A clear understanding of the distinction between biosafety cabinets and fume hoods / ultra clean benches is required
The fume hood and super clean bench are not biosafety cabinets and cannot be used in the experiment or production process involving microbial materials
Biological safety cabinets (BSCs) are designed to protect workers, laboratory environment and experimental products from exposure to infectious aerosols and splashes that may be generated during the above operations when operating infectious experimental materials such as primary cultures, bacterial strains and diagnostic specimens
The laboratory biosafety manual published by who clearly states that "biosafety cabinet can effectively reduce laboratory infection and cross contamination of culture caused by aerosol exposure, while biosafety cabinet can also protect the working environment"
Of course, the premise of effective work of safe cabinet is to choose qualified safe cabinet and use safe cabinet correctly
The fume hood (fume hood) is designed to remove corrosive chemical gases and toxic fumes during chemical experiments
As there is no HEPA filter, the fume hood can not effectively remove the microbial media
Microbial samples placed in the fume hood will be spread outside the fume hood, polluting the laboratory environment
Ultra clean bench (ultra clean bench) is designed to protect the test article or product
It can prevent the test article or product from being polluted by dust or bacteria outside the work area by blowing the vertical or horizontal laminar air of the work area
Once the microbial sample is placed in the working area, the laminar air will blow the air with microbial medium to the front desk staff, which will cause danger
Because most users don't know much about the performance, test and detection of the safety cabinet and super clean platform, it creates a blind area to understand these instruments
But sometimes these blind spots can cause fatal injuries, such as the virus leakage in Zui's laboratories near Singapore, Taiwan and Beijing
It is not enough to measure the safety of super clean platform or safe cabinet only by wind speed
The standard inspection and certification rules ensure the reliability of the inspection and the safety performance of the safety cabinet
At present, the international standards of super clean platform are: air cleanliness level meets iso14644.1; Australian standard as1807; east-rp-cc002.2
Biosafety cabinet standard: American ANSI / nsf49 (secondary cabinet); European standard en12469:2000 (primary, secondary and tertiary cabinet); super clean table can only protect samples, not operators, and its certification includes the following steps: 1) measure the air flow rate of the super clean platform with the rotating impeller anemometer and heat anemometer
The average value of safe air flow: 0.4-0.5m/s, Zui big deviation 20%
2) measure the integrity of ultra clean filter: use natural wet agent detector
3) measure the internal light intensity and noise of super clean platform
Biosafety cabinet is closely related to scientific research at present, which includes two-level biosafety cabinet and three-level biosafety cabinet
There are several types of secondary biosafety cabinets, but the type A / B3 with 30% gas discharge, 70% gas circulation and type B2 with 100% gas discharge are often used in the laboratory
Biosafety cabinet can not only protect samples but also operators, so it is called "safe" cabinet
The detection steps are as follows: 1) measure the inflow air flow (forward air flow): use a heat anemometer or dim hood
2) measurement of downward air flow: according to nsf49 and en12469 standards, there are two ways
But they all use heat anemometers to measure the down flow rate
3) ULPA filter detection: wet agent photometer, wet agent generator, pressure measuring instrument, Pao measuring instrument
4) there are also noise, light intensity and vibration intensity measurement
5) after Zui, use smoke generator to test the air flow visualization.
