EN 14790:2017

Stationary source emissions - Determination of the water vapour in ducts - Standard reference method

This European Standard specifies the standard reference method (SRM) based on a sampling system with a condensation/adsorption technique to determine the water vapour concentration in the flue gases emitted to atmosphere from ducts and stacks.
This European Standard specifies the performance characteristics to be determined and performance criteria to be fulfilled by measuring systems based on the measurement method. It applies to periodic monitoring and to the calibration or control of automated 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 to the SRM by application of prEN 14793.
This European Standard is applicable in the range of water vapour content from 4 % to 40 % as volume concentrations and of water vapour mass concentration from 29 g/m3 to 250 g/m3 as a wet gas, although for a given temperature the upper limit of the method is related to the maximum pressure of water in air or in the gas.
In this European Standard all the concentrations are expressed at standard conditions (273 K and 101,3 kPa).
NOTE 1   For saturated conditions the condensation/adsorption method is not applicable. Some guidance is given in this European Standard to deal with flue gas when droplets are present.
This European Standard has been evaluated during field tests on waste incineration, co-incineration and large combustion plants. It has been validated for sampling periods of 30 min in the volume concentration range of 7 % to 26 %.
NOTE 2   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 von Wasserdampf in Kanälen - Standardreferenzverfahren

Diese Europäische Norm legt das Standardreferenzverfahren (SRM) auf Basis einer Probenahmeeinrichtung mit einer Kondensations-/Adsorptionstechnik zur Bestimmung der Konzentration von Wasserdampf in Abgasen, die aus Abgaskanälen in die Atmosphäre emittiert werden, fest.
Diese Europäische Norm legt zu bestimmende Verfahrenskenngrößen und Mindestanforderungen fest, die von Messeinrichtungen auf Basis dieses 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 EN 14793:2017 fest.
Diese Europäische Norm gilt für einen Bereich des Wasserdampfgehalts von 4 % bis 40 % als Volumenkonzentration und für Wasserdampfkonzentrationen im feuchten Abgas von 29 g/m3 bis 250 g/m3. Die Obergrenze des Verfahrens hängt bei einer vorgegebenen Temperatur vom maximalen Wasserdampfdruck in Luft oder Gas ab.
In dieser Europäischen Norm werden alle Konzentrationen auf Normbedingungen bezogen (273 K und 101,3 kPa).
ANMERKUNG 1   Das Kondensations-/Adsorptions-Verfahren ist nicht für den gesättigten Zustand anwendbar. Einige Hinweise in dieser Europäischen Norm behandeln den Umgang mit Abgasen in Gegenwart von Tröpfchen.
Diese Europäische Norm wurde in Feldversuchen an Abfallverbrennungsanlagen, Mitverbrennungsanlagen und Großfeuerungsanlagen mit Probenahmedauern von 30 min für Volumenkonzentrationen von 7 % bis 26 % validiert.
ANMERKUNG 2   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 vapeur d'eau dans les conduits - Méthode de référence normalisée

La présente Norme européenne spécifie la méthode de référence normalisée (SRM) basée sur un système de prélèvement associé à une technique de condensation/adsorption, pour déterminer la concentration en vapeur d'eau des effluents gazeux émis dans l'atmosphère par les conduits et cheminées.
La présente Norme européenne spécifie les caractéristiques de performance devant être déterminées et les critères de performance devant être remplis par les systèmes de mesurage fondés sur cette méthode de mesurage. Elle s'applique à la surveillance périodique et à l'étalonnage ou au contrôle des systèmes de mesurage automatisés (AMS, Automated 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 » à la méthode de référence normalisée par l'application du prEN 14793.
La présente Norme européenne s'applique dans la gamme de teneur en vapeur d'eau comprise entre 4 % et 40 % en concentrations volumiques et dans la gamme de concentration massique en vapeur d'eau comprise entre 29 g/m3 et 250 g/m3 sous forme de gaz humide, bien qu'à une température donnée, la limite supérieure de la méthode soit liée à la pression maximale de l'eau dans l'air ou le gaz.
Dans la présente Norme européenne, toutes les concentrations sont exprimées dans des conditions normales (273 K et 101,3 kPa).
NOTE 1   La méthode de condensation/d'adsorption ne s'applique pas dans des conditions saturées. La présente Norme européenne fournit des lignes directrices pour le traitement des effluents gazeux en présence de vésicules.
La présente Norme européenne a été évaluée au cours d'essais sur site pratiqués sur des installations destinées à l'incinération et à la coincinération des déchets ainsi que sur de grandes installations de combustion. Elle a été validée pour des périodes de prélèvement de 30 min, dans une gamme de concentration volumique de 7 % à 26 %.
NOTE 2   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 vodne pare v odvodnikih - Standardna referenčna metoda

Ta evropski standard določa standardno referenčno metodo (SRM) na podlagi sistema vzorčenja s tehniko kondenzacije/absorpcije za določanje koncentracije vodne pare v dimnih plinih, ki prehajajo v ozračje iz vodov in odvodnikov.
Ta evropski standard določa lastnosti zmogljivosti in merila zmogljivosti, ki jih morajo izpolnjevati merilni sistemi na podlagi te merilne metode. Uporablja se za redno spremljanje in umerjanje 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 standardni referenčni metodi z uporabo standarda prEN 14793.
Ta evropski standard se uporablja v območju vsebnosti vodne pare 4–40 % kot prostorninskih koncentracij in koncentracije mase vodne pare 29–250 g/m3 kot vlažnega plina, čeprav je pri določeni temperaturi zgornja meja metode povezana z največjim tlakom vode v zraku ali v plinu.
V tem evropskem standardu so vse koncentracije izražene pri standardnih pogojih (273 K in 101,3 kPa).
OPOMBA 1:Metoda kondenzacije/absorpcije se ne uporablja pri nasičenih pogojih. V tem evropskem standardu je podanih nekaj smernic za obravnavanje dimnega plina, kadar so prisotne kapljice.
Ta evropski standard je bil ocenjen med preskusi sežiganja odpadkov, sosežiga in velikih kurilnih naprav na terenu. Potrjen je bil za 30-minutna obdobja vzorčenja v razponu prostorninske koncentracije 7–26 %.
OPOMBA 2:Lastnosti naprav, pogoji med preskusi na terenu ter vrednosti ponovljivosti in reprodukcije na terenu so podani v dodatku A.

General Information

• Status: Published
• Publication Date: 10-Jan-2017
• Withdrawal Date: 30-Jul-2017
• ICS: 13.040.40 - Stationary source emissions
• Technical Committee: CEN/TC 264 - Air quality
• Drafting Committee: CEN/TC 264 - Air quality
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 15-Sep-2022
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 14790:2017 - Stationary source emissions - Determination of the water vapour in ducts - Standard reference method

Relations

• Replaces: EN 14790:2005 - Stationary source emissions - Determination of the water vapour in ducts
• Effective Date: 18-Jan-2017

Overview - EN 14790:2017 (water vapour determination, SRM)

EN 14790:2017 is a CEN standard that defines the standard reference method (SRM) for determining water vapour in ducts and stacks from stationary source emissions. The method is based on a condensation/adsorption sampling technique and specifies performance characteristics, field procedures and acceptance criteria for periodic monitoring and for calibration or control of automated measuring systems (AMS). Concentrations are expressed at standard conditions (273 K, 101.3 kPa). The method is applicable for water vapour volume fractions from 4 % to 40 % and mass concentrations from 29 g/m3 to 250 g/m3 (wet gas); validation was performed for 30 min samples in the 7–26 % range. The method is not applicable under saturated conditions (droplets present), although guidance is provided for such cases.

Key topics and technical requirements

• Measurement principle: condensation/adsorption sampling to collect water vapour from flue gas.
• Performance characteristics: defined criteria for accuracy, repeatability and reproducibility of the SRM and measuring systems.
• Measurement components: requirements and descriptions for sampling probe, filter housing and particle filter, trapping system, optional cooling, sample gas pump, gas volume meter, barometer, balance and temperature measurement.
• Field procedures: measurement planning, sampling strategy (measurement section/plane, number and location of points), equipment assembly, leak testing and sampling operation.
• Data and reporting: calculation of water vapour concentration at standard conditions and content of the measurement report.
• Equivalence: criteria and procedure to demonstrate equivalence of an alternative method to the SRM using EN 14793.
• Validation & uncertainty: field validation details (waste incineration, co‑incineration, large combustion plants) and guidance on uncertainty estimation consistent with ISO/IEC Guide 98‑3 (GUM).

Applications and users

• Regulatory compliance monitoring of stationary source emissions (stacks and ducts).
• Periodic stack testing and calibration/control of AMS permanently installed on stacks.
• Environmental laboratories, stack testing service providers and plant operators (waste incineration, co‑incineration, large combustion plants).
• Manufacturers and integrators of continuous emission monitoring systems who need reference methods for performance verification.

Related standards

• EN 14793:2017 - Demonstration of equivalence of alternative methods.
• EN 15259:2007 - Measurement sections, sites and reporting requirements.
• EN 14791:2017, EN 1911 - Other SRMs for stack pollutant measurements.
• ISO/IEC Guide 98‑3 (GUM) - Uncertainty of measurement.

Keywords: EN 14790:2017, water vapour determination, stationary source emissions, condensation/adsorption, flue gas, stack monitoring, standard reference method, AMS, EN 14793.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2017
1DGRPHãþD
SIST EN 14790:2005
(PLVLMHQHSUHPLþQLKYLURY'RORþHYDQMHYRGQHSDUHYRGYRGQLNLK6WDQGDUGQD
UHIHUHQþQDPHWRGD
Stationary source emissions - Determination of the water vapour in ducts - Standard
reference method
Emissionen aus stationären Quellen - Bestimmung von Wasserdampf in Leitungen -
Standardreferenzverfahren
Emissions de sources fixes - Détermination de la vapeur d'eau dans les conduits -
Méthode de référence normalisée
Ta slovenski standard je istoveten z: EN 14790:2017
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 14790
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2017
EUROPÄISCHE NORM
ICS 13.040.40 Supersedes EN 14790:2005
English Version
Stationary source emissions - Determination of the water
vapour in ducts - Standard reference method
Emissions de sources fixes - Détermination de la Emissionen aus stationären Quellen - Bestimmung von
vapeur d'eau dans les conduits - Méthode de référence Wasserdampf in Kanälen - Standardreferenzverfahren
normalisée
This European Standard was approved by CEN on 26 September 2016.

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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management
Centre has the same status as the official versions.

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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14790:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Symbols and abbreviations . 11
4.1 Symbols . 11
4.2 Abbreviated terms . 12
5 Principle . 12
5.1 General . 12
5.2 Adsorption or condensation/adsorption method . 12
5.3 Temperature method . 12
6 Description of the measuring system . 13
6.1 General . 13
6.2 Sampling probe . 13
6.3 Filter housing . 13
6.4 Particle filter . 14
6.5 Trapping system . 14
6.6 Cooling system (optional) . 14
6.7 Sample gas pump . 14
6.8 Gas volume meter . 14
6.9 Barometer . 15
6.10 Balance . 15
6.11 Temperature measurement . 15
7 Performance characteristics of the SRM . 15
8 Field operation . 16
8.1 Measurement planning . 16
8.2 Sampling strategy. 17
8.2.1 General . 17
8.2.2 Measurement section and measurement plane . 17
8.2.3 Minimum number and location of measurement points . 17
8.2.4 Measurement ports and working platform . 17
8.3 Assembling the equipment . 17
8.4 Leak test. 18
8.5 Performing sampling . 18
8.5.1 Introduction of the sampling probe in the duct . 18
8.5.2 Sampling . 18
8.6 Repeatability of the weighing . 19
8.7 Procedure for gas streams saturated with water (droplets present) . 19
9 Water vapour determination . 19
10 Equivalence of an alternative method . 21
11 Measurement report . 21
Annex A (informative) Validation of the method in the field . 22
A.1 General . 22
A.2 Characteristics of installations . 22
A.3 Repeatability and reproducibility in the field . 23
A.3.1 General . 23
A.3.2 Repeatability . 24
A.3.3 Reproducibility . 25
Annex B (normative) Determination of water vapour concentration for water saturated
gas, at p = 101,325 kPa . 26
ref
Annex C (informative) Type of sampling equipment . 30
Annex D (informative) Example of assessment of compliance of standard reference method
for water vapour with given uncertainty requirements . 31
D.1 General . 31
D.2 Elements required for the uncertainty determinations . 31
D.3 Example of an uncertainty calculation. 31
D.3.1 Specific conditions in the field . 31
D.3.2 Performance characteristics . 32
D.3.3 Model equation and application of the rule of the uncertainty propagation . 34
D.3.3.1 Water vapour content . 34
D.3.3.2 Effect of the collection efficiency . 35
D.3.3.3 Calculation of the combined uncertainty of the water vapour content taking into
account the collection efficiency . 35
D.3.3.4 Calculation of sensitivity coefficients . 36
D.3.3.5 Calculation of the standard uncertainty of the collection efficiency . 36
D.3.3.6 Calculation of the standard uncertainty of measured dry gas volume corrected to
standard conditions . 37
D.3.3.7 Calculation of the combined uncertainty of the water vapour content . 38
D.3.3.8 Results of standard uncertainties calculations. 38
D.3.4 Estimation of the combined uncertainty . 41
Annex E (informative) Significant technical changes . 42
Bibliography . 43

European foreword
This document (EN 14790:2017) has been prepared by Technical Committee CEN/TC 264 “Air quality”,
the secretariat of which is held by DIN.
This document supersedes EN 14790:2005.
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 July 2017, and conflicting national standards shall be
withdrawn at the latest by July 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
Annex E provides details of significant technical changes between this document and the previous
edition.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: 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 European Standard specifies the standard reference method (SRM) based on a sampling system
with a condensation/adsorption technique to determine the water vapour concentration in the flue
gases emitted to atmosphere from ducts and stacks.
This European Standard specifies the performance characteristics to be determined and performance
criteria to be fulfilled by measuring systems based on the measurement method. It applies to periodic
monitoring and to the calibration or control of automated 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 to
the SRM by application of EN 14793:2017.
This European Standard is applicable in the range of water vapour content from 4 % to 40 % as volume
3 3
concentrations and of water vapour mass concentration from 29 g/m to 250 g/m as a wet gas,
although for a given temperature the upper limit of the method is related to the maximum pressure of
water in air or in the gas.
In this European Standard all the concentrations are expressed at standard conditions (273 K and
101,3 kPa).
NOTE 1 For saturated conditions the condensation/adsorption method is not applicable. Some guidance is
given in this European Standard to deal with flue gas when droplets are present.
This European Standard has been validated during field tests on waste incineration, co-incineration and
large combustion plants. It has been validated for sampling periods of 30 min in the volume
concentration range of 7 % to 26 %.
NOTE 2 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 1911, Stationary source emissions - Determination of mass concentration of gaseous chlorides
expressed as HCl - Standard reference method
EN 14791:2017, Stationary source emissions — Determination of mass concentration of sulphur oxides —
Standard reference method
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
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]
3.2
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]
3.3
measurement method
method described in a written procedure containing all the means and procedures required to sample
and analyse, namely field of application, principle and/or reactions, definitions, equipment, procedures,
presentation of results, other requirements and measurement report
[SOURCE: EN 14793:2017]
3.4
alternative method
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 14793:2017]
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]
3.7
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 systems (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: In case of manual methods the applicable reference can be reference materials used as
calibration standards to establish the relationship between the output signal of the analytical device and the
reference values.
Note 3 to entry: Calibration should not be confused with adjustment of a measuring system.
3.8
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.
3.9
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]
3.10
measurement plane
plane normal to the centre line of the duct at the sampling position
Note 1 to entry: Measurement plane is also known as sampling plane.
[SOURCE: EN 15259:2007]
3.11
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]
3.12
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]
3.13
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]
3.14
absorber
device in which water vapour is absorbed
3.15
droplets
small liquid particles of condensed water vapour or water liquid in the flue gas (e.g. coming from a
scrubber)
Note 1 to entry: In adiabatic equilibrium conditions, droplets could arise only if a gas stream is saturated with
water.
3.16
dew point
temperature below which the condensation of water vapour begins at the given pressure condition of
the flue gas
3.17
vapour pressure
pressure of water in vapour form
3.18
performance characteristic
one of the quantities (described by values, tolerances, range) assigned to equipment in order to define
its performance
3.19
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 European Standard the repeatability is expressed as a value with a level of confidence of
95 %.
3.20
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 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 %.
3.21
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 to entry: These conditions 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 %.
3.22
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
standard uncertainty
u
uncertainty of the result of a measurement expressed as a standard deviation
3.24
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)
3.25
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 ku×
c
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.
3.26
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
=
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the following symbols apply.
C measured volume concentration
C water vapour mass concentration on dry basis
w
h measured water vapour content on wet basis expressed as volume
m
concentration
k coverage factor
m mass of water vapour trapped in the trapping system
w
Mw molecular weight of water, 18,01534 g/mol rounded to 18 g/mol
p absolute pressure at the gas volume meter
m
p (T ) saturation vapour pressure of water at the temperature T of the gas
s m m
volume meter
p standard pressure, 101,3 kPa
ref
s reproducibility standard deviation
R
s maximum allowable repeatability standard deviation
r,limit
T ith temperature reading
i
T mean absolute temperature of the sampled gas at the gas volume meter
m
T standard temperature, 273 K
ref
u standard uncertainty
u combined uncertainty
c
U expanded uncertainty
V gas volume reading from the gas volume meter at the beginning of the
sampling period, at actual conditions of temperature, pressure and
humidity
V2 gas volume reading from the gas volume meter at the end of the sampling
period, at actual conditions of temperature, pressure and humidity
V difference between the readings at the gas volume meter at the beginning
m
and at the end of the sampling period
V measured dry gas volume, corrected to standard conditions
m,ref
V molar volume at standard conditions, in m /mol at p and T
mol
ref ref
4.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
AM alternative method
AMS automated measuring system
PTFE Polytetrafluoroethene
SRM standard reference method
5 Principle
5.1 General
This European Standard describes the standard reference method (SRM) for determining the water-
vapour content emitted to atmosphere from ducts and stacks. The specific components and the
requirements for the measuring system are described in Clause 6. A number of performance
characteristics, together with associated performance criteria are specified for the measurement
method (see Table 1 in Clause 7). The expanded uncertainty of the method shall meet the specifications
given in this European Standard.
The measurement method described hereafter is appropriate when the flue gas is free of droplets.
Within the scope of this European Standard, it is assumed that gas streams in stacks or ducts are more
or less in adiabatic (thermodynamic) equilibrium. In those conditions, droplets can arise only if a gas
stream is saturated with water. When no droplets are present in the gas stream, the gas stream is then
assumed to be unsaturated with water. A gas sample is extracted at a constant rate from the stack. The
water vapour of that sample is subsequently trapped by adsorption or by condensation plus adsorption;
the mass of the vapour is then determined by weighing the mass gain of the trapping system.
When droplets are present in the gas stream, the implementation of the measurement method
described in this European Standard leads to an overestimation of the water vapour content. If the
measured value is equal to or higher than the expected value shown in the table in Annex B for
saturated conditions at the temperature and pressure of the flue gas, that means that the presence of
droplets can lead to biased results; such results shall be rejected.
In such cases, the evidence suggests that the gas stream is saturated with water vapour. Under these
conditions, the method is abridged to a determination of the gas temperature. Then, the water vapour
concentration is calculated from the theoretical mass of water vapour per unit of standard gas volume
at liquid-gas equilibrium, given the actual temperature, pressure and composition of the gas stream.
5.2 Adsorption or condensation/adsorption method
A measured quantity of sampled gas is extracted from the gas stream through a trapping system, which
meets the specifications of efficiency (see 8.5.2). The mass gain of the trapping system is measured in
order to determine the mass or the volume water vapour content, on the basis of the volume sampled.
5.3 Temperature method
This method applies when gases are water saturated.
A temperature probe is placed in the gas stream saturated with water vapour, until it reaches
equilibrium. The amount of water vapour present in the gas is subsequently derived from the
temperature, using a water liquid-gas equilibrium chart or table (see Annex B).
6 Description of the measuring system
6.1 General
A known volume of flue gas is extracted representatively from a duct or chimney during a certain
period of time at a controlled flow rate. A filter removes the dust in the sampled volume; thereafter the
gas stream is passed through a trapping system. It is important that all parts of the sampling equipment
upstream of the trapping system are heated and that the components shall not react with or absorb
water vapour (e.g. stainless steel, borosilicate glass, quartz glass, PTFE or titanium are suitable
materials).
An example of suitable sampling trains is shown in Annex C. The user can choose between a trapping
system made up with either:
— adsorption system (Figure C.1) or
— condensation and adsorption system (Figure C.2).
The choice shall be made to fulfil the efficiency that is required in 8.5.2.
6.2 Sampling probe
In order to reach the measurement points of the measurement 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.
NOTE 1 The probe can be marked before sampling in order to demonstrate that the measurement points in the
measurement plane have been reached.
The sampling probe shall be surrounded by a heating jacket capable of producing a controlled
temperature of at least 120 °C and 20 °C higher than the (acid) dew point of gases and shall be
protected and positioned using an outer tube.
NOTE 2 It is possible to perform the sampling of SO and water vapour simultaneously with the same probe
(without nozzle providing no droplets are present).
NOTE 3 It is possible to perform the sampling of HCl and water vapour simultaneously with the same probe
(without nozzle providing no droplets are present).
6.3 Filter housing
The filter housing shall be made of materials inert to water vapour and shall have the possibility to be
connected with the probe thereby avoiding leaks.
The filter housing may be located either:
— in the duct or chimney, mounted directly behind the entry nozzle (in-stack filtration) or
— outside the duct or chimney, mounted directly behind the suction tube (out-stack filtration).
The filter housing shall be connected to the probe without any cold path between the two.
In special cases where the sample gas temperature is greater than 200 °C, the heating jacket around the
sampling probe, filter housing and connector fine may be omitted. However the temperature in the
sampled gas just after the filter housing should not fall below the acid dew point temperature.
6.4 Particle filter
Particle filters and filter housings of different designs may be used, but the residence time of the sample
gas should be minimised.
6.5 Trapping system
The trapping system shall be made up with:
— adsorption system or
— condensation and adsorption system.
The set-up of the trapping system shall be as follows:
a) When using the adsorption system alone, it shall consist of at least one cartridge, impinger or
absorber, filled with a suitable drying agent, for example coloured silica gel.
b) The condensation and adsorption system shall consist of two stages:
1) the first one shall be a condensation stage with an optional cooling system;
2) the second one shall be an adsorption stage as described in a).
The temperature at the outlet of the condensation system shall be as low as possible.
The efficiency of the sampling system shall be checked according to the procedure described in 8.5.2.
The trapping efficiency can be increased by increasing the residence time of sampled gases in the
trapping system and/or by improving the efficiency of the cooling system. The sampled volume should
be sufficient to reach an appropriate accuracy of the measurement (see 6.8 and Clause 7).
Condensation of water shall be avoided in all parts of the sampling system that are not weighed.
6.6 Cooling system (optional)
Any kind of cooling system may be used to condense water vapour in the sampled flue gas (e.g. crushed
ice or cryogenic system).
6.7 Sample gas pump
A leak-free pump capable of drawing sample gas at a set flow-rate is required.
NOTE 1 A rotameter (optional) could make easier the adjustment of the nominal sampling flow-rate.
NOTE 2 A small surge tank can be used between the pump and rotameter to eliminate the pulsation effect of
the diaphragm pump on the rotameter.
NOTE 3 A regulating valve (optional) would also be useful for adjusting the sample gas flow-rate.
6.8 Gas volume meter
Two variants of gas volume meter may be used:
— dry-gas volume meter; or
— wet-gas volume meter.
The gas volume meter (wet or dry) shall have a relative expanded uncertainty not exceeding 5,0 % of
the measured volume (at actual conditions).
The gas volume meter shall be equipped with a temperature measuring device with a relative expanded
uncertainty not exceeding 2,0 % and shall be associated to an absolute pressure measurement with a
relative expanded uncertainty not exceeding 2,0 %. The absolute pressure can be determined from the
relative pressure and the ambient pressure.
When using a dry gas volume meter, a condenser and/or a gas drying system shall be used which can
achieve a residual water vapour content of less than 10,0 g/m (equivalent to a dew point of 10,5 °C or
a volume content of 1,25 %).
NOTE For example, a glass cartridge or adsorption bottle packed with silica gel (1 mm to 3 mm particle size)
which has been previously dried at least at 110 °C for at least 2 h.
When using a wet gas volume meter, a correction shall be applied for water vapour, using the table in
Annex B.
6.9 Barometer
Barometer capable of measuring atmospheric pressure present at the measurement site, with an
expanded uncertainty that does not exceed 1 kPa.
6.10 Balance
The resolution of the balance shall be equal or better than 0,1 g or 2,0 % of the water weight to be
measured.
6.11 Temperature measurement
The uncertainty of the calibrated thermometer for flue gas temperature determination with a
measurement range from 273 K to 373 K shall not exceed 2,5 K. That thermometer shall have a low
thermal inertia, in order to be rapidly in thermal equilibrium with the stack gas.
7 Performance characteristics of the SRM
Table 1 gives an overview of the performance characteristics and the associated performance criteria of
the whole measurement method.
The laboratory implementing the method shall demonstrate that:
— performance characteristics of the method meet the performance criteria given in Table 1 and
— the relative expanded uncertainty calculated by combining values of selected performance
characteristics by means of an uncertainty budget does not exceed 20,0 % at the measured value.
Table 1 — Performance characteristics of the SRM to be determined
in the laboratory (L) and in the field (F) and associated performance criteria
Performance characteristic L F Performance criterion
Gas volume meter:
standard uncertainty of the sample
X  ≤ 2,5 % of the volume of sampled gas
a
volume
a
X  ≤ 2,0 % of the absolute temperature
standard uncertainty of temperature
standard uncertainty of absolute
X  ≤ 2,0 % of the absolute pressure
a
pressure
Leak in the sample gas line  X ≤ 2,0 % of the nominal flow rate
Weighing of collected water:
b
X X
uncertainty associated to the balance
uncertainty associated to weighing in the
X
c
field
a
The uncertainties of sample volume, temperature and absolute pressure are a combination of uncertainties due
to calibration, resolution or reading, drift between two consecutive calibrations and standard deviation of the mean
when several values have been collected to get the result. When a barometer is used, see 6.9.
b
The uncertainty contributions of the balance can be for example resolution, repeatability and uncertainty of
calibration of the balance. See 6.10.
c
When weighing is carried out in the field, variations of ambient conditions can be an uncertainty source, for
example temperature variations, air currents and vibrations.
The principle of calculation of the combined uncertainty is based on the law on propagation of
uncertainty laid down in ISO/IEC Guide 98-3 (GUM):
— determine the standard uncertainties attached to the performance characteristics to be included in
the calculation of the uncertainty budget according to ISO/IEC Guide 98-3;
— calculate the uncertainty budget by combining all the standard uncertainties according to
ISO/IEC Guide 98-3;
— values of standard uncertainty that are less than 5 % relative of the maximum standard uncertainty
may be neglected;
— calculate the combined uncertainty at the measured value.
An example of the calculation of an uncertainty budget is given in Annex D.
8 Field operation
8.1 Measurement planning
Emission measurements at a plant shall be carried out such that the results are representative for the
emissions from this plant and comparable with results obtained for other comparable plants. Therefore,
water vapour measurements, often used to bring correction to measurement results and to express
them on dry conditions, shall be planned in accordance with EN 15259.
Before carrying out any measurements, the purpose of the sampling and the sampling procedures shall
be discussed with the plant personnel concerned. The nature of the plant process, e.g. steady-state or
cyclic, can affect the sampling programme. If the process can be performed in a steady-state, it is
important that this is maintained during sampling.
Dates, starting times, duration of survey and sampling periods as well as plant operating conditions
during these periods shall be agreed with the plant management.
If no suitable location exists in the plant, and/or that measurements have been carried out during non-
steady-state conditions of the plant, which leads to an increase of the uncertainty of the measurements,
it shall be stated in the measurement report.
8.2 Sampling strategy
8.2.1 General
Sampling requires a suitable measurement section and measurement plane.
The measurement plane shall be easily reached from convenient measurement ports and a safe working
platform (see EN 15259).
8.2.2 Measurement section and measurement plane
The measurement section and measurement plane shall meet the requirements of EN 15259.
8.2.3 Minimum number and location of measurement points
It is necessary to ensure that the gas concentrations measured are representative of the average
conditions inside the waste gas duct. Measurements may be performed at one representative
measurement point or at any measurement point, if the corresponding requirements on the distribution
of the water vapour volume concentration or any other relevant component specified in 8.3 of
EN 15259 are fulfilled. In all other cases the measurements shall be performed as grid measurements.
In that case, EN 15259 specifies the minimum number of measurement points to be used and the
location in the measurement plane for circular and rectangular ducts.
8.2.4 Measurement ports and working platform
Measurement ports shall be provided for access to the measurement points selected in accordance with
EN 15259.
Examples of suitable measurement ports are given in EN 15259.
For safety and practical reasons, the working platform shall comply with the requirements of EN 15259.
8.3 Assembling the equipment
When using a condensation system with impingers or absorbers, these shall be filled with water, the
volume of which is less than half the content of the absorber.
The water can be replaced by the appropriate absorption solution used in EN 14791, EN 1911 or in any
other European Standards using water in the preparation of the absorption solution, when the operator
wants to collect water vapour with the same sampling train as for another component such as SO or
HCl. When using an adsorption system, fill the last impinger or absorber or cartridge with a drying
agent.
NOTE This
...