Biosafety cabinet tips
First, the introduction of biological safety cabinet 　
Biosafety cabinets are biosafety isolation devices for microbiology, biomedical, biosafety laboratories and other laboratories. It uses advanced air purification technology and negative pressure cabinet design to protect the environment, personnel and samples, prevent the diffusion of harmful aerosols and aerosols, and provide cross-infection and environmental protection between operators, samples and samples. Safety protection is the basic safety protection device of Zui in the first-level protective barrier of laboratory biosafety. With a bracket structure, the bracket and the box can be separated for easy handling and seating.
　　 Second, the functional characteristics of the biological safety cabinet
1. The ergonomic 10° tilt angle design makes the operation feel better;
2. The shell is made of high-quality cold-rolled steel plate and electrostatically sprayed; the stainless steel (SUS304) integrated structure is used on the three sides of the safety cabinet operation area, and the internal washable part is treated with 8mm rounded corners for easy cleaning;
3. Unique internal cavity safety negative pressure design, air curtain type isolation, to ensure no leakage under normal use, 70% gas circulation, 30% exhaust laminar flow, in line with YY0569-2005 Class II biological safety cabinet standard;
4. The integrally formed work surface adopts the tray structure, which is easy to remove and clean. The side wall is provided with one water and one air faucet, and the sump is arranged under the operation table, and the sewage valve is arranged below;
5. Equipped with filter blocking alarm, blower overload alarm, working window open limit alarm system.
6. Integrated sliding safety sliding door, which can be positioned freely, easy to operate, and can be completely closed for sterilization.
7.Using ultra-high efficiency air filter, the filtration efficiency is 99.999% (0.1-0.2 micron particles). The filter membrane material is made of non-separator borosilicate glass fiber;
8. Front window and germicidal lamp interlocking design: when the current window is raised, the germicidal lamp is extinguished;
9. Bracket type safety cabinet, the bracket and the upper box can be separated for easy handling and seating.
10. It has parameter memory protected by power failure and data loss of crash state, call recovery function.
　　 Third, the classification of biological safety cabinet
According to the main international standards for biosafety cabinets, safety cabinets can be divided into three categories: first, second and third to meet different biological research and epidemic prevention requirements. The classification level of the safety cabinet is independent of the biosafety level.
The primary biosafety cabinet protects the worker and the environment without protecting the sample. The airflow principle is the same as for a laboratory fume hood, except that the vent is fitted with a HEPA filter. All types of biosafety cabinets use HEPA filters in the exhaust and air intakes. The first-class biological safety cabinet itself has no fan, and relies on the fan in the external ventilation pipe to drive the airflow. Since it cannot protect the products in the cabinet, it has been used less frequently.
The secondary biosafety cabinet is currently used in a wide range of cabinet types. According to the provisions of NSF49, the secondary biosafety cabinet can be divided into four levels according to the inlet airflow speed, exhaust mode and circulation mode: A1 type, A2 type (formerly B3 type), B1 type and B2 type. All secondary biosafety cabinets provide protection for workers, the environment and products.
The three-level biosafety cabinet is designed for the biosafety level of the 3-4 laboratory. The cabinet is completely airtight. The staff is operated by the gloves connected to the cabinet. It is commonly called Glove box. The door's transfer box enters and exits the safety cabinet to ensure it is free from contamination and is suitable for high-risk biological testing.
　　 Fourth, the choice of biological safety cabinet
The choice of biosafety cabinet depends largely on the type of test substance used in the biological test:
1. If the biological test involves only microbial samples, a basic type of biosafety cabinet can be used;
2. If microbiological samples and trace chemicals (non-corrosive) are involved in the biological test, it is necessary to use a safety cabinet equipped with an external piping. Because HEPA filters do not effectively filter and remove chemical gases, if they are not effluxed, they will pose a threat to workers and the environment in the laboratory;
3. If the biological test involves cytotoxic drugs, such as various cancer treatment drugs, the cytotoxic safety cabinet must be used.
In addition, a clear understanding of the distinction between biosafety cabinets and fume hoods/clean benches is required. Fume hoods and clean benches are not biosafety cabinets and should not be used in experiments or production processes involving microbial materials.
　　 Fume hoods (ventilation cabinets) are designed to remove corrosive chemical gases and toxic fumes during chemical experiments. The fume hood does not effectively remove microbial media because it is not equipped with a HEPA filter. Microbiological samples placed in the fume hood will spread out of the cabinet and contaminate the laboratory environment.
　　 The ultra-clean workbench (clean bench) is designed to protect the test piece or product. It prevents the test article or product from being contaminated by dust or bacteria outside the work area by blowing vertical or horizontal laminar air through the work area. Once the microbial sample is placed in the work area, laminar air will create a hazard by blowing air with microbial media to the front desk staff.
1. Explain the use and restrictions of the safety cabinet to all users who may use the biosafety cabinet in accordance with national standards and relevant regulations. Staff should be issued a written regulation or safety manual, operation manual. In particular, the staff must be clearly told that the safety cabinet cannot protect the operator in the event of spills, crushing, or improper methods.
2. The safety cabinet can only be used when it is working properly.
3. The glass observation window on the front of the safety cabinet must not be opened when the safety cabinet is in use.
4. The instruments and materials placed in the cabinet must be kept at a low quantity. The air circulation at the rear of the static pressure box must not be obstructed. The material should be decontaminated before it is placed in the work area of ​​the cabinet.
5. Bunsen burners (a type of gas lamp) must not be used in the cabinet, as the heat generated may interfere with the airflow and may damage the filter. Micro-electric incinerators can be used, but it is better to use disposable sterilization rings.
6. All work in the cabinet should be carried out in the middle or rear of the work surface and can be seen from the viewing panel.
7. The activity behind the operator should be less than Zui.
8. The operator should not extend the arm back and forth into the cabinet to avoid interference with the airflow.
9. The forward style grille must not be blocked by notes, droppers or other materials, otherwise it will interfere with the airflow and may contaminate the material and expose the personnel.
10. Clean the surface of the cabinet with a suitable disinfectant after each work and at the end of the day.
11. The fan of the cabinet should be operated for 5 minutes before the start of work and after the work is completed.
Biosafety cabinet placement
The airflow rate from the opening in the front of the biosafety cabinet to the cabinet is about 0.45 m/s. At this wind speed, the consistency of the one-way flow in the cabinet is easily disturbed, and it is easily disturbed by the walking, windowing, air distribution, and door switches of the personnel near the safety cabinet. In an ideal arrangement, it should be placed away from activities and where there may be interference with airflow. Try to leave 30 cm of space on the back and sides of the cabinet to facilitate maintenance. A height of 30 to 35 cm is left above the cabinet to accurately measure the wind speed of the exhaust filter and leave enough space for the replacement of the exhaust filter.
Cleaning and disinfection of biological safety cabinets
All items in the biosafety cabinet, including equipment, should be surface decontaminated and removed from the cabinet after work is completed, as residual culture media may provide microbial growth conditions. The inner surface of the cabinet should be decontaminated before and after each use. To wipe the surface of the table and the inner wall with a disinfectant, the disinfectant used should be able to kill all microorganisms that may be present in the cabinet. At the end of the day, the surface decontamination treatment should be carried out after the Zui, that is, the inside of the workbench, each side, the back and the glass should be completely wiped. Bleaching powder or 70% alcohol can be used, a disinfectant that is effective against the target organism. If a corrosive disinfectant such as bleach is used, it should be wiped twice with sterile water. It is recommended that the work cabinet be in working condition when it is cleaned and disinfected. If it is not in operation, it should be run for 5 minutes to remove the gas before the cabinet is closed.
Decontamination treatment of biological safety cabinet
Decontamination of Class 1 and Class 2 biosafety cabinets is to place an appropriate amount of paraformaldehyde (80% of the final concentration of paraformaldehyde in the air in the cabinet) on a hot plate or frying pan (from outside the cabinet) control). In addition, a hot plate or frying pan with 10% more hydrogen carbonate than paraformaldehyde is placed in the cabinet (controlled outside the cabinet). This second container should be covered with a cover that can be removed from a distance (for example, on a line that can be pulled from outside the cabinet). This can make the early neutralization of paraformaldehyde reach a small size.
If the relative temperature is below 70%, open the container with hot water. If there is no front bulkhead, use a raw plastic baffle and tape it to the front face to ensure that no gas leaks into the room. When the paraformaldehyde in the pan has completely evaporated or the switch has been turned on for 1 hour, the switch is turned off. Leave the safety cabinet for a whole night and do not touch it. The lid of the second tray is then removed and the switch is opened and the ammonia bicarbonate begins to evaporate. At this time, turn off the switch of the plate, let the safety cabinet start working, and let the ammonia hydrogencarbonate circulate for 1 hour. The front bulkhead (or plastic baffle) can then be removed and the safety cabinet ready for use.
2. The safety cabinet can only be used when it is working properly.
3. The glass observation window on the front of the safety cabinet must not be opened when the safety cabinet is in use.
4. The instruments and materials placed in the cabinet must be kept at a low quantity. The air circulation at the rear of the static pressure box must not be obstructed. The material should be decontaminated before it is placed in the work area of ​​the cabinet.
5. Bunsen burners (a type of gas lamp) must not be used in the cabinet, as the heat generated may interfere with the airflow and may damage the filter. Micro-electric incinerators can be used, but it is better to use disposable sterilization rings.
6. All work in the cabinet should be carried out in the middle or rear of the work surface and can be seen from the viewing panel.
7. The activity behind the operator should be less than Zui.
8. The operator should not extend the arm back and forth into the cabinet to avoid interference with the airflow.
9. The forward style grille must not be blocked by notes, droppers or other materials, otherwise it will interfere with the airflow and may contaminate the material and expose the personnel.
10. Clean the surface of the cabinet with a suitable disinfectant after each work and at the end of the day.
11. The fan of the cabinet should be operated for 5 minutes before the start of work and after the work is completed.
Biosafety cabinet placement
The airflow rate from the opening in the front of the biosafety cabinet to the cabinet is about 0.45 m/s. At this wind speed, the consistency of the one-way flow in the cabinet is easily disturbed, and it is easily disturbed by the walking, windowing, air distribution, and door switches of the personnel near the safety cabinet. In an ideal arrangement, it should be placed away from activities and where there may be interference with airflow. Try to leave 30 cm of space on the back and sides of the cabinet to facilitate maintenance. A height of 30 to 35 cm is left above the cabinet to accurately measure the wind speed of the exhaust filter and leave enough space for the replacement of the exhaust filter.
Cleaning and disinfection of biological safety cabinets
All items in the biosafety cabinet, including equipment, should be surface decontaminated and removed from the cabinet after work is completed, as residual culture media may provide microbial growth conditions. The inner surface of the cabinet should be decontaminated before and after each use. To wipe the surface of the table and the inner wall with a disinfectant, the disinfectant used should be able to kill all microorganisms that may be present in the cabinet. At the end of the day, the surface decontamination treatment should be carried out after the Zui, that is, the inside of the workbench, each side, the back and the glass should be completely wiped. Bleaching powder or 70% alcohol can be used, a disinfectant that is effective against the target organism. If a corrosive disinfectant such as bleach is used, it should be wiped twice with sterile water. It is recommended that the work cabinet be in working condition when it is cleaned and disinfected. If it is not in operation, it should be run for 5 minutes to remove the gas before the cabinet is closed.
Decontamination treatment of biological safety cabinet
Decontamination of Class 1 and Class 2 biosafety cabinets is to place an appropriate amount of paraformaldehyde (80% of the final concentration of paraformaldehyde in the air in the cabinet) on a hot plate or frying pan (from outside the cabinet) control). In addition, a hot plate or frying pan with 10% more hydrogen carbonate than paraformaldehyde is placed in the cabinet (controlled outside the cabinet). This second container should be covered with a cover that can be removed from a distance (for example, on a line that can be pulled from outside the cabinet). This can make the early neutralization of paraformaldehyde reach a small size.
If the relative temperature is below 70%, open the container with hot water. If there is no front bulkhead, use a raw plastic baffle and tape it to the front face to ensure that no gas leaks into the room. When the paraformaldehyde in the pan has completely evaporated or the switch has been turned on for 1 hour, the switch is turned off. Leave the safety cabinet for a whole night and do not touch it. The lid of the second tray is then removed and the switch is opened and the ammonia bicarbonate begins to evaporate. At this time, turn off the switch of the plate, let the safety cabinet start working, and let the ammonia hydrogencarbonate circulate for 1 hour. The front bulkhead (or plastic baffle) can then be removed and the safety cabinet ready for use.
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