Principle and classification of biological safety cabinets
Biological safety cabinet is a vital experimental equipment, widely used in life science, medicine, biotechnology, microbiology and pharmaceutical fields. It is designed to protect the operator, the laboratory environment, and experimental materials from exposure to infectious aerosols and spills that may be generated during such operations.
Working principle
The working principle of the biological safety cabinet is mainly to pump the air inside the cabinet outwards, so that the cabinet maintains a negative pressure state, and protects the staff through vertical airflow. The outside air is filtered through a high efficiency air filter (HEPA) into the safety cabinet to avoid contamination of the treated sample. The air in the cabinet also needs to be filtered by HEPA filters before being discharged into the atmosphere to protect the environment.
Classification
According to the difference in the level of biological safety protection, it can be divided into three types: one, two and three:
- Level one biological safety cabinet: Protects workers and the environment without protecting samples. The airflow principle is basically the same as the laboratory fume hood, the difference is that the exhaust port is installed with a HEPA filter, which filters the exhaust air to prevent the spread of microbial aerosols and cause pollution. The first-level biological safety cabinet itself has no fan and relies on the fan in the external connected air duct to drive the air flow. Because it cannot protect the products in the cabinet, it has been used less.
- Level two biological safety cabinet: It is the most widely used cabinet at present. All types of Level two biological safety cabinets provide protection for workers, the environment and samples. They can be divided into type A1, type A2, type B1 and type B2 according to the inlet air speed, exhaust mode and circulation mode. A1 and A2 cabinet front window airflow speed has a certain requirement, and part of the gas through the HEPA filter recirculated to the work area, part of the gas through the exhaust filter discharged. Type B1 and type B2 differ in the exhaust and circulation mode, type B2 is 100% full discharge safety cabinet, no internal circulation air flow, can provide biological and chemical safety control.
Level three biological safety cabinet: It is designed for the biological safety protection level 4 laboratory, the cabinet is completely airtight, and the staff operates through the gloves connected in the cabinet, commonly known as the glove box (Golve box). The test products enter and exit the safety cabinet through a double-door transfer box to ensure that they are not contaminated and are suitable for high-risk biological tests.
Suzhou Pharma Machinery Co.,Ltd.
2025/05/19
Tia
