NSF is the National Sanitation Foundation, and Standard No. 49 is the design, construction and testing document that establishes a minimum standard for Class II biological safety cabinets.
The AFM (air flow monitor) is an audio-visual mass airflow alarm system that indicates when exhaust airflow drops below a set point. A warning light and buzzer are activated when exhaust airflow drops below that point.
A performance envelope gives the operational airflow balance extremes within which a given cabinet design will pass the microbiological aerosol tracer test for personnel and product protection.
A petcock is a service fixture with a valve within the workspace for gas, air or vacuum.
The ideal location for a biological safety cabinet is at a dead-end corner of the laboratory, away from personnel traffic, vents, doors, windows and other sources of disruptive air currents.
As a general rule, an annual certification is usually sufficient, although some institutions’ protocols require a more frequent schedule. Re-certification is also needed whenever filters are changed, the unit is relocated or the type of work that has been performed within the cabinet changes. This is true regardless of when the cabinet was last certified. Consult your safety officer to be sure to follow your facility’s guidelines.
Baker recommends that biological safety cabinets are run continuously. If a unit is turned off, the viewscreen should be closed completely. Allow the unit to run at least three minutes before loading to clear any particulates from the air inside the cabinet.
Wash your hands with germicidal soap before and after the procedure performed inside the cabinet. Wear sterile gloves and a lab coat or gown – use good aseptic technique. Avoid blocking the front grille – work only on or over the solid surface. Adjust your chair so your armpits are at the same level as the lower window edge. Avoid rapid movement during procedures, within the biosafety cabinet and within the room. Move hands and arms straight into and out of the work area. Never rotate your hand or arm out of the work area during a procedure. Move laterally inside the work area.
Load only items needed for the procedure. Do not block rear or front exhaust grilles. Disinfect the exterior of all containers before beginning the procedure. Arrange materials to minimize movement within the cabinet. Once the cabinet is loaded, lower the viewscreen and wait three minutes to allow contamination in the work area to be purged. Non-sterile items should never be upstream of sterile items.
After completing your work, run the biosafety cabinet for three minutes before unloading. Disinfect the exterior of all containers before removing them from the cabinet. Decontaminate the interior work surfaces of the cabinet with disinfectant.
Consult your laboratory director or local safety officer on the appropriate disinfectant. When using the disinfectant, you should clean well with detergent and then rinse with cold water. Do not use anything that may harm or corrode stainless steel.
Most times, a problem with your equipment needs the attention of a qualified safety professional who has been trained in biological safety cabinets, or your certifier. There are a few things, however, that a user can do to try to troubleshoot a problem. You can relay the information you obtain to your certifier if you need to call one. First, check the blower switch. Is it in the “on” position? If yes, check the plug. Is the cabinet plugged in? If yes, turn on the light switch. Do the lights come on? If none of this results in your cabinet blower working, call your building maintenance department. Perhaps there is a circuit breaker within your building that needs to be reset. If you still have no results, consult your safety professional or certifier.
To help you quickly identify the class and type of biological safety cabinet that is best for your application, download our biosafety cabinet decision map. Just answer a few straightforward questions, and find out the technology that will best fit your specific containment and protection needs.