A cowl is a usually hood-shaped covering used to increase the draft of a chimney and prevent backflow. The cowl, usually made of galvanized iron, is fitted to the chimney pot to prevent wind blowing the smoke back down into the room below. Undoubtedly named after the resemblance of many designs to the cowl garment worn by monks, they have been in use for centuries.
When using an open fire to heat a room the smoke rises through a flue to a chimney pot on the roof. Under normal conditions the warm air from the fire will rise up the chimney emitting the smoke with it and dispersing it at rooftop level where it is less of a nuisance.
In strong winds the pressure of the wind may overwhelm the updraft and push the airflow in reverse down the flue. Smoke will then fill the room it is intended to heat posing a health and fire risk, causing discomfort and dirtying furnishings in its path.
When raw coal rather than smokeless fuel is burnt, the amount of smoke may be considerable and measures to prevent backflow occurring are a necessity.
A secondary function is to prevent birds and squirrels from nesting in the chimney. Cowls often also act as a rain guard to keep rain from going down the chimney. A metal wire mesh is sometimes added as a spark arrestor. Wooden cowls were used on oasts to prevent the ingress of rain into kilns, and create a flow of air through the kiln.
An H-style cap (cowl) is a chimney top constructed from chimney pipes shaped like the letter H. It is an age-old method to regulate draft in situations where prevailing winds or turbulence cause downdraft and back-puffing. Although the H-cap has a distinctive advantage over most other downdraft caps, it fell out of favor because of its bulky looks. It is found mainly in marine use but has been gaining popularity again for its energy saving functionality. The H-cap stabilizes the draft rather than increasing it. Other downdraft caps are based on the Venturi effect, solving downdraft problems by increasing the updraft constantly resulting in much higher fuel consumption.
Cowls are also used where flues are no longer in use and therefore need to be capped off for protection against ingress of precipitation and nesting birds. Such cowls are designed to afford protection to the flue while still allowing a degree of ventilation.
Wikimedia Commons has media related to Chimney cowls.
Wolverhampton History and Heritage Society. Accessed April 2007
at English Heritage thesaurus. Accessed April 2007
Chimney sweep houston
August 24, 2023
cowl, chimney, cowl, usually, hood, shaped, covering, used, increase, draft, chimney, prevent, backflow, cowl, usually, made, galvanized, iron, fitted, chimney, prevent, wind, blowing, smoke, back, down, into, room, below, undoubtedly, named, after, resemblanc. A cowl is a usually hood shaped covering used to increase the draft of a chimney and prevent backflow The cowl usually made of galvanized iron is fitted to the chimney pot to prevent wind blowing the smoke back down into the room below Undoubtedly named after the resemblance of many designs to the cowl garment worn by monks they have been in use for centuries Cowl designs from a 1910 catalogueThis article includes a list of references related reading or external links but its sources remain unclear because it lacks inline citations Please help to improve this article by introducing more precise citations December 2022 Learn how and when to remove this template message When using an open fire to heat a room the smoke rises through a flue to a chimney pot on the roof Under normal conditions the warm air from the fire will rise up the chimney emitting the smoke with it and dispersing it at rooftop level where it is less of a nuisance In strong winds the pressure of the wind may overwhelm the updraft and push the airflow in reverse down the flue Smoke will then fill the room it is intended to heat posing a health and fire risk causing discomfort and dirtying furnishings in its path When raw coal rather than smokeless fuel is burnt the amount of smoke may be considerable and measures to prevent backflow occurring are a necessity A secondary function is to prevent birds and squirrels from nesting in the chimney Cowls often also act as a rain guard to keep rain from going down the chimney A metal wire mesh is sometimes added as a spark arrestor Wooden cowls were used on oasts to prevent the ingress of rain into kilns and create a flow of air through the kiln An H style cap cowl is a chimney top constructed from chimney pipes shaped like the letter H It is an age old method to regulate draft in situations where prevailing winds or turbulence cause downdraft and back puffing Although the H cap has a distinctive advantage over most other downdraft caps it fell out of favor because of its bulky looks It is found mainly in marine use but has been gaining popularity again for its energy saving functionality The H cap stabilizes the draft rather than increasing it Other downdraft caps are based on the Venturi effect solving downdraft problems by increasing the updraft constantly resulting in much higher fuel consumption Contents 1 Examples 2 See also 3 Further reading 4 ReferencesExamples Edit Wind directional cowl found on many homes along the windy Oregon coast USA An oast cowl A H style cowl Wind rolling home cowl Boat s ventilator cowlCowls are also used where flues are no longer in use and therefore need to be capped off for protection against ingress of precipitation and nesting birds Such cowls are designed to afford protection to the flue while still allowing a degree of ventilation See also EditChimneyFurther reading EditDifferent types Methods for Measuring Emissions Kamin kaufen in German References Edit Wikimedia Commons has media related to Chimney cowls Davies Brothers amp Co Ltd 1910 Catalogue Wolverhampton History and Heritage Society Accessed April 2007 Chimney Cowl at English Heritage thesaurus Accessed April 2007 Chimney sweep houston Retrieved from https en wikipedia org w index php title Cowl chimney amp oldid 1160762654, wikipedia, wiki, book, books, library,
