Teledyne 9110T instruction manual Level 1 Calibrations Versus Level 2 Checks

Model 9110T NOx Analyzer EPA Protocol Calibration

∙Any repairs which might affect its calibration.

∙Physical relocation of the analyzer.

∙Any other indication (including excessive zero or span drift) of possible significant inaccuracy of the analyzer.

Following any of the activities listed above, the zero and span should be checked to determine if a calibration is necessary. If the analyzer zero and span drifts exceed the calibration limits in Section 12 of the Q.A. Handbook6, a calibration should be performed.

10.4. LEVEL 1 CALIBRATIONS VERSUS LEVEL 2 CHECKS

All monitoring instruments are subject to some drift and variation in internal parameters and cannot be expected to maintain accurate calibration over long periods of time the EPA requires a schedule of periodic checks of the analyzer’s calibration be implemented. Zero and span checks must be used to document that the data remains within required limits. These checks are also used in data reduction and system validation.

A Level 1 Span check is used to document that the 9110T is within control limits and must be conducted every 2 weeks. A Level 2 Span Check is to be conducted between the Level 1 Checks on a schedule to be determined by the user.

Table 10-2: Definition of Level 1 and Level 2 Zero and Span Checks

LEVEL 1 ZERO AND SPAN CALIBRATION	LEVEL 2 ZERO AND SPAN CHECK
A Level 1 zero and span calibration is a simplified,	A Level 2 zero and span check is an "unofficial" check of an
two-point analyzer calibration used when analyzer	analyzer's response. It may include dynamic checks made with
linearity does not need to be checked or verified.	uncertified test concentrations, artificial stimulation of the
(Sometimes when no adjustments are made to the	analyzer's detector, electronic or other types of checks of a
analyzer, the Level 1 calibration may be called a	portion of the analyzer, etc.
zero/span check, in which case it must not be	Level 2 zero and span checks are not to be used as a basis for
confused with a Level 2 zero/span check.) Since	analyzer zero or span adjustments, calibration updates, or
most analyzers have a reliably linear or near-	adjustment of ambient data. They are intended as quick,
linear output response with concentration, they	convenient checks to be used between zero and span
can be adequately calibrated with only two	calibrations to check for possible analyzer malfunction or
concentration standards (two-point concentration).	calibration drift. Whenever a Level 2 zero or span check
Furthermore, one of the standards may be zero	indicates a possible calibration problem, a Level 1 zero and
concentration, which is relatively easily obtained	span (or multipoint) calibration should be carried out before any
and need not be certified. Hence, only one	corrective action is taken.
certified concentration standard is needed for the	If a Level 2 zero and span check is to be used in the quality
two-point (Level 1) zero and span calibration.
	control program, a "reference response" for the check should be
Although lacking the advantages of the multipoint
	obtained immediately following a zero and span (or multipoint)
calibration, the two-point zero and span
	calibration while the analyzer's calibration is accurately known.
calibration--because of its simplicity--can be (and
	Subsequent Level 2 check responses should then be compared
should be) carried out much more frequently.
	to the most recent reference response to determine if a change
Also, two-point calibrations are easily automated.
	in response has occurred. For automatic Level 2 zero and span
Frequency checks or updating of the calibration
	checks, the first scheduled check following the calibration
relationship with a two-point zero and span
	should be used for the reference response. It should be kept in
calibration improves the quality of the monitoring
	mind that any Level 2 check that involves only part of the
data by helping to keep the calibration relationship
	analyzer's system cannot provide information about the portions
more closely matched to any changes (drifts) in
	of the system not checked and therefore cannot be used as a
the analyzer response.
	verification of the overall analyzer calibration.

In addition, an independent precision check between 0.08 and 0.10 ppm must be carried out at least once every two weeks. Table 10-1 summarizes the quality assurance activities for routine operations. A discussion of each activity appears in the following sections.

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