Ecotech Serinus 30 - Interferents

TÜV Rheinland Energie und Umwelt GmbH
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Report on the performance testing of the Serinus 30 ambient air quality
monitoring system manufactured by Ecotech Pty Ltd measuring CO, Report
no.: 936/21221977/D_EN
EP_Ecotech_Serinus30_en.docx
7.1 8.4.11 Interferents
Interferents at zero and at a concentration c
t
(at a level of the 8-hour limit =
8.6 µmol/mol for CO). The highest permissible response to the interfering compo-
nents CO
2
, NO, and N
2
O shall not exceed 5.0 µmol/mol (i.e. 5.8 mg/m
3
) respectively
and 10.0 µmol/mol (i.e. 11.6 mg/m
3
) for H
2
O.
7.2 Test procedure
The analyser response to certain interferents, which are to be expected to be present in am-
bient air, shall be tested. The interferents can give a positive or negative response. The test
shall be performed at zero and at a test concentration (c
t
) of carbon monoxide similar to the
8-hour limit value (8.6 µmol/mol for CO).
The concentration of the mixtures of the test gases with the interferent shall have an ex-
panded uncertainty of ≤ 5 % and shall be traceable to nationally accepted standards. The in-
terferents to be tested and their respective concentrations are given in Table 22. The influ-
ence of each interferent shall be determined separately. A correction on the concentration of
the measurand shall be made for the dilution effect due to addition of an interferent (e.g. wa-
ter vapour).
After adjustment of the analyser at zero and span level, the analyser shall be fed with a mix-
ture of zero gas and the interferent to be investigated with the concentration as given in Ta-
ble 22. With this mixture, one independent measurement followed by two individual meas-
urements shall be carried out. This procedure shall be repeated with a mixture of the meas-
urand at concentration c
t
and the interferent to be investigated. The influence quantities at
zero and concentration c
t
are calculated from:
zz
xX =
int,
tctct
cxX −=
int,
where
z
X
int,
is the influence quantity of the interferent at zero, in µmol/mol;
z
x
is the average of the measurements at zero, in µmol/mol;
ct
X
int,
is the influence quantity of the interferent at concentration c
t
, in µmol/mol;
ct
x
is the average of the measurements of CO at concentration c
t
, in µmol/mol;
t
c
is the carbon monoxide test gas concentration at the level of the 8-hour limit val-
ue, in µmol/mol.
The influence quantities of the interferents shall comply with the performance criteria as stat-
ed above, both at zero and at concentration c
t
.
7.3 Testing
The test was performed in accordance with the requirements on testing as stipulated in DIN
EN 14626. The systems were adjusted to zero concentration and to the concentration c
t
(ap-
prox. 8.6 µmol/mol). Zero and test gas with various interferents were then applied. Inter-
ferents and their respective concentrations used during testing are provided in Table 22.