There is a difference between an exhaust fan and a ventilation fan, although in everyday language the terms are often mixed. In simple terms, an exhaust fan is a type of fan that only removes air from a space, while a ventilation fan is any fan that is part of a system designed to move fresh air in and contaminated air out. In mining and industrial environments, engineers normally talk about the whole ventilation system rather than a single exhaust unit.
An exhaust fan is installed to pull air out of a room, tunnel or underground heading. It creates negative pressure so that warm, humid or contaminated air is discharged to a safe location. Typical examples include bathroom fans, kitchen hood fans, roof exhaust fans in factories and auxiliary exhaust fans that pull diesel exhaust and blasting fumes away from an underground face. On its own, an exhaust fan does not control where fresh air comes from; it simply removes air and relies on openings or leakage for replacement air.
A ventilation fan is a broader concept. It can be a supply fan, an exhaust fan or a combination of both used to create a controlled airflow pattern. In a balanced industrial ventilation system, supply fans bring in outdoor air through filters or air handling units, and exhaust fans remove air from hot or contaminated zones. In underground mining, large axial main fans are often called “ventilation fans” because they drive the entire airflow through intake and return airways, not just exhaust a single room.
From a practical point of view, the difference matters because a complete ventilation solution must consider both supply and exhaust. Adding more exhaust fans without providing make-up air can cause drafts, door slamming and poor capture at hoods. Likewise, adding supply fans without enough exhaust can pressurise a building or mine section and push contaminants into unwanted areas. Good design treats exhaust fans as one part of a larger ventilation system with defined intake, exhaust and pressure control.
In summary, an exhaust fan is a specific device used to remove air, while a ventilation fan is any fan that forms part of a system for bringing in fresh air and removing contaminated air. For mining and industrial projects, the focus should be on the overall ventilation system, not just on individual exhaust units.
