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:
“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)
“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)
“The desire to serve the common good must without fail be a requisite of the soul, a necessity for personal happiness; if it issues not from there, but from theoretical or other considerations, it is not at all the same thing.”
—Anton Pavlovich Chekhov (1860–1904)