Biological Safety Cabinets

The biological safety cabinet is designed to reduce the potential escape of research material into the worker's environment and to remove contaminants from the research work zone. Danger to personnel and to success of the scientific investigations from carelessly or improperly used protective equipment cannot be over-emphasized.

The following equipment provides a clean work zone (product protection), aerosol protection for the operator (personnel protection) and environmental protection through use of a High Efficiency Particulate Air (HEPA) filter:

Class II, Type A cabinets (see APPROVED LIST) are suitable for work with low to moderate risk biological agents requiring BL-1, BL-2 or BL-3 containment in the absence of volatile toxic chemicals and volatile radionuclides. This type of cabinet exhausts HEPA-filtered air into the non-return building exhaust via a canopy; and may have positive pressure contaminated ducts and plenums.

TYPE A cabinet

Class II, Type B1 cabinets (see APPROVED LIST) are suitable for work with biological agents requiring BL-2 or BL-3 containment. They may also be used with biological agents treated with minute quantities of toxic chemicals and trace amounts of radionuclides required as an adjunct to microbiological studies if the chemicals or radionuclides will not interfere with the work when recirculated in the downflow air. This type of cabinet exhausts most of the contaminated downflow air through a dedicated duct exhausted to the atmosphere after passing through a HEPA filter and has all biologically contaminated ducts and plenums under negative pressure, or surrounded by negative pressure ducts and plenum.

TYPE B cabinet

Class II, Type B2 cabinets(see APPROVED LIST) are suitable for work with biological agents requiring BL-1, BL-2, BL-3 containment. They may also be used with biological agents treated with toxic chemicals and radionuclides required as an adjunct to microbiological studies. This type of cabinet is sometimes referred to as a "Total Exhaust Cabinet".



The cabinet exhausts downflow air through a dedicated duct to the atmosphere after filtration through a HEPA filter without recirculation in the cabinet or return to the laboratory room air. All contaminated ducts and plenums are under negative pressure, or surrounded by directly exhausted (non-recirculated through the work area) negative pressure ducts and plenums.

TYPE B2 cabinet