SIST EN 15058:2017

Stationary source emissions - Determination of the mass concentration of carbon monoxide - Standard reference method: non-dispersive infrared spectrometry

This European Standard specifies the standard reference method (SRM) based on the infra-red (IR) absorption principle. It includes the sampling and the gas conditioning system, and allows the determination of the carbon monoxide CO in flue gases emitted to the atmosphere from ducts and stacks.
This European Standard specifies the characteristics to be determined and the performance criteria to be fulfilled by measuring systems using the IR measurement method. It applies for periodic monitoring and for the calibration or control of automatic measuring systems (AMS) permanently installed on a stack, for regulatory or other purposes.
This European Standard specifies criteria for demonstration of equivalence of an alternative method (AM) to the SRM by application of prEN 14793.
This European Standard has been validated during field tests on waste incineration, co-incineration and large combustion plants and on a recognized test bench. It has been validated for CO concentrations with sampling periods of 30 min in the range of 0 mg/m3 to 400 mg/m3 for large combustion plants and 0 mg/m3 to 740 mg/m3 for waste and co-incineration. Directive 2010/75/EC lays down emission values which are expressed in mg/m3, on dry basis at a specified value of oxygen and at standard conditions of 273 K and 101,3 kPa.
NOTE    The characteristics of installations, the conditions during field tests and the values of repeatability and reproducibility in the field are given in Annex A.

Emissionen aus stationären Quellen - Bestimmung der Massenkonzentration von Kohlenmonoxid - Standardreferenzverfahren: Nicht-dispersive Infrarotspektrometrie

Diese Europäische Norm legt das Standardreferenzverfahren (SRM) auf Basis des Infrarot-Absorptionsverfahrens zur Bestimmung von Kohlenmonoxid fest. Es beinhaltet die Einrichtungen zur Probenahme und zur Probengasaufbereitung und erlaubt die Bestimmung von Kohlenmonoxid in Abgasen, die aus Abgaskanälen in die Atmosphäre emittiert werden.
Diese Europäische Norm legt zu bestimmende Verfahrenskenngrößen und Mindestanforderungen fest, die von Messeinrichtungen auf Basis des Infrarot-Messverfahrens eingehalten werden müssen. Sie gilt für wiederkehrende Messungen und für die Kalibrierung oder Überprüfung von automatischen Messeinrichtungen (AMS), die aus gesetzgeberischen oder anderen Gründen stationär an einem Abgaskanal installiert sind.
Diese Europäische Norm legt Anforderungen zum Nachweis der Gleichwertigkeit von Alternativverfahren (AM) mit dem Standardreferenzverfahren (SRM) durch Anwendung der prEN 14793 fest.
Diese Europäische Norm wurde in Feldversuchen an Abfallverbrennungsanlagen, Mitverbrennungsanlagen und Großfeuerungsanlagen sowie an einem anerkannten Prüfstand validiert. Sie wurde mit Probenahmedauern von 30 min für CO-Konzentrationen im Bereich von 0 mg/m3 bis 400 mg/m3 für Großfeuerungsanlagen und im Bereich von 0 mg/m3 bis 740 mg/m3 für Abfallverbrennungsanlagen und Mitverbrennungsanlagen validiert. Die Richtlinie 2010/75/EU legt Emissionsgrenzwerte fest, die in Milligramm je Kubikmeter für trockenes Gas bei einem festgelegten Bezugssauerstoffgehalt und Normbedingungen von 273 K und 101,3 kPa angegeben sind.
ANMERKUNG   Die Einzelheiten der Anlagen, die Bedingungen bei den Feldversuchen und die Werte der Wiederhol- und der Vergleichpräzision im Feld werden in Anhang A aufgeführt.

Emissions de sources fixes - Détermination de la concentration massique de monoxyde de carbone - Méthode de référence normalisée : spectrométrie infra-rouge non dispersive

La présente Norme européenne spécifie la méthode de référence normalisée (SRM, Standard Reference Method) basée sur le principe de l'absorption infrarouge (IR). Elle inclut le prélèvement et le système de conditionnement des gaz et permet de déterminer la teneur en monoxyde de carbone (CO) dans les effluents gazeux émis dans l'atmosphère par des conduits et des cheminées.
La présente Norme européenne spécifie les caractéristiques devant être déterminées et les critères de performance devant être remplis par les systèmes de mesurage utilisant la méthode de mesurage IR. Elle s'applique à la surveillance périodique et à l'étalonnage ou au contrôle des systèmes de mesurage automatisés (AMS, Automatic Measuring Systems) installés à demeure sur une cheminée, à des fins réglementaires ou à d’autres fins.
La présente Norme européenne spécifie les critères permettant de démontrer l'équivalence d'une méthode « alternative » (AM, Alternative Method) à la méthode de référence normalisée par l'application du prEN 14793.
   La présente Norme européenne a été validée au cours d'essais sur site pratiqués sur des installations destinées à l'incinération et à la coincinération des déchets, sur de grandes installations de combustion ainsi que sur un banc d'essai reconnu. Elle a été validée pour des concentrations en CO mesurées pendant des périodes de prélèvement de 30 min et comprises entre 0 mg/m3 et 400 mg/m3 pour les grandes installations de combustion et entre 0 mg/m3 et 740 mg/m3 pour les installations d'incinération et de coincinération des déchets. La Directive 2010/75/CE fixe des valeurs d'émission exprimées en mg/m3, sur sec à une valeur spécifiée d'oxygène et dans des conditions normales de 273 K et 101,3 kPa.
NOTE   Les caractéristiques des installations, les conditions des essais sur site et les valeurs de répétabilité et de reproductibilité sur site sont indiquées à l'Annexe A.

Emisije nepremičnih virov - Določevanje masne koncentracije ogljikovega monoksida - Standardna referenčna metoda: nedisperzna infrardeča spektrometrija

Ta evropski standard določa standardno referenčno metodo (SRM) na podlagi IR absorpcije. Vključuje sistem za vzorčenje in kondicioniranje plinov ter omogoča določanje ogljikovega monoksida CO v dimnih plinih, ki prehajajo v ozračje iz vodov in odvodnikov.
Ta evropski standard določa lastnosti in merila zmogljivosti, ki jih morajo izpolnjevati merilni sistemi, ki uporabljajo IR merilno metodo. Uporablja se za redno spremljanje in kalibracijo ali nadzor avtomatskih merilnih sistemov (AMS), ki so trajno nameščeni na odvodnik, in sicer za zakonske ter druge namene.
Ta evropski standard določa merila za prikaz enakovrednosti alternativne metode (AM) standardni referenčni metodi z uporabo standarda prEN 14793.
Ta evropski standard je bil potrjen med preskusi sežiganja odpadkov, sosežiga in velikih kurilnih naprav na terenu ter na ustrezni preskusni mizi. Potrjen je bil za koncentracije CO s 30-minutnimi obdobji vzorčenja v razponu od 0 mg/m3 do 400 mg/m3 za velike kurilne naprave in od 0 mg/m3 do 740 mg/m3 za odpadke in sosežig. Direktiva 2010/75/ES določa mejne vrednosti emisij, ki so izražene v mg/m3 na suhi osnovi pri podani vrednosti kisika in standardnih pogojih 273 K in 101,3 kPa.
OPOMBA: Lastnosti naprav, pogoji med preskusi na terenu ter vrednosti ponovljivosti in reprodukcije na terenu so podani v dodatku A.

General Information

• Status: Published
• Public Enquiry End Date: 08-Feb-2015
• Publication Date: 01-Feb-2017
• ICS: 13.040.40 - Stationary source emissions
• Technical Committee: KAZ - Air quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-Jan-2017
• Due Date: 26-Mar-2017
• Completion Date: 02-Feb-2017
• Directive: 2016-01-0285 - Uredba o sežigalnicah odpadkov in napravah za sosežig odpadkov
• Ref Project: EN 15058:2017 - Stationary source emissions - Determination of the mass concentration of carbon monoxide - Standard reference method: non-dispersive infrared spectrometry

Relations

• Replaces: SIST EN 15058:2006 - Stationary source emissions - Determination of the mass concentration of carbon monoxide (CO) - Reference method: Non-dispersive infrared spectrometry
• Effective Date: 01-Mar-2017

Overview

EN 15058:2017 (CEN) defines the standard reference method (SRM) for determining the mass concentration of carbon monoxide (CO) in flue gases using non-dispersive infrared (NDIR) spectrometry. The standard covers the full measurement chain - sampling, gas conditioning and analyser - for CO emissions from ducts and stacks. It is intended for periodic monitoring, calibration or control of permanently installed automated measuring systems (AMS) and for portable AMS (P-AMS).

Key validation facts:

• Validated in field tests (waste incineration, co‑incineration, large combustion plants) and on a test bench.
• Validated ranges (30 min sampling): 0–400 mg/m3 for large combustion plants; 0–740 mg/m3 for waste and co‑incineration.
• Results referenced on a dry basis at specified O2 and standard conditions (273 K, 101.3 kPa) to align with Directive 2010/75/EU.

Key topics and requirements

• Measuring principle: NDIR absorption for CO detection.
• Sampling system: probe, particulate filters, sample lines, gas conditioning (drying/temperature control), pumps, flow controllers and secondary filters.
• Analyser performance: pressure/temperature compensation, interferences from other IR-absorbing gases, calibration and span/zero checks.
• Performance criteria: characteristics to be determined (repeatability, reproducibility, uncertainty) and acceptance criteria for P‑AMS and AMS.
• Quality assurance: field operation planning, measurement strategy (measurement plane/points), ongoing quality control and frequency of checks.
• Equivalence of alternative methods: criteria and procedure using EN 14793 to demonstrate an alternative method (AM) is equivalent to the SRM.
• Uncertainty assessment: procedures and informative annexes (examples and calculation methods) to evaluate measurement uncertainty on dry gas and at reference O2.

Applications and users

EN 15058:2017 is used for:

• Regulatory compliance monitoring of stationary source emissions (power plants, waste incinerators, industrial boilers).
• Commissioning, calibration and performance control of permanent AMS and portable AMS.
• Emissions testing performed by environmental laboratories, plant operators, stack testers and consultants.
• Manufacturers of NDIR analysers and sampling systems to meet performance and certification requirements.

Related standards

• EN 14793:2017 - Demonstration of equivalence of an alternative method
• EN 15259:2007 - Measurement sections and measurement plan/report
• EN 15267-4:2017 - Certification/performance criteria for AMS
• EN ISO 14956:2002 and ISO/IEC Guide 98-3:2008 - Uncertainty evaluation

EN 15058:2017 provides a practical, validated SRM for CO emissions monitoring based on NDIR technology, supporting regulatory enforcement and reliable emissions measurement programs.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NRYHJDVSHNWURPHWULMDEmissionen aus stationären Quellen - Bestimmung der Massenkonzentration von Kohlenmonoxid - Standardreferenzverfahren: Nicht-dispersive InfrarotspektrometrieEmissions de sources fixes - Détermination de la concentration massique de monoxyde de carbone - Méthode de référence normalisée : spectrométrie infra-rouge non dispersiveStationary source emissions - Determination of the mass concentration of carbon monoxide - Standard reference method: non-dispersive infrared spectrometry13.040.40Stationary source emissionsICS:Ta slovenski standard je istoveten z:EN 15058:2017SIST EN 15058:2017en,fr,de01-marec-2017SIST EN 15058:2017SLOVENSKI
STANDARDSIST EN 15058:20061DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15058
January
t r s y ICS
s uä r v rä v r Supersedes EN
s w r w zã t r r xEnglish Version
Stationary source emissions æ Determination of the mass concentration of carbon monoxide æ Standard reference methodã nonædispersive infrared spectrometry Émissions de sources fixes æ Détermination de la concentration massique de monoxyde de carbone æ Méthode de référence normalisée ã spectrométrie infrarouge non dispersive
Emissionen aus stationären Quellen æ Bestimmung der Massenkonzentration von Kohlenmonoxid æ Standardreferenzverfahrenã Nichtædispersive Infrarotspektrometrie This European Standard was approved by CEN on
t x September
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
t r s y CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s w r w zã t r s y ESIST EN 15058:2017

European foreword . 5 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Symbols and abbreviations . 13 4.1 Symbols . 13 4.2 Abbreviated terms . 14 5 Principle . 14 5.1 General . 14 5.2 Measuring principle . 14 6 Description of the measuring system . 15 6.1 General . 15 6.2 Sampling and sample gas conditioning system . 16 6.2.1 Sampling probe . 16 6.2.2 Filter . 16 6.2.3 Sample gas line . 16 6.2.4 Sample gas conditioning system . 16 6.2.5 Sample gas pump . 17 6.2.6 Secondary filter . 17 6.2.7 Flow controller and flow meter . 17 6.3 Analyser equipment . 17 6.3.1 General . 17 6.3.2 Pressure and temperature effects . 18 6.3.3 Sampling pump for the analyser . 18 6.3.4 Interferences due to infrared absorbing gases . 18 7 Performance characteristics of the SRM . 18 8 Suitability of the measuring system for the measurement task . 20 9 Field operation . 20 9.1 Measurement planning . 20 9.2 Sampling strategy. 21 9.2.1 General . 21 9.2.2 Measurement section and measurement plane . 21 9.2.3 Minimum number and location of measurement points . 21 9.2.4 Measurement ports and working platform . 21 9.3 Choice of the measuring system . 21 9.4 Setting of the measuring system on site . 22 9.4.1 General . 22 9.4.2 Preliminary zero and span check, and adjustments . 22 9.4.3 Zero and span checks after measurement . 23 SIST EN 15058:2017

Validation of the method in the field . 26 A.1 General . 26 A.2 Characteristics of installations . 26 A.3 Repeatability and reproducibility in the field . 27 A.3.1 General . 27 A.3.2 Repeatability . 28 A.3.3 Reproducibility . 29 Annex B (informative)
Schematics of non-dispersive infrared spectrometer . 31 Annex C (informative)
Calculation of the uncertainty associated with a concentration expressed on dry gas and at an oxygen reference concentration . 33 C.1 Uncertainty associated with a concentration expressed on dry gas . 33 C.2 Uncertainty associated with a concentration expressed at a oxygen reference concentration . 35 Annex D (informative)
Example of assessment of compliance of non-dispersive infrared method for CO with requirements on emission measurements . 37 D.1 General . 37 D.2 Elements required for the uncertainty determinations . 37 D.2.1 Model equation . 37 D.2.2 Combined uncertainty . 38 D.2.3 Expanded uncertainty . 38 D.2.4 Determination of uncertainty contributions in case of rectangular distributions . 39 D.2.5 Determination of uncertainty contributions by use of sensitivity coefficients . 39 D.3 Example of an uncertainty calculation. 40 D.3.1 Site specific conditions . 40 D.3.2 Performance characteristics . 41 D.3.3 Determination of the uncertainty contributions . 42 D.3.4 Result of uncertainty calculation . 45 D.3.4.1 Standard uncertainties . 45 D.3.4.2 Combined uncertainty . 46 D.3.4.3 Expanded uncertainty . 46 D.3.4.4 Evaluation of the compliance with the required measurement quality . 46 Annex E (informative)
Example of correction of data from drift effect . 47 SIST EN 15058:2017

Significant technical changes . 49 Bibliography . 50
This European Standard specifies criteria for demonstration of equivalence of an alternative method (AM) to the SRM by application of EN 14793:2017. This European Standard has been validated during field tests on waste incineration, co-incineration and large combustion plants and on a recognized test bench. It has been validated for CO concentrations with sampling periods of 30 min in the range of 0 mg/m3 to 400 mg/m3 for large combustion plants and 0 mg/m3 to 740 mg/m3 for waste and co-incineration. Directive 2010/75/EU lays down emission values which are expressed in mg/m3, on dry basis at a specified value of oxygen and at standard conditions (273 K and 101,3 kPa). NOTE The characteristics of installations, the conditions during field tests and the values of repeatability and reproducibility in the field are given in Annex A. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. 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 emission – 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 14956:2002, Air quality - Evaluation of the suitability of a measurement procedure by comparison with a required measurement uncertainty (ISO 14956:2002) 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. 3.1 standard reference method
SRM reference method prescribed by European or national legislation
[SOURCE: EN 15259:2007] SIST EN 15058:2017

AM
measurement method which complies with the criteria given by this European Standard with respect to the reference method
Note 1 to entry:
An alternative method can consist of a simplification of the reference method. [SOURCE: EN 14793:2016] 3.5 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] 3.6 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] SIST EN 15058:2017

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] 3.8 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. 3.9 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. 3.10 span gas test gas used to adjust and check a specific point on the response line of the measuring system 3.11 measurand particular quantity subject to measurement
[SOURCE: EN 15259:2007] Note 1 to entry:
The measurand is a quantifiable property of the stack gas under test, for example mass concentration of a measured component, temperature, velocity, mass flow, oxygen content and water vapour content. 3.12 interference negative or positive effect upon the response of the measuring system, due to a component of the sample that is not the measurand SIST EN 15058:2017

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. 3.16 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] 3.17 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] 3.18 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] 3.19 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] SIST EN 15058:2017

Note 1 to entry: Measurement point is also known as sampling point. [SOURCE: EN 15259:2007] 3.21 performance characteristic one of the quantities (described by values, tolerances, range) assigned to equipment in order to define its performance 3.22 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. 3.23 short-term zero drift difference between two zero readings at the beginning and at the end of the measurement period 3.24 short-term span drift difference between two span readings at the beginning and at the end of the measurement period 3.25 lack of fit systematic deviation, within the measurement range, 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 to entry: Lack of fit can be a function of the measurement result. Note 2 to entry: The expression “lack of fit” is often replaced in everyday language by “linearity” or “deviation from linearity”. SIST EN 15058:2017

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 measurement
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 can be expressed quantitatively in terms of the dispersion characteristics of the results. Note 3 to entry: In this European Standard, the repeatability under field conditions is expressed as a value with a level of confidence of 95 %. SIST EN 15058:2017

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 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 European Standard, the reproducibility under field conditions is expressed as a value with a level of confidence of 95 %. 3.29 residence time in the measuring system time period for the sample gas to be transported from the inlet of the probe to the inlet of the measurement cell 3.30 uncertainty parameter associated with the result of a measurement, that characterises the dispersion of the values that could reasonably be attributed to the measurand 3.31 standard uncertainty u uncertainty of the result of a measurement expressed as a standard deviation 3.32 combined uncertainty uc 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) 3.33 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 cUku=× Note 1 to entry: In this European Standard, 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. SIST EN 15058:2017

(result given by the analyser after adjustment at t0 at span point – result given by the analyser after adjustment at t0 at zero point) / (calibration gas concentration at span point – calibration gas concentration at zero point) B(t0)
result given by the analyser after adjustment at t0 at zero point
C measured concentration Ccorr
measured concentration corrected for drift Drift(A)
{[(result given by the analyser during the drift check at tend at span point – result given by the analyser during the drift check at tend at zero point) / (calibration gas concentration at span point – calibration gas concentration at zero point)] – A(t0)} / (tend – t0) Drift(B) (result given by the analyser during the drift check at tend at zero point – result given by the analyser after adjustment at t0 at zero point) / (tend – t0) f volume fraction k coverage factor Mmol
molar mass sR
reproducibility standard deviation sr,limit
maximum allowable repeatability standard deviation t time t0 time of adjustment tend time of check for drift at the end of the measurement period u standard uncertainty uc combined uncertainty U expanded uncertainty Vmol
molar volume SIST EN 15058:2017

For example, the Non Dispersive Infra-Red (NDIR) method is suitable for CO measurements: gas concentration is measured electro-optically by its absorption of a specific wavelength in the infrared (IR). The IR light is directed through the sample chamber towards the detector. In parallel there is another chamber with an enclosed reference gas, typically nitrogen. The detector has an optical filter in front of it that eliminates all light except the wavelength that the selected gas molecules can absorb. Ideally other gas molecules do not absorb light at this wavelength, and do not affect the amount of light reaching the detector to compensate for interfering components. For instance, CO2 and H2O often initiate cross sensitivity in the infrared spectrum. Different technical solutions have been developed to suppress, cross-sensitivity, instability and drift in order to design automatic monitoring systems with acceptable properties (e.g. Gas Filter Correlation technique). Special attention shall be paid to IR radiation absorbing-gases such as water vapour, carbon dioxide, nitrous oxide and hydrocarbons. IR analysers are associated to an extractive sampling system and a gas conditioning system. A sample of gas is taken from the stack with a sampling probe and conveyed to the analyser through the sample gas line and gas conditioning system. The values from the analyser are recorded and/or stored by means of electronic data processing systems. SIST EN 15058:2017

A volume is extracted from the flue gas for a fixed period of time at a controlled flow rate. The sampling system consists of: — a sampling probe; — a filter; — a sample gas line; — a conditioning system. A filter removes the dust in the sampled volume before the sample is conditioned and passed to the analyser.
Different sampling and conditioning configurations are available in order to avoid the water vapour condensation in the measuring system.
Possible configurations are: — Configuration 1: removal of water vapour by condensation using a cooling system; — Configuration 2: removal of water vapour through elimination using a permeation drier; — Configuration 3: dilution with dry, clean, ambient air or nitrogen of the gas to be characterized; — Configuration 4: heating of the complete sampling system from the nozzle to the heated analyser at a temperature above the dew point”. Configurations 1 to 3 require that the user shall check that the dew point temperature or the outlet temperature of the conditioning system is lower or equal to 4 °C at the inlet of the analyser.
For configuration 4 the user may correct the results for the remaining water content in order to report results on a dry basis (see Annex B in EN 14790:2017). 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 CO.
The temperature of all components of the sampling equipment coming into contact with the wet sample gas shall be maintained at a sufficiently high temperature to avoid any condensation. Conditions and layout of the sampling equipment contribute to the combined uncertainty of the measurement. In order to minimize this contribution to the combined measurement uncertainty, performance criteria for the sampling equipment and sampling conditions are given in 6.2 and in Clause 7. Some other sample gas conditioning systems may exist and could be acceptable, provided they fulfil the requirements of this European Standard and have been validated with success during the certification process. For example, some systems put gas in depression using a simple Sonic nozzle in the collection probe in order to create a partial vacuum (between 50 hPa absolute and 100 hPa absolute) so that the head of collection and the sample gas line does not need to be heated and water vapour condensation is avoided. NOTE NOx converter can produce CO. Therefore, it is not appropriate to place a CO analyser downstream the NOx converter.
Due to ammonium-salt deposition on the permeation tube, the permeation system shall be used when the NH3 concentration is outside the range specified by the manufacturer. 6.2.4.2 Dilution system (configuration 3) The dilution technique is an alternative to hot gas monitoring or sample gas drying. The flue gas is diluted with dry, clean, ambient air or nitrogen. The dilution gas shall be dry and free from nitrogen oxides. The dilution ratio shall be chosen according to the objectives of the measurement and shall be compatible with the range of the analytical unit. It shall remain constant through the period of the test.
The contribution of the dilution system to the uncertainty shall be added to the uncertainty budget. NOTE 1 Analysers that are used in combination with dilution probes work with measurement ranges, which are typical for ambient air analysers (0 mg/m3 – 1 mg/m3 – 5 mg/m3 – 10 mg/m3 – 25 mg/m3). NOTE 2 Configuration 3 was not included in the validation of the method in the field. 6.2.4.3 Heated line and heated analyser (configuration 4) To avoid condensation, the sample gas line up to the analyser and the analyser itself shall be heated. The concentrations are given on wet basis and shall be corrected so that they are expressed on dry basis. The correction shall be made from the water vapour concentration in the flue gases and the uncertainty attached to this correction shall be added to the uncertainty budget (see Clause 8). SIST EN 15058:2017

Configuration 4 was not included in the validation of the method in the field. 6.2.5 Sample gas pump
When a pump is not an integral part of the analyser, an external pump is necessary to draw the sampled gas 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. The whole sampling system associated to the analyser, including the pump, has to meet the criterion in Table 1 related to the influence of gas pressure. 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. 6.2.6 Secondary filter The secondary filter is used to separate fine dust, with a pore size of 1
be made of glass-fibre, sintered ceramic, stainless steel or PTFE. NOTE No additional secondary filter is necessary when they are part of the analyser itself. 6.2.7 Flow controller and flow meter This apparatus sets the required sample gas flow. A corrosion resistant material shall be used. The sample gas flow rate into the analyser shall be maintained within the analyser manufacturer’s requirements. A controlled pressure drop across restrictors is usually employed to maintain flow rate control into the IR analyser. NOTE No additional flow controller or flow meter is necessary when they are part of the analyser itself. 6.3 Analyser equipment 6.3.1 General The main parts of the analyser are typically: — source of infrared radiation; — optics to focus the radiation through the measuring cell to the infrared detector; — way of modulating the infrared beam; — means to select a suitable wavelength or wavelengths to measure the gas; — measuring cell that the sample gas enters. There may be a reference cell in some designs; — infrared detector; — amplifier and signal processing system to give an electrical output proportional to the CO concentration. The standard of construction and vibration/corrosion resistance shall be suited to industrial environments and to the composition of the flue gas. In Annex B schematic diagrams are given of two types of non-dispersive infrared analysers. SIST EN 15058:2017

Table 1 gives an overview of the performance characteristics of the whole measurement method including the analyser and the sampling and sample gas conditioning system. These performance characteristics shall be determined in a general performance test according to the test procedures described in EN 15267-4:2017, by an independent test laboratory accredited or recognized by the competent authorities for the implementation of tests procedures of EN 15267-4:2017. The independent test-laboratory shall check the conformity of the analyser with its sampling and sample gas conditioning system to fulfil the performance criterion attached to each performance characteristics. 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. SIST EN 15058:2017
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