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A fume hood or fume cupboard is a type of local〔"Study of Factors Affecting Fume Hood Energy Consumption()".pdf by American AutoMatrix〕 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: * protect the user from inhaling toxic gases (fume hoods, biosafety cabinets, glove boxes); * protect the product or experiment (biosafety cabinets, glove boxes); * protect the environment (recirculating fume hoods, certain biosafety cabinets, and any other type when fitted with appropriate filters in the exhaust airstream). Secondary functions of these devices may include explosion protection, spill containment, and other functions necessary to the work being done within the device. == History and design == The need for ventilation has been apparent from early days of chemical research and education. Some early approaches to the problem were adaptations of the conventional chimney. A hearth constructed by Thomas Jefferson in 1822-1826 at the University of Virginia was equipped with a sand bath and special flues to vent toxic gasses. The draft of a chimney was also used by Thomas Edison as what has been called the "first fume hood".〔(【引用サイトリンク】title=Fume hood history )〕 The first known modern "fume cupboard" design with rising sashes was introduced at the University of Leeds in 1923. Modern fume hoods are distinguished by methods of regulating air flow independently of combustion, improving efficiency and potentially removing volatile chemicals from exposure to flame. Fume hoods were originally manufactured from timber, but during the seventies and eighties epoxy powder coated steel became the norm. During the nineties wood pulp derivatives treated with phenolic resin (plastic laminates and solid grade laminates) for chemical resistance and flame spread retardency started to become widely accepted. Fume hoods (fume cupboards) 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 can accommodate from one to three operators. 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 shape they are generally dim inside, 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 of the unit are often also glass, so that several pupils can look into a fume hood at once. Low air flow alarm control panels are common, see below. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「fume hood」の詳細全文を読む スポンサード リンク
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