Labconco Biological Safety Cabinets 30468 Series - Manual (Page 11)

Chapter 2: Prerequisites
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Original instructions
If additional room exhaust is needed
to be drawn through the exhaust
system, install an additional duct and
balancing damper downstream of the
cabinet’s damper. This will allow for
proper balancing of the system.
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 a direct measurement using a flow hood at the cabinet.
The Concurrent Balance Values are measured in the exhaust duct via
traverse methodology, and will always be higher due to differences in volume
measurement methodologies.
Axiom Type C1
Airflows
Airflow Volume
Concurrent
Balance Value
Recommended
Duct Vacuum
1
ft 3 /min m 3 /sec ft 3 /min m 3 /sec WC Pa
4-foot, 8" Sash 323 0.15 387 0.18 0.30 75
4-foot, 10" Sash 400 0.19 480 0.23 0.30 75
6-foot, 8" Sash 463 0.22 556 0.26 0.30 75
6-foot, 10" Sash 570 0.27 684 0.32 0.30 75
1 – Unlike Type B cabinets, the recommended vacuum will remain constant
throughout the life of the Exhaust HEPA filter. Duct vacuums below 0.2 WC
(25 Pa), or above 0.5 WC (125 PA) may result in erratic operation.
Figure 2-1e
Table 2-1