Filter
Top Products
M400E Ozone Analyzer Operator’s Manual 346BEPA Protocol Calibration
10.3.5. O
3
LOSS CORRECTION FACTOR
In spite of scrupulous cleaning and preconditioning, some O
3
may be lost on contact with the photometer cell
walls and the gas-handling components. Any significant loss of O
3
must be quantitatively determined and used
to correct the output concentration assay. In any case, the O3 loss must not exceed 5%.
To determine O
3
loss:
1. Calibrate a stable ozone analyzer with the UV calibration system, assuming no losses.
2. Generate an O
3
concentration, and measure it with the analyzer as close as possible to the actual inlet
of the photometer cell.
3. Measure the concentration as close as possible to the outlet of the cell.
4. Repeat each measurement several times to get a reliable average.
5. Measure the concentration at the output manifold. The tests should be repeated at several different O
3
concentrations.
The percentage of O
3
loss is calculated as,
Equation 10-3
100
C
2
)CC(
C
lossO%
m
oi
m
3
×
+
=
Where
C
i
= O
3
concentration measured at cell inlet, ppm
C
o
= O
3
concentration measured at cell outlet, ppm, and
C
m
= O
3
concentration measured at output manifold, ppm.
For other configurations, the % O
3
loss may have to be calculated differently. The ozone loss correction factor is
calculated as:
L = 1 - 0.01 × % O
3
loss.
10.3.6. SPAN DRIFT CHECK
The first level of data validation should accept or reject monitoring data based upon routine periodic analyzer
checks. It is recommended that results from the Level 1 span checks be used as the first level of data validation.
This means up to two weeks of monitoring data may be invalidated if the span drift for a Level 1 span check is
25%. For this reason, it may be desirable to perform Level 1 checks more often than the minimum
recommended frequency of every 2 weeks.
10.4. AUDITING PROCEDURES
An audit is an independent assessment of the accuracy of data. Independence is achieved by having the audit
made by an operator other than the one conducting the routine field measurements and by using audit standards
and equipment different from those routinely used in monitoring. The audit should be a true assessment of the
measurement process under normal operations without any special preparation or adjustment of the system.
Routine quality control checks (such as zero and span checks) conducted by the operator are necessary for
obtaining and reporting good quality data, but they are not considered part of the auditing procedure.
Three audits are recommended: two performance audits and a systems audit. These audits are summarized in
10.4.3 at the end of this section. See Appendix 15 of the Q.A. Handboo
k (Reference 11) for detailed procedures
for a systems audit and for a performance audit, respectively.
04315 Rev. C1 179