Guidelines for Standard Operating Procedures and Specifications for Biosafety Cabinets

1、 Classification and characteristics of biosafety cabinets
Level I biosafety cabinet
Protective features: It can protect operators and the environment, but does not provide protection for experimental samples
Applicable scenarios: commonly used for low-risk microbial operations or preliminary treatment of volatile toxic substances
Level II biosafety cabinet
Protective features: capable of simultaneously protecting operators, experimental samples, and the environment
Main types:
A2 type: 70% airflow circulation, 30% external discharge, suitable for routine microbiological experiments
B2 type: 100% full external discharge design, suitable for handling volatile chemicals and radioactive substances
Grade III biosafety cabinet
Protective features: Sealed glove box, providing high-level protection
Application area: Operations related to high-risk pathogens (such as BSL-4 laboratory)
2、 Introduction to Operating Principle
The biosafety cabinet achieves protection function through directional airflow design and efficient filtration system:
Airflow control: Adopting a combination of vertical descending airflow and inward intake to form an air curtain barrier

HEPA filtration system: capable of effectively intercepting over 99.97% of 0.3 μ m particles, including microbial aerosols

3、 Standard Operating Procedure
Preparation before use
Equipment inspection: Confirm that the power supply, fan, lighting, and UV function are normal
Tabletop disinfection: Use 70% ethanol or other suitable disinfectants to wipe the work area
Personal protection: Wear lab coats, gloves, and protective goggles
Start the program
Pre operation: Start the fan in advance and run it for at least 10 minutes to stabilize the airflow
Parameter setting: Adjust the working face height and operating parameters according to experimental requirements
Experimental operation specifications
Item placement: Reasonably arrange experimental equipment to avoid blocking airflow channels
Operation technique: Reduce frequent arm movements and maintain airflow balance
Anti pollution measures: Strictly implement aseptic operation standards and use work areas in designated areas
End operation
Table cleaning: Immediately disinfect the table after the experiment is completed
Waste disposal: Collect and dispose of waste according to biosafety requirements
Equipment shutdown: Turn off the fan and lighting, and activate the UV disinfection function (if necessary)