ID and FD fans are abbreviations widely used in power plants, heavy industry and some mining facilities to describe two key types of draft fans: Induced Draft (ID) fans and Forced Draft (FD) fans. Both are industrial ventilation fans that control the movement of combustion air and flue gases around boilers, kilns, furnaces and process heaters, helping to maintain stable draft, efficient combustion and safe exhaust of hot gases.
An FD fan (Forced Draft fan) is installed on the air supply side of the system. It pushes fresh air into the boiler or furnace, forcing combustion air through air pre-heaters, ducts and burners. FD fans are typically centrifugal fans designed to deliver controlled air pressure and flow rate, often with inlet vanes or variable-speed drives so operators can fine tune the air–fuel ratio. In some cold-climate mines, FD fans also support surface heating or ventilation systems that pre-condition air before it enters the mine.
An ID fan (Induced Draft fan) is installed on the exhaust side, downstream of the boiler or furnace and often after dust collectors, scrubbers or heat-recovery equipment. The ID fan pulls hot flue gases out of the combustion chamber and draws them through the gas-cleaning system and stack. By maintaining a slight negative pressure inside the furnace, the ID fan prevents hot gases and dust from leaking into the boiler house or plant, improving safety and housekeeping.
In many industrial and mining-related facilities, ID and FD fans work together as part of a coordinated draft system. The FD fan controls how much air is pushed into the boiler, while the ID fan controls how much gas is pulled out. Proper balance between ID and FD fan pressures keeps furnace draft within the design range, stabilises flame conditions and maximises energy efficiency.
From a ventilation perspective, both ID and FD fans must be selected with care. They deal with high temperatures, dust and sometimes corrosive gases, so materials of construction, bearing arrangements, sealing and cooling all need to be engineered correctly. In coal-fired or metallurgical operations associated with mines, it is particularly important to match the ID/FD fans to the boiler and gas-cleaning equipment to avoid excessive wear, vibration or energy waste.
In summary, FD fans supply combustion air by pushing it into the system, while ID fans remove flue gases by pulling them through the boiler and treatment equipment. Together, these industrial ventilation fans control draft, protect equipment and contribute to safe, clean and efficient operation in power plants and heavy industry linked to mining and mineral processing.
