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Clarification of the Proposed Class II, Type C1 Biosafety Cabinet


Recently, a slightly different new style of Class II Biosafety Cabinet was introduced into the life science market. The manufacturer of this new style cabinet designated it as a Type C1 because it could not be precisely defined with the current definitions as stated in the NSF/ANSI 49-2014 standard. The new style cabinet is listed to NSF/ANSI 49, however no cabinet type designation has been assigned by NSF. So to date, the Type C1 designation is only designated by the manufacturer who created it and is not recognized in industry by the NIH or CDC.

So what is different about this new style of cabinet that can’t be defined by NSF?

This new style of cabinet is basically a type B1 cabinet in terms of airflow pattern. The cabinet exhausts approximately 64% of the work zone airflow through a dedicated portion of the depressed work tray/grill pattern and recirculates the remaining 36% of work zone airflow through the non-dedicated portion work tray grill area. However, what makes this cabinet different from a type B1 is that it has an internal exhaust motor/blower to push the airflow through the exhaust HEPA filter. Traditional type B1 cabinets require the facilities exhaust system to pull airflow through the exhaust HEPA filter and thus require to be direct connected. This new style cabinet is more like a type A2 with respect to exhaust in that it can be exhausted back into the room or through a canopy like exhaust connection.