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Safety cabinet

A biosafety cabinet (BSC), also known as a microbiological safety cabinet, is a closed, internally convective operating cabinet for the manipulation of pathogenic (or potentially pathogenic) microorganisms. .
The primary use of biosafety cabinets is to protect laboratory personnel as well as the surrounding environment from pathogenic microorganisms. All exhaust air will pass through a HEPA filter that eliminates harmful bacteria and viruses.
In addition, the biosafety cabinet maintains sterility of the materials working inside the cabinet.
The US Centers for Disease Control and Prevention (CDC) has classified biological safety cabinets into 3 levels. The levels and categories within each class will be distinguished based on two ways: the degree of protection of people and the surrounding environment, and the degree of protection of the sample.


Besides the NSF/ANSI 49 standard, the biosafety cabinet can also be applied to the European technical standard EN12469: 2000. There are also some less common local national standards such as Japan, Korea, India, and China.

Class 1 biological safety cabinet
Class 1 biological safety cabinets have the ability to protect the individual and the surrounding environment but do not protect the sample, the inlet gas can contaminate the sample. Its turbulent air flow is similar to a toxic fume hood, but there is a HEPA filter in the exhaust system to protect the environment. This old style cabinet is rarely found in biomedical and microbiological laboratories. The inlet air flow is usually 75ft/min. Class 1 biological safety cabinets are typically used for centrifuges or experiments where aerosols can be generated.

Class 2 biological safety cabinet
Class 2 biosafety cabinets protect the user, the test material and the environment as all air passes through the HEPA filter. There are 4 types: type A1, A2, B1 and B2. Each type is designed based on NSF international standards. Approximately 95% of biosafety cabinets used are grade A2.

Biological safety cabinets operate on the principle of creating an air film around the sample collection by an exhaust fan above the cabinet. This layer of gas will then recede below the work surface, then go up to the top of the cabinet through the HEPA filter. The gas layer in front of the cabinet is also drawn down below the working surface. This layer of gas also acts as a barrier of contaminated air inside back to the operator.

Class 2 biological safety cabinets are the most common type in biomedical and microbiological laboratories. The air flow in the room around the user is sucked into the air holes on the front of the cabinet to protect the user. In addition, the downward laminar flow through the HEPA filter protects the test material inside the cabinet. The exhaust gas flow through the HEPA filter should no longer contain contaminants, protect the environment, and can be recirculated back into the laboratory in the Class 2 cabinet of Class A, or by the duct to the outside in the Class 2 cabinet of Class B. .

Biosafety cabinet level 3
Class 3 biosafety cabinets are commonly used in laboratories with the highest levels of toxicity where biohazardous agents (biological toxicity level 4) need to be protected at the highest level. This system is airtight, all materials entering or exiting must pass through a two-door autoclave. Class 3 biological safety cabinets are fully enclosed systems. Cabinet with convection HEPA filter fitted with gloves, decontamination of incoming or outgoing samples. This type of cabinet ensures a high level of personal and environmental protection from contaminated aerosols.

Biological safety cabinets
Despite their similar appearance, the microbiological cabinet is not a biological safety cabinet. Room air passes through pre-filter and HEPA filter to remove contamination, dust and other particles. The purified air will enter the work surface through a direct, turbulent air stream. This type of cabinet protects the sample but does not protect the user. Do not use the microbiological cabinet to handle any biohazardous agents or other hazardous materials.

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