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13
Chapter 3: Getting Started
Setting the Downflow Velocity
with the Speed Control
Adjustment of the speed control gives the correct downflow
velocity and is located behind the front panel. The downflow
velocity should be from 30-65 fpm for Class 100 (ISO Class 5)
conditions. ISO Class 5 clean air conditions are maximized at a
setting within this range. The Filtered PCR Enclosure is factory
set at 55 ± 10 fpm downflow velocity. (Consult your Safety
Officer for airflow recommendations for your application).
Working at the lowest downflow velocity appropriate for the
application will give the quietest operation. Downflow velocity
measurements are made using an anemometer. An electric
anemometer can be obtained from your laboratory supply dealer.
Downflow velocity measurements should be taken 6" below the
interior upper diffuser. Using a small Phillips screwdriver, adjust
the speed control to give the required downflow velocity. See
Figures 6-1 and 6-2 in Chapter 6 to locate the speed control. The
downflow velocity is increased by turning the speed control
counterclockwise and clockwise to decrease downflow velocity.
Validating the Filtered PCR
Enclosure
To determine the actual downflow velocity, airflow velocity
readings are taken. This should be done 6" down from the upper
diffuser located inside the top of the enclosure. The “average
downflow velocity” is achieved by taking readings in three rows
across the enclosure with the readings 6" from the ends and evenly
spaced every 6". Refer to the exhaust specifications table in
Chapter 2 for proper airflow volumes and downflow velocities for
your particular model. Validation should be completed by a
certified technician.
The Purifier Filtered PCR Enclosures have been tested at
Labconco before shipment and provide ISO Class 5 clean air
conditions inside the enclosure. Labconco also performed
extensive performance testing to validate the Filtered PCR’s for
product protection under ISO Class 5 conditions. For copies of
these validation reports, contact Labconco Customer Service.