Precautions For Protecting High-efficiency Air Filter Technology During The Use Of Biosafety Cabinets

One of the core functions of a biosafety cabinet is to rely on HEPA filters to protect operators, experimental samples, and the environment. The technical protection of HEPA filters is directly related to the safety and service life of the safety cabinet. The following are key precautions during use:

ration and placement of items:

• Simplify items: Only put the necessary items for this experiment into the cabinet, reduce the number of items in the cabinet, and maintain the ideal airflow pattern.
•  Placement principle: Follow the principle of "clean area to contaminated area". Clean items (such as culture medium) should be placed on the upwind side (near the bottom of the air supply filter plate), and contamination operations (such as inoculation and vortexing) should be carried out on the downwind side (near the front window). All items should be placed as far back as possible, but should not block the rear grille.
•  Avoid obstruction: Never cover the front grille (air intake) and rear exhaust grille with objects. This is the lifeline of airflow circulation.
•  Surface disinfection: Before starting work, wipe the surface inside the cabinet with a suitable disinfectant (such as 70% alcohol) to remove any particulate pollutants that may be inhaled by the airflow.

• Operating standards:
•  Slow movement: All arm and object movements should be gentle, avoiding rapid passage through the front window opening, which can severely disrupt air flow and potentially cause pollutant leakage or significant inhalation of unfiltered air.
• Maintain window height: Within the allowable range of the equipment, use a lower front window opening height as much as possible (usually 200mm or according to the manufacturer's specifications). This can maintain the optimal surface wind speed and airflow barrier.
• "Waiting" principle: After opening the safety cabinet, it should be operated for at least 3-5 minutes (or as required by the instructions) for "self-cleaning" to empty residual pollutants and stabilize the airflow before starting the operation. After the operation is completed, let the safety cabinet continue to run for 2-3 minutes to purify the air inside the cabinet.
•  Avoid introducing particulate matter:
• Prohibit the use of open flames: Open flames (such as alcohol lamps, Bunsen lamps) can produce a large amount of ultrafine particles (aerosols), which can quickly clog HEPA filters and seriously disrupt laminar airflow. Sterile disposable inoculation rings or electric sterilization ring sterilizers should be used.
•  Use equipment that generates aerosols with caution: Centrifuges, vortex oscillators, etc. should be used steadily in the back position of the cabinet, and shock absorption measures should be taken to prevent the generated aerosols from directly impacting the filter or interfering with the airflow.
• Control spillage: Immediately clean any spillage with gauze or towel soaked in disinfectant to prevent it from drying and forming particles that can be inhaled into the system.
•  Item management:
• Waste bags: The biological waste bags inside the cabinet should be tightly tied and placed in a container on one side of the safety cabinet. They should not be placed on the ground to avoid obstructing the air intake grille.
• Reduce walking: Operators should try to minimize walking back and forth in front of the safety cabinet, and others should also stay away from the operating area to prevent disturbing the airflow.

• 1. Cleaning and Disinfection: After each use, thoroughly wipe the inner surface, side walls, back wall, and inside of the observation window with disinfectant. Regularly (such as weekly or based on usage frequency) clean and disinfect drainage and collection tanks.
•  Regular testing and certification:
• The most important thing is that annual certification must be conducted by professional technicians in accordance with national standards (such as YY 0569 in China) and manufacturer requirements. This includes HEPA filter integrity testing (typically using aerosols such as PAO, DOP, and photometer scanning) to ensure that the filter membrane is leak free.
• Airflow velocity test (surface wind speed, descending wind speed). Airflow mode (smoke) test.
• .Daily monitoring: Users can simply observe the ribbons or strips hanging by the window to confirm that the airflow direction is normal, but this cannot replace professional certification.

When the following situations occur, it should be considered to contact professionals for testing and possible replacement:

•  After professional testing, it was found that the filter was leaking (integrity test failed).
• After adjusting the surface wind speed to the maximum value, it still cannot meet the minimum requirement (usually 0.3-0.5 m/s).
•  Excessive resistance of the filter can cause the fan to continue running at high speed or trigger an alarm.
•  Achieve the manufacturer's recommended service life (usually related to the usage environment).

• The operation should be slow and the window should be low
• Open flames are prohibited and placed in an orderly manner
• Don't block the grille, wait for self-cleaning
• Clean in a timely manner, certified for years
• By strictly adhering to these precautions, HEPA filters can be maximally protected, ensuring long-term, stable, and reliable operation of the biosafety cabinet, and providing a solid barrier for personnel and the environment. Any operation related to filter replacement or maintenance must be carried out by trained professionals.