Biosafety Cabinet ClassesA biosafety cabinet is a ventilated enclosure to protect the user, the product, and the environment from aerosols arising from the handling of potentially hazardous microorganisms. The biosafety cabinets are classified into 3 classes based on their containment abilities when working with biological agents. The occupational safety and health administration has  set standard guidelines related to biosafety to promote a safe working environment

Choosing the biosafety cabinet, you need to identify your workplace needs and determine which cabinet serves your purpose. Here are the different biosafety cabinets.

Class I

A class 1 cabinet is a ventilated cabinet to protect personnel and the environment. The cabinets pull room air through the front away from the operator. The airflow pattern is similar to the chemical fume hood but in addition, they have HEPA filters at the exhaust outlet. Cabinets may use ducts or sometimes it’s ductless. These cabinets are idle for agents looking for Level 1,2,3,4 containment.

Class II

Cabinet II provides both kinds of protection to the samples and the environment. These cabinets have a fan mounted on the top that circulates clean

Air over the workstation where biological products are handled. The exhaust then sucks out the air from the facility, this mechanism acts as a barrier against the contaminated air and the operator.

Class II BSCs are divided into 5 types depending on the exhaust system and mechanism.

The types are A1,A2 , B1, B2, and type C1.

Type A1

These types of cabinets have a minimum face velocity of 75ft/mn, the incoming airflow enters the cabinet through the front door, which then gets filtered by HEPA.At a distance of 6-18 cm

From the worksurface, it splits into a descending action. Half of the contaminated air getting out through the front exhaust grill and the other half goes through the rear. The produced aerosols are gathered by downward airflow and get expelled via front or rear exhaust grills to ensure the best level of product protection. If you are dealing with poisonous or radioactive substances then go for other options.

Type A2

Cool air is sucked into the cabinet through the front grill. A plenum in the back wall allows air to be sucked up from under the desk by a motor blower. Then, after passing through a HEPA filter, the filtered air is pumped into the center plenum from the top of the cabinet. The remaining 70% of the air is recirculated into the work area through a HEPA filter in a laminar (unidirectional) flow pattern. When the fan is turned on, the air flows over the workspace, through the front airflow grill, up the back wall, and back under the workspace. 

Type A2 Biosafety Cabinets are approved for use with both radionuclides and dangerous compounds.

Type B1

Type B1 cabinets maintain a minimum average inflow velocity of 100 fpm through the sash opening. They have HEPA-filtered downflow air composed mostly of uncontaminated recirculated inflow air and exhaust most of the contaminated downflow air through a dedicated duct that exhausts outside after passing through a HEPA filter. Like Type A2 cabinets, Type B1 cabinets are safe for work involving agents treated with minute quantities of toxic chemicals and tracer amounts of radionuclides.

Type B2

A Class II, Type B2 cabinet maintains an inflow velocity of 100 fpm through the sash opening. They have HEPA-filtered downflow air drawn from the lab or the outside air (not recirculated from the cabinet exhaust) and exhaust all inflow and downflow air to the atmosphere after filtration through a HEPA filter without recirculation in the cabinet or return to the lab. Because of this, they are sometimes referred to as 100% Exhaust or Total Exhaust cabinets. Type B2 cabinets are suitable for work involving biological agents treated with hazardous chemicals and radionuclides required as an adjunct to microbiology applications. 

Type C1

A Class II, Type C1 cabinet maintains an inflow velocity of 100 fpm through the sash opening. Type C1 cabinets can operate as either a Type A cabinet when in recirculating mode or a Type B cabinet when exhausting. C1 cabinets can be changed from one mode to the other by connecting or disconnecting the exhaust and having the cabinet recertified. When in exhausted Type B mode, Type C1 cabinets clearly define the areas where users can work safely using delineated areas for storage, and a central work area with direct exhaust for use with chemical vapors, radionuclides, or chemotherapy preparations.

Class III

A Class III cabinet is a totally enclosed, ventilated cabinet with leak-tight construction and attached rubber gloves for performing operations in the cabinet. The cabinet has a transfer chamber with interlocked doors that allow for the sterilization of materials before entering/exiting the glove box. The cabinet is maintained under negative pressure and supply air is drawn in through HEPA filters. The exhaust air is treated with either double HEPA filtration or single HEPA filtration followed by incineration. Class III cabinets are safe for work requiring Biosafety Level 1, 2, 3, or 4 containment. Lab furniture goes a long way in the quality promotion of a product. 

Get in touch to find out how we can help equip your lab with the safest biohazard cabinets.