Necessity
When people or animals are present in buildings, ventilation air is necessary to dilute odors and limit the concentration of carbon dioxide and airborne pollutants such as dust, smoke and volatile organic compounds (VOCs). Ventilation air is often delivered to spaces by mechanical systems which may also heat, cool, humidify and dehumidify the space. Air movement into buildings can occur due to uncontrolled infiltration of outside air through the building fabric (see stack effect) or the use of deliberate natural ventilation strategies. Advanced air filtration and treatment processes such as scrubbing, can provide ventilation air by cleaning and recirculating a proportion of the air inside a building.
Read more about this topic: Ventilation (architecture)
Famous quotes containing the word necessity:
“I don’t believe in villains or heroes, only in right or wrong ways that individuals are taken, not by choice, but by necessity or by certain still uncomprehended influences in themselves, their circumstances and their antecedents.”
—Tennessee Williams (1914–1983)
“He says a man may perhaps answer, that the necessity of things held by him, is not a stoical necessity, but a Christian necessity, &c. But this distinction I have not used, nor indeed have ever heard before, nor could I think any man could make stoical and Christian two kinds of necessity, though they may be two kinds of doctrine”
—Thomas Hobbes (1579–1688)