White Paper: Controlling Airflow In Class II Biosafety Cabinets

By Jim Hunter, Senior Project Engineer, Mark Meinders, Product Manager, and Brian Garrett, Product Specialist, Labconco Corporation

Class II biosafety cabinets are defined by the National Sanitation Foundation (NSF International) as:

"A ventilated cabinet for personnel, product, and environmental protection having an open front with inward airflow for personnel protection, downward HEPA fi ltered laminar airfl ow for product protection, and HEPA filtered exhausted air for environmental protection." (1 NSF International, "NSF/ANSI 49 - 2009: Biosafety Cabinetry: Design, Construction, Performance, and Field Certifi cation." 2009, p. 5.)

In order to maintain proper containment, NSF stipulates that recirculating and exhausted airflow volumes, and therefore velocities, must be maintained within a tolerance of +/- 5 feet per minute (FPM).(2 Ibid., p. 28.)HEPA filter loading can compromise a biological safety cabinet's ability to maintain proper airflow. This paper will review the current technologies used by various biosafety cabinet manufacturers to monitor and maintain proper airflows as HEPA filters load.