Class I BSCs can be hard-ducted and used in conjunction with building systems. Room air is drawn into the BSC through the front opening and moves directly across the negatively-pressurized workspace. The potentially contaminated air is discharged directly to the outside atmosphere through a HEPA filter. Glove ports are optional.
Return to the previous link - Fig. 1a
Class I BSCs can be complete with internal motor/blower assembly. Room air is drawn into the BSC through the front opening and moves directly across the workspace. The potentially contaminated air within the negatively-pressurized BSC is discharged into the containment zone through a HEPA filter. Glove ports are optional.
Return to the previous link - Fig. 1b
Class II Type A1 BSCs can be room re-circulated or air gap type (thimble). Above the work area and half way between the front and rear grilles, the room air and a portion of the BSCs potentially contaminated re-circulated air is drawn through the front grille. The other portion of the potentially contaminated air is drawn through the rear grille. The potentially contaminated air then moves from a negatively-pressurized area to a positively-pressurized plenum where a portion of the air passes through a HEPA filter before getting exhausted out of the cabinet. The remaining portion is re-circulated and passed through a HEPA filter before flowing again downward towards the work area.
Return to the previous link - Fig. 2
Class II Type A2 BSCs can be room re-circulated or air gap type (thimble). Above the work area and half way between the front and rear grilles, the room air and a portion of the BSCs potentially contaminated re-circulated air is drawn through the front grille. The other portion of the potentially contaminated air is drawn through the rear grille. This air then moves from a negatively-pressurized plenum to a positively-pressurized plenum that it surrounds. A portion of the potentially contaminated air passes through a HEPA filter before getting exhausted out of the cabinet. The remaining portion is re-circulated and passed through a HEPA filter before flowing again downward towards the work area.
Return to the previous link - Fig. 3
Class II Type B1 BSCs are hard-ducted. Above the work area and half way between the front and rear grilles, the room air and a portion of the BSCs potentially contaminated air is drawn into the front grille. The other portion of the potentially contaminated air is drawn through the rear grille. This air then moves through a HEPA filter located in a negatively-pressurized area below the work surface. The HEPA filtered air then flows upwards through the positively-pressurized side plenums. A portion of HEPA filtered air flows downwards over the work area while the other portion flows through a HEPA filter before being exhausted out of the BSC.
Return to the previous link - Fig. 4
Class II Type B2 BSCs are hard-ducted. In this type of BSC, the supply blower draws room air into the positively-pressurized top of the cabinet, through a HEPA filter and then downwards over the work surface. Above the negatively-pressurized work area and half way between the front and rear grilles, the room air and a portion of the BSCs potentially contaminated re-circulated air is drawn into the front grille. The other portion of the potentially contaminated air is drawn through the rear grille. The building exhaust draws this air into a negatively-pressurized contaminated plenum and then through a HEPA filter before being exhausted out of the BSC directly to the outside atmosphere.
Return to the previous link - Fig. 5
Class III BSCs are hard-ducted, completely enclosed and contain glove ports. In this type of BSC, the supply blower draws room air through a HEPA filter and then downwards over the work surface. The potentially contaminated air within the negatively-pressurized BSC is exhausted directly to the outside atmosphere through two consecutive HEPA filters.