PureAire Monitoring Systems, Inc.
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1.
Fill the calibration gas Tedlar bag with the methyl iodide cylinder span gas.
IMPORTANT
:
Be sure to perform the calibration before the concentration of the gas changes.
Also, verify that the concentration of the calibration gas is the same after calibration as
it was before.
5.4.5 Span Calibration
NOTE:
When using cylinder span gas, gas must be a mixture of the target gas blended with
air. Never connect the gas cylinder directly to the sampling system. Exhaust the gas
from the cylinder into a Sample gas tedlar bag.
To access the span function, while in the Sensor Adjustment Menu, push the joystick right until the
”Set Sensor Span” menu appears. Push the joystick to the right to display the span menu.
1.
Connect the waste bag to the exhaust and open the valve on the waste bag and connect the system exhaust tubing to the
gas waste tedlar bag. Inspect the flow rate again on the flow meter and adjust to the proper flow rate.
2.
Open the valve on the calibration span gas Tedlar bag and connect it to the sampler inlet and expose the monitor to gas
for 1 minute. Adjust the display to the span gas reading by pushing the joystick up or down to set the concentration
value on the PPM display.
4. Press
ENTER
to accept the calibration value.
After calibration, disconnect the span gas Tedlar bag and permit the sampling system display to return to zero.
NOTE:
The Methyl iodide monitor has an internal pyrolizer that converts the gas.
Typical fall times can range from 1 to 4 minutes depending on the exposure concentration. The higher
the concentration, the longer the fall time to zero.
3.
Return the system to the monitoring mode by pushing the joystick to the left until the “CH
3
I” appears on the top line of
the display. Reattach the front cover to the sampling system.
Note: The remaining span gas and collected waste gas should be properly exhausted.
114
0.0 PPM
139
6.0ppm
