume, pressure, temperature resistance, noise level, energy efficiency, and redundancy. Duct layout, air inlets, discharge points, and coordination with make‑up air systems must be carefully planned to create effective smoke control zones and maintain tenable conditions along escape routes.Regular inspection, testing, and maintenance are essential to ensure long‑term reliability. Periodic functional tests verify that the smoke exhaust fan starts correctly, reaches the required speed, and responds to control signals. Mechanical components should be checked for wear, corrosion, or imbalance, while electrical parts and control circuits must be inspected for faults. Well‑maintained smoke exhaust fans significantly increase the safety level of buildings, helping to protect human life, property, and critical infrastructure in the event of a fire.