Teledyne T200, Operation Manual, Page: 181 / 425

Teledyne API
– T200 NO/NO
2
/NO
X
Analyzer Operation Manual Calibration Procedures
179
9.1.2. CALIBRATION GASES
9.1.2.1. ZERO AIR
Zero air or zero calibration gas is defined as a gas that is similar in chemical
composition to the measured medium but without the gas to be measured by the
analyzer.
For the T200, this means zero air should be devoid of NO, NO
2
, CO
2
, NH
3
or H
2
O
vapor.
Note Moderate amounts of NH
3
and H
2
O can be removed from the sample gas stream
by installing the optional sample gas dryer/scrubber (see Section 3.3.2.6).

If your application is not a measurement in ambient air, the zero calibration gas
should be matched to the composition of the gas being measured.

Pure nitrogen (N
2
) could be used as a zero gas for applications where NO
X
is
measured in nitrogen.

If your analyzer is equipped with an external zero air scrubber option, it is capable
of creating zero air from ambient air.
For analyzers without the external zero air scrubber, a zero air generator such as the
Teledyne API's Model 701 can be used. Please visit the company website for more
information.
If your analyzer is equipped with an external zero air scrubber option, it is capable of
creating zero air from ambient air.

If your application is not a measurement in ambient air, the zero calibration gas
should be matched to the composition of the gas being measured.

Pure nitrogen could be used as a zero gas for applications where NO
X
is measured
in nitrogen.
9.1.2.2. SPAN GAS
Span calibration gas is a gas specifically mixed to match the chemical composition of
the type of gas being measured at near full scale of the desired reporting range. To
measure NO
X
with the T200, it is recommended that you use a span gas with an NO
concentration equal to 80% of the measurement range for your application
EXAMPLE:

If the application is to measure NOX in ambient air between 0 ppm and 500 ppb, an
appropriate span gas would be 400 ppb.

If the application is to measure NOX in ambient air between 0 ppm and 1000 ppb,
an appropriate span gas would be 800 ppb.
We strongly recommend that span calibration be carried out with NO span gas.
Alternatively it is possible to use NO
2
gas in a gas phase titration (GPT) calibration
system.
06858E DCN7057