Teledyne T200, Operation Manual, Page: 182 / 425

Calibration Procedures Teledyne API
– T200 NO/NO
2
/NO
X
Analyzer Operation Manual
180
Even though NO gas mixed into in nitrogen gas (N
2
) could be used as a span gas, the
matrix of the balance gas is different and may cause interference problems or yield
incorrect calibrations.

The same applies to gases that contain high concentrations of other compounds
(for example, CO
2
or H
2
O).
Note The span gas should match all concentrations of all gases of the measured
medium as closely as possible.
Cylinders of calibrated NO
x
and NO gas traceable to NIST-standards specifications (also
referred to as EPA protocol calibration gases or Standard Reference Materials) are
commercially available..
9.1.2.3. SPAN GAS FOR MULTIPOINT CALIBRATION
Some applications, such as EPA monitoring, require a multipoint calibration where span
gases of different concentrations are needed. We recommend using an NO gas of higher
concentration combined with a gas dilution calibrator such as a Teledyne API's Model
T700. For more information see Section 3.3.2.1 and Section 10.
9.1.2.4. NO
2
PERMEATION TUBES
Teledyne API offers an optional internal span gas generator that utilizes an NO
2
permeation tube as a span gas source. The accuracy of these devices is only about ±5%.
Whereas this may be sufficient for quick, daily calibration checks, we recommend using
certified NO gases for accurate calibration.
CAUTION!
Insufficient gas flow allows gas to build up to levels that will contaminate
the instrument or present a safety hazard to personnel.
In units with a permeation tube option installed, either the tube must be
removed and stored in sealed container (use original container that tube
was shipped in) during periods of non-operation, or vacuum pump must
be connected and powered on to maintain constant gas flow though the
analyzer at all times.
(See Figure 3-6 for location and Section 11.3.6 for instructions on how to remove the
perm tube when the unit is not in operation).
06858E DCN7057