1. Objects protected by biological safety cabinets
Samples, operators, environment
2. Application field of biological safety cabinet
A2/B2: tissue culture, cell culture, blood element analysis, QA/QC, genetic engineering, anti-tumor drug preparations;
B2: Volatile toxic and harmful chemical substances, trace radioactive substances, toxic dust and suspended substances.
3. Main structure and configuration
1. Structure: power switch, air supply and exhaust speed sensor, air supply and exhaust high-efficiency filter, fan, ultraviolet lamp, fuse holder, stainless steel working cavity, lower bracket, electrical box, lighting, water and air port, sewage port valve, cabinet, Operation panel, front window, liquid collection tank, negative pressure channel, adjustable feet, universal casters.
2. Configuration: DC motor, energy-saving mode, display screen, socket (including backup), water and gas valve, UV lamp scheduled opening, front window, full opening and arbitrary positioning lift (upper and lower limit alarm system), side windows, brackets, people Machine dialogue function.
4. Working principle of biological safety cabinet
Mainly suck the air in the cabinet to the outside to maintain a negative pressure in the cabinet, and protect the staff through the vertical airflow; the outside air is filtered by a high-efficiency particulate air filter (HEPA filter) to enter safety Inside the cabinet to avoid contamination of processed samples; the air in the cabinet also needs to be filtered by a HEPA filter before being discharged into the atmosphere to protect the environment. SICOLAB summarizes the eight words "inhalation, decline, circulation, and discharge".
Five, the selection of biological safety cabinets
1. Level 1 biological safety cabinet
The first-level biological safety cabinet can protect the staff and the environment without protecting the samples.
The airflow principle is basically the same as that of a laboratory fume hood, but the difference is that the exhaust port is equipped with a HEPA filter to filter the external exhaust flow to prevent the spread of microbial aerosols and cause pollution.
Level 1 biological safety cabinets have no fans and rely on fans in external ventilation ducts to drive airflow. Because they cannot protect the products in the cabinet, they are rarely used at present.
2. Secondary biological safety cabinet
The secondary biological safety cabinet is currently the most widely used cabinet type.
According to the provisions of "The People's Republic of China Pharmaceutical Industry Standard YY0569-2005 Biological Safety Cabinets", the secondary biological safety cabinets can be divided into 4 levels according to the inlet air velocity, exhaust mode and circulation mode: Type A1, Type A2, Type B1 And type B2.
All secondary biological safety cabinets can provide protection for workers, the environment and products.
Type A1:
The minimum air velocity of the front window or the measured average value should be at least 0.38m/s. 70% of the gas is recirculated to the work area through the HEPA filter, and 30% of the gas is filtered out through the exhaust port.
Type A2:
The minimum air velocity of the front window or the measured average value should be at least 0.5m/s. 70% of the gas is recirculated to the work area through the HEPA filter, and 30% of the gas is filtered out through the exhaust port.
The second-level type B biological safety cabinets are all safety cabinets connected to the exhaust system. The fan connected to the exhaust duct of the safety cabinet is connected to the emergency power supply. The purpose is to maintain the negative pressure of the safety cabinet even when the power is cut off, so as to prevent dangerous gas from leaking out of the laboratory. The minimum airflow velocity or the measured average value of the front window should be at least 0.5m/s (100fpm).
Type B1:
70% of the gas is removed through the exhaust port HEPA filter, and 30% of the gas is recirculated to the work area through the supply port HEPA filter.
Type B2:
The 100% full row safety cabinet has no internal circulating air flow. It can provide both biological and chemical safety control. It can operate microbiological experiments with volatile chemicals and volatile nuclear radiation as additives.
3. Three-level biological safety cabinet
The three-level biological safety cabinet is designed for laboratories with a biological safety protection level of level 4. The cabinet is completely airtight, and the staff can operate through the gloves connected to the cabinet, commonly known as the glove box (Golvebox), and the test product passes through double doors The transfer box enters and exits the safety cabinet to ensure that it is not contaminated, and is suitable for high-risk biological tests, such as SARS and Ebola virus related experiments.