EN 14789:2005

SLOVENSKI STANDARD
01-december-2005
(PLVLMHQHSUHPLþQLKYLURY'RORþHYDQMHYROXPVNHNRQFHQWUDFLMHNLVLND2±
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Stationary source emissions - Determination of volume concentration of oxygen (O2) -
Reference method - Paramagnetism
Emissionen aus stationären Quellen - Bestimmung der Volumenkonzentration von
Sauerstoff (O2) - Referenzverfahren - Paramagnetismus
Emissions de sources fixes - Détermination de la concentration volumique en oxygene
(O2) - Méthode de référence: Paramagnétisme
Ta slovenski standard je istoveten z: EN 14789:2005
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14789
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2005
ICS 13.040.40
English Version
Stationary source emissions - Determination of volume
concentration of oxygen (O2) - Reference method -
Paramagnetism
Emissions de sources fixes - Détermination de la Emissionen aus stationären Quellen - Bestimmung der
concentration volumique en oxygène (O2) - Méthode de Volumenkonzentration von Sauerstoff - Referenzverfahren -
référence: Paramagnétisme Paramagnetismus
This European Standard was approved by CEN on 30 September 2005.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14789:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .4
1 Scope.5
2 Normative references.5
3 Terms and definitions.5
4 Principle.10
4.1 General.10
4.2 Measuring principle.10
5 Description of measuring equipment - Sampling and sample gas conditioning systems.10
5.1 General.10
5.2 Sampling line components.11
5.2.1 Sampling line.11
5.2.2 Filter.11
5.2.3 Sample cooler or permeation drier.11
5.2.4 Sample pump.11
5.2.5 Secondary filter.12
5.2.6 Flow controller and flow meter .12
6 Analyser equipment.12
7 Determination of the characteristics of the SRM : analyser, sampling and conditioning

line.13
7.1 General.13
7.2 Relevant performance characteristics of the SRM and performance criteria .13
7.3 Establishment of the uncertainty budget.14
8 Field operation.15
8.1 Sampling location.15
8.2 Sampling point(s).15
8.3 Choice of the measuring system .16
8.4 Setting of the SRM on site.16

8.4.1 General.16
8.4.2 Preliminary zero and span check, and adjustments .17
8.4.3 Zero and span checks after measurement.17
9 Ongoing quality control.18
9.1 General.18
9.2 Frequency of checks .18
10 Expression of results.18
11 Evaluation of the method in the field.18
12 Equivalence with an alternative method .19
13 Test report.19
(informative)
Annex A Schematic diagram of the measurement system .21
Annex B (informative) Example of assessment of compliance of paramagnetic method for O with
requirements on emission measurements.22
B.1 Process of uncertainty estimation.22

B.1.1 General.22
B.1.2 Determination of model function .22
B.1.3 Quantification of uncertainty components .22
B.1.4 Calculation of the combined uncertainty .22
B.2 Specific conditions in the site.23
B.3 Performance characteristics of the method .24
B.4 Calculation of the standard uncertainty of the concentration values given by the analyser.25
B.4.1 Model equation and application of the rule of the uncertainty propagation .25

B.4.2 Calculation of the partial uncertainties .26
B.4.3 Results of uncertainty calculation.31
Annex C (informative) Procedure of correction of data from drift effect .33
Annex D (informative) Evaluation of the method in the field .34
D.1 General.34
D.2 Characteristics of installations.34
D.3 Repeatability and reproducibility in the field.35
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive.38
Bibliography.39

Foreword
This European Standard (EN 14789:2005) has been prepared by Technical Committee CEN/TC 264 “Air
quality”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2006, and conflicting national standards shall be withdrawn at the
latest by May 2006.
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this European
Standard.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
1 Scope
This European Standard describes the paramagnetic method, including the sampling and the gas conditioning
system, to determine the oxygen concentrations in flue gases emitted to the atmosphere from ducts and
stacks.
This European Standard is the Standard Reference Method (SRM) for periodic monitoring and for the
calibration or control of Automatic Measuring Systems (AMS) permanently installed on a stack, for regulatory
purposes or other purposes. To be used as the SRM, the user shall demonstrate that the performance
characteristics of the method are better than the performance criteria defined in this European Standard and
that the overall uncertainty of the method is less than ± 6,0 % of the measured concentration.
NOTE When paramagnetism is the measurement principle used for AMS, reference should be made to EN 14181
and other relevant standards provided by CEN/TC 264.
An alternative method to this SRM may be used provided that the user can demonstrate equivalence
according to the Technical Specification CEN/TS 14793, to the satisfaction of his national accreditation body
or law.
This Standard Reference Method has been evaluated during field tests on waste incineration, co-incineration
and large combustion installations. It has been validated for sampling periods of 30 min in the range: 5 % to
26 %. Oxygen concentration values, expressed in % volume, are used in order to allow emission
measurements of pollutants to be standardised to the reference O concentration and dry gas conditions
required by the following Council Directives:
 Council Directive 2001/80/EC on the limitation of emissions of certain pollutants into the air from large
combustion plants;
 Council Directive 2000/76/EC on waste incineration plants.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
CEN/TS 14793, Stationary source emission – Intralaboratory validation procedure for an alternative method
compared to a reference method.
ENV 13005, Guide to the expression of uncertainty in measurement.
EN ISO 14956, Air quality - Evaluation of the suitability of a measurement procedure by comparison with a
required measurement uncertainty (ISO 14956:2002).
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
NOTE In this European Standard, the concentration of O is expressed in % volume.
3.1
adjustment (of a measuring system)
operation of bringing a measuring system into a state of performance suitable for its use
[VIM 4.30]
3.2
ambient temperature
temperature of the air around the measuring device
3.3
automatic measuring system (AMS)
measuring system permanently installed on site for continuous monitoring of emissions
NOTE 1 An AM is a method which is traceable to a reference method.
NOTE 2 Apart from the analyser, an AMS includes facilities for taking samples (e.g. probe, sample gas lines, flow
meters, regulators, delivery pumps) and for sample conditioning (e.g. dust filter, moisture removal devices, converters,
diluters). This definition also includes testing and adjusting devices, that are required for regular functional checks.
[EN 14181]
3.4
calibration
statistical relationship between values of the measurand indicated by the measuring system (AMS) and the
corresponding values given by the standard reference method (SRM) used during the same period of time
and giving a representative measurement on the same sampling plane
NOTE The result of calibration permits to establish the relationship between the values of the SRM and the AMS
(calibration function).
3.5
drift
difference between two zero (zero drift) or span readings (span drift) at the beginning and at the end of a
measuring period
3.6
emission limit value (ELV)
emission limit value according to EU Directives on the basis of 30 min, 1 hour or 1 day
3.7
influence quantity
quantity that is not the measurand but that affects the result of the measurement
[adapted VIM 2.7]
NOTE Examples:
 ambient temperature;
 atmospheric pressure;
 presence of interfering gases in the flue gas matrix;
 pressure of the gas sample.
3.8
interference
negative or positive effect upon the response of the measuring system, due to a component of the sample that
is not the measurand
3.9
lack of fit
systematic deviation within the range of application between the measurement result obtained by applying the
calibration function to the observed response of the measuring system measuring test gases and the
corresponding accepted value of such test gases
NOTE 1 Lack of fit may be a function of the measurement result.
NOTE 2 The expression "lack of fit" is often replaced in everyday language by "linearity" or "deviation from linearity".
3.10
measurand
particular quantity subject to measurement
[VIM 2.6]
3.11
measuring system
complete set of measuring instruments and other equipment assembled to carry out specified measurements
[VIM 4.5]
3.12
performance characteristic
one of the quantities (described by values, tolerances, range) assigned to equipment in order to define its
performance
3.13
repeatability in the laboratory
closeness of the agreement between the results of successive measurements of the same measurand carried
out under the same conditions of measurement
NOTE 1 Repeatability conditions include:
 same measurement procedure;
 same laboratory;
 same measuring instrument, used under the same conditions;

same location;
 repetition over a short period of time.
NOTE 2 Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard the repeatability is expressed as a value with a level of confidence of 95 %.
[VIM 3.6]
3.14
repeatability in the field
closeness of the agreement between the results of simultaneous measurements of the same measurand
carried out with two sets of equipment under the same conditions of measurement
NOTE 1 These conditions include:
 same measurement procedure;
 two sets of equipment, the performances of which are fulfilling the requirements of the reference method, used under
the same conditions;
 same location;
 implemented by the same laboratory;
 typically calculated on short periods of time in order to avoid the effect of changes of influence parameters
(e.g 30 min).
NOTE 2 Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard, the repeatability under field conditions is expressed as a value with a level of
confidence of 95 %.
3.15
reproducibility in the field
closeness of the agreement between the results of simultaneous measurements of the same measurand
carried out with several sets of equipment under the same conditions of measurement
NOTE 1 These conditions are called field reproducibility conditions and include:
 same measurement procedure;
 several sets of equipment, the performances of which fulfil the requirements of the reference method, used under the
same conditions;
 same location;
 implemented by several laboratories.
NOTE 2 Reproducibility may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard, the reproducibility under field conditions is expressed as a value with a level of
confidence of 95 %.
3.16
residence time in the measuring system
time period for the sampled gas to be transported from the inlet of the probe to the inlet of the measurement
cell
3.17
response time
time interval between the instant when a stimulus is subjected to a specified abrupt change and the instant
when the response reaches and remains within specified limits around its final steady value
NOTE By convention time taken for the output signal to pass from 0 % to 90 % of the final change.
[VIM 5.17]
3.18
sampling location
specific area, close to the sampling plane, where the measurement devices are set up
3.19
sampling plane
plane normal to the centreline of the duct at the sampling position
[EN 13284-1]
3.20
sampling point
specific position on a sampling line at which a sample is extracted
[EN 13284-1]
3.21
span gas
test gas used to adjust and check a specific point on the response line of the measuring system
NOTE This concentration is often chosen around 80 % of the upper limit of the range.
3.22
Standard Reference Method (SRM)
measurement method recognised by experts and taken as a reference by convention, which gives, or is
presumed to give, the accepted reference value of the concentration of the measurand (3.10) to be measured
3.23
uncertainty
parameter associated with the result of a measurement, that characterises the dispersion of the values that
could reasonably be attributed to the measurand
3.23.1
standard uncertainty u
uncertainty of the result of a measurement expressed as a standard deviation u
3.23.2
combined uncertainty u
c
standard uncertainty u attached to the measurement result calculated by combination of several standard
c
uncertainties according to GUM
3.23.3
expanded uncertainty U
quantity defining a level of confidence about the result of a measurement that may be expected to encompass
a specific fraction of the distribution of values that could reasonably be attributed to a measurand
U = k x u
NOTE In this European Standard, the expanded uncertainty is calculated with a coverage factor of k=2, and
with a level of confidence of 95 %.
3.23.4
overall uncertainty U
c
expanded combined standard uncertainty attached to the measurement result calculated according to GUM
U = k x u
c c
3.24
uncertainty budget
calculation table combining all the sources of uncertainty according to EN ISO 14956 or ENV 13005 in order
to calculate the overall uncertainty of the method at a specified value
4 Principle
4.1 General
This European Standard describes the Standard Reference Method (SRM), based on the paramagnetism
principle for sampling and determining oxygen O concentration in flue gases emitted to atmosphere from
ducts and stacks. The specific components and the requirements for the sampling system and the
paramagnetic analyser are described. A number of performance characteristics, together with associated
minimum performance criteria are specified for the analyser. These performance characteristics and the
overall uncertainty of the method shall meet the performance criteria given in this European Standard.
Requirements and recommendations for quality assurance and quality control are given for measurements in
the field (see Table 1 in 7.2).
4.2 Measuring principle
The paramagnetic method is based on the principle that oxygen molecules are strongly attracted to a
magnetic field. This property, known as paramagnetism, can be used for the selective measurement of
oxygen in flue gases where the other constituents are either slightly or non-paramagnetic. The magnetic
susceptibility or degree of magnetisation produced in a gas sample by a magnetic field is inversely
proportional to its absolute temperature. A gas sample containing oxygen, when exposed to the combined
effect of a magnetic gradient in a confined space, shall be constrained to flow in the direction of the magnetic
field. The magnitude of this flow, other factors being equal, is dependent on the oxygen concentration in the
gas sample induced flow. A number of devices, described in clause 6 have been developed to measure the
paramagnetically induced flow.
Paramagnetic analysers are combined with an extractive sampling system and a gas conditioning system. A
representative sample of gas is taken from the stack with a sampling probe and conveyed to the analyser
through a sampling line and suitable gas conditioning system. The values from the analyser are recorded
and/or stored by means of electronic data processing.
5 Description of measuring equipment - Sampling and sample gas conditioning
systems
5.1 General
A representative volume of flue gas (see 8.2) is extracted from the emission source for a fixed period of time
at a controlled flow rate. A filter removes the dust in the sampled volume before the sampled gas is
conditioned and passed to the analyser.
Two different sampling and conditioning configurations are available in order to avoid uncontrolled water
condensation in the measuring system. Both approaches require that the user shall check that the dew point
temperature is lower or equal to 4 °C at the outlet of the analyser. The user may correct the results for the
remaining water content in order to report results on a dry basis (refer to the table of Annex A in
EN 14790:2003).
These configurations are:
 configuration 1: removal of water vapour by condensation using a cooling system;
 configuration 2: removal of water vapour through elimination within a permeation drier.
Schematic diagrams of typical measuring systems are shown in Annex A.
It is important that all parts of the sampling equipment upstream of the analyser are made of materials that do
not react with or absorb O . Except for the cooling system of configuration 1, the temperature of its
components coming into contact with the gas, shall be maintained at a sufficiently high temperature to avoid
any condensation.
Conditions and layout of the sampling equipment contribute to the overall uncertainty of the measurement. In
order to minimise this contribution to the overall measurement uncertainty, the performance criteria for the
sampling equipment and sampling conditions are given in sections 5.2 and 6.
5.2 Sampling line components
5.2.1 Sampling line
In order to access the representative measurement point(s) of the sampling plane, probes of different lengths
and inner diameters may be used. The design and configuration of the probe used shall ensure the residence
time of the sample gas within the probe is minimised in order to reduce the response time of the measuring
system.
The procedure of sub-clause 8.2 shall be used when the operator suspects that the flue gas is
inhomogeneous.
The probe may be marked before sampling in order to demonstrate that the representative measurement
point(s) in the measurement plane has (have) been reached.
The line shall be made of a suitable, corrosion resistant material (e.g. stainless steel, borosilicate glass,
ceramic, titanium, PTFE is only suitable for flue gas temperatures lower than 200 °C).
A seal-able connection may be installed on the probe in order to introduce test gases for adjustment.
5.2.2 Filter
The particle filter shall be made of an inert material (e.g. ceramic or sinter metal filter with an appropriate pore
size). It shall be heated above the water or acid dew point. The particle filter shall be changed or cleaned
periodically depending on the dust loading at the sampling site.
NOTE Overloading of the particle filter may increase the pressure drop in the sampling line.
5.2.3 Sample cooler or permeation drier
The sample cooler or permeation drier is used before the gas enters the analyser in order to separate water
vapour from the flue gas. A maximum dew-point temperature of 4 °C shall not be exceeded at the outlet of the
system.
NOTE The measured oxygen concentration, given by these sampling configurations, can be considered to be dry.
However, the user may correct the results for the remaining water (refer to the Table of Annex A in EN 14790:2003).
5.2.4 Sample pump
When a pump is not an integral part of the paramagnetic analyser, an external pump is necessary to draw the
sampled air through the apparatus. It shall be capable of operating according to the specified flow
requirements of the manufacturer of the analyser and pressure conditions required for the reaction chamber.
The pump shall be resistant to corrosion and consistent with the requirements of the analyser to which it is
connected.
NOTE The quantity of sample gas required can vary between 15 l/h and 500 I/h, depending upon the analyser and
the expected response time.
5.2.5 Secondary filter
The secondary filter is used to separate fine dust, with a pore size of 1 µm to 2 µm. It may be made in glass-
fibre, sintered ceramic, stainless steel or PTFE.
NOTE No additional secondary filter is necessary when they are part of the analyser itself.
5.2.6 Flow controller and flow meter
This apparatus sets the required flow. A corrosion resistant material shall be used. The sample flow rate into
the instrument shall be maintained according to the analyser manufacturer’s requirements. A controlled
pressure drop across restrictors is usually employed to maintain flow rate control into the analyser.
NOTE No additional flow controller or flow meter is necessary when they are part of the analyser itself.
6 Analyser equipment
Several variants of application of the paramagnetism principle are available. Some of them are described
below:
 Thermo-magnetic:
Two separate chambers (reference and measuring chambers) are equipped with thermo-sensitive resistors,
which form an assembly with a Wheatstone bridge. The measuring chamber is located in a magnetic field
while the reference is not. When the concentration of oxygen increases, the flow in the measurement chamber
is greater than the flow in the reference chamber. This creates a differential cooling effect on the resistors.
The equilibrium of the Wheatstone bridge is restored by an increase of an electric current in the resistors and
this current is proportional to the oxygen concentration.
 Magneto-mechanic:
In one measuring chamber, two permanent magnets create a non-homogenous magnetic field in which a very
light float is suspended. When the gas is injected into the chamber, the oxygen molecules are attracted by the
magnetic field. This in turn creates a differential partial pressure, which then alters the position of the float. An
electromagnetic field is then applied to compensate for this change, while the strength of the applied
compensatory field is proportional to the concentration of oxygen.
 Magneto-pneumatic:
The sampled gas and a reference gas circulate within an electromagnet. Each gas is subject to a modification
of pressure that is proportional to the oxygen concentration. This pressure difference then alters the position
of the membrane of a capacitor. The variation in capacitance allows the conversion of the pressure signal to
an electric signal, which in turn is proportional to the partial pressure of oxygen.
7 Determination of the characteristics of the SRM : analyser, sampling and
conditioning line
7.1 General
When this European standard is used as the SRM, the user shall demonstrate that:
 performance characteristics of the method are better than the minimum performance criteria given in
Table 1; and
 overall uncertainty calculated by combining values of standard uncertainties associated to the
performance characteristics given in Table 1 is less than ± 6,0 % rel. of the measured value expressed on
dry basis.
The values of the selected performance characteristics shall be evaluated by means of a laboratory test and a
field test. An experienced laboratory recognised by the competent authority shall perform the laboratory tests
according to the procedures described in the relevant CEN/TC 264 standards or technical specifications. The
user shall perform the field tests.
The performance characteristics and performance criteria given in this European Standard do not necessarily
correspond to those of an AMS. For AMS performance characteristics and performance criteria the user shall
refer to the relevant standards provided by CEN/TC 264.
7.2 Relevant performance characteristics of the SRM and performance criteria
The uncertainty of the measured values given by an analyser is not only influenced by the performance
characteristics of the analyser itself but also by:
 sampling system including conditioning;
 site specific conditions;
 calibration gas used.
Table 1 gives an overview of the minimum performance characteristics and performance criteria, which shall
be determined during laboratory and field tests according to the relevant CEN procedures, and indicates
values included in the calculation of the overall uncertainty.
Table 1 — Minimum performance characteristics of the SRM
Performance characteristic Performance
Lab. Test Field Performance criterion
for the test characteristics to be
analyser
included in calculation
of overall uncertainty
Response time X X ≤ 200 s
Detection limit X
≤ ± 0,20 % relative of the range
Lack of fit X X
≤ ± 0,30 % volume
Zero drift
X ≤ ± 0,20 % volume/24 h X
Span drift X X
≤ ± 0,20 % volume/24 h
≤ ± 3,0 % relative of the range
Sensitivity to atmospheric X X
pressure for 2 kPa
a
Sensitivity to sample volume X X
flow or sample pressure
Sensitivity to ambient X
≤ 0,30 % volume/10 K X
temperature
Sensitivity to electric voltage X X
≤ ± 0,10 % volume/10 V
b
X
Interferents  Total ≤ ± 0,20 % volume X
c
≤ ± 0,20 % relative of the range X
Standard deviation of X
repeatability in laboratory at
zero
c
Standard deviation of X X
≤ 0,40 % relative of the range
repeatability in laboratory at
span level
Losses and leakage in the X
≤ ± 2,0 % relative of the
X
sampling line and conditioning
measured value
system
a
The tested volume flow range or pressure is defined in the manufacturer's recommendations.
b
Interferents that shall be tested are at least those given in Table 2.
The value of max algebric sums of contributions to uncertainty producing positive effects on the result, (sum of contributions to uncertainty
producing negative effects) shall be compared with the performance criterion.
c
Only one of both values shall be included in the calculation: the first possibility is to choose the repeatability standard deviation got from
laboratory tests corresponding to the closest concentration to the actual concentration in stack, or the higher (relative) standard deviation of
repeatability independently of the concentration measured in stack.
7.3 Establishment of the uncertainty budget
An uncertainty budget shall be established to determine if the analyser and its associated sampling system
fulfil the requirements for a maximum allowable overall uncertainty.
The overall uncertainty for this method used as a reference shall be lower than 6,0 % of the measured value
expressed on dry basis.
The principle of calculation of the overall uncertainty is based on the law of propagation of uncertainty laid
down in ENV 13005:
 determine the standard uncertainties attached to the performance characteristics to be included in the
calculation of the uncertainty budget by means of laboratory and field tests, and according to ENV 13005;
 calculate the uncertainty budget by combining all the standard uncertainties according to ENV 13005,
including the uncertainty of the calibration gas and taking variations range of influence quantities and
interferents of the specific site conditions into account. If these conditions are unknown, default values
defined in Table 2 shall be applied;
 values of standard uncertainty that are less than 5 % of the maximum standard uncertainty can be
neglected;
 calculate the overall uncertainty at the measured value, reported as a dry gas value.
Table 2 — Default variations ranges of influence quantities and values of interferents to be applied for
the uncertainty budget
Influence quantity Variations range on site
Atmospheric pressure
± 2 kPa
in accordance with the manufacturer's
Sample volume flow or pressure variation
recommendations
Ambient temperature ± 15 °C
Electric voltage at span level
230 V ± 20 V
NO
300 mg NO/m
NO
30 mg NO /m
CO
15 % volume
An example of an uncertainty budget is given in Annex B.
8 Field operation
8.1 Sampling location
The sampling location chosen for the measurement devices and samplings shall be of sufficient size and
construction, that a representative emission measurement can be made that is suitable for the measurement
task and technically perfect is possible. In addition, the sampling location shall be chosen with regard to safety
of the personnel, accessibility and availability of electrical power.
8.2 Sampling point(s)
The gas concentrations measured shall be representative of the average condition of the waste gas. In most
cases, a single sampling point situated in the middle of the duct shall be selected. For larger ducts, this point
may be situated close to the sampling port provided that there is no disturbance of the flow or concentration
due to the influence of the sampling port.
However, when non-homogeneity of the flue gas is suspected, it shall be demonstrated if the flue gas is
homogeneous or not. The homogeneity can be demonstrated with a continuous measurement of O or CO
2 2
using a fixed and a moving probe. Sampling in non-homogeneous flue gases is required to follow relevant
standards or Technical Specifications proposed by CEN/TC 264.
8.3 Choice of the measuring system
The following flue gas characteristics shall be determined, before the field campaign, so that an appropriate
analyser and sampling line configuration (including conditioning unit) can be adopted:
 flue gas moisture content;
 temperature of exhaust gases;
 dust loading;
 expected concentration of potentially interfering substances, including at least the components listed in
Table 2.
The sampling line should be as short as possible to avoid long response times. If necessary a bypass pump
together with a heated filter appropriate to the dust loading shall be used.
The laboratory shall verify that the analyser is functioning in accordance with the required performance criteria
fixed in this European Standard, and that the sampling line and conditioning unit are in good operational
conditions before conducting field measurements.
8.4 Setting of the SRM on site
8.4.1 General
The complete measuring system, including the conditioning unit, the sampling line and the analyser, shall be
connected according to the manufacturer’s instructions and the nozzle of the probe placed at the
representative point(s) in the duct (see 8.2).
The conditioning unit, sampling probe, filter, connection tube and analyser shall be stabilised at the required
temperature. At the same time, a constant pressure shall be achieved in the measuring chamber of the
analyser.
After pre-heating, the flow passing through the sampling system and the analyser shall be adjusted to the
chosen flow rate to be used during measurement. This flow shall be maintained at a constant level (+/- 10 %).
When both the instrument and sampling system have been set-up, the proper functioning of the instrument
and sampling system shall be checked. The results of these checks shall fulfil the requirements and limitations
as set out by the manufacturer of the instrument as well as the requirements (such as materials used and so
on) given in this European Standard. Compliance with the requirements of this European Standard shall be
documented.
Any data recording, data processing and telemetry system used in conjunction with the measuring system
shall be checked for proper functioning. If any components are changed, then these checks shall be repeated.
All checks shall be documented. The time resolution of the data used to calculate the mean values shall be
below or equal to 1 min.
8.4.2 Preliminary zero and span check, and adjustments
8.4.2.1 Test gases
8.4.2.1.1 Zero gas
The zero gas shall be free of oxygen (< 0,05 % vol).
8.4.2.1.2 Span gases
The span gas used to adjust the analyser shall have a certified concentration of O . The expanded uncertainty
on the analytical certificate of the span gas shall be less than ± 2 %. Ambient air, the concentration of which is
20,9 % vol O , can also be used for adjustment of the analyser (uncertainty: ± 0,5 % rel). This air shall be
clean and dried by passing through an appropriate agent (e.g. silicagel).
8.4.2.2 Adjustment of the analyser
At the beginning of the measuring period, zero and span gases or air are supplied to the analyser directly,
without passing through the sampling system. Adjustments are made until the correct zero and span gas
values are reached by the data sampling system and are stable:
 adjust the zero value;
 adjust the span;
 finally, check again zero to see if there is no significant changes (zero deviation lower than 2 times the
repeatability at zero). If there is any problem, repeat the procedure.
8.4.2.3 Check of the sampling system
Before starting the measurement, one of these two following procedures shall be applied to check that there is
no significant leakage in the sampling line:
 zero and span gas are supplied to the analyser through the sampling system, as close as possible to the
nozzle (in front of the filter if possible). Differences on the readings shall be lower than 2 % rel;
 check the sampling line for leakage according to the following procedure or any other relevant procedure.
Assemble the complete sampling system. Close the nozzle and switch on the pump. After reaching minimum
pressure, read or measure the flow rate with an appropriate measuring device. The leak flow rate shall not
exceed 2 % of the expected sample gas flow rate used during measurement.
8.4.3 Zero and span checks after measurement
At the end of the measuring period and at least once a day, zero and span checks shall be performed at the
inlet of the sampling system by supplying test gases. The information shall be documented. In case of
deviation between checks after measurement and preliminary adjustments, values of deviation shall be
indicated in the report.
If the span or zero drifts are bigger than 2 % of the span value, it is necessary to correct both for zero and
span drifts (see in Annex C a procedure of correction of data for drift effect).
The drift of zero and span shall be lower than 5 % of the span value; otherwise, the results shall be rejected.
9 Ongoing quality control
9.1 General
Quality control is critically important in order to ensure that the uncertainty of the measured values is kept
within the stated limits during extended continuous monitoring periods in the field. This means that
maintenance, as well as zero and span adjustment procedures, shall be followed, as they are essential for
obtaining accurate and traceable quality data.
9.2 Frequency of checks
Table 4 shows the minimum required frequency of checks. The laboratory shall implement the relevant
European Standards for determination of performanc
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