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
Technical Committee
Drafting Committee
Current Stage
9020 - Submission to 2 Year Review Enquiry - Review Enquiry
Due Date
15-Apr-2022
Completion Date
15-Apr-2022

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SLOVENSKI STANDARD
SIST EN 14790:2017
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
SIST EN 14790:2017 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14790:2017
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SIST EN 14790:2017
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.
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SIST EN 14790:2017
EN 14790:2017 (E)
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

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EN 14790:2017 (E)

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

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SIST EN 14790:2017
EN 14790:2017 (E)
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.
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SIST EN 14790:2017
EN 14790:2017 (E)
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)
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EN 14790:2017 (E)
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

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

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]
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EN 14790:2017 (E)
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]
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SIST EN 14790:2017
EN 14790:2017 (E)
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
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EN 14790:2017 (E)
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 %.
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EN 14790:2017 (E)
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
uncertainty of the result of a measurement expressed as a standard deviation
3.24
combined uncertainty

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

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×

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

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EN 14790:2017 (E)
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
h measured water vapour content on wet basis expressed as volume
concentration
k coverage factor
m mass of water vapour trapped in the trapping system
Mw molecular weight of water, 18,01534 g/mol rounded to 18 g/mol
p absolute pressure at the gas volume meter
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
s maximum allowable repeatability standard deviation
r,limit
T ith temperature reading
T mean absolute temperature of the sampled gas at the gas volume meter
T standard temperature, 273 K
ref
u standard uncertainty
u combined uncertainty
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
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
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SIST EN 14790:2017
EN 14790:2017 (E)
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 St
...

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