Envirco NSF Biohazard Cabinet - Manual (Page 22)

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XII. AIRFLOW ADJUSTMENT
Airflow adjustments can be made with either the solid state speed control inside the
electrical control panel and/or with the exhaust damper. Access to the damper
adjusting rod is gained through the plugged access hole in the front access panel of
the cabinet. The recirculating supply airflow and the exhaust airflow velocities must
be set per values on page 10 of this manual. The recirculating supply and exhaust
airflows are interactive; therefore some re-adjustments may be required if either is
changed significantly.
Equipment
1. An airflow thermal anemometer with sensing probe at least eight inches long
and less than ½ -inch in diameter.
2. A Shortridge Airdata Multimeter ADM-870 with 8” x 24” hood. This
recommended, but not required.
Downflow - Recirculating Supply Airflow Measurement
The recirculation supply air velocity is measured within the work area enclosed by
perimeter walls and viewscreen in the horizontal plane defined by the bottom edge
of the viewscreen. Measurement points are shown in Figures 8-9. Measure and
record all points and calculate the average zone velocities. Adjust the solid state
speed control and/or exhaust damper as required to achieve averages within the
above stated limits.
Rear of work deck
Probe set at the bottom edge of the window
Figure 8: Downflow Velocity Grid, 10448 - EBC 47, 4-Ft Type A/B3
(Typical)
6.00” 5.58”
4.42 2”
6.00”
4.42”
4.42”