Biological safety cabinet or BSC, also known as biological safety cabinets, are enclosed, ventilated laboratory workspace areas designed to protect the user and surrounding environment from pathogens. The biological safety cabinet is used to protect the operator, laboratory environment, and experimental materials from exposure to the operation process when handling infectious experimental materials such as primary cultures, bacterial strains, and diagnostic specimens, which are designed for possible infectious aerosols and splashes.
Biofafety cabinets classes are categories describing how the cabinet works and what it protects. Biosafety cabinets are divided into three classes: I, II, and III.
Class I biofafety cabinet provides protection for the user and surrounding environment, but no protection for the sample being manipulated.
Class II biological safety cabinet provides protection for the user, environment, and sample, and is divided into four types: A1, A2, B1, and B2. The main differences are their minimum inflow velocities and exhaust systems.
Class III biosafety cabinet, also known as laboratory glove box, provides maximum protection; the enclosure is gas-tight, and all materials enter and leave through a dunk tank or double-door autoclave.
Therefore, the choice of biosafety cabinets depends on the levels of protection needed for the laboratory worker and the interested sample.
Class 2 biological safety cabinet can provide protection for the sample, environment, and user all at once. Based on the market demand, Heal Force specializes in Class 2 biological safety cabinets. Class II biological safety cabinets provide three kinds of protection (samples, user, and environment) since makeup air is also HEPA-filtered.
Class II biological safety cabinet use motor-driven blowers (fans) mounted in the cabinet to draw directional mass airflow around a user and into the air grille - protecting the operator.
The air is then drawn underneath the work surface and back up to the top of the cabinet where it passes through the HEPA filters. A column of HEPA-filtered, sterile air is also blown downward, over products and processes to prevent contamination.
Air is also exhausted through a HEPA filter, and depending on the type of Class II biological safety cabinet, the air is either recirculated back into the laboratory or pulled by an exhaust fan, through ductwork where it is expelled from the building.
The Class II biological safety cabinet has a front window operation port through which the person conducts the operation. The negative pressure air flow drawn inward from the front window operation port is used to protect the safety of the operator; The downward airflow is used to protect the experimental items in the biosafety cabinet; the airflow is discharged through a high-efficiency filter.
As a first-level barrier in the biosafety laboratory, the biological safety cabinet is indispensable hardware equipment in the current anti-pandemic research laboratory.
Class II biological safety cabinet provides protection for the user, environment, and sample, and is divided into four types: A1, A2, B1, and B2. Heal Force mainly provides Class II A2 biosafety cabinet and Class II B2 biosafety cabinet.
The Differences in Features:
Class II Type A2 biological safety cabinet (airflow) is 70 % recirculation and 30 % exhaust. All polluted parts in the biosafety cabinet are under negative pressure or surrounded by negative pressure channels and negative pressure ventilation systems.
Class II Type B2 biological safety cabinet (airflow) is 100 % Exhaust. The inflow and downdrafts are filtered by high-efficiency filters and then discharged into the atmosphere through special exhaust pipes (hard connection), and are not allowed to return to biosafety cabinets and laboratories; all polluted parts are under negative pressure or surrounded by directly exhausted negative pressure channels and negative pressure ventilation systems (that do not circulate in the work area).
The Differences in Application:
When Class II Type A2 biological safety cabinet is used for microbiological experiments using trace amounts of volatile toxic chemicals and trace amounts of radionuclides as auxiliary agents, a properly functioning exhaust hood (exhaust pipe) must be connected.
Class II Type B2 biosafety cabinet can be used for microbial experiments with volatile toxic chemicals and radionuclides as auxiliary agents. It is suitable for samples with biosafety hazard levels 1, 2, and 3.
Safe Airflow Pattern: The safety cabinet adopts a professional design, and the ratio of descending airflow and inflow airflow is stable. At the same time, it is equipped with multiple wind speed and flow sensor monitoring to protect the safety of test samples, personnel, and the environment.
HEPA Filter: Using imported brand ultra-efficient air filter (ULPA), the filtration efficiency is 99.999% for particles ≧0.12μm.
Breeze Sensing Technology: The wind speed is measured by the micro wind speed sensor technology, and the external visible micro wind speed sensor is installed to measure the wind speed in real-time.
Cabinet Leak-proof Design: Each safety cabinet has passed the strict pressure decay method test before leaving the factory, and the anti-leakage performance of the cabinet meets the requirements of the national biological safety cabinet industry standard.
Comfortable Working Environment: The ergonomic design provides the operator with a more comfortable working environment and reduces the operator's fatigue during long-term operation.
As with work on open bench tops, work performed within biological safety cabinet must be performed carefully and safely. To avoid contamination and the risk of personnel exposure, the CDC advises investigators to follow best practices to reduce and control splatter and aerosol generation, such as keeping clean materials at least 12 inches (30 cm) from aerosol-generating activities and arranging the workflow "from clean to contaminated". On the basis of technical experience for decades, we have summarized the following precautions referring to customer feedback and common problems:
1. Once the filter end-of-life prompt appears, it is recommended that you stop using the biological safety cabinet and detect whether there are other abnormalities, and notify the professional engineers of the manufacturer to test the filter integrity and airflow rate of the device. In case this requirement can not be satisfied, inform the relevant personnel immediately to replace the air filter.
2. If any items need to be taken out or moved in during operation, please move your arm as slowly as possible to reduce air disturbance and avoid the escape of pollution caused by the disturbance of the airflow layer.
3. Place the items needed for the work as far as possible in front of you to avoid twisting your neck frequently.
4. Place items reasonably in the working area to reduce your operating distance.
5. Use your entire shoulders and arms instead of just your wrists while moving items
6. Take a break of 5-10 minutes after working continuously for more than 2 hours. By doing radio gymnastics, you can stretch and adjust your limbs and reduce fatigue. Eye exercises are recommended to protect eyes and eyesight.
7. Personal protection requirements: Wear PPE clothing, masks, cap, and gloves when operating biological safety cabinets. Wear protective goggles or a face mask as needed
8. Principles for placing items in biological safety cabinets: Open flames can cause the airflow of the biological safety cabinet to be turbulent. Interfering with the airflow pattern could damage the ULPA air filter, causing danger when handling volatile and flammable materials. The use of alcohol lamps should be prohibited, use infrared sterilizers instead.
9. Biological safety cabinet’s environmental requirement: indoor use, avoid direct sunlight, 10-30 ℃ ambient temperature； the wind speed must be re-corrected at high altitudes.
10. Biological safety cabinet should be installed on an immovable horizontal surface.
11. The biosafety cabinet must be installed close to a fixed power outlet. Under the circumstances of no external drainage system, the top is at least 200mm away from the top of the room or the top obstacle, at least 200mm away from the wall on both sides, and at least 300mm away from the wall to facilitate smooth exhaust airflow.
The positions A, D, and E in the picture are the most suitable for the installation of biological safety cabinets. In order to prevent interference, the equipment should not be installed in the passageway where people come and go. Do not make the biological safety cabinet sliding front window too close to the laboratory doors or windows. Besides, the room needs to be clean.
Biological safety cabinet routine maintenance is very important. Normally, we have to clean the countertop of the biosafety cabinet to avoid residues of dirt after the experiment. If the contamination of the operating surface of the biological safety cabinet is not cleaned up in time, we can use 75% alcohol and gauze for cleaning.
After years of experience by experimenters, it is not recommended to use absorbent cotton products to wipe the tabletop, because it will cause fine cotton wool to hang on the tabletop, easy to breed bacteria. Cleaning agents containing chlorine are also not recommended that will cause certain corrosion of stainless steel countertops.
If an alarm occurs in the biosafety cabinet, contact a professional maintenance engineer for the first time who would provide on-site guidance to perform equipment maintenance.
In view of the expiration of the filter's service life, professional engineers are required to conduct fumigation and disinfection and then dismantle and replace it. The replaced filter should be treated as experimental waste and not treated as domestic waste.