Biological Safety Cabinets

Biological safety cabinets are designed to provide both a clean work environment and protection for employees who work with biological hazards. They use vertical laminar airflow to create a barrier to airborne particles, such as microorganisms. High Efficiency Particulate Air (HEPA) filters are used to clean air going into the work area and out to the environment. The HEPA filter removes airborne particles from the air, but does not remove chemical fumes. A biosafety cabinet is different from a chemical fume hood, which are only designed to remove (not decontaminate) chemical fumes and aerosols away from the work area. A single exception is a specific special model of Class II Type B2 biological safety cabinet that is UL classified as a fume hood.

When the need arises for manipulation of pathogens that are likely to create aerosols (such as vortexing open tubes, pipetting, opening caps after centrifuging, sonicating, aspirating with a syringe, etc.). Use for all manipulation of airborne transmitted pathogens.

Cabinets previously classified as Class II, Type A/B3 are now classified as Class II, Type A2. These biosafety cabinets may be exhausted to the room, or connected to a facility exhaust system via a "canopy" connection. (NSF recommends a canopy connection for cabinets exhausted to the outdoors.) The Class II, Type B3 classification no longer exists for new units. See the chart below for the New NSF Classification, adopted 2002.

NSF Classification Adopted 2002 Previous Classification General Description
A1 Class II

70% air recirculated

30% exhausted from a common plenum to the room

75FPM intake

May have biologically contaminated positive pressure plenum

A2 Class II, Type A/B3

70% air recirculated

30% exhausted from a common plenum to the room

100FPM intake

Biologically contaminated plenum under negative pressure or surrounded by negative pressure

B1 Class II, Type B3

40% air recirculated

60% exhausted from cabinet

Exhaust air pulled through dedicated exhaust duct into facility exhaust system

100FPM intake

All biologically contaminated plenum are negative to the room or surrounded by negative pressure plenums

B2 Class II, Type B2

0% air recirculated

100% exhausted from cabinet

exhaust air pulled through dedicated exhaust duct into facility exhaust system

100FPM intake

All ducts and plenums are under negative pressure

All biologically contaminated plenum are negative to the room or surrounded by negative pressure plenums

 

Certification of biological safety cabinets policy (hosted by the Office of Research)

Primary Containment for Biohazardous book about selection, installation and use of biological safety cabinets (CDC)

An Introduction to biosafety cabinets describes the classifications, Biosafety Levels and Applications in plain language with illustrations from The Baker Company

Learn how to select a biological safety cabinet from NuAire

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