Fume Cabinets

Also known as fume hoods, fume cabinets are large pieces of safety equipment with ventilation to limit exposure to hazardous or toxic fumes, vapours or dust. They are usually set against walls and often have internal lights and a vapour proof cover. They have a mains-powered control panel and a sash window usually made of glass which only opens partially. There are two basic types of fume cabinets: ducted and recirculating (ductless). Most laboratories contain ducted cabinets where the air is drawn from the working area and then dispersed through ducts. This type of hood may be a variable air volume system (VAV) or a constant air volume (CAV). The latter often have a bypass system installed to decrease air velocities which disturb instrumentation and experiments. The newest generation of hoods are connected electronically to the laboratory's ventilation system and contains monitors and alarms. In ducted cabinets, the air is filtered and fed back into the laboratory but this process is discouraged because of the risk of contamination. Fume cabinets are installed in laboratories to evacuate hazardous levels of contaminants. They protect the user from inhaling toxins, protect the product and the experiment as well as safeguarding the environment.