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:
“Our good schools today are much better than the best schools of yesterday. When I was your age and a pupil in school, our teachers were our enemies.
Can any thing ... be more painful to a friendly mind, than a necessity of communicating disagreeable intelligence? Indeed it is sometimes difficult to determine, whether the relator or the receiver of evil tidings is most to be pitied.”
—Frances Burney (1752–1840)
“Whoever is not in the possession of leisure can hardly be said to possess independence. They talk of the dignity of work. Bosh. True work is the necessity of poor humanity’s earthly condition. The dignity is in leisure. Besides, 99 hundredths of all the work done in the world is either foolish and unnecessary, or harmful and wicked.”
—Herman Melville (1819–1891)
“The use of force alone is but temporary. It may subdue for a moment; but it does not remove the necessity of subduing again: and a nation is not governed, which is perpetually to be conquered.”
—Edmund Burke (1729–1797)