With the development and progress of the medical level, many hospitals have established pathogenic microorganism laboratories in order to provide timely and reliable clinical diagnosis and treatment.
Basis. The interpretation of pathogenic microorganisms detection results and the determination of infection are important basis for clinical diagnosis and the basis for correct treatment in the later stage. In the pathogen
In the first few steps of microorganism extraction, it is necessary to directly contact the biological samples of the case. The process involves heating and cracking. When inspectors hit
When opening the sample container, aerosols containing pathogenic microorganisms may be dispersed into the air environment. Therefore, operate in the biological safety cabinet of the negative pressure laboratory
Make it safer.

When exhausting through the exhaust system of the facility or using biological agents, ensure that
Protect the environment and personnel from aerosols, but cannot protect products from pollution.
dye. The air discharged from the outside or the room is recirculated to the laboratory and used in the exhaust
HEPA filter.
1.2 Level 2
Properly ventilate and handle biological agents and hazards through the facility’s exhaust system
Protect the product, laboratory personnel and the environment when risking drugs. For HEPA filter
For external exhaust or room recirculation, HEPA is used in both air supply and exhaust
filter. Therefore, it is the most widely used. According to inlet air velocity and exhaust
In the wind circulation mode, the second-level biological safety cabinet can be divided into four levels: A1, A2, B1, and B2 [2].
1.2.1 In the A1 safety cabinet, the minimum average of the suction port through the opening surface of the workbench
The wind speed is maintained at 0.38m/s; the vertical downward air after being processed by the high efficiency filter
70% of the original circulating gas is filtered, and 30% is newly inhaled and passed
Filtered supplementary gas, 30% of the original circulating gas is efficiently filtered through the exhaust port
The filter is discharged into the laboratory.
1.2.2 In A2 safety cabinet, the minimum average wind passing through the suction port of the open surface of the workbench
The speed is maintained at 0.5m/s; the vertical downward air flow after being processed by the high efficiency filter,
70% of the original circulating gas is filtered, and 30% is newly sucked and filtered
Supplementary gas, 30% of the original circulating gas passes through the exhaust port high efficiency filter
The filter is discharged outdoors and no longer returned to the laboratory.
1.2.3 In the B1 safety cabinet, the smallest average of the suction port through the open surface of the workbench
The wind speed is maintained at 0.5m/s; the vertical downward air after being processed by the high-efficiency filter
30% of the original circulating gas is filtered, and 70% is the newly inhaled filtered supplementary gas, that is, most of the original circulating gas is efficiently passed through the exhaust port.
The filter filters and discharges to the outdoors without returning to the laboratory. All organisms
The contaminated air duct and static pressure box should be kept under negative pressure, or the negative pressure air pipe and static pressure box should be enclosed
stand up.
1.2.4 In the B2 safety cabinet, the minimum average of the suction port through the open surface of the workbench
The wind speed is maintained at 0.5m/s; the vertical downward air flow after being processed by the high efficiency filter
All are the newly inhaled filtered gas, and all the original circulating gas passes through the exhaust
The air port high efficiency filter filters and discharges to the outdoors, not returning to the laboratory. all
Contaminated air ducts and static pressure boxes should maintain negative pressure or be directly exhausted by air ducts
Surrounded with static pressure box.