CEN/TS 17337:2019

Stationary source emissions - Determination of mass concentration of multiple gaseous species - Fourier transform infrared spectroscopy

This document describes a method for sampling and determining the concentration of gaseous emissions to atmosphere of multiple species from ducts and stacks by extractive Fourier transform infrared (FTIR) spectroscopy.
This method is applicable to periodic monitoring and to the calibration or control of automated measuring systems (AMS) permanently installed on a stack, for regulatory or other purposes.

Emissionen aus stationären Quellen - Ermittlung der Massenkonzentration von mehreren gasförmigen Stoffen - Fourier-Transform-Infrarot-Spektroskopie

Dieses Dokument beschreibt ein Verfahren zur Probenahme und Bestimmung der Konzentration von gasförmigen Emissionen mehrerer Stoffe in die Atmosphäre aus Leitungen und Abgaskanälen mithilfe der extraktiven Fourier-Transform-Infrarot (FTIR)-Spektroskopie.
Dieses Verfahren ist für die wiederkehrende Überwachung und für die Kalibrierung oder Kontrolle von dauerhaft an einem Abgaskanal installierten automatischen Messeinrichtungen (AMS) aufgrund gesetzlicher Vorschriften oder für andere Zwecke anwendbar.

Émissions de sources fixes - Détermination de la concentration en masse de multiples substances gazeuses - Spectroscopie infrarouge à transformée de Fourier

Emisije nepremičnih virov - Določevanje masne koncentracije posameznih plinov v zmesi - Infrardeča spektroskopija s Fourierjevo transformacijo (FTIR)

Ta tehnična specifikacija opisuje metodo za vzorčenje in določevanje koncentracije plinastih emisij v ozračju pri več zvrsteh iz vodov in odvodnikov z infrardečo spektroskopijo s Fourierjevo transformacijo (FTIR). Ta metoda se uporablja za redno spremljanje in umerjanje ali nadzor avtomatskih merilnih sistemov (AMS), ki so trajno nameščeni na odvodnik, in sicer za zakonske ter druge namene.

General Information

• Status: Published
• Publication Date: 04-Jun-2019
• ICS: 13.040.40 - Stationary source emissions
• Technical Committee: CEN/TC 264 - Air quality
• Drafting Committee: CEN/TC 264/WG 36 - Measurement of stack gas emissions using FTIR instruments
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 05-Dec-2022
• Completion Date: 23-Sep-2025
• Ref Project: SIST-TS CEN/TS 17337:2019 - Stationary source emissions - Determination of mass concentration of multiple gaseous species - Fourier transform infrared spectroscopy

Overview

CEN/TS 17337:2019 establishes a standardized extractive Fourier transform infrared (FTIR) spectroscopy method for determining the mass concentration of multiple gaseous species in emissions from stationary sources (ducts and stacks). The Technical Specification is intended for periodic monitoring, and for the calibration or control of automated measuring systems (AMS) permanently installed on stacks, supporting regulatory compliance and other emission-management needs.

Key topics and requirements

• Measuring principle: Extractive FTIR spectroscopy for simultaneous multi‑component gas analysis.
• Sampling system: Requirements for probe, filter, sample gas line, pump and optional oxygen sensor to ensure representative sampling from ducts and stacks.
• Performance characterization: Procedures to determine method performance for components covered and not covered by standard reference materials (SRM).
• Field operation: Guidance on measurement site selection, measurement points, instrument setup, selection of test gases, start/end checks, drift determination and measurement execution.
• Quality control (QC): Frequency of checks, annual calibration or calibration validation, response time testing, data storage and ongoing QA practices.
• Detection limit & interference tests: Procedures for detection limit determination, computational interference testing, and annual lack-of-fit assessments (Annex B).
• Uncertainty: Detailed uncertainty budget methodology, including model functions, combined and expanded uncertainties and example budgets (Annex C).
• Reporting: Expression of results and required measurement report content to support regulatory submissions and traceability.

Applications

CEN/TS 17337:2019 is practical for:

• Environmental laboratories performing stack and duct emissions testing with FTIR analysers.
• Operators and consultants conducting periodic emissions monitoring for compliance with permits and air-quality regulations.
• Manufacturers and integrators of AMS (automated measuring systems) using FTIR for in‑situ control and calibration.
• Regulatory agencies evaluating multi‑component gas measurements and approving alternative methods.

Practical benefits include simultaneous quantification of multiple gases, flexible application across industries (power plants, waste incineration, chemical plants), and a framework for robust uncertainty and QC management.

Related standards

This Technical Specification references and aligns with several standards, notably:

• EN 14793:2017 (equivalence of alternative methods)
• EN 15259:2007 (measurement site and objective requirements)
• EN 15267-4:2017 (AMS performance criteria for periodic measurements)
• EN ISO 14956 (evaluation vs required measurement uncertainty)
• ISO/IEC Guide 98-3:2008 (GUM) (uncertainty of measurement)

Keywords: FTIR, extractive FTIR spectroscopy, stationary source emissions, stack emissions monitoring, mass concentration, gaseous species, AMS calibration, emissions uncertainty, regulatory compliance.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2019
Emisije nepremičnih virov - Določevanje masne koncentracije posameznih plinov
v zmesi - Infrardeča spektroskopija s Fourierjevo transformacijo (FTIR)
Stationary source emissions - Determination of mass concentration of multiple gaseous
species - Fourier transform infrared spectroscopy
Emissionen aus stationären Quellen - Messung von Emissionen im Abgas mit FTIR-
Geräten
Émissions de sources fixes - Détermination de la concentration en masse de multiples
substances gazeuses - Spectroscopie infrarouge à transformée de Fourier
Ta slovenski standard je istoveten z: CEN/TS 17337:2019
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17337
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
June 2019
TECHNISCHE SPEZIFIKATION
ICS 13.040.40
English Version
Stationary source emissions - Determination of mass
concentration of multiple gaseous species - Fourier
transform infrared spectroscopy
Émissions de sources fixes - Détermination de la Emissionen aus stationären Quellen - Messung von
concentration en masse de multiples substances Emissionen im Abgas mit FTIR-Geräten
gazeuses - Spectroscopie infrarouge à transformée de
Fourier
This Technical Specification (CEN/TS) was approved by CEN on 1 April 2019 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17337:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 14
4.1 Symbols . 14
4.2 Abbreviated terms . 15
5 Principle . 15
5.1 General . 15
5.2 Measuring Principle . 15
6 Sampling system . 16
6.1 General . 16
6.2 Apparatus requirements . 16
6.2.1 General . 16
6.2.2 Sampling probe . 16
6.2.3 Filter . 16
6.2.4 Sample gas line . 17
6.2.5 Pump . 17
6.2.6 Oxygen sensor (optional) . 17
7 Determination of the performance characteristics of the method . 17
7.1 Measured components covered by SRM . 17
7.2 Measured components not covered by SRM . 18
7.3 Establishment of an uncertainty budget . 18
8 Field operation . 18
8.1 Measurement site . 18
8.2 Measurement points . 18
8.3 Choice of the measuring system . 18
8.4 Setting up of the analyser on site . 19
8.4.1 General . 19
8.4.2 Selection of test gases . 19
8.4.3 Tests at the start of measurement period . 21
8.4.4 Emission measurements . 23
8.4.5 Tests at the end of the measurement period . 25
8.4.6 Determining drift across measurement period . 25
9 Ongoing quality control . 25
9.1 Introduction . 25
9.2 Frequency of checks . 26
9.3 Annual calibration or calibration validation . 27
9.3.1 General . 27
9.3.2 Annual calibration . 27
9.3.3 Calibration validation . 27
9.4 Annual response time test . 28
9.5 Measurement campaign data storage . 28
10 Expression of results . 28
11 Measurement report . 29
Annex A (informative) Sampling with a side stream . 30
Annex B (normative) Detection limit, computational interference and annual tests . 31
B.1 General . 31
B.2 Response time . 31
B.3 Detection limit . 31
B.3.1 General . 31
B.3.2 Approach A . 32
B.3.3 Approach B . 32
B.4 Computational interferent test for components not covered by SRM . 32
B.5 Annual lack of fit test . 33
B.5.1 Description of test procedure . 33
B.5.2 Establishment of the regression line . 33
B.5.3 Calculation of the residuals . 34
B.5.4 Test requirements . 35
Annex C (informative) Uncertainty determination . 36
C.1 General . 36
C.2 Elements required for the uncertainty determinations . 36
C.2.1 Model function . 36
C.2.2 Determination of uncertainty . 36
C.2.3 Combined standard uncertainty . 37
C.2.4 Expanded uncertainty . 38
C.2.5 Uncertainty budget template . 39
C.3 Example uncertainty budget . 39
C.3.1 General . 39
C.3.2 Identification of uncertainty sources . 39
C.3.2.1 General . 39
C.3.2.2 Concentration indicated by the analyser . 40
C.3.2.3 Uncertainty sources with rectangular probability distributions . 40
C.3.2.4 Cross-sensitivity . 41
C.3.2.5 Uncertainty sources with normal probability distributions . 41
C.3.3 Site specific conditions . 42
C.3.4 Result of example uncertainty calculation . 42
C.4 Comparison of expanded uncertainty to required measurement uncertainty . 47
Annex D (informative) Selection of test gases for Check Gas approach . 48
D.1 General . 48
D.2 Example 1 . 48
D.3 Example 2 . 49
Annex E (informative) Example of correction of data from drift effect . 54
Annex F (informative) Calculation of the uncertainty associated with a concentration
expressed on dry gas and at an oxygen reference concentration . 56
F.1 Uncertainty associated with a concentration expressed on dry gas . 56
F.2 Uncertainty associated with a concentration expressed at a oxygen reference
concentration . 58
Bibliography . 60

European foreword
This document (CEN/TS 17337:2019) has been prepared by Technical Committee CEN/TC 264 “Air
quality”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
1 Scope
This document describes a method for sampling and determining the concentration of gaseous emissions
to atmosphere of multiple species from ducts and stacks by extractive Fourier transform infrared (FTIR)
spectroscopy.
This method is applicable to periodic monitoring and to the calibration or control of automated
measuring systems (AMS) permanently installed on a stack, for regulatory or other purposes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
EN 14793:2017, Stationary source emissions - Demonstration of equivalence of an alternative method with
a reference method
EN 15259:2007, Air quality - Measurement of stationary source emissions - Requirements for measurement
sections and sites and for the measurement objective, plan and report
EN 15267-4:2017, Air quality - Certification of automated measuring systems - Part 4: Performance criteria
and test procedures for automated measuring systems for periodic measurements of emissions from
stationary sources
EN ISO 14956, Air quality - Evaluation of the suitability of a measurement procedure by comparison with a
required measurement uncertainty (ISO 14956)
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
FTIR spectrometer
interferometer that uses infrared wavelengths of the electromagnetic spectrum for measurements and
normally includes a sample cell and detector
Note 1 to entry: The interferometer records an interferogram which represents the detection systems response
as a function of time. The Fourier-transform function is applied to produce optical intensity as a function of
frequency or wavelength.
3.2
sample cell
part of the FTIR instrument where the infrared beam is transmitted through the sample
3.3
standard reference method
SRM
reference method prescribed by European or national legislation
[SOURCE: EN 15259:2007]
3.4
reference method
RM
measurement method taken as a reference by convention, which gives the accepted reference value of
the measurand
Note 1 to entry: A reference method is fully described
Note 2 to entry: A reference method can be a manual or an automated method
Note 3 to entry: Alternative methods can be used if equivalence to the reference method has been demonstrated
[SOURCE: EN 15259:2007]
3.5
alternative method
AM
measurement method which complies with the criteria given by EN 14793 with respect to the reference
method
Note 1 to entry: An alternative method can consist of a simplification of the reference method.
[SOURCE: EN 14793:2017]
3.6
measuring system
set of one or more measuring instruments and often other devices, including any reagent and supply,
assembled and adapted to give information used to generate measured quantity values within specified
intervals for quantities of specified kinds
[SOURCE: JCGM 200:2012]
3.7
automated measuring system
AMS
entirety of all measuring instruments and additional devices for obtaining a result of measurement
Note 1 to entry: Apart from the actual measuring device (the analyser), an AMS includes facilities for taking
samples (e.g. probe, sample gas lines, flow meters and regulator, delivery pump) and for sample conditioning (e.g.
dust filter, pre-separator for interferents, cooler, converter). This definition also includes testing and adjusting
devices that are required for functional checks and, if applicable, for commissioning.
Note 2 to entry: The term “automated measuring system” (AMS) is typically used in Europe. The term
“continuous emission monitoring system” (CEMS) is also typically used in the UK and USA.
[SOURCE: EN 15267-4:2017]
3.8
portable automated measuring system
P-AMS
automated measuring system which is in a condition or application to be moved from one to another
measurement site to obtain measurement results for a short measurement period
Note 1 to entry: The measurement period is typically 8 h for a day.
Note 2 to entry: The P-AMS can be configured at the measurement site for the special application but can be also
set-up in a van or mobile container. The probe and the sample gas lines are installed often just before the
measurement task is started.
[SOURCE: EN 15267-4:2017]
3.9
calibration
set of operations that establish, under specified conditions, the relationship between values of quantities
indicated by a measuring method or measuring system, and the corresponding values given by the
applicable reference
Note 1 to entry: In case of automated measuring system (AMS) permanently installed on a stack the applicable
reference is the standard reference method (SRM) used to establish the calibration function of the AMS.
Note 2 to entry: Calibration should not be confused with adjustment of a measuring system.
[SOURCE: EN 15058:2017]
3.10
adjustment
set of operations carried out on a measuring system so that it provides prescribed indications
corresponding to given values of a quantity to be measured
Note 1 to entry: The adjustment can be made directly on the instrument or using a suitable calculation procedure.
[SOURCE: EN 15058:2017]
3.11
span gas
test gas used to adjust and check a specific point on the response line of the measuring system
[SOURCE: EN 15058:2017]
3.12
measurand
particular quantity subject to measurement
Note 1 to entry: The measurand is a quantifiable property of the waste gas under test, for example mass
concentration of a measured component, temperature, velocity, mass flow, oxygen content and water vapour
content.
[SOURCE: EN 15259:2007]
3.13
interference
negative or positive effect upon the response of the measuring system, due to a component of the sample
that is not the measurand
[SOURCE: EN 15058:2017]
3.14
influence quantity
quantity that is not the measurand but that affects the result of the measurement
Note 1 to entry: Influence quantities are e.g. presence of interfering gases, ambient temperature, pressure of the
gas sample.
[SOURCE: EN 15058:2017]
3.15
ambient temperature
temperature of the air around the measuring system
[SOURCE: EN 15058:2017]
3.16
emission limit value
ELV
limit value given in regulations such as EU Directives, ordinances, administrative regulations, permits,
licences, authorisations or consents
Note 1 to entry: ELV can be stated as concentration limits expressed as half-hourly, hourly and daily averaged
values, or mass flow limits expressed as hourly, daily, weekly, monthly or annually aggregated values.
[SOURCE: EN 15058:2017]
3.17
measuring campaign
given by the measurement task described in the measurement plan in accordance with EN 15259
3.18
measuring period
period encompassed by the drift test
3.19
measurement site
place on the waste gas duct in the area of the measurement plane(s) consisting of structures and technical
equipment, for example working platforms, measurement ports, energy supply
Note 1 to entry: Measurement site is also known as sampling site.
[SOURCE: EN 15259:2007]
3.20
measurement plane
plane normal to the centreline of the duct at the sampling position
Note 1 to entry: Measurement plane is also known as sampling plane.
[SOURCE: EN 15259:2007]
3.21
measurement port
opening in the waste gas duct along the measurement line, through which access to the waste gas is
gained
Note 1 to entry: Measurement port is also known as sampling port or access port.
[SOURCE: EN 15259:2007]
3.22
measurement line
line in the measurement plane along which the measurement points are located, bounded by the inner
duct wall
Note 1 to entry: Measurement line is also known as sampling line.
[SOURCE: EN 15259:2007]
3.23
measurement point
position in the measurement plane at which the sample stream is extracted or the measurement data are
obtained directly
Note 1 to entry: Measurement point is also known as sampling point.
[SOURCE: EN 15259:2007]
3.24
absorbance spectrum
negative logarithm of the transmission spectrum
3.25
transmittance spectrum
ratio of a single channel spectrum where the component(s) is present to a single channel spectrum where
it is not (the background), both spectra being acquired under the same conditions
3.26
background spectrum
single channel spectrum recorded in the absence of component (usually zero gas) used for deriving the
transmission spectrum
3.27
single channel spectrum
response of the FTIR instrument as a function of wavenumber to a sample of either the component(s) or
background
3.28
spectral feature
referring to one or more absorbance peaks in a spectrum
3.29
resolution
minimum separation that two spectral features can have and still be distinguished from one another
Note 1 to entry: Defined as the reciprocal of the optical path difference of the interferometer.
3.30
analytical window
upper and lower wavenumber range (or set of ranges) between which the measurand is interpreted the
instruments analytical model
3.31
analytical model
algorithm used to interpret a spectrum and output quantitative (or qualitative) information
Note 1 to entry: The analytical model will usually fit (in a least squares sense) reference spectra to a spectrum of
the sample in order to identify which compounds are present and derive concentration data.
3.32
performance characteristic
quantity assigned to the P-AMS in order to define its performance
Note 1 to entry: The values of relevant performance characteristics are determined in the performance testing and
compared to the applicable performance criteria.
[SOURCE: EN 15267-4:2017]
3.33
response time
duration between the instant when an input quantity value of a measuring instrument or measuring
system is subjected to an abrupt change between two specified constant quantity values and the instant
when a corresponding indication settles within specified limits around its final steady value
Note 1 to entry: By convention time taken for the output signal to pass from 0 % to 90 % of the final variation of
indication.
[SOURCE: EN 15058:2017]
3.34
drift
difference between two readings of a reference material at the beginning and at the end of a measuring
period
3.35
lack of fit
systematic deviation, within the measurement range, between the accepted value of a reference material
applied to the measuring system and the corresponding result of measurement produced by the
calibrated measuring system
Note 1 to entry: In common language lack of fit is often called “linearity” or “deviation from linearity”. Lack of fit
test is often called “linearity test”.
[SOURCE: EN 15267-4:2017]
3.36
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 to entry: Repeatability conditions include:
— same measurement method;
— same laboratory;
— same measuring system, used under the same conditions;
— same location;
— repetition over a short period of time.
Note 2 to entry: Repeatability can be expressed quantitatively in terms of the dispersion characteristics of the
results.
Note 3 to entry: In this document the repeatability is expressed as a value with a level of confidence of 95 %.
[SOURCE: EN 15058:2017]
3.37
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 to entry: These conditions include:
— same measurement method;
— 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 to entry: Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the
results.
Note 3 to entry: In this document, the repeatability under field conditions is expressed as a value with a level of
confidence of 95 %.
[SOURCE: EN 15058:2017]
3.38
reproducibility in the field
closeness of the agreement between the results of simultaneous measurements of the same measurand
carried out using several sets of equipment under the same conditions of measurement
Note 1 to entry: These conditions are called field reproducibility conditions and include:
— same measurement method;
— several sets of equipment, the performances of which are fulfilling the requirements of the measurement
method, used under the same conditions;
— same location;
— implemented by several laboratories.
Note 2 to entry: Reproducibility can be expressed quantitatively in terms of the dispersion characteristics of the
results.
Note 3 to entry: In this document, the reproducibility under field conditions is expressed as a value with a level
of confidence of 95 %.
[SOURCE: EN 15058:2017]
3.39
uncertainty
parameter associated with the result of a measurement, that characterises the dispersion of the values
that could reasonably be attributed to the measurand
[SOURCE: ISO/IEC Guide 98-3:2008]
3.40
standard uncertainty
u
uncertainty of the result of a measurement expressed as a standard deviation
[SOURCE: ISO/IEC Guide 98-3:2008]
3.41
combined uncertainty
u
c
standard uncertainty attached to the measurement result calculated by combination of several standard
uncertainties according to the principles laid down in ISO/IEC Guide 98-3 (GUM)
[SOURCE: EN 15058:2017]
3.42
expanded uncertainty
U
quantity defining an interval about the result of a measurement that may be expected to encompass a
large fraction of the distribution of values that could reasonably be attributed to the measurand
U ku×
c
Note 1 to entry: In this document, the expanded uncertainty is calculated with a coverage factor of k = 2, and with
a level of confidence of 95 %.
Note 2 to entry: The expression overall uncertainty is sometimes used to express the expanded uncertainty.
[SOURCE: EN 15058:2017]
=
3.43
uncertainty budget
calculation table combining all the sources of uncertainty according to EN ISO 14956 or
ISO/IEC Guide 98-3 in order to calculate the combined uncertainty of the method at a specified value
[SOURCE: EN 15058:2017]
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the following symbols apply.
c concentration of the test gas at the end of the measurement period
e
c concentration of the test gas at the start of the measurement period
s
C concentration expressed at oxygen reference conditions
corr
C measured concentration at the actual volume fraction of oxygen
m
C measured concentration on dry basis
dry
Cwet measured concentration on a wet basis
d drift
th
f ratio of the reported concentration of the j component to the certified value of the
j
associated reference spectrum
m number of components
th
max|r | maximum modulus value across the analytical band used to quantify the j measured
i
component in the residual spectrum
th
max|s | maximum modulus value across the analytical band used to quantify the j measured
k
component in the sample spectrum
h measured water vapour content as volume fraction, in percent
m
om,dry actual volume fraction of oxygen in the dry flue gas
o oxygen reference concentration expressed as a volume fraction on dry basis
ref,dry
th
r residual created at the i wavenumber by subtracting all scaled reference spectra from
i
the sample spectrum
th th
R absorbance value at the i wavelength in the reference spectrum of the j component
ij
th
s sample spectrum absorbance at the i wavenumber
i
u standard uncertainty
u combined uncertainty
c
U expanded uncertainty
th
δ indication of the percentage of information in the analytical band used for the j
j
measured component not explained by the fitted reference spectrum
4.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
AM alternative method
AMS automated measuring system
CW central wavenumber
ELV emission limit value
FTIR Fourier transform infrared
IR infrared
LOD limit of detection
P-AMS portable automated measuring system
SRM standard reference method
5 Principle
5.1 General
This document describes a method for sampling, and determining the concentration of gaseous emissions
to atmosphere from ducts and stacks by extractive FTIR spectroscopy. The specific components and
requirements for the measuring system are described. A number of performance characteristics with
associated minimum performance criteria are specified for the measuring system. These performance
characteristics and the expanded uncertainty of the method shall meet the specifications given in this
document.
There are no restrictions on the type of analytical model used for interpreting recorded spectra, however,
the performance requirements shall be demonstrated across the applicable component range.
NOTE For measurements at waste incineration plants the certification range is defined as 1,5 times the daily
average emissions limit value (ELV), for all other applications it is defined as 2,5 times the daily average emissions
limit value (ELV) (see EN 15267-4 and JRC ROM).
5.2 Measuring Principle
Polychromatic light covering the IR region is passed through the sample cell. Each component present
absorbs the radiation at a series of characteristic wavelengths enabling identification, whilst the extent
of attenuation (absorbance) of light provides concentration information as described by the Lambert-
Beer law. FTIR is capable of measuring a broad range of components with the exception of symmetrical
molecules that do not exhibit a dipole change upon vibration (e.g. oxygen and chlorine).
A number of cross-interferences are possible within the recorded spectrum, but are dependent on the
nature of the analytical model. For example, some models account for interference by simultaneous fitting
of absorbance features, whilst others can exclude parts of the spectrum to avoid the interference
altogether. The most common interferent is water vapour (followed by carbon dioxide) as this molecule
exhibits absorption features across large parts of the IR region.
6 Sampling system
6.1 General
The sampling system consists of:
— sampling probe;
— filter;
— sample gas line;
— pump (can be part of the FTIR analyser).
Whilst it is assumed that the system is operated at elevated temperatures and can handle wet samples,
the use of conditioning units is not precluded. However, if a conditioning unit is used the overall system
(i.e. including the conditioning unit) shall meet the performance characteristic requirements of this
document.
If a hot/wet system is used, the probe filter box and sample gas line is generally be heated to a similar
temperature as the sample cell. Furthermore, the selected temperature shall be at least 180 °C. If this
creates a conflict with the temperature used in demonstrating conformity of the P-AMS with EN 15267-4,
then the temperature used in the testing according to EN 15267-4 should be used instead.
All parts of the sampling system positioned upstream of the FTIR analyser shall be made of materials that
do not react with or absorb any of the components.
The temperature and pressure in the FTIR sample cell are important parameters as they directly affect
the determined concentrations. These parameters also help confirm that condensation of the sample in
the gas cell is prevented. In contrast, the flow rate through the gas cell does not affect the determined
concentration if all other parameters remain unchanged.
Sampling using a side stream configuration can be necessary if the required extraction flow rate exceeds
the upper limits specified for the FTIR analyser. An example configuration for such sampling is provided
in Annex A.
6.2 Apparatus requirements
6.2.1 General
Information on materials suitable for sampling can be found in ISO 10396.
6.2.2 Sampling probe
The sampling probe shall be able to convey a representative sample of the stack gas to the FTIR analyser.
The probe shall be able to resist absorbance of components and be of sufficient length.
6.2.3 Filter
A filter of inert material shall be positioned after or as part of the sample probe and be of an appropriate
pore size to prevent particulate matter entering the remainder of the system. The filter shall be changed
or cleaned periodically depending on the dust loading at the site. If the filter is located outside of the stack,
it shall be heated to at least 180 °C.
NOTE 1 A pore size of 3 μm is sufficient for many sites.
NOTE 2 An increase in the pressure drop across the filter is likely to indicate a significant number of blocked
pores and the need for replacement or cleaning.
6.2.4 Sample gas line
To facilitate system response time the sample gas line shall be as short as is practical. The line shall be
made of inert material that is able to resist absorbance of the components. The line shall be heated to at
least 180 °C.
6.2.5 Pump
The sample pump shall be capable of operating to any specified flow requirements and pressure
conditions required for the sample cell. The pump shall be resistant to corrosion. An external pump shall
be consistent with the analyser to which it is connected.
6.2.6 Oxygen sensor (optional)
Some systems include an oxygen sensor to allow measurement and automatic correction to oxygen
reference conditions. Any such sensor shall conform with and be operated in accordance with EN 14789.
7 Determination of the performance characteristics of the method
7.1 Measured components covered by SRM
Table 1 of EN 15267-4 provides performance characteristics applicable to P-AMS. When the method
described in this document is used as an alternative method (AM) to a standard reference method (SRM),
these performance characteristics shall be determined in a general performance test according to the test
procedures described in EN 15267-4, which includes demonstration of equivalence to the SRM in
accordance with EN 14793, by an independent test laboratory accredited or recognized by the competent
authorities for the implementation of test procedures of EN 15267-4.
The independent test laboratory shall check the conformity of the P-AMS with the performance criterion
attached to each performance characteristic. The maximum allowable deviations as absolute values of
the measured values are given as mass concentrations or as percentages of the upper limit of the range.
The applicable range is defined as 1,5 times the ELV for waste incineration processes and 2,5 times the
ELV for all other processes.
NOTE At the time of publication the Industrial Emissions Directive (IED) defines the applicable range of 1,5
times the ELV for waste incineration processes and 2,5 times the ELV for all other processes.
As stated above, this document requires that when used as an AM for measurements in place of the
applicable SRM that the P-AMS shall meet the performance criteria of EN 15267-4. EN 15267-4 requires
performance testing on at least 5 different process types and cross-interference testing to at least the
components listed in Annex B of EN 15267-4 and any other components known to be present on any of
the 5 processes. The user should be aware that if the P-AMS is used outside of its certification, i.e. at a
different process to the five included in the performance test with a different emission matrix, then there
is a risk of biased measurement data due to un-characterized cross-interference effects. Whilst the
Spectral Residual Test in many circumstances can identify an issue, nonetheless, the user should be aware
that failure to use an appropriately certified P-AMS represents this risk, as would be the case for many P-
AMS's based on optical technologies, not only FTIR.
For reference some example SRM are listed below:
— EN 1911: hydrogen chloride;
— EN 14790: water vapour;
— EN 14791: sulphur dioxide;
— EN 14792: nitric oxide and nitrogen dioxide;
— EN 15058: carbon monoxide;
— EN ISO 21258: dinitrogen monoxide;
— EN ISO 25139: methane.
7.2 Measured components not covered by SRM
For components not covered by a SRM, and where the national competent authority allows, a less onerous
set of performance characteristic tests may be performed. These tests shall be carried out by a laboratory
accredited or recognized by the local competent authority for the implementations of such performance
tests. The minimum performance characteristics that shall be determined are:
— zero (≤2,0 % of range);
— response time (<400 s for NH , HCl and HF, < 200
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