A biosafety cabinet is a ventilated cabinet that uses a variety of combinations of air filters, unidirectional air flow, and containment to provide personnel, product, and cross contamination against particulates or aerosols from bio-hazardous agents. Conventional biosafety cabinets include one or more High Efficiency Particulate Arresting (HEPA) filters, although other types of air filters may be used as well. A HEPA filter is a type of air filter that can remove at least 99.97% of airborne particles down to 0.3 micrometers (μm) in diameter.
Typically, biosafety cabinets have an opening allowing the user to gain physical access to a working area, workspace, or chamber within the cabinet. The user can close off the opening using a door, a panel, or the like, which is done for purposes of conducting experiments or some process within the cabinet that would emit hazardous byproducts or germicidal (ultraviolet) light. The door may include a sliding view screen, may be replaced by a sliding view screen, or may be of some other variation known to those of ordinary skill in the art. For purposes of consistency, the term “door” is used throughout the application to refer to all such variations. The door, panel, or the like, is often made of glass or some other substantially transparent material, and can form all or a portion of a substantially transparent panel referred to as a sliding view screen.
The biosafety cabinets may include one or more air filters below the work surface to capture the contaminated particulates in the air leaving the workspace area but before the particulates reach other areas of the biosafety cabinet including the cabinet blower and positive pressure plenums inside the biosafety cabinet. The conventional biosafety cabinets required the use of mechanical clamps, hardware and extruded gasket to seal the air filters to the biological safety cabinet, making it hard to clean around the sealing material. To keep a safe clean-air-level inside the biosafety cabinet, the air filters need to be replaced at certain intervals. The filters are replaced when the cabinet air flows can no longer be set to within ±5% feet-per-minute (FPM) of the nominal set point by adjusting the speed control and/or balancing damper. The filters are also replaced if they are damaged.
With the conventional biosafety cabinets, when removing the air filter, it is necessary to remove an exterior panel to gain access to the air filter. Before any seal panels are removed, the cabinet should be decontaminated. The filters collect microorganisms and other potentially harmful particles generated in the work area during their lifetime, and maintenance personnel should not be exposed to these microorganisms. Clothing and/or breathing apparatus may be required during the filter change to reduce the hazard. It is advisable to seal the contaminated side of the filter by taping a plastic sheet or cardboard over the face before removal. This should minimize the number of particles shaken loose from the filter. Once removed, the filter should immediately be sealed in a chemical hazard bag and then disposed of safely in accordance with environmental regulations. After filter replacement has been completed, the cabinet and the room should be cleaned and decontaminated in a manner consistent with the nature of the hazardous material. The cleaning materials, along with the protective gear and clothing should be properly disposed.