Fume hood
A common modern fume hood.
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| Other names | Hood Fume cupboard Fume closet |
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| Uses | Fume removal Blast/flame shield |
| Related items | Laminar flow cabinet |
A fume hood (sometimes called a fume cupboard or fume closet) is a type of local ventilation device that is designed to limit exposure to hazardous or toxic fumes, vapors or dusts.
A fume hood is typically a large piece of equipment enclosing five sides of a work area, the bottom of which is most commonly located at a standing work height.
Two main types exist, ducted and recirculating (ductless). The principle is the same for both types: air is drawn in from the front (open) side of the cabinet, and either expelled outside the building or made safe through filtration and fed back into the room. This is used to:
Secondary functions of these devices may include explosion protection, spill containment, and other functions necessary to the work being done within the device.
Fume hoods are generally set back against the walls and are often fitted with infills above, to cover up the exhaust ductwork. Because of their recessed shape they are generally poorly illuminated by general room lighting, so many have internal lights with vapor-proof covers. The front is a sash window, usually in glass, able to move up and down on a counterbalance mechanism. On educational versions, the sides and sometimes the back of the unit are also glass, so that several pupils can look into a fume hood at once. Low air flow alarm control panels are common, see below.
Fume hoods are generally available in 5 different widths; 1000 mm, 1200 mm, 1500 mm, 1800 mm and 2000 mm. The depth varies between 700 mm and 900 mm, and the height between 1900 mm and 2700 mm. These designs can accommodate from one to three operators.
For exceptionally hazardous materials, an enclosed glovebox may be used, which completely isolates the operator from all direct physical contact with the work material and tools. The enclosure may also be maintained at negative air pressure to ensure that nothing can escape via minute air leaks.
Most fume hoods are fitted with a mains-powered control panel. Typically, they perform one or more of the following functions:
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