1. Chemical Fume hood or Biosafety Cabinet
What are the Requirements?

2. Types of Hood/Ventilation Systems
Laminar Flow Hood
Chemical Fume Hood
Biosafety Cabinet

3. Laminar Flow Hood
Designed to protect work only – no protection of the employee or room.
Air flow across the work surface into the employee face.
Used for Tissue Culture, pouring gels etc.
No specific testing requirements
Disinfect before and after each use

4. Biological Safety Cabinets

5. Class II, Type A2 Biosafety Cabinets
The Class II, Type A2 cabinet recirculates approximately 70% of the air through a supply filter, and exhausts approximately 30% of the air through an exhaust filter to the room or through a canopy exhaust connection to a facility exhaust system.
HEPA-filtered air descends through the work zone in a vertical, unidirectional flow.
At the approximate center of the work area, the air splits as it flows to the base of the cabinet. A portion flows through a perforated front grille, and the balance flows through the perforated rear grille.
Room air entering through the front access opening is drawn into the perforated front grille. It does not enter the work area.
At the cabinet base, the total volume of room and recirculated air is moved by the blower/motor through the rear and side airflow ducts to the top of the cabinet.
At the top, approximately 30% of the air is moved through the exhaust filter to - re-enter the room, or - exhausted to a facility exhaust system through a canopy connection where: -- untreated exhaust protects personnel and the product against vapors and gases -- treated exhaust protects personnel, product and the environment against vapors and gases.
The remaining air is moved through the supply filter and recirculated to the work area as clean, vertical flowing air

6. Class II, A2 BSC
Purifier Logic Class II, Type A2 Biosafety Cabinets provide personnel, product and environmental protection from hazardous particulates such as agents that require Biosafety Level 1, 2 or 3 containment. Other appropriate applications include work with antineoplastic drugs, genetic material, carcinogens, allergens and additional substances that generate hazardous airborne particulates. All models are NSF-Listed.
During operation, room air is drawn into the inlet grille at the work access opening and through a supply HEPA filter. Approximately 70% of the HEPA-filtered air is circulated through the cabinet, while 30% passes through an exhaust HEPA filter and is discharged. These biohazard cabinets are designed to discharge HEPA-filtered exhaust air directly into the laboratory, or into an exhaust system through the optional Canopy Connection. When canopy-ducted, these biological safety cabinets may be used for applications involving minute quantities of volatile toxic chemicals and tracer amounts of radionuclides as an adjunct to microbiological research.

7. Class II, Type B1 Biosafety Cabinets
From above the work surface, HEPA-filtered air descends in a vertical unidirectional airflow over the work area. This air splits at the approximate center as it flows to the base of the cabinet.
Approximately 60% of descending air is pulled directly through the rear grille of the work area into a dedicated negative pressure plenum. This air passes through an exhaust HEPA filter, then to an appropriate treatment system or outdoors via the facility’s exhaust system.
Approximately 40% of the descending air is pulled forward where it mixes with room air entering the perforated front grille. This air passes through HEPA supply filter directly below the work surface, then is circulated under positive pressure through a duct to the top of the cabinet, then through another HEPA supply filter, where the process is repeated

8. Class II, B2 BioSafety Cabinet
Airflow through a B2 cabinet is similar to that of a fume hood, externally exhausting 100% of the air pulled through the cabinet. The purpose of this design is to completely remove any toxic chemical vapors or radioactive compounds that are generated inside the cabinet. Room air is brought into the cabinet through both an opening in the top of the cabinet and through the inlet grille. This air flows through an initial HEPA filter and then downward through the work area. All of the contaminated air is then drawn into a negatively pressured plenum and exhausted through a second HEPA filter. A dedicated exhaust system and remote blower draw all of the filtered exhaust air out of the laboratory.

9. BSC – Class II, B2
The Class II, Type B2 cabinet provides 100% exhaust, with absolutely no recirculation of air in the cabinet. Germfree invented and patented the total exhaust BSC which was later classified as a Class II B2 Cabinet.

10. Chemical Fume Hoods

11. Improper Utilization Chemical Fume Hood ARS Requirements
Operate 24/7 – 50% reduction in flow when lab is un-occupied
Flow rate 80 – 100 full sash opening of 18”
Multiple kinds of Fume hoods -

12. Testing and Maintenance Requirements
Fume hood
Must run 24/7
Must be marked in a manner to show constant air flow
Annual face velocity test – 80 to 100 fpm across the face
Whenever serviced
Whenever moved
If out of service – must be flagged
Biosafety Cabinet
Must run when in use a (start and operate 2-3 minutes after loading)
Decontaminate before and after each use.
Certified air flow on an annual basis – HEPA filter
Certify when moved or serviced
Generally not for chemical
Some vent to room some to outside