MRK-D-0048 V4
Aeroqual Dust Sentry / AQS User Guide
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Flow meters for gas flow measurement
It is important to have a high quality flow meter for the gas flow measurement.
Figure 7-2 Recommended high quality flow meters. Left: Bios DryCal, Right: Aeroqual R7 flow meter.
Gas module field calibration frequency
Typically only advanced users will need to field calibrate their monitor. All other users can depend
upon 12 monthly factory calibration of the gas module.
For some monitoring applications such as compliance monitoring the calibration frequency may be
regulated. Some monitoring applications may require periodical validation of the data and field
calibration is the best way to achieve this.
Field calibration frequency is a balance between cost and data quality objectives. Field calibration will
incur cost of time and materials. Therefore more frequent calibration costs more because it requires
more time and materials.
At the high cost end of the spectrum are national ambient monitoring networks. The US EPA Quality
Assurance Handbook (see
http://www.epa.gov/ttnamti1/qalist.html )
is a good example of how
prescriptive calibration requirements for such applications can be.
Aeroqual makes the following recommendations about calibration frequency for the monitor:
Follow all local regulatory calibration requirements if these are defined for the monitoring
activity.
Plan routine calibrations at an interval that is consistent with the data quality objectives for
your monitoring purpose.
Field calibration may be necessary if the gas module is operating out of specification and all
other trouble-shooting steps have been taken.
Record your observations and calibration results in the calibration records.
The service and calibration forms at the end of this document in Appendix 5 are used with this
procedure, information arising from the calibration should be entered into the appropriate
sections of the forms.
The Journal feature in Connect/Cloud can also be used to record observations and make
comments throughout the calibration process.
Assumptions
This SOP assumes the monitor and calibration equipment are in good working condition and the
monitor
is “ready for calibration”.
The monitor has been running for at least 6 hours.
The gas lines and inlet filter is clean.
You are familiar with the operation of all of the calibration equipment.
All calibration equipment, such as calibrators and gas bottles are working and within
calibration where necessary.
You will need to know:
The total flow rate measured last time the monitor was serviced. Record this in Table 5.
The individual gas module flow rates last time the monitor was serviced. Record this in Table
6.
The current gain and offset for each module. See Figure 3. Record these in Tables 7 and 8 in
the Calibration form in Appendix 5.