Biological safety cabinets or BSCs are an enclosed, ventilated hood or workspace that allow for the safe handling of pathogens, contaminants or other potentially hazardous materials.
This type of equipment is also referred to as biosafety cabinets or microbiological safety cabinets. When outfitted with glove systems (in the case of Class III biosafety cabinets), they are also called gloveboxes. There are various classes of biological safety cabinets, each defined by the required level of biosafety and containment as well as the required configuration of the cabinetry.
The primary purpose of a biosafety cabinet is to protect the operator and the surrounding environment from biological contaminants and other hazardous materials. These cabinets are designed to provide various levels of protection. The proper class and type must be selected to match the need for the specific application and level of bio-containment required.
Classes and Types of Biological Safety Cabinets (BSC)
BSCs (in the US and many other countries) are officially designated and described in the Biosafety in Microbiological and Biomedical Laboratories 5th Edition BMBL. The biological safety manual is produced by the U.S. Centers for Disease Control and Prevention and National Institutes of Health. According to the BMBL these cabinets are designated as follows:
Class I BSCs provide personnel and environmental protection, but does not provide product protection. It is similar in terms of air movement to a chemical fume hood. However the Class I BSC has a HEPA filtration system that handles the air exiting the unit, providing protection for the environment.
Class II hoods provide personnel, environmental and product protection for a range or low to moderate risk materials. These biological safety cabinets are used in research, clinical, industrial and pharmacy settings.
Airflow is drawn into the front grille of the unit, providing personnel protection. In addition, the downward flow of HEPA-filtered air provides product protection by minimizing the chance of cross-contamination across the work surface of the hood. Exhaust air is passed through a certified HEPA filter. This provides particulate filtration to protect the environment. Air may be recirculated to the laboratory (for Class II, Type A1 and A2 BSCs) or alternatively allowing the air to be discharged from the building via a canopy or “thimble” connected to the building exhaust. Class II, Types B1 and B2 BSCs must be discharged directly to the outdoors via a hard connection. (BMBL). These hoods are commonly used in the hospital pharmacy, in addition to a wide range of clinical and research applications.
Class III cabinets are utilized for work with highly infectious microbiological agents and for the conduct of hazardous operations and provides maximum protection for the environment and the worker. It is a gas-tight enclosure with a non-opening view window. Access for passage of materials into the cabinet is through a dunk tank, that is accessible through the cabinet floor, or double-door pass-through box (e.g., an autoclave) that can be decontaminated between uses. Reversing that process allows materials to safely be removed. Both the supply and the exhaust air of the unit is HEPA-filtered. The air that is exhausted from the unit must pass through two HEPA filters, or HEPA-filtration in combination with an air incinerator, before discharge of air (directly outdoors). Class III BSCs are not discharged through the general laboratory exhaust system. (BMBL). Gloves are attached to the unit, utilizing gas-tight ports. This allows the user to directly manipulate the materials inside the cabinet. Class III units may also be joined together to implement a larger capacity containment area.
Biosafety Cabinets as Compared to Standard Clean Benches
Biosafety cabinets (BSC) should not be confused with clean air workbenches or standard laminar flow workstations. Standard horizontal or vertical laminar flow clean benches are not BSCs. Basic clean air workstations provide HEPA filtration that protects the product. Biological safety cabinets protect both the worker and environment from hazards within the cabinet. The proper BSC is also specified for the appropriate level of product protection, depending on the type and class required for the application. Note: The Class I BSC is not designed for product protection.
Germfree manufactures a wide range of Biological Safety Cabinets that are utilized in applications within healthcare, research, security and industry. These units include Class I & Class II hoods and Class III gloveboxes that allow for the safe handling of potentially hazardous agents as well as the sterile preparation of materials. Learn more about Germfree’s Biological Safety Cabinets.