To B2 Or Not To B2 — A Biological Safety Cabinet Story

By Mark Meinders, Product Specialist, Labconco

It is often our experience that when a customer inquires about the purchase of a Class II, Type B2 Total Exhaust biological cabinet, they have the misconception that this configuration offers superior biological containment to a Class II, Type A2 cabinet. The decision to use a Type B2 cabinet is one that should be carefully weighed. Type B2 cabinets are specifically designed for applications when the microbiological work requires the use of volatile toxic chemicals or radionuclides.

Airflow through a B2 cabinet is similar to that of a fume hood, externally exhausting 100% of the air pulled through the cabinet. The purpose of this design is to completely remove any toxic chemical vapors or radioactive compounds that are generated inside the cabinet. Room air is brought into the cabinet through both an opening in the top of the cabinet and through the inlet grille. This air flows through an initial HEPA filter and then downward through the work area. All of the contaminated air is then drawn into a negatively pressured plenum and exhausted through a second HEPA filter. A dedicated exhaust system and remote blower draw all of the filtered exhaust air out of the laboratory.