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10. EPA PROTOCOL CALIBRATION
10.1. CALIBRATION REQUIREMENTS
If the T100 is to be used for EPA SLAMS monitoring, it must be calibrated in
accordance with the instructions in this section.
In order to insure that high quality, accurate measurements are obtained at all times, the
T100 must be calibrated prior to use. A quality assurance program centered on this
aspect and including attention to the built-in warning features of the T100 , periodic
inspection, regular zero/span checks and routine maintenance is paramount to achieving
this.
The US EPA strongly recommends obtaining a copy of the Quality Assurance
Handbook for Air Pollution Measurement Systems, Volume II, Part I (abbreviated Q.A.
Handbook Volume II).
Special attention should be paid to Section 2.9 of the EPA handbook which deals with
fluorescence based SO
2
analyzers and upon which most of this section is based. Specific
regulations regarding the use and operation of ambient sulfur dioxide analyzers can be
found in 40 CFR 50 and 40 CFR 58.
10.1.1. CALIBRATION OF EQUIPMENT
In general, calibration is the process of adjusting the gain and offset of the T100 against
some recognized standard. The reliability and usefulness of all data derived from any
analyzer depends primarily upon its state of calibration. In this section the term dynamic
calibration is used to express a multipoint check against known standards and involves
introducing gas samples of known concentration into the instrument in order to adjust
the instrument to a predetermined sensitivity and to produce a calibration relationship.
This relationship is derived from the instrumental response to successive samples of
different known concentrations. As a minimum, three reference points and a zero point
are recommended to define this relationship. The true values of the calibration gas must
be traceable to NIST-SRM (refer to Table 9-1).
All monitoring i
nstrument systems are subject to some drift and variation in internal
parameters and cannot be expected to maintain accurate calibration over long periods of
time. Therefore, it is necessary to dynamically check the calibration relationship on a
predetermined schedule. Zero and span checks
must be used to document that the data
remains within control limits. These checks are also used in data reduction and
validation. Table 10-1 summarizes the initial quality assurance activities for calibrating
equipment. Table 10-2 is a matrix for th
e actual dynamic calibration procedure.
06807C DCN6650