Biological Safety Cabinets

Biological Safety Cabinets (BSC) are primary barrier protection for individuals working with biological materials.  This primary containment device is designed to remove aerosols at the site of their generation and therefore limit spread by contact with the user. A BSC not only provides protection of the user, but it also protects the environment and provides a clean work environment which protects the product. 

How does the BSC work?

Personnel Protection: 

BSCs use vertical laminar airflow to create a barrier at the front of the cabinet. This air curtain protects the user from the biohazardous aerosols that may be created during procedures inside the cabinet. This air curtain can be interrupted by opening doors, quick movements in and out of the cabinet, or movement from side to side. The proper location of the cabinet within the laboratory and safe work practices are important in the proper function of the cabinet. It is important that all users understand the importance of the air curtain as it is the barrier between the user and the potentially infectious aerosols within the cabinet.

Product and Environment:

Room air is drawn down into the front grill of the cabinet without entering the cabinet. This room air along with air being drawn out from within the cabinet are cleaned with High-Efficiency Particulate Air (HEPA) filters before being supplied to the work area in the cabinet or released to the environment.

When should I use a BSC?

BSCs should be used for all procedures with potentially infectious or infectious materials that are likely to create aerosols. Aerosols can be created by any activity where energy is exerted including opening caps, pipetting, vortexing, aspirating, sonicating, etc. Therefore, a BSC is recommended for all manipulations of infectious materials.

What if what I’m working with is only a contact hazard?

While aerosols are suspended in air, they are an inhalation hazard. However, as aerosols settle they become a contact hazard. BSCs remove aerosols at the site of generation limiting the spread by contact with the user. Therefore, a BSC is still recommended for manipulations of infectious agents that are only spread by direct contact.

BSC vs Fume Hood

BSCs are not fume hoods and should not be used for work with volatile chemicals or radioactive materials. If your biohazardous work requires the use of chemicals or radioactive materials, you must use a class II type B2 BSC that is also UL classified as a fume hood. Very few laboratories on the University campus have this type cabinet.

BSC vs Clean Air Bench

Clean Air Benches are not biological safety cabinets.  Clean Air Benches provide only product protection through a unidirectional airflow toward the operator.  These benches may not be used when handling cell culture materials or drug formulations, or when manipulating potentially infectious materials. These devices should not be used in research, biomedical or veterinary laboratories at the University. 

Open Flames in a BSC

Open flames are not permitted in BSCs at the University of Maryland, Baltimore. The use of open flames, such as Bunsen burners, in a BSC disrupts the air flow in the cabinet which in turn compromises the protection of both the worker and the product. In addition,  open flames can cause damage to the HEPA filter because the heat may melt the adhesive holding the HEPA filter together or if the flame is too large or ignites an ethanol wash bottle it could burn a hole in the filter.  An alternative to using an open flame is a sterilizing device called a Bacti-Cinerator.  This device sterilizes using infrared heat and eliminates the need for an open flame or hazardous gas inside of the BSC.

For more information, please visit: Bacti-Cinerator

UV Lights

The Centers for Disease Control (CDC) and the National Institute of Health (NIH) agree that UV lamps are not recommended nor required in biological safety cabinets.  Overexposure to UV light is not only detrimental to humans but its use as a sterilization or decontamination tool is also limited by a number of factors.  These include: penetrating power, relative humidity, temperature, cleanliness, and age.  The American Biological Safety Association (ABSA) has published a paper which sets forth their position regarding the use of UV Lights in BSC’s.

View ABSA’s paper on UV Lights

Purchasing or Moving

Before a Biosafety Cabinet is relocated, disposed of, or moved in any way, it must be decontaminated by B&V Testing.  After decontamination, B&V will place a certification sticker on the cabinet, indicating that the cabinet has been decontaminated.  The Biosafety Officer must then approve the location for the cabinet to be relocated. Once relocated, B&V must certify the cabinet in its new location.

Certification Requirements:
New biosafety cabinets must be validated by certification before they are put into service All biosafety cabinets must be certified annually and after they been repaired or relocated; Certification of Biosafety Cabinets.