The negative air pressure generated by buoyancy of hot gases inside a furnace. The temperature difference between gases within the furnace and in the atmosphere along with furnace and stack height basically determine the amount of draft generated by the furnace. Draft is generally measured in negative inches of water column. ('-w.c.'; 27.7 inches w.c. = 1 psig)
Related Terms |
RESTRICTOR
A device for producing a deliberate pressure drop or resistance in a line by reducing the cross-sectional flow area.
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SAFETY CONTROL
Device to stop unit, equipment or system if unsafe pressure and/or temperatures and/or dangerous conditions are reached.
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AIR COOLER
A factory-encased assembly of elements whereby the temperature of air passing through the device is reduced.
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CONTAMINANT CAPACITY
The weight of a specified artificial contaminant that must be added to the influent to produce a given differential pressure across a filter at specified conditions. Used as an indication of relative service life. Also known as Dirt capacity, Dust capacity
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BUBBLE POINT
The differential gas pressure at which the first steady stream of gas bubbles is emitted from a wetted filter element under specified test conditions.
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AIR INFILTRATION
The leakage of air into a room through cracks in doors, windows, and other openings.
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CLEAN ROOM
A facility or enclosure in which air content and other conditions (such as temperature, humidity, and pressure) are controlled and maintained at a specific level by special facilities and operating processes and by trained personnel.
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CLEAN ROOM
A facility or enclosure in which air content and other conditions (such as temperature, humidity, and pressure) are controlled and maintained at a specific level by special facilities and operating processes and by trained personnel.
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OUTDOOR AIR
Air taken from outdoors and, therefore, not previously circulated through the system.
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SPREAD
The divergence of the air stream in a horizontal or vertical plane after it leaves the outlet.
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