CHAPTER 3, CALIBRATION
98307600 Rev. C-1 3-5
3.2.1.2.5 Output Manifold
The output manifold should be of sufficient diameter to ensure an insignificant
pressure drop at the analyzer connection. The system must have a vent designed to
ensure atmospheric pressure at the manifold and enough inlet flow to prevent
ambient air from entering the manifold.
3.2.1.3 Reagents
3.2.1.3.1 CO Concentration Standard(s)
Cylinder(s) of CO in air containing appropriate concentration(s) of CO suitable for
the selected operating range of the analyzer under calibration; CO standards for the
dilution method may be contained in a nitrogen matrix if the zero air dilution ratio
is not less than 100:1. The assay of the cylinder(s) must be traceable either to a
National Institute of Standards and Technology (NIST) CO in air Standard
Reference Material (SRM) or to an NIST/EPA approved commercially available
Certified Reference Material (CRM). CRM’s are described in Calibration
Reference 2, and a list of CRM sources is available from the address shown for
Calibration Reference 2. A recommended protocol for certifying CO gas cylinders
against either a CO SRM or a CRM is given in Calibration Reference 1. CO gas
cylinders should be recertified on a regular basis as determined by the local quality
control program.
3.2.1.3.2 Dilution Gas (Zero Air)
Zero air is described as air free of contaminants which will cause a detectable
response on the CO analyzer. The zero air should contain <0.1 ppm CO. A
procedure for generating CO zero air is given in Calibration Reference 1; the
Ecotech GasCal 1000 calibrator and 8301 Zero Air source calibrator has CO-free air
capability sufficient for this operation.
3.2.1.4 Procedure Using Dynamic Dilution Gas Method
1. Assemble a dynamic calibration system such as the one shown in Figure 3-1.
All calibration gases including zero air must be introduced into the sample
inlet of the analyzer system. The EC9830 instrument sample inlet is labeled
Inlet and is located on the rear panel.
2. Ensure that all flowmeters are properly calibrated, under the conditions of use,
if appropriate, against an authoritative standard such as a soap-bubble meter
or wet-test meter. All volumetric flow rates should be corrected to 25° C and
760 mm Hg (101 kPa). A discussion on calibration of flowmeters is given in
Calibration Reference 1.
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