How to classify biosafety cabinets?

Level I biosafety cabinets protect workers and the environment without protecting samples. The air flow principle is the same as the laboratory kitchen, the difference is that the exhaust port is installed with a filter. All types of biosafety cabinets use filters at the exhaust and intake ports. The first-level biosafety cabinet has no fan itself, and relies on the fan in the external connected air pipe to drive the air flow. Because it cannot provide protection for the test products or products, it has been used less.

Level 2 biosafety cabinet is the most widely used cabinet at present. According to the provisions of the "People's Republic of China pharmaceutical industry standard YY0569-2005 Biosafety Cabinet", the secondary biosafety cabinet can be divided into four levels according to the inlet air speed, exhaust mode and circulation mode: A1, A2, B1 and B2.

All Level 2 biosafety cabinets provide protection for workers, the environment and products.

A1 type safety cabinet front window airflow velocity minimum or measured average should be at least 0.38m/s. 70% of the gas is recirculated to the working area through the HEPA filter, and 30% is filtered out through the exhaust port.

A2 type safety cabinet front window airflow velocity minimum or measured average should be at least 0.5m/s. 70% of the gas is recirculated to the working area through the HEPA filter, and 30% is filtered out through the exhaust port.

Class B biosafety cabinets are safety cabinets connected to exhaust systems. The fan connected to the exhaust pipe of the safety cabinet is connected to the emergency supply power to maintain the negative pressure of the safety cabinet in case of power failure, so as to avoid the leakage of dangerous gases out of the laboratory. The minimum airflow velocity or measured average of the front window should be at least 0.5m/s(100fpm).

70% of the B1 gas is removed through the exhaust port HEPA filter, and 30% of the gas is recirculated to the working area through the supply port HEPA filter.

Type B2 is a 100% full-discharge safety cabinet with no internal circulating air flow, which provides both biological and chemical safety control, and can operate microbial experiments with volatile chemicals and volatile nuclear radiation as additives.

The Level 3 biosafety cabinet is designed for the level 4 laboratory biosafety level and is currently the highest level of safety protection in the world. The cabinet is completely airtight, 100% full discharge, all gases do not participate in the cycle, the staff through the glove connected to the cabinet, commonly known as the glove box (Golvebox), the test product through the two-door transfer box in and out of the safety cabinet to ensure that it is not contaminated, suitable for high-risk biological tests.