"A thorough understanding of biological safety cabinets"

"A Comprehensive Understanding of Biological Safety Cabinets"

Li Kang----Dong Yong

The WHO Laboratory Biosafety Manual emphasizes that biological safety cabinets are crucial in reducing laboratory infections and cross-contamination caused by aerosol exposure. These cabinets also provide protection to the working environment. In reality, their primary focus is on safeguarding the operator and the surroundings. A biosafety cabinet functions as a vacuum filtration exhaust system, preventing the spread of pathogenic microorganisms during operations and thus avoiding personal injury and environmental pollution.

Key International and Domestic Standards for Biological Safety Cabinets; 1. Domestic and international standards include: National Standard of the People's Republic of China GB19489-2004 "General Requirements for Laboratory Biosafety"; Health Industry Standard of the People's Republic of China WS233-2002 "Microbiology and Biomedical Laboratory General Guidelines for Biosafety"; Regulations of the State Council of the People's Republic of China on Biosafety Management of Pathogenic Microorganisms; Pharmaceutical Industry Standards of the People's Republic of China YY0569-2005 Biological Safety Cabinets; World Health Organization Laboratory Biosafety Manual (WHO) Third Edition 2004; the industrial industry standard for the construction of the "Biosafety Cabinet JG170-2005" prepared by the Ministry of Construction, implemented June 1, 2005; EN12469:2000 issued by the European Committee for Standardization (CEN) «Biotechnology Biosafety Cabinet Performance Requirements» (English Version); American National Standard Institute (ANSI) officially recognized NSF/ANSI49-2002 «Class II (Laminar Flow) Biosafety Cabinet» (English Version); Guidelines for HIV Professional Occupational Exposure Prevention for Medical Staff 2004; "Hospital Infections Management Measures" 2006; 2, differences between domestic and international biosafety standards; more stringent definitions: the biggest difference is that EN12469 only has a basic definition of "secondary biosafety cabinet," while YY0569 and NSF49 similarly divide the secondary biosafety cabinet into four types according to window inflow air velocity, exhaust mode, and circulation mode: A1 type, A2 type (formerly B3 type), B1 type, and B2 type. Both YY0569 and NSF49 specify that aerosol hairsprays (e.g., DOP, PAO, etc.) are used in the filter integrity test; the European EN12469 standard (using the same test method) uses another natural aerosol (natural air) test method.

It's important to understand the distinction between biosafety cabinets and fume hoods or clean benches. Fume hoods and clean benches are not biosafety cabinets and should not be used in experiments involving microbial materials. The fume hood is designed to remove corrosive chemical gases and toxic fumes during chemical experiments, but it does not effectively remove microbial media because it lacks a HEPA filter. Placing microbiological samples in the fume hood can lead to contamination of the lab environment. An ultra-clean workbench protects the test sample by blowing vertical or horizontal laminar air through the work area, but if microbial samples are placed inside, the airflow can create hazards by blowing contaminated air toward the operator.

Selection Points for Biological Safety Cabinets; 1 、Ultra-efficient air filter for particles larger than 0.1 um~0.2um in diameter, with a filtration efficiency of 99.999%. Li Kang’s biosafety cabinets are all equipped with ultra-high efficiency filters. 2. Fixed wind speed fans: such fans have fixed wind speeds. When the high-efficiency air filter becomes clogged, the filter pressure needs to be manually adjusted. Self-inductive fan, biological safety cabinet can automatically control the fan wind speed to adjust according to the load change within a certain range, ensuring optimal output air volume and stable negative pressure in the biological safety cabinet. YY0569-2005 biosafety cabinet pharmaceutical industry standard requires that the fan of the safety cabinet should ensure that when the wind pressure change of the filter exceeds 50%, the flow rate of the descending airflow through the filter is less than 10% without adjusting the motor power of the fan; 3. Pressure leakage test: National pharmaceutical industry YY0569-2005 standard stipulates that the biosafety cabinet is pressurized to 500Pa, and the pressure is not lower than 450Pa after 30 minutes. 4. The minimum average flow rate of the inflow airflow of the front window operating port of the safety cabinet specified in the Chinese YY0569-2005 standard shall be 0.50m/s, the average flow rate for the downdraft should be 0.25m/s and 0.5m/s between, and to display the inflow and descending airflow rates of the safety cabinet in real time on the control panel. 5. At the same time, through the “Biolaw Personnel Protection Test” and “KI Law Personnel Protection Test”, the Likang Biosafety Cabinet is tested simultaneously in two ways;

Common Misconceptions in Purchasing Biosafety Cabinets; 1. Advanced selection; secondary biosafety cabinets, A2 displacement at 458-687m3/h, B2 displacement in 927-1854m3/h; the exhaust of ordinary household exhaust fans is about 80m3/h; indoor air is discharged in a large amount. To ensure that the temperature in the laboratory meets the experimental requirements, the load of the air conditioner and the heater is very large. The established laboratory cannot meet the requirements at all, and it also causes energy waste; if there is not enough supplementary air supply, the room where the biosafety cabinet is located becomes a high negative pressure state, and the biosafety cabinet cannot work normally; 2. Many installation problems; 1) The A2 type biosafety cabinet is connected to the exhaust fan with an external exhaust fan by using a closed hard tube. In the system, its safe operation completely depends on the exhaust system. When the exhaust system is clogged, it will pollute the environment and samples. The best solution is to make the interface open; 2) When the pipeline is too long, the original standard fan air volume has not reached the requirements, so a more powerful fan 3, but the needs of a given air flow valve and the linkage; in addition to the high risk subjects operating chemical or chemical agent capable of generating odor, It is safe and feasible for the secondary A2 biosafety cabinet to be exhausted indoors;

Importance of Biosafety Cabinet Testing ; currently there is no qualified organization to carry out the testing of biosafety cabinets. Some users have been using it as long as the biosafety cabinet can be turned over, which has become a great hidden danger; the biosafety cabinet is installed and moved. After the position, after the inspection, after the filter is replaced, the on-site inspection is carried out; the biosafety cabinet is a direct place for the operation of microorganisms, and the safety of the organism is directly determined by the biological safety cabinet, which requires the manufacturer and the customer to regularly carry out biological work on the biological safety cabinet. Safety airflow, filter leakage, cleanliness, wind speed and UV light illuminance detection, annual inspection, factory inspection, installation inspection; Li Kang - HealForce annual annual inspection service for customers and guarantee each factory biological safety cabinet All have qualified test reports, and can also be installed and tested during installation, which effectively ensures the biosafety of the equipment.

Precautions when using the biosafety cabinet; wear personal protective clothing when wearing the biosafety cabinet, wear gloves (the gloves should be placed outside the gown), and wear eye protection or a mask as needed. It can't be operated within 5 minutes after starting the machine. The safety cabinet should have a self-cleaning process. Move the arm as slowly as possible during operation. Keep the safety cabinet in the position away from the aisle to avoid airflow fluctuations. When operating the sample, separate the clean area, the operation area and the pollution area. Place the items; avoid the use of vibrating instruments (such as centrifuges, vortex shakers, etc.) in the cabinet, because the vibration will cause the particulate matter accumulated on the filter to shake off, resulting in a decrease in the cleanliness inside the operating room, and if Failure of the front operating surface balance can also cause contamination of the operator by the safety cabinet. Do not block the negative pressure passages to avoid airflow chaos; open flames can cause airflow disorder in the biosafety cabinet and interfere with the airflow mode; thoroughly clean the surface, side walls, rear walls and windows of the inner working area of the safety cabinet with 70% alcohol. Try not to use a chlorine-containing fungicide because it may damage the 304 stainless steel structure of the safety cabinet. Clean the UV lamp and power outlet surfaces as necessary. When cleaning the inner area of the safety cabinet, the operator can not enter the safety cabinet except for the hand. If there is dirt flowing into the sump, it should be cleaned in time; after the end of the experiment, the inner wall and the countertop of the biological safety cabinet wipe, wait for 5 minutes, close the front window, turn off the light, turn off the fan, and turn off the system power after 30 minutes of UV light. Proper and regular maintenance is critical to maintaining the proper functioning of any equipment, maintaining the cabinet and maintaining its optimum performance. Each time the power is turned on/off, the relevant operating parameters should be recorded in accordance with the SOP file.

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