NO/NO2 Audit and Calibration
Purpose: The NO/NO2 audit and calibration is to assure
that the NO/NO2 analyzer/system has the correct gas response. This can be accomplished by introducing a
known quantity of gas to the inlet and auditing the response on the
instrument. The terminology for this
type of audit is GRC (Gas Replacement Calibration). Each GRC has a RF (Response Factor). This RF value should be 1.000 +/- 2%.
Required Equipment: Precision flat head
screwdriver
Analyzer Setup
1. The
Background (BKG) and Coefficient (COEF) on the analyzer should be set to 0.0
and 1.000.
2.
On the “C” or “CTL”
model analyzers press “Menu” and scroll to “Calibration Factors” and press
“Enter”. At this point, the parameters
should be set as follows: Pre BKG PPB
=0.0, NO BKG PPB= 0.0, NOx BKG PPB =0.0, NO COEF =1.000, NOx COEF =1.000 &
NO2 COEF =1.000. Press Run when
finished.
Analyzer Audit
1. This
procedure will obtain the current RF value for the NO/NO2 analyzer.
2.
Open the Gas Calibration
Worksheet and enter the correct NO concentration (found on the gas cylinder) in
the blank provided.
3.
On Site Manager screen go to the Tools tab and select Trigger Cals.
4.
In the Trigger Cals menu
select NO/NO2 Zero and press Start Calibration.
5.
Under the Tools tab
select Query 1-Minute Data.
6.
In the query data tool
menu select the Air MFC, Gas MFC, NO and NO2.
7.
Wait 13 minutes and
verify the Zeros for NO and NO2 are stable (+/-0.1 ppb). Contact
8.
Enter the Air MFC, NO
and NO2 data in the appropriate blank for the NO/NO2 Zero on the Gas
Calibration Worksheet in the As Found section.
9.
Go to Trigger Cals and
press Stop Calibration then select NO/NO2 NO GRC Point 1 and press Start
Calibration.
10.
Wait 13 minutes and
verify the data for NO and NO2 are stable (+/- 0.2ppb), then press Get Data.
11.
Enter the Air MFC, Gas
MFC, NO and NO2 data in the appropriate blanks for the NO/NO2 NO GRC Point 1 on
the Gas Calibration Worksheet in the As Found section.
12.
The RF is now displayed
at the far right of the worksheet. If
the RF is between 0.98 and 1.02, the audit is complete.
13.
Close the Trigger Cals
and Query Data windows.
14.
Save the Gas calibration
worksheet.
15.
If the RF is not within
1.000 +/- 2% continue with the Analyzer Calibration procedure.
Analyzer Calibration
1. This
procedure will be used to adjust the analyzer and obtain a corrected RF value
for the NO/NO2
analyzer.
2.
Enter the As Found data
for NO/NO2 Zero in the box for NO/NO2 Zero.
3.
In Site Manager go to the
Tools tab and select Trigger Cals.
4.
In the Trigger Cals menu
select NO/NO2 Zero and wait 5 minutes for data to be captured for First Light
use.
5.
In the Trigger Cals menu
select NO/NO2 NO GRC Point 1 and press Start Calibration.
6.
Under the Tools tab
select Query 1-Minute Data.
7.
In the Query Data Tool
Menu select the Air MFC, Gas MFC, NO and NO2.
8.
Wait 13 minutes and
verify the data for NO and NO2 are stable (+/- 0.2 ppb). If the query data numbers are approximately
equal to the number on Site Manager, then the data is stable and an average can
be taken.
9.
Adjust the instrument to
the Actual Expected value from the As Found section of the worksheet.
a.
On “C” or “CTL” class
analyzers the PMT can be adjusted by taking the top off of the analyzer. With the top of the analyzer off look on the
right side of the bulkhead at the front.
There is a blue box with an orange grommet on the top. Inside the grommet is the PMT adjustment
screw. Some CTL model analyzers have
been modified so that the PMT can be adjusted through the front panel. Adjust the analyzer until the NO channel on
the analyzer or NO on Site Manager is approximately equal to the Actual
Expected value from the As Found section worksheet.
10.
When the analyzer
adjustments are complete, let the analyzer stabilize for 5 minutes.
11.
On the Query 1-Minute
Data tool press Get Data.
12.
Enter the Air MFC, Gas
MFC, NO and NO2 data in the appropriate box for the NO/NO2 NO GRC Point 1 on
the Gas Calibration Worksheet in the As Left section.
13.
The RF is now displayed
in the worksheet. If the RF is between
0.98 and 1.02, the calibration adjustment is complete. If the RF is not within specification, repeat
the adjustment part of the procedure again.
14.
When the instrument is
finished being calibrated make sure to put it back
into the Run mode.
15.
Close the Trigger Cals
and Query Data windows.
16.
Save the Gas Calibration
worksheet.
NO/NO2 NO2 Conversion Efficiency Audit
1.
This procedure will
obtain the current RF value for the NO2 Conversion Efficiency.
2.
Open the Gas Calibration
Worksheet and go to the NO2 Conv Eff Worksheet tab. Enter the correct NO and NO2 concentrations
(found on the gas cylinder) in the blanks provided.
3.
An NO audit of the
analyzer has to be completed before the NO2 conversion efficiency can be
completed. You may use that day’s
information if available. If it is
available enter the information and start with Step 14. Otherwise continue with the next Step.
4.
On the Site Manager
screen go to the Tools tab and select Trigger Cals.
5.
In the Trigger Cals menu
select NO/NO2 Zero and press Start Calibration.
6.
Under the Tools tab
select Query 1-Minute Data.
7.
In the query data tool
menu select the Air MFC, Gas MFC, NO and NO2.
8.
Wait 13 minutes and
verify the Zeros for NO and NO2 are stable (+/-0.1 ppb). Contact
9.
Enter the Air MFC, NO
and NO2 data in the appropriate blank for the NO/NO2 Zero on the NO2 Conv Eff
Worksheet in the NO/NO2 Analyzer Response section.
10.
Go to Trigger Cals and
press Stop Calibration then select NO/NO2 NO GRC Point 1 and press Start
Calibration.
11.
Wait 13 minutes and
verify the data for NO and NO2 are stable (+/- 0.2ppb), then press Get Data.
12.
Enter the Air MFC, Gas
MFC, NO and NO2 data in the appropriate blanks for the NO/NO2 NO GRC Point 1 on
the NO2 Conv Eff Worksheet in the NO/NO2 Analyzer Response section.
13.
The RF is now displayed
at the far right of the worksheet.
14.
Save the Gas Calibration
Worksheet.
15.
In the Trigger Cals menu
select NO/NO2 Zero and press Start Calibration.
16.
Under the Tools tab
select Query 1-Minute Data.
17.
In the query data tool
menu select the Air MFC, Gas MFC, NO and NO2.
18.
Wait 13 minutes and
verify the Zeros for NO and NO2 are stable (+/-0.1 ppb). Contact
19.
Enter the Air MFC, NO
and NO2 data in the appropriate blank for the NO/NO2 Zero on the NO2 Conv Eff
Worksheet in the NO/NO2 NO2 Conversion Efficiency section.
20.
Go to Trigger Cals and
press Stop Calibration then select NO/NO2 NO2 GRC Point 1 and press Start
Calibration.
21.
Wait 13 minutes and
verify the data for NO and NO2 are stable (+/- 0.2ppb), then press Get Data.
22.
Enter the Air MFC, Gas
MFC, NO and NO2 data in the appropriate blanks for the NO/NO2 NO2 GRC Point 1
on the NO2 Conv Eff Worksheet in the NO/NO2 NO2 Conversion Efficiency section.
23.
The RF is now displayed
at the far right of the worksheet.
24.
If the RF is less than
0.35 it is out of spec and the RF will turn red.
25.
Contact
26.
Close the Trigger Cals
and Query Data windows.
27.
Save the Gas Calibration
Worksheet.