A biosafety cabinet is designed to protect operators, laboratory environments, and laboratory supplies from exposure to infectious atmospheric aerosols and splashes that may occur during actual operations when collecting primary cell materials, bacterial strains, and test specimens, as well as infectious laboratory supplies.
According to the differences in biosafety protection levels, biosafety cabinets can be divided into three categories: Level 1, Level 2, and Level 3. The first level biosafety cabinet can ensure the safety of relevant personnel and the environment, but it does not guarantee the safety of samples. The principle of gas flow is roughly the same as that of a laboratory fume hood, with the difference being that the ventilation opening is equipped with a HEPA filtration device, which filters the external exhaust gas flow to prevent secondary pollution caused by the diffusion of microbial species and atmospheric aerosols. The first level biosafety cabinet actually does not have fans and relies on fans in external ventilation ducts to drive gas flow. Considering the inability to guarantee the equipment inside the cabinet, it is currently being used sparingly.
The secondary biosafety cabinet is a widely used cabinet type in the current application field. According to the requirements of the pharmaceutical industry standard YY0569-2005 Biosafety Cabinet of the People's Republic of China, secondary biosafety cabinets can be divided into four levels based on the inlet gas flow speed, exhaust method, and circulation form: A1 type, A2 type, B1 type, and B2 type. Each secondary biosafety cabinet can ensure the maintenance of relevant personnel, natural environment, and products. The minimum or average gas flow velocity in the front window of A1 type safety cabinet shall not be less than 0.38m/s. 70% of the gas is recycled to the work area through a HEPA filtration device, and 30% of the gas is discharged through a vent filtration system. The minimum or average gas flow velocity in the front window of A2 type safety cabinet shall not be less than 0.5m/s. 70% of the gas is recycled to the work area through a HEPA filtration device, and 30% of the gas is discharged through a vent filtration system.
Class B biosafety cabinets are all safety cabinets connected to exhaust systems. The fan connected to the exhaust duct of the safety cabinet is connected to the emergency power supply, which can maintain the negative pressure of the safety cabinet even in the event of a power outage to prevent dangerous gas leakage. The minimum or average gas flow velocity in the front window shall not be less than 0.5m/s (100fpm). 70% of the B1 type gas is discharged through the ventilation HEPA filtration device, and 30% of the gas is recycled to the work area through the supply port HEPA filtration device. The B2 type is a 100% full row safety cabinet with no internal structural circulation airflow. It can provide both biological and chemical safety management and can use volatile chemicals and volatile nuclear radiation as additives for microbiological experiments.
The third level biosafety cabinet is tailor-made for biosafety protection level 4 inspection. The cabinet is completely sealed, and the relevant personnel work through gloves connected to the cabinet, also known as Golvebox. The experimental samples pass through two transfer boxes, one in and one out of the safety cabinet, to ensure that they are not contaminated. It is mainly used for high-risk biological inspections, such as conducting SARS, Ebola virus related inspections, etc.
A biosafety cabinet is designed to protect the operator, laboratory environment, and experimental materials from exposure to infectious aerosols and splashes that may occur during the operation of primary cultures, bacterial strains, diagnostic specimens, and other infectious experimental materials.
It can artificially control the emission of contaminated air in the operating area through specialized filtering channels, and is a specialized equipment for safe microbial experiments and production. Widely used in related industries such as biological laboratories, healthcare, and biopharmaceuticals, it has a good effect on improving process conditions, protecting the health of operators, and the environment.
