Labconco Logic Vue User Manual page 14

Labconco highly recommends installing an air-tight balancing damper at the canopy's
duct collar when connected to a building exhaust system. See
information on the following pages. The air-tight damper allows for fine adjustment of
the exhaust air volume provided, in order to correctly set the necessary exhaust airflow
for each enclosure. It also allows the enclosure to be sealed off from the building
exhaust system, should it become necessary to do so.
The use of an exhaust manifolded to other equipment should be avoided when possible.
If the Logic Vue is canopy-connected to a manifolded system, a variable air volume
valve (preferably one that is fast-acting, such as a venturi valve) should be used. Failure
to maintain required exhaust volume on the Logic Vue duct during startup, operation,
and shutdown may result in an exhaust alarm condition.
The exhaust system must be capable of moving the following volumes of exhaust air at
the negative pressures listed. The Airflow Volumes are the values recorded via direct
measurement using a flow hood at the duct drop and include 100 CFM for the canopy
connection inlet. The Concurrent Balance Values are measured in the exhaust duct
via traverse methodology, and will always be higher, and may vary, due to differences in
volume measurement methodologies and the location of the sample in the exhaust
system.
LogicVue 4-foot Model
40 FPM downflow/
105 FPM inflow
45 FPM downflow/
105 FPM inflow
50 FPM downflow/
105 FPM inflow
LogicVue 6-foot Model
40 FPM downflow/
105 FPM inflow
45 FPM downflow/
105 FPM inflow
50 FPM downflow/
105 FPM inflow
1: Unlike Type B biosafety cabinets, the recommended vacuum will remain constant throughout the life of the exhaust
HEPA filter. Duct vacuum is measured at the outlet of the Logic Vue Canopy duct stub. Duct vacuums below 0.05
inches H O (12 Pa) or above 0.5 inches H
2
from the product.
2: WC = Inches of Water Column, typically expressed in units of inches H
Estimated Concurrent
Exhaust Volume
3 3
ft /min m 3 /hr ft /min
1200 2040 1320
1260 2140 1385
1320 2240 1452
Estimated Concurrent
Exhaust Volume
3 3
3
ft /min m /hr ft /min
1575 2675 1733
1675 2845 1843
1775 3015 1953
O (125 Pa) may result in erratic operation and cause an alarm condition
2
14
Air-Tight Damper
Recommended Duct
Balance Value Vacuum
2
m 3 /hr WC
2242 0.21
2353 0.21
2467 0.21
Recommended Duct
Balance Value Vacuum
2
3
m /hr WC
2944 0.21
3131 0.21
3318 0.21
O.
2
Table 2-1
1
Pa
52
52
52
1
Pa
52
52
52