Fume hood
A fume hood, also known as fume cupboard is a type of local ventilation device that is designed to limit exposure to hazardous or toxic fumes, vapors or dusts.
Design
Fume hoods consist of a cabinet like enclosing, where the back panel is an opaque solid material either straight or oblique, the bottom panel is also solid and flat, the two lateral sides can be either opaque solid material or sliding glass doors, while the top part contains the exhaust vent. The bottom panel is set at standing work height. Under the work stand, there is usually a cabinet where chemicals are kept. At the far end of the work stand, there are at least two water sinks. The lower half of the back panel contains water taps, or sometimes compressed air, inert gas, vacuum, etc. They are controlled by valves set outside the fume hood. The front panes is the most important part of the fume hood. It consists of a sash window, usually made of tempered or laminated glass. It can be moved up and down on a counterbalance mechanism.
Two main types of fume hoods exist: ducted, where the air is evacuated from the room and recirculating (ductless), where the air is evacuated, filtered and sent back in the lab.
Fume hoods are lined with various chemical resistant materials, such as fiberglas reinforced polyester (FRP), epoxy resins, phenolic resins, stainless steel.
Uses
Fume hoods are virtually indispensable in chemistry, as they provide an adequate environment where chemical reactions can be safely performed, as well as a good safety location for various hazardous processes or reagents.
Safety
Fume hoods prevent the build-up of explosive gasses, and can be used as a ventilation device for removing persistent smells from the lab.
