Thermo 1284 - Exhaust Requirements; Direct Room Exhaust; External Exhaust System; Optional Exhaust Transition

Class II, A2 Biological Safety Cabinets_______________________________________________________________Installation
3 - 2
3.4 Exhaust Requirements
Filtered air from the cabinet may be exhausted directly into
the room or vented to the outside through an external exhaust
system. Consult a biological safety officer or other qualified
individual for cabinet-type exhaust requirements. Refer to NSF
Standard, NSF 49-2002, Annex E.
a. Direct Room Exhaust
A cardboard cover plate is shipped under the exhaust filter
guard. It must be removed before the unit is placed into service.
Locate the exhaust filter guard on the top of the cabinet.
Remove the guard and discard the cardboard. Secure the exhaust
filter guard as previously.
b. External Exhaust System (For Class II Type A2)
If an external exhaust system is needed, use a canopy (thim-
ble) connection (Figure 3-3). When the cabinet is certified,
check the opening in the canopy to ensure inward airflow, using
a smoke stick. Ensure proper air balance at the front access
opening for adequate containment. Verify that the building
exhaust system is sized to exhaust 30% more air than the cabinet
exhausts. Models 1284 and 1285 exhaust an air volume of 358-
391 CFM. Models 1286 and 1287 exhaust an air volume of 531-
580 CFM.
IMPORTANT! The exhaust air must be drawn
from the cabinet through a dedicated exhaust sys-
tem (only one BSC per exhaust system). The
exhaust system may be connected to the collar
(optional exhaust transition) located on the top of
the unit.
The exhaust system should have safeguards
against exhaust failure. It is required that a bio-
logical safety officer, industrial hygienist or other
qualified individual review the agents and chemi-
cals used inside the cabinet to determine if addi-
tional filtration treatment is necessary before vent-
ing to the atmosphere.
c. Optional Exhaust Transition
Canopy/Thimble style - P/N 191570 Release 1-5 units,
P/N 191782 Release 6. Refer to the unit serial tag to determine
release level.
d. Nominal Exhaust Requirements - 4 foot models
Nominal 375 CFM Direct method and calculated method.
Nominal 487 CFM, when sizing to exhaust 30% more air
(than the cabinet exhausts)
e. Nominal Exhaust Requirements - 6 foot models
Nominal 556 CFM
Nominal 722 CFM, when sizing to exhaust 30% more air
(than the cabinet exhausts)