Plenum

From Wikipedia, the free encyclopedia

Plenum may refer to:

• the antithesis of a vacuum; in other words, completely-filled, positive-pressure space (see Plenism).
• the pressures slightly above atmospheric, usually inside air or gas systems as the result of the action of fans or blowers. The plenum is measured in small units of pressure such as pascals (Pa) or ounces-force per square inch or millimeters of mercury.
• a legislative meeting in which all members of the body are present and voting. Frequently this is used to refer to a full meeting of a Communist Party central committee. Compare to quorum.
• a second set of bellows in devices such as hand or foot pumped organs with a weight on the top which acts as an air reservoir.
• Plenums in buildings are enclosed spaces that are not for human occupancy, but are often used for heating, ventilating, and/or air-conditioning equipment and airflow, and for other equipment such as cables, piping, and luminaires. 'Plenum boxes' or sections are portions of HVAC air handlers or terminal units.
• Plenum cable refers to structured cabling permitted under building codes for plenum spaces. Plenum rated cable has slow-burning, fire-resistant casing that emits little smoke

• Plenum chamber a pressurised housing containing a fluid, usually air, at greater than ambient pressure. Such chambers are used within supercharging of internal combustion engines, hovercraft and sometimes steam engines. One function of the plenum is to equalise pressure from a single, perhaps pulsating, source to distribute it evenly between cylinders or over time.

• Plenum filtration, a method of aquarium filtration using a deep sand bed with a gap below it.

[edit] See also

• Plenary, the related adjective.