The term auxiliary fan refers to a secondary ventilation fan that supports the main ventilation system by delivering air to areas that are difficult to reach. Instead of serving the whole building, plant or mine, an auxiliary fan is dedicated to local or temporary ventilation duties where additional airflow is needed.
In underground mining, auxiliary fans are a central part of development and production ventilation. Main fans move large volumes of air through primary intake and return airways, but headings, dead ends and remote stope areas may still suffer from low airflow or poor air quality. An auxiliary fan, often connected to flexible ducting, is installed closer to the working face to push fresh air in or pull contaminated air out. This helps dilute diesel exhaust, blasting fumes and dust at the exact location where workers are present.
Auxiliary fans in mines are typically compact axial flow fans because they provide high volume at moderate pressure in a relatively small package. They can be moved as development advances, and additional booster fans may be added in long duct runs. Regulations usually define minimum airflow and gas limits at faces, so auxiliary fans must be sized, installed and maintained in line with the official ventilation plan.
In industrial and commercial buildings, auxiliary fans have a similar supporting role. They may be used to ventilate small plant rooms, basement areas, mezzanine levels or enclosures that are not adequately served by the main air handling system. Examples include small exhaust fans installed in battery rooms, paint mixing areas or welding booths. These auxiliary fans provide targeted airflow where a full redesign of the main system would be impractical.
Auxiliary fans can also act as temporary ventilation solutions. During maintenance, retrofitting or construction, portable fans are brought in to provide extra cooling and fume removal. Once the work is complete, these fans can be relocated to other projects. Their flexibility and relatively low cost make them a common tool for site engineers and safety managers.
In summary, an auxiliary fan means a secondary, supportive ventilation fan whose purpose is to deliver local airflow to specific areas that the main system does not adequately reach. It is especially important in underground mining and in industrial spaces with confined or high risk zones.
