Ventilation is the process of supplying fresh air to a space and removing stale or contaminated air. It can occur naturally through openings such as windows and vents, or it can be provided mechanically by fans and duct systems. The goal of ventilation is to control air quality, temperature, humidity and air movement so that people, equipment and processes can operate safely and comfortably.
At its most basic, ventilation replaces indoor air with outdoor air. Fresh air brings in oxygen and helps dilute carbon dioxide, odours and pollutants generated by people, equipment and processes. Exhaust air carries away heat, moisture, dust, fumes and gases. In homes, this may simply involve opening windows and using small fans. In industrial plants and underground mines, ventilation requires carefully designed networks of main fans, auxiliary fans, ducts, shafts, louvers and regulators.
There are two main categories of ventilation: natural ventilation and mechanical ventilation. Natural ventilation uses wind and temperature differences to drive airflow through openings placed on walls and roofs. For example, cross ventilation through windows or stack ventilation via roof vents are natural methods. Mechanical ventilation uses fans to move air regardless of outdoor conditions. Supply fans push fresh air into buildings or mines, and exhaust fans remove contaminated air. Many real systems combine both methods, using fans to assist or control natural airflow.
In industrial environments, ventilation includes both general ventilation and local exhaust. General ventilation uses large flows of air to dilute contaminants in a space, while local exhaust ventilation captures fumes and dust close to their source using hoods and ducts connected to exhaust fans. This two-level approach helps keep contaminant levels below occupational exposure limits and protects workers’ health.
In underground mining, ventilation is a critical safety function. Main mine fans force or exhaust huge volumes of air through intake and return airways to supply fresh air to working faces, dilute explosive gases, remove diesel exhaust and control temperature. Auxiliary fans and ducts bring air into blind headings where the main flow cannot reach. Regulations strictly define minimum air quantities and gas limits, and the mine ventilation system is monitored continuously.
Proper ventilation design considers airflow quantity, direction and quality. Engineers calculate how much air is needed, define the desired path from intake to exhaust and select fans, ducts and vents to achieve that pattern with acceptable energy use and noise. Without adequate ventilation, spaces can become hot, humid, stuffy or dangerous, with elevated gas concentrations, dust levels or oxygen deficiency.
In summary, ventilation is the controlled exchange of indoor and outdoor air, using natural forces or mechanical systems to provide fresh air, remove contaminants and maintain safe, comfortable conditions in buildings, industrial plants and mines.
