Types of BSCs - Class II Type B1 BSC Characteristics

Class II Type B1 BSC Characteristics

Exhaust approximately 70% of total air handled and recirculate 30%
Unique in that the air in the back of the cabinet is exhausted to the outdoors through a dedicated exhaust plenum and the air in the front is recirculated
Minimum inflow air velocity is 100 fpm (0.51 m/s) through the front opening
Must be hard ducted to the outside for the cabinet to function
Requires audiovisual alarm when exhaust loses 20% of volume - must shut down cabinet blower within 15 sec
Have all biologically contaminated ducts and plenums under negative pressure or surrounded by negative pressure ducts and plenums


		Type B1 cabinets may be used for work treated with minute quantities of volatile toxic chemicals and tracer amounts of radionuclide required as an adjunct to microbiological studies if work is done in the direct exhausted portion of the cabinet, or if the chemicals or radionuclide will not interfere with the work when recirculated in the downflow air.