Labconco Class I Enclosure Models 3980423 - Manual (Page 45)

Chapter 6: Maintaining Your Filtered Enclosure
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Calibration
1. Ensure the flow switch and alarm circuit board are installed and
operational.
2. Allow the enclosure to operate for at least two minutes.
3. If factory installed, the monitor will alarm at 60±10 fpm with the inflow
velocity set at 90±10 fpm.
4. To change the factory setting, set the inflow velocity required by your
Safety Officer to the desired alarm condition using the speed control
adjustment procedure outlined in Chapter 6. Once the alarm condition is
set, use a small screwdriver to turn the adjustment screw on the airflow
switch counterclockwise (facing the screw) until the “low” airflow red
LED lights and the audible flow alarm sounds.
5. Adjust the inflow velocity to the nominal operating point required by your
Safety Officer.
6. Over time the HEPA filter will load and eventually slow the inflow
velocity. Once the alarm condition is met, simply increase the speed
control outlined in Chapter 6 or replace the HEPA filter if the speed control
is maximized.
7. The table below lists typical alarm conditions based on normal operating
conditions. Typical alarm conditions are set at face velocities of 10 to 30
feet per minute below the normal operating conditions due to supply air
and exhaust air fluctuations, as well as room air cross drafts. Consult your
Safety Officer for proper operating speeds.
Enclosure Operating In-Flow
Speed
Alarm Condition Set Point
Speed
100 ± 10 fpm 70-90 fpm
90 ± 10 fpm 60-80 fpm
80 ± 10 fpm 50-70 fpm
70 ± 10 fpm 50-60 fpm
60 ± 10 fpm 50 fpm