Ever wonder what the difference is between all those hoods? Which hood was it that protects the operator? Which was it that protected the operator and the work zone?
These enclosures are built to protect only the user from airborne particulates. Air from the room is pulled into the cabinet through the work area, and passes through a HEPA filter at the top of the cabinet.
Class II Type A2:
This type of Biosafety Cabinet protects both the user and the product they are working with. HEPA-filtered air bathes the interior of the cabinet, creating a safe space for the worker in front of the cabinet, as well as an uncontaminated space inside of the cabinet to protect materials that the user works with.
Class II Type B2:
This type of Biological Safety Cabinet bathes the interior of the cabinet with clean, filtered air, and exhausts contaminated air from its interior outside of the laboratory, further protecting both the user and the materials he or she is working with.