Ventilation is the process of introducing outdoor air into a space and distributing it within the space). The purpose of ventilation is to control indoor air quality by diluting and displacing indoor pollutants, and to provide oxygen for metabolism and to dilute metabolic pollutants such as carbon dioxide and odors. Ventilation can be accomplished by either natural or mechanical means.
There are two types of ventilation:
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Natural ventilation: This type of ventilation relies on natural forces such as winds and thermal buoyancy force due to indoor and outdoor air density differences to drive outdoor air through purpose-built, building envelope openings such as windows, doors, solar chimneys, wind towers, and trickle ventilators.
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Mechanical ventilation: This type of ventilation is the intentional fan-driven flow of outdoor air into a building. Mechanical ventilation systems may include supply fans (which push outdoor air into a building), exhaust fans (which draw air out of a building and thereby cause equal ventilation flow into a building), or a combination of both. Mechanical ventilation is often provided by equipment that is also used to heat and cool a space).
In addition to intentional ventilation, air inevitably enters a building by the process of air infiltration, which is the uncontrolled flow of air into a space through adventitious or unintentional gaps and cracks in the building envelope. The corresponding loss of air from an enclosed space is termed exfiltration.
Ventilation is also used in medical settings to assist patients with breathing. A ventilator is a machine that helps a patient breathe in oxygen and blow out carbon dioxide. Depending on the patients condition, a ventilator can be set up to do some or all of the work for the patients breathing.
In summary, ventilation is the process of introducing outdoor air into a space to control indoor air quality and provide oxygen for metabolism. It can be accomplished by natural or mechanical means and is also used in medical settings to assist patients with breathing.
