Biological Safety Cabinets (BSCs)

Biological safety cabinets (BSCs) are among the most effective, as well as the most commonly used primary containment devices in laboratories.

Biological cabinets types

The three general types available (Class I, II, III) have performance characteristics and applications which are described here. Properly maintained Class I and II BSCs, when used in conjunction with appropriate microbiological techniques, provide an effective containment system for safe manipulation of moderate and high-risk microorganisms (Biosafety Levels 2 and 3 agents).

  • Both Class I and II BSCs have inward face velocities (75-100 linear feet per minute) that provide comparable levels of containment for laboratory workers and the immediate environment from infectious aerosols generated within the cabinet.
  • Class II BSCs have the additional advantage of providing protection to the research material by high-efficiency particulate air (HEPA)-filtration of the air flow down across the work surface (vertical laminar flow).
  • Class III cabinets offer the maximum protection to laboratory personnel, the community, and the environment because all hazardous materials are contained in a totally enclosed, ventilated cabinet.
  • In Horizontal laminar flow cabinets, positive pressure streams of the filtered air move toward the operator. This type of cabinets does not provide protection to the operator and should not be used when working with tissue culture or other biological agents.

Procedures requiring the use of biological cabinets:

1. When operating aerosol producing equipment, such as sonicators, centrefuges, driers and blenders.

2. When growing genetically modified microorganisms, containing biosafety level 2 or a higher level of DNA fragments, in shakers or fermenters that lack air drainage.

3. For virus infected cells.

4. For protection against allergens or immune-stimulating substances.

5. For animal experiments requiring a primary barrier. For example, when using filter top cages or when transferring infected animals from one cage to another.




Guidelines for working in a biological cabinet

  1. Plan procedures carefully.
  2. Start-up the biosafety cabinet and let it run at least 10-15 minutes before beginning to work.
  3. Do not overload cabinet. Separate clean from contaminated items (work from clean to dirty).
  4. Wear gloves and long sleeves lab coats.
  5. Decontaminate the cabinet with disinfectant before and after work is completed.
  6. Protect vacuum system by trap.
  7. Avoid disruption of airflow (turbulence); extra items storage and movement in and around the cabinet.
  8. Perform work 10-15 cm. back from the front intake grille.
  9. Equipment that causes turbulence should be placed in back 1/3 of work surface. Do not block the back grille.
  10. Avoid use of flame. Turbulence and filter damage may occur.
  11. Check the periodical test performance sticker affixed on the cabinet