Note fan not in stream of exhaust

  1. REQUIREMENTS
    1. All biological safety cabinets shall meet the specifications within the most recent edition of the National Sanitation Standard 49 – Class II (Laminar Flow) Biohazard Cabinetry.
    2. The following biological safety cabinet manufacturers are currently approved for campus:
      1. Baker, Nu-Aire, and Forma or equal. Manufacturer’s specifications for specific model types shall be submitted to OSU EH&S for pre-approval. The University’s Representative (OSU Project Manager) must acquire pre- approval from OSU EH&S for any “equal” substitution.
      2. Biosafety cabinet face velocity shall be maintained at the optimum face velocity for the type of cabinet being used. 
      3. Each cabinet shall be equipped with one front mounted magnahelic gauge or digital equivalent indicating the differential pressure across the filter.
      4. The noise level as measured 12 inches in front of the cabinet and 15 inches above the work surface shall not exceed 67 dBA.
      5. All biosafety cabinets must be tested per National Sanitation Foundation (NSF) Standard 49 or manufacturer’s specifications after installation and annually thereafter. The University’s Representative should forward the testing results to OSU EH&S for review.
    3. Class II Type B biosafety cabinets must be installed on a dedicated stainless steel exhaust system.  Consult with EH&S if Class II Type B biosafety cabinets are being considered.
    4. Exhaust in-place HEPA filters must be of the bag-in/bag-out type, and installed to allow for safe and efficient filter change.

  2. CLASSES AND TYPES OF BIOLOGICAL SAFETY CABINETS
    1. Class II Type A1 cabinets (formerly designated Type A)
      1. Maintain minimum average inflow velocity of 75  fpm through the work access opening;
      2. Have HEPA filtered down flow air that is a portion of the mixed down flow and inflow air from a common plenum (i.e., a plenum from which a portion of the air is exhausted from the cabinet and the remainder supplied to the work area);
      3. May exhaust HEPA filtered air back into the laboratory or to the external environment through an exhaust canopy; and
      4. May have positive pressure contaminated ducts and plenums that are not surrounded by negative pressure plenums.
      5. Type A1 cabinets are not suitable for work with volatile toxic chemicals and volatile radionuclides.
    2. Class II, Type A2 Cabinets (formerly designated Type B3)
      1. Maintain a minimum average inflow velocity of 100 fpm (0.5 m/s) through the work access opening;
      2. Have HEPA filtered down flow air that is a portion of the mixed down flow and inflow air from a common exhaust plenum;
      3. May exhaust HEPA filtered air back into the laboratory or to the environment through an exhaust canopy; and
      4. Have all biologically contaminated ducts and plenums under negative pressure or surrounded by negative pressure ducts and plenums.
      5. Type A2 cabinets used for work with minute quantities of volatile toxic chemicals and tracer amounts of radionuclides required as an adjunct to microbiological studies must be exhausted through properly functioning exhaust canopies to the exterior.
    3. Class II, Type B1 Cabinets
      1. Maintain a minimum average inflow velocity of 100 fpm (0.5 m/s) through the work access opening;
      2. Have HEPA filtered down flow air composed largely of uncontaminated recirculated inflow air;
      3. Exhaust most of the contaminated down flow air through a dedicated duct exhausted to the external atmosphere after passing through a HEPA filter; and
      4. Have all biologically contaminated ducts and plenums under negative pressure or surrounded by negative pressure ducts and plenums.
      5. Type B1 cabinets may be used for work with minute quantities of volatile toxic chemicals and tracer amounts of radionuclides required as an adjunct to microbiological studies if work is done in the direct exhausted portion of the cabinet, or if the chemicals or radionuclides will not interfere with the work when recirculated in the down flow air.
    4. Class II, Type B2 Cabinets (sometimes referred to as “total exhaust”)
      1. Maintain a minimum average inflow velocity of 100 fpm (0.5 m/s) through the work access opening;
      2. Have HEPA filtered down flow air drawn from the laboratory or the outside air (i.e., down flow air is not recirculated from the cabinet exhaust air);
      3. Exhaust all inflow and down flow air into the external atmosphere after filtration through a HEPA filter without recirculation in the cabinet or return to the laboratory; and
      4. Have all contaminated ducts and plenums under negative pressure or surrounded by directly exhausted (non-recirculated through the work area) negative pressure ducts and plenums.
      5. Type B2 cabinets may be used for work with volatile toxic chemicals and radionuclides required as adjuncts to microbiological studies.
    5. Class III Cabinets (Glove Boxes)
      1. A totally enclosed, ventilated cabinet of leak-tight construction. Operations in the cabinet are conducted through attached rubber gloves. The cabinet is maintained under negative air pressure of at least 0.50 in. w.g. (120 Pa). Down flow air is drawn into the cabinet through HEPA filters. The exhaust air is treated by double HEPA filtration or by HEPA filtration and incineration.
      2. A glove box may also be required for special applications using highly toxic, extremely reactive or regulated carcinogens.
      3. Glove boxes shall meet ANSI standard Z9.5, “Standard on Lab Ventilation” and the American Glove Box Society Standard, “Guidelines for Glove Boxes”.
      4. Reactive chemical work may require a glove box positively pressurized with inert atmosphere during reactions.

  3. SPECIALTY HOODS AND LOCAL EXHAUST/SNORKEL HOODS
    1. General
      1. Histology hoods, specimen, welding and other local exhaust specialty hoods require a minimum operating face velocity of 100 fpm with a range of 100-120 fpm. Higher values may be required based on setup. Design will be coordinated with EHS.
      2. An audible/visual flow alarm may be required depending on intended use.
    2. Placement
      1. Locate biological safety cabinets at least six feet from doors and high- traffic areas and away from open-able windows, fume hoods, or other draft producing laboratory equipment. Locate so that air supply/exhaust diffusers do not affect airflow at the BSC face (laminar diffusers preferred). If more than one BSC will be installed, situate BSCs across from each other rather than adjacent.
      2. Provide at least 12 inches of clearance above the BSC for testing and decontamination of HEPA filters. Set six inches out from the rear wall to allow for cleaning and adequate air return.
      3. Biological safety cabinets that are hard-ducted or connected by a thimble connection to the ventilation system must be designed so the duct work does not interfere with air flow or block access to the exhaust filter for testing of HEPA filter integrity.
      4. Biosafety cabinets and fume hoods should be seismically anchored