Forma Scientific, Inc._______________________________________________Introduction
2-1
Section 2 - Introduction
2.1 Description
The Models 1284, 1285, 1286, 1287, 1288, 1290 and 1291 are Class II, Type A/B
3
cabinets. The "Type A/B
3
" designation indicates two alternative uses of the cabinet. When
vented directly into the laboratory room, the unit serves as a "Type A" unit. When vented to
the outside atmosphere, through an in-house exhaust system, it serves as a "Type B
3
" unit.
Either usage of the cabinet offers both personnel and product protection.
The cabinet can be used in low-to-moderate risk environments and is designed to
NSF, International Standard #49. Class 1, 2, and 3 (low-to-moderate risk) agents are
described in the "Biosafety In Microbiological And Biomedical Laboratories"; CDC NIH
Publication No. (NIH) 88-8395, 3rd Edition, May 1993.
The cabinet's window permits the user to place auxiliary equipment and research
implements in the work area. The work opening must be held to 10" during all work
procedures. If the window is raised higher than the designated 10", the air barrier at the front
of the cabinet will be weakened and containment will be seriously impaired.
2.2 Theory of Operation
Clean, filtered air descends through the work zone with approximately 40% being
discharged through the exhaust HEPA filter with the remaining air recirculating through the
supply HEPA filter into the work area. Exhausted air is replaced by room air entering the
system through the front access opening.
Room air entering the work zone, through the front access opening, completes the
air barrier at the unit face and is responsible for the containment properties of the unit. All
work must be performed beyond the intake grille, on the solid work tray.
To Next Page
Loading...