Biosafety Cabinets

Biosafety cabinets (BSCs) are frequently used as a primary barrier to protect against release of biologically hazardous agents in both research and clinical biomedical labs. The number of laboratory acquired infections (LAIs) has dramatically decreased since these containment devices have become commonly available in biomedical laboratories. Biosafety (Biohazard Compliance) recommends the use of Class II BSCs in all Biosafety Level 2 laboratories. Each lab should have at least one BSC available for work with pathogenic microorganisms or materials that may contain them (e.g., human materials, non-human primate materials).

BSC training may be accessed on Learning Central by using the search term “biosafety” under Find Learning.  You may also contact Biosafety (Biohazard Compliance) for assistance with Learning Central course assignments.

A few things are critical to know before purchasing and using BSCs.

• Biosafety (Biohazard Compliance) must review the purchase of all new BSCs to determine if the type being purchased is appropriate for the types of materials that will be used.
• TO WORK SAFELY AND ASCEPTICALLY IN A BSC ONE MUST KNOW HOW TO USE IT PROPERLY. Never allow an employee to use a BSC without first training them on its proper use. Require all users to complete the Learning Central BSC training prior to BSC use. Appendix A (Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets) of the CDC BMBL may also be used as a training reference. 
• Clean benches (Class 100 cabinets) are NOT BSCs; they offer product protection only. Class 100 hoods blow air from the work surface into the user’s face. NEVER use Class 100 cabinets as a protective device in your lab. Only sterile non-sensitizing agents (such as saline) are allowed in Class 100 cabinets. If you have a clean bench in your lab please check with Biosafety (Biohazard Compliance) to determine if you are using it properly and for the correct operations.
• BSCs have class types, which are Class I, Class II and Class III
  1. Class I BSCs draw air inward at 75 linear feet per minute (LFP) and are designed to protect the user from airborne contaminants but don’t protect the product. They don’t offer a sterile work environment and are less often used. Class II BSCs draw air inward at 100 LFP and are designed to protect the user and the product from airborne contaminants. They come in 3 types, A, B & C.  The exhaust from type A BSCs is re-circulated in to the laboratory after HEPA filtration. Type A BSCs are the preferred choice when only particulate hazards are involved (microbial or chemical particles). Type B & C BSCs exhaust a portion or all of the air to the exterior of the building. Type B & C BSCs should only be necessary if volatile chemicals or carcinogens are used together with microbial agents in experiments. The main disadvantages of type B & C BSCs is that they must be ducted to the building’s exhaust system and are more expensive to purchase, operate, install, and maintain. Their main advantage over type A BSCs, is that they will expel volatile chemicals that pass through the exhaust HEPA filter to the exterior of the building. A secondary advantage is that they will expel heat buildup from a laboratory. Class II, type A & B BSCs must be certified to meet NSF Standard 49 to be classified as a containment device. All new cabinets purchased with a germicidal lamp (UV) must provide a safety cut-off to protect users from UV burns during use.
  2. Class III BSCs are gas tight cabinets (under negative pressure) and are designed to protect the user and the product from airborne contaminants with HEPA filtered supply and exhaust. Class III BSCs are less commonly used and are generally only needed for high level containment situations such as Biosafety Level 4 work or aerosol experiments involving lesser pathogens. The gas tight glove ports are difficult to work with and intensive maintenance and practice/expertise is critical for their safe use. Class III BSCs may be exhausted to the exterior of the building and have all the additional installation and maintenance concerns of Class II, type B & C BSCs.