Biological safety cabinets (BSCs) are designed to protect the operator, the laboratory environment and work materials from exposure to infectious aerosols and splashes that may be generated when manipulating materials containing infectious agents, such as primary cultures, stocks and diagnostic specimens BSCs, when properly used, have been shown to be highly effective in reducing laboratory-acquired infections and cross-contaminations of cultures due to aerosol exposures. The Biological Cabinets divide to 3 classes: Class I biological safety cabinet, Class II biological safety cabinets, Class III biological safety cabinet.
The Biological Cabinets divide to 3 classes:
Class I biological safety cabinet
The Class I BSC was the first recognized BSC and, because of its simple design, is still in wide use throughout the world. It has the advantage of providing personnel and environmental protection and can also be used for work with radionuclides and volatile toxic chemicals.
Class II biological safety cabinets
The Class II BSC was designed not only to provide personnel protection but also to protect work surface materials from contaminated room air.
Class II BSCs, of which there are four types (A1, A2, B1 and B2), differ from Class I BSCs by allowing only air from a HEPA-filtered (sterile) supply to flow over the work surface.
The Class II BSC can be used for working with infectious agents in Risk Groups 2 and 3.
Class II BSCs can be used for working with infectious agents in Risk Group 4 when positive-pressure suits are used
Class III biological safety cabinet
This type provides the highest level of personnel protection and is used for Risk Group 4 agents. All penetrations are sealed “gas tight”. Supply air is HEPA-filtered and exhaust air passes through two HEPA filters. Airflow is maintained by a dedicated exhaust system exterior to the cabinet, which keeps the cabinet interior under negative pressure (about 124.5 Pa). Access to the work surface is by means of heavy duty rubber gloves, which are attached to ports in the cabinet. Class III BSCs are suitable for work in Biosafety Level 3 and 4 laboratories.
How to work with biological cabinets?
- Wash hands before and after working with the cabinets
- Protective clothing must be worn while using the hood. Long clothing, gloves and a robe.
- Smooth airflow must be maintained in the laboratory
- The vapors must be cleaned regularly