Ecotech Serinus 30 - Reproducibility Standard Deviation for CO under Field Conditions; Table 30: Determination of the Reproducibility Standard Deviation on the Basis of All Data Collected During the Field Test

TÜV Rheinland Energie und Umwelt GmbH
Luftreinhaltung
Report on the performance testing of the Serinus 30 ambient air quality moni-
toring system manufactured by Ecotech Pty Ltd measuring CO, Report no.:
936/21221977/D_EN
Page 107 of 253
EP_Ecotech_Serinus30_en.docx
7.1 8.5.5 Reproducibility standard deviation for CO under field conditions
The reproducibility standard deviation under field conditions shall not exceed 5 % of
the average over a period of 3 months.
7.2 Test procedure
The reproducibility standard deviation under field conditions is calculated from the measured
8-hour averaged data during the three-month period.
The difference
if
x
,
∆
for each (ith) parallel measurement is calculated from:
ififif
xxx
,2,,1,,
−=∆
where
if
x
,
∆
is the ith difference in a parallel measurement, in µmol/mol;
if
x
,1,
is the ith measurement result of analyser 1, in µmol/mol;
if
x
,2,
is the ith measurement result of analyser 2, in µmol/mol.
The reproducibility standard deviation under field conditions is calculated according to:
100
*2
1
2
,
,
×










∆
=
∑
=
f
n
i
if
fr
c
n
x
s
where
fr
s
,
is the reproducibility standard deviation under field conditions, in %;
n
is the number of parallel measurements;
f
c
is the average concentration of carbon monoxide measured during the field test,
in µmol/mol.
The reproducibility standard deviation under field conditions,
fr
s
,
, shall comply with the per-
formance criterion as stated above.
7.3 Testing
On the basis of the 8-hour averages obtained during the field test, the repeatability standard
deviation under field conditions was determined using the equations given above.
In order to demonstrate that the measuring system operates reliably at higher concentrations
as well, the sample air was enriched with CO from time to time.
7.4 Evaluation
Table 30: Determination of the reproducibility standard deviation on the basis of all data col-
lected during the field test
Reproducibility standard deviation in the field test
Number of measurements
n
=
279
Average of both analysers
=
30.92
µmol/mol
Standard deviation from paired measurements
sd
=
1.07
µmol/mol
Reproducibility standard deviation (%)
Sr,f
=
3.45
%
The reproducibility standard deviation under field conditions is 3.45 % of the average.