AskDefine | Define flue

Dictionary Definition



1 flat blade-like projection on the arm of an anchor [syn: fluke]
2 organ pipe whose tone is produced by air passing across the sharp edge of a fissure or lip [syn: flue pipe, labial pipe]
3 a conduit to carry off smoke

User Contributed Dictionary



  • IPA: /fluː/
  • Rhymes: -uː



  1. A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace).
  2. An enclosed passageway in which to direct air or other gaseous current along.

Related terms


pipe that carries gaseous combustion products away from their origin
enclosed passageway for a gas
Translations to be checked






  1. early

Extensive Definition

A flue is a duct, pipe, or chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. In U.S.A. and for water heaters and modern furnaces, they are also called 'vents'; for boilers they are 'breeching'. They usually operate by buoyancy, also known as the stack effect, or the combustion products may be 'induced' via a blower. As combustion products contain carbon monoxide and other dangerous compounds, proper 'draft', and admission of replacement air is imperative. Building codes, and other standards, regulate their materials, design, and installation.
Flues are designed to release noxious gases to the atmosphere, but they often have the disadvantage of releasing useful heat to the atmosphere. In some countries, wood fire flues are often built into a heat preserving construction within which the flue gases circulate over heat retaining bricks before release to the atmosphere. The heat retaining bricks are covered in a decorative material such as brick, tiles or stone. This flue gas circulation avoids the considerable heat loss to the chimney and ouside air in conventional systems. The heat from the flue gases is absorbed quickly by the bricks and then released slowly to the house rather than the chimney. In a well insulated home, a single load fire burning for one and a half hours twice a day is enough to keep an entire home warm for a 24 hour period. In this way, less fuel is used, and noxious emissions are reduced. Sometimes, the flue incorporates a second combustion chamber where combustibles in the flue gas are burnt a second time, reducing soot, noxious emissions and increasing overall efficiency.
The term flue is also used to define certain pipe organ pipes, or rather, their construction or style.


Flue-types include
flue in German: Rauchfang

Synonyms, Antonyms and Related Words

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