SIST ISO 14164:1999
(Main)Stationary source emissions -- Determination of the volume flowrate of gas streams in ducts -- Automated method
Stationary source emissions -- Determination of the volume flowrate of gas streams in ducts -- Automated method
This International Standard describes the operating principles and the most important performance characteristics
of automated flow-measuring systems for determining the volume flowrate in the ducts of stationary sources.
Procedures to determine the performance characteristics of automated volume flow-measuring systems are also
contained in this International Standard.
The performance characteristics are general and not limited to specific measurement principles or instrument
systems.
NOTE Commercial systems which use the operating principles described and meet the requirements of this International
Standard are readily available.
Émissions de sources fixes -- Détermination du débit-volume des courants gazeux dans des conduites -- Méthode automatisée
La présente Norme internationale décrit les principes de fonctionnement et les caractéristiques de performance les
plus importantes des systèmes de mesurage automatiques destinés à déterminer le débit-volume dans les
conduites de sources fixes. Les modes opératoires permettant de déterminer les caractéristiques de performance
des systèmes automatiques de mesurage du débit-volume figurent également dans la présente Norme
internationale.
Les caractéristiques de performance sont d'ordre général et ne sont pas limitées à des principes spécifiques de
mesurage ou à des systèmes spécifiques d'instrumentation.
NOTE Des systèmes du commerce utilisant ces principes de fonctionnement et respectant les exigences de la présente
Norme internationale sont disponibles.
Emisije nepremičnih virov – Določevanje volumskega pretoka plinskih tokov v odvodnikih – Avtomatska metoda
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-1999
(PLVLMHQHSUHPLþQLKYLURY±'RORþHYDQMHYROXPVNHJDSUHWRNDSOLQVNLKWRNRYY
RGYRGQLNLK±$YWRPDWVNDPHWRGD
Stationary source emissions -- Determination of the volume flowrate of gas streams in
ducts -- Automated method
Émissions de sources fixes -- Détermination du débit-volume des courants gazeux dans
des conduites -- Méthode automatisée
Ta slovenski standard je istoveten z: ISO 14164:1999
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 14164
First edition
1999-04-01
Stationary source emissions —
Determination of the volume flowrate of gas
streams in ducts — Automated method
Émissions de sources fixes — Détermination du débit-volume des courants
gazeux dans des conduites — Méthode automatisée
A
Reference number
Contents
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Measuring principles of commercially available AMS .3
5 Numerical performance characteristics and their applicability .6
6 Test report .6
Annex A (normative) Determination of the main performance characteristics .7
Annex B (informative) Additional performance characteristics .11
Bibliography.13
© ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
ii
© ISO
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 14164 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee
SC 1, Stationary source emissions.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iii
INTERNATIONAL STANDARD © ISO ISO 14164:1999(E)
Stationary source emissions — Determination of the volume
flowrate of gas streams in ducts — Automated method
1 Scope
This International Standard describes the operating principles and the most important performance characteristics
of automated flow-measuring systems for determining the volume flowrate in the ducts of stationary sources.
Procedures to determine the performance characteristics of automated volume flow-measuring systems are also
contained in this International Standard.
The performance characteristics are general and not limited to specific measurement principles or instrument
systems.
NOTE Commercial systems which use the operating principles described and meet the requirements of this International
Standard are readily available.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 6879: 1995, Air quality — Performance characteristics and related concepts for air quality measuring methods.
ISO 7935:1992, Air quality — Stationary source emissions — Determination of mass concentration of sulfur
dioxide — Performance characteristics of automated measuring methods.
ISO 9096:1992, Stationary source emissions — Determination of concentration and mass flow rate of particulate
material in gas-carrying ducts — Manual gravimetric method.
ISO 9169:1994, Air quality — Determination of performance characteristics of measurement methods.
ISO 10155:1995, Stationary source emissions — Automated monitoring of mass concentrations of particles —
Performance characteristics, test methods and specifications.
ISO 10780:1994,
Air quality — Stationary source emissions — Measurement of velocity and volume rate of flow of
gas streams in ducts.
ISO 10849:1996, Stationary source emissions — Determination of the mass concentration of nitrogen oxides —
Performance characteristics and calibration of automated measuring systems.
1)
ISO 12039: — , Stationary source emissions — Determination of the volumetric concentration of CO, CO and
O — Performance characteristics and calibration of automated measuring systems.
1)
To be published.
© ISO
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
automated flow-measuring system
AMS
system that may be attached to a duct to continuously measure and record the volume flow of a gas
3.2
analyzer
that part of an AMS that measures the parameters used to calculate the volume flow of a gas
3.3
duct
stack, chimney or final exit duct on a stationary process, used for the dispersion of residual process gases
3.4
comparative measurements
measurements of volume gas flow in the duct by the AMS under test (evaluation) and compared to volume flow
simultaneously determined in the same duct in accordance with ISO 10780
3.5
comparative method
method for determination of volume gas flow in a duct in accordance with ISO 10780
NOTE Since the purpose of the comparative test is to demonstrate that the AMS under test yields an accurate estimate of the
volume flow in the duct, it is necessary for the comparative method to measure the volume flow profile of the entire duct. An
AMS cannot be used as the comparative method because all AMS used for measuring volume flow measure the velocity in a
small area of the duct and then extrapolate this measurement to obtain the volume flow in the duct.
3.6
standard deviation
s
A
a measure of the working precision of the installed AMS
NOTE 1 It is derived using the differences between the pairs of volume flow values obtained by comparative testing of the
AMS against ISO 10780 on the basis that a statistically sufficient number of comparative measurements are taken over the
period of unattended operation (see annex A). The value of
s is expressed as a function of the full-scale range of the AMS and
A
is calculated on the assumption that is an estimate of the precision of a normally distributed set of measurements.
s
A
NOTE 2 Whenever possible, the comparative method should measure the same portion of the gas flow as the AMS.
NOTE 3 It is not possible to determine directly the standard deviation of an AMS in a laboratory, because wind tunnels do
not normally reproduce all the properties of stack gases and do not replicate all possible measurement conditions. This is the
reason the standard deviation is determined after the AMS has been installed in the duct. Applying the comparative method in
conjunction with the test for systematic errors (see A.4.2.3) ensures that the AMS has a satisfactory accuracy.
NOTE 4 In addition to random error, s contains the effect that local site variables such as changes in the gas steams
A
temperature, fluctuations in the electrical power supplied to the AMS and zero and span drift have on the overall precision of
the AMS. It also includes the standard deviation of the comparative method. s is an estimate of the upper limiting value for the
A
precision of the AMS.
NOTE 5 The procedure in this International Standard is suitable for finding the uncertainty of the data obtained from the
AMS, as long as the standard deviation of the measured values of the comparative method, s , is significantly smaller than the
C
standard deviation, s , of the difference between the pairs of measured values.
D
3.7
period of unattended operation
period for which given values of the performance characteristics of an instrument can be guaranteed to remain
within 95 % probability without servicing or adjustment
[ISO 6879]
© ISO
NOTE For long-term monitoring installations, a minimum of seven days of unattended operation is required.
3.8
response time
time it takes the AMS to display 90 % of the high-level calibration value on the data acquisition system, starting from
the time of initiation of the high-level calibration cycle
NOTE The response time may be determined either in the laboratory or after the AMS is installed.
3.9
stationary source emission
gas emitted by a stationary plant or process and transported to a duct for dispersion into the atmosphere
3.10
calibration
the setting and checking of the installed AMS before determining its performance characteristics or
before beginning any volume flow measurement
3.11
calibration function
correlation over the span range of the AMS between the volume flowrate of the duct as measured by the installed
AMS and as measured in accordance with the reference flowrate
NOTE 1 ISO 10780 is an example of a reference flow standard.
NOTE 2 A nonlinear calibration function is acceptable, provided this nonlinearity is compensated for in the output of the
AMS.
3.12
linearity
measure of the degree of agreement between the measurements of the comparative method (ISO 10780) and the
AMS when the differences between the AMS and the comparative method across a range of volume flows are
subjected to a linear regression
3.13
span
difference between the AMS output (reading) for a known flowrate and a zero flowrate
3.14
zero drift
change in the output of the AMS over a stated time interval when exposed to an unchanging zero flowrate
3.15
span drift
change in the output of the AMS over a stated time interval when exposed to an unchanging flowrate near the span
value
3.16
AMS location
point in the duct where the AMS is installed
4 Measuring principles of commercially available AMS
4.1 General
Most commercially available AMS operate on one of the following three principles: pressure differential, rate of heat
loss, or change in the speed of a sound wave. A brief description of each common type of AMS and the advantages
and disadvantages of each are presented below.
© ISO
Before selecting a specific type of AMS for installation, the characteristics of the flow profile shall be established at
the location in the duct where the AMS is to be installed (see clause A.2 in annex A). Volume flow-measuring AMS
systems should not be used in ducts where non-uniform, asymmetrical, developing, swirling and/or stratified flow is
present.
4.2 Differential pressure-sensing systems
4.2.1 Single Pitot tube methods
ISO 10780, the manual reference method for measuring velocity and volume flow in ducts, uses Pitot tubes, the
traditional means used to determine flow in ducts. A number of Pitot tubes are available, but the Type-S and Type-L
Pitot tubes specified in ISO 10780 are those used for the vast majority of flow measurements in ducts. Some Pitot
tube-based AMS simply combine devices which continuously record the pressure differential and the stack
temperature, an automated data reduction system such as a data-logger or a computer, and a Pitot tube to yield a
continuous measurement of flowrate.
Pitot tubes use the temperature of the gas stream and the difference in pressure measured at two or more points on
the Pitot’s surface to determine the velocity of the gas stream at individual points across a cross-section of the duct.
The volume flowrate is then determined by multiplying the average velocity across the cross-section by the area of
this cross-section.
These systems are simple and relatively inexpensive to install, operate and maintain, but are subject to the same
errors as the Pitot tubes described in clause 6 of ISO 10780:1994. For example, unless special precautions are
taken, Pitot tubes can give erroneous results when used to measure gas streams having any of the following
conditions:
a) Reynolds numbers less than 1 200;
b) velocities less than 5 m/s or greater than 50 m/s;
c) cyclonic or angular flow;
d) irregular pressure f
...
INTERNATIONAL ISO
STANDARD 14164
First edition
1999-04-01
Stationary source emissions —
Determination of the volume flowrate of gas
streams in ducts — Automated method
Émissions de sources fixes — Détermination du débit-volume des courants
gazeux dans des conduites — Méthode automatisée
A
Reference number
Contents
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Measuring principles of commercially available AMS .3
5 Numerical performance characteristics and their applicability .6
6 Test report .6
Annex A (normative) Determination of the main performance characteristics .7
Annex B (informative) Additional performance characteristics .11
Bibliography.13
© ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
ii
© ISO
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 14164 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee
SC 1, Stationary source emissions.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iii
INTERNATIONAL STANDARD © ISO ISO 14164:1999(E)
Stationary source emissions — Determination of the volume
flowrate of gas streams in ducts — Automated method
1 Scope
This International Standard describes the operating principles and the most important performance characteristics
of automated flow-measuring systems for determining the volume flowrate in the ducts of stationary sources.
Procedures to determine the performance characteristics of automated volume flow-measuring systems are also
contained in this International Standard.
The performance characteristics are general and not limited to specific measurement principles or instrument
systems.
NOTE Commercial systems which use the operating principles described and meet the requirements of this International
Standard are readily available.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 6879: 1995, Air quality — Performance characteristics and related concepts for air quality measuring methods.
ISO 7935:1992, Air quality — Stationary source emissions — Determination of mass concentration of sulfur
dioxide — Performance characteristics of automated measuring methods.
ISO 9096:1992, Stationary source emissions — Determination of concentration and mass flow rate of particulate
material in gas-carrying ducts — Manual gravimetric method.
ISO 9169:1994, Air quality — Determination of performance characteristics of measurement methods.
ISO 10155:1995, Stationary source emissions — Automated monitoring of mass concentrations of particles —
Performance characteristics, test methods and specifications.
ISO 10780:1994,
Air quality — Stationary source emissions — Measurement of velocity and volume rate of flow of
gas streams in ducts.
ISO 10849:1996, Stationary source emissions — Determination of the mass concentration of nitrogen oxides —
Performance characteristics and calibration of automated measuring systems.
1)
ISO 12039: — , Stationary source emissions — Determination of the volumetric concentration of CO, CO and
O — Performance characteristics and calibration of automated measuring systems.
1)
To be published.
© ISO
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
automated flow-measuring system
AMS
system that may be attached to a duct to continuously measure and record the volume flow of a gas
3.2
analyzer
that part of an AMS that measures the parameters used to calculate the volume flow of a gas
3.3
duct
stack, chimney or final exit duct on a stationary process, used for the dispersion of residual process gases
3.4
comparative measurements
measurements of volume gas flow in the duct by the AMS under test (evaluation) and compared to volume flow
simultaneously determined in the same duct in accordance with ISO 10780
3.5
comparative method
method for determination of volume gas flow in a duct in accordance with ISO 10780
NOTE Since the purpose of the comparative test is to demonstrate that the AMS under test yields an accurate estimate of the
volume flow in the duct, it is necessary for the comparative method to measure the volume flow profile of the entire duct. An
AMS cannot be used as the comparative method because all AMS used for measuring volume flow measure the velocity in a
small area of the duct and then extrapolate this measurement to obtain the volume flow in the duct.
3.6
standard deviation
s
A
a measure of the working precision of the installed AMS
NOTE 1 It is derived using the differences between the pairs of volume flow values obtained by comparative testing of the
AMS against ISO 10780 on the basis that a statistically sufficient number of comparative measurements are taken over the
period of unattended operation (see annex A). The value of
s is expressed as a function of the full-scale range of the AMS and
A
is calculated on the assumption that is an estimate of the precision of a normally distributed set of measurements.
s
A
NOTE 2 Whenever possible, the comparative method should measure the same portion of the gas flow as the AMS.
NOTE 3 It is not possible to determine directly the standard deviation of an AMS in a laboratory, because wind tunnels do
not normally reproduce all the properties of stack gases and do not replicate all possible measurement conditions. This is the
reason the standard deviation is determined after the AMS has been installed in the duct. Applying the comparative method in
conjunction with the test for systematic errors (see A.4.2.3) ensures that the AMS has a satisfactory accuracy.
NOTE 4 In addition to random error, s contains the effect that local site variables such as changes in the gas steams
A
temperature, fluctuations in the electrical power supplied to the AMS and zero and span drift have on the overall precision of
the AMS. It also includes the standard deviation of the comparative method. s is an estimate of the upper limiting value for the
A
precision of the AMS.
NOTE 5 The procedure in this International Standard is suitable for finding the uncertainty of the data obtained from the
AMS, as long as the standard deviation of the measured values of the comparative method, s , is significantly smaller than the
C
standard deviation, s , of the difference between the pairs of measured values.
D
3.7
period of unattended operation
period for which given values of the performance characteristics of an instrument can be guaranteed to remain
within 95 % probability without servicing or adjustment
[ISO 6879]
© ISO
NOTE For long-term monitoring installations, a minimum of seven days of unattended operation is required.
3.8
response time
time it takes the AMS to display 90 % of the high-level calibration value on the data acquisition system, starting from
the time of initiation of the high-level calibration cycle
NOTE The response time may be determined either in the laboratory or after the AMS is installed.
3.9
stationary source emission
gas emitted by a stationary plant or process and transported to a duct for dispersion into the atmosphere
3.10
calibration
the setting and checking of the installed AMS before determining its performance characteristics or
before beginning any volume flow measurement
3.11
calibration function
correlation over the span range of the AMS between the volume flowrate of the duct as measured by the installed
AMS and as measured in accordance with the reference flowrate
NOTE 1 ISO 10780 is an example of a reference flow standard.
NOTE 2 A nonlinear calibration function is acceptable, provided this nonlinearity is compensated for in the output of the
AMS.
3.12
linearity
measure of the degree of agreement between the measurements of the comparative method (ISO 10780) and the
AMS when the differences between the AMS and the comparative method across a range of volume flows are
subjected to a linear regression
3.13
span
difference between the AMS output (reading) for a known flowrate and a zero flowrate
3.14
zero drift
change in the output of the AMS over a stated time interval when exposed to an unchanging zero flowrate
3.15
span drift
change in the output of the AMS over a stated time interval when exposed to an unchanging flowrate near the span
value
3.16
AMS location
point in the duct where the AMS is installed
4 Measuring principles of commercially available AMS
4.1 General
Most commercially available AMS operate on one of the following three principles: pressure differential, rate of heat
loss, or change in the speed of a sound wave. A brief description of each common type of AMS and the advantages
and disadvantages of each are presented below.
© ISO
Before selecting a specific type of AMS for installation, the characteristics of the flow profile shall be established at
the location in the duct where the AMS is to be installed (see clause A.2 in annex A). Volume flow-measuring AMS
systems should not be used in ducts where non-uniform, asymmetrical, developing, swirling and/or stratified flow is
present.
4.2 Differential pressure-sensing systems
4.2.1 Single Pitot tube methods
ISO 10780, the manual reference method for measuring velocity and volume flow in ducts, uses Pitot tubes, the
traditional means used to determine flow in ducts. A number of Pitot tubes are available, but the Type-S and Type-L
Pitot tubes specified in ISO 10780 are those used for the vast majority of flow measurements in ducts. Some Pitot
tube-based AMS simply combine devices which continuously record the pressure differential and the stack
temperature, an automated data reduction system such as a data-logger or a computer, and a Pitot tube to yield a
continuous measurement of flowrate.
Pitot tubes use the temperature of the gas stream and the difference in pressure measured at two or more points on
the Pitot’s surface to determine the velocity of the gas stream at individual points across a cross-section of the duct.
The volume flowrate is then determined by multiplying the average velocity across the cross-section by the area of
this cross-section.
These systems are simple and relatively inexpensive to install, operate and maintain, but are subject to the same
errors as the Pitot tubes described in clause 6 of ISO 10780:1994. For example, unless special precautions are
taken, Pitot tubes can give erroneous results when used to measure gas streams having any of the following
conditions:
a) Reynolds numbers less than 1 200;
b) velocities less than 5 m/s or greater than 50 m/s;
c) cyclonic or angular flow;
d) irregular pressure fluctuations; and
e) high concentrations of particles and/or aerosols.
These latter two problem areas frequently can be avoided by ensuring that the Pitot tube does not vibrate and by
periodically back-purging through the Pitot tube. Gas stream pressure fluctuations can be compensated for by
employing a damping device in the measurement system.
4.2.2 Multiple-point Pitot tube (MPPT) method
The MPPT is a modified form of the Pitot tube; it contains three or more openings (ports) in a pipe, located at the
traverse points corresponding to the centres of equal areas of the stack cross-section. The openings facing in the
direction of flow give the average impact pressure across the stack diameter, while those facing away from the
direction of flow give the average wake pressure. A divider in the centre of the tube separates the two pressure legs
of the MPPT. The average impact and wake pressures are compared using an electrical pressure transducer or
other differential pressure-sensing device. Since the orifice loca
...
NORME ISO
INTERNATIONALE 14164
Première édition
1999-04-01
Émissions de sources fixes —
Détermination du débit-volume des
courants gazeux dans des conduites —
Méthode automatisée
Stationary source emissions — Determination of the volume flowrate of gas
streams in ducts — Automated method
A
Numéro de référence
Sommaire
1 Domaine d’application .1
2 Références normatives .1
3 Termes et définitions.2
4 Principes de mesurage des AMS disponibles .4
5 Caractéristiques de performance numériques et leur applicabilité.6
6 Rapport d'essai .6
Annexe A (normative) Détermination des principales caractéristiques de performance.8
Annexe B (informative) Caractéristiques de performance supplémentaires .13
Bibliographie.15
© ISO 1999
Droits de reproduction réservés. Sauf prescription différente, aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque
forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur.
Organisation internationale de normalisation
Case postale 56 • CH-1211 Genève 20 • Suisse
Internet iso@iso.ch
Imprimé en Suisse
ii
© ISO
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée aux
comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du comité
technique créé à cet effet. Les organisations internationales, gouvernementales et non gouvernementales, en
liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec la Commission
électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI, Partie 3.
Les projets de Normes internationales adoptés par les comités techniques sont soumis aux comités membres pour
vote. Leur publication comme Normes internationales requiert l'approbation de 75 % au moins des comités
membres votants.
La Norme internationale ISO 14164 a été élaborée par le comité technique ISO/TC 146, Qualité de l'air, sous-
comité SC 1, Émissions de sources fixes.
L’annexe A fait partie intégrante de la présente Norme internationale. L’annexe B est donnée uniquement à titre
d’information.
iii
NORME INTERNATIONALE © ISO ISO 14164:1999(F)
Émissions de sources fixes — Détermination du débit-volume des
courants gazeux dans des conduites — Méthode automatisée
1 Domaine d’application
La présente Norme internationale décrit les principes de fonctionnement et les caractéristiques de performance les
plus importantes des systèmes de mesurage automatiques destinés à déterminer le débit-volume dans les
conduites de sources fixes. Les modes opératoires permettant de déterminer les caractéristiques de performance
des systèmes automatiques de mesurage du débit-volume figurent également dans la présente Norme
internationale.
Les caractéristiques de performance sont d'ordre général et ne sont pas limitées à des principes spécifiques de
mesurage ou à des systèmes spécifiques d'instrumentation.
NOTE Des systèmes du commerce utilisant ces principes de fonctionnement et respectant les exigences de la présente
Norme internationale sont disponibles.
2 Références normatives
Les documents normatifs suivants contiennent des dispositions qui par suite de la référence qui en est faite,
constituent des dispositions valables pour la présente Norme internationale. Pour les références datées, les
amendements ultérieurs ou les révisions de ces publications ne s’appliquent pas. Toutefois, les parties prenantes
aux accords fondés sur la présente Norme internationale sont invitées à rechercher la possibilité d'appliquer les
éditions les plus récentes des documents normatifs indiqués ci-après. Pour les références non datées, la dernière
édition du document normatif en référence s’applique. Les membres de la CEI et de l'ISO possèdent le registre des
Normes internationales en vigueur à un moment donné.
ISO 6879:1995, Qualité de l'air — Caractéristiques de fonctionnement et concepts connexes pour les méthodes de
mesurage de la qualité de l'air.
ISO 7935:1992, Émissions de sources fixes — Détermination de la concentration en masse de dioxyde de
soufre — Caractéristiques de performance des méthodes de mesurage automatiques.
ISO 9096:1992, Émissions de sources fixes — Détermination de la concentration et du débit-masse de matières
particulaires dans des veines gazeuses — Méthode gravimétrique manuelle.
ISO 9169:1994, Qualité de l'air — Détermination des caractéristiques de fonctionnement des méthodes de
mesurage.
ISO 10155:1995, Émissions de sources fixes — Contrôle automatique des concentrations en masse de
particules — Caractéristiques de fonctionnement, modes opératoires d'essai et spécifications.
ISO 10780:1994, Émissions de sources fixes — Mesurage de la vitesse et du débit-volume des courants gazeux
dans des conduites.
ISO 10849:1996, Émissions de sources fixes — Détermination de la concentration en masse des oxydes d'azote —
Caractéristiques de performance des systèmes de mesurage automatiques.
1)
ISO 12039:— , Émissions de sources fixes — Dosage du monoxyde de carbone, du dioxyde de carbone et de
l’oxygène — Méthodes automatisées.
1)
À publier.
© ISO
3 Termes et définitions
Pour les besoins de la présente Norme internationale, les termes et définitions suivants s'appliquent.
3.1
système automatique de mesurage du débit
AMS
système pouvant être fixé sur une conduite pour mesurer et enregistrer en continu le débit-volume d’un gaz
3.2
analyseur terme
partie d'un AMS qui mesure les paramètres servant à calculer le débit-volume d’un gaz
3.3
conduite
gaine, cheminée ou conduit de rejet d'une source fixe d'émission servant à la dispersion des gaz résiduels du
processus
3.4
mesurages comparatifs
mesurages de l'écoulement de gaz effectués dans la conduite par l'AMS soumis à l'essai (évaluation) et comparés
au débit-volume mesuré simultanément dans la même conduite, conformément à l'ISO 10780
3.5
méthode comparative
méthode pour la détermination du débit-volume d’un gaz dans une conduite, conformément à l'ISO 10780
NOTE L'essai comparatif ayant pour but de montrer que l'AMS soumis à l'essai donne une estimation exacte du
débit-volume dans la conduite, la méthode comparative nécessite le mesurage de la répartition du débit-volume sur la section
entière de la conduite. Il n'est pas possible d'utiliser un AMS comme méthode comparative car tous les AMS servant à mesurer
le débit-volume mesurent la vitesse dans une petite zone de la conduite et extrapolent ensuite ce mesurage pour obtenir le
débit-volume dans la conduite.
3.6
écart-type
s
A
mesure de la fidélité de travail de l'AMS installé
NOTE 1 L’écart-type est estimé d'après les différences entre les paires de valeurs du débit-volume obtenues en effectuant
des essais comparatifs de l'AMS conformément à l'ISO 10780 et en se basant sur le fait que le nombre de mesurages
comparatifs effectué sur la période de fonctionnement sans intervention (voir annexe A) est statistiquement suffisant. La valeur
de s s'exprime en fonction de l'étendue de mesure de l'AMS et est calculée en prenant pour hypothèse que s est une
A A
estimation de la fidélité d'une série de mesurages normalement répartis.
NOTE 2 Il convient, dans la mesure du possible, que la méthode comparative mesure la même portion d'écoulement de gaz
que l'AMS.
NOTE 3 Il n'est pas possible de déterminer directement l'écart-type d'un AMS dans un laboratoire car les souffleries ne
reproduisent pas normalement toutes les propriétés des gaz dans les conduites et ne sont pas la réplique de toutes les
conditions possibles de mesurage. L'écart-type est donc déterminé après installation de l'AMS dans la conduite. L'application
de la méthode comparative associée à l'essai de recherche d'erreurs systématiques (voir A.4.2.3) garantit une précision
satisfaisante de l'AMS.
NOTE 4 Outre l'erreur aléatoire, s englobe l'effet sur la fidélité globale de l'AMS de variables locales propres au site, telles
A
que variations de température du flux gazeux, fluctuations d'alimentation électrique de l'AMS ainsi que de la dérive de zéro et
du gain. Il inclut également l'écart-type de la méthode comparative. s est une estimation de la limite supérieure pour la fidélité
A
de l'AMS.
NOTE 5 Le mode opératoire de la présente Norme internationale convient pour trouver l'incertitude des données fournies
par l'AMS tant que l'écart-type des valeurs mesurées de la méthode comparative, s , est nettement inférieur à l'écart-type de la
C
différence entre les paires de valeurs mesurées, s .
D
© ISO
3.7
période de fonctionnement sans intervention
période pour laquelle les valeurs données des caractéristiques de performance d'un instrument peuvent être
garanties avec une probabilité de 95 %, sans entretien ou réglage
[ISO 6879]
NOTE Un fonctionnement minimum de sept jours sans intervention est requis pour les installations de surveillance à long
terme.
3.8
temps de réponse
temps mis par l'AMS pour afficher 90 % du niveau élevé de la valeur d'étalonnage sur le système d'acquisition de
données à partir du moment du lancement du cycle d'étalonnage de haut niveau
NOTE Le temps de réponse peut être déterminé en laboratoire ou après installations de l'AMS.
3.9
émissions de sources fixes
gaz émis par une usine ou un processus fixe et transportés vers une conduite pour dispersion dans l'atmosphère
3.10
étalonnage
Æau titre de la présente Norme internationaleæ réglage et vérification de l'AMS installé avant de déterminer ses
caractéristiques de performance ou avant de commencer tout mesurage du débit-volume
3.11
fonction étalonnage
corrélation, dans la plage de gain de l'AMS, entre le débit-volume circulant dans la conduite, mesuré par l'AMS
installé, et le débit-volume de référence
NOTE 1 L'ISO 10780 est un exemple de norme de débit de référence.
NOTE 2 Une fonction étalonnage non linéaire est acceptable à condition de compenser cette non-linéarité dans la valeur de
sortie de l'AMS.
3.12
linéarité
dans une plage de débits-volumes, mesure du degré d'accord entre les mesurages de la méthode comparative
(ISO 10780) et ceux de l'AMS lorsque les différences entre l'AMS et la méthode comparative sont soumises à une
régression linéaire
3.13
gain
différence entre la valeur de sortie de l'AMS (valeur lue) pour un débit connu, et un débit nul
3.14
dérive de zéro
variation de la valeur de sortie de l'AMS, dans un intervalle de temps donné, lors d'une exposition à un débit nul
3.15
dérive du gain
variation de la valeur de sortie de l'AMS, dans un intervalle de temps donné, lors d'une exposition à un débit
constant proche de la valeur du gain
3.16
emplacement de l'AMS
point de la conduite où l'AMS est installé
© ISO
4 Principes de mesurage des AMS disponibles
4.1 Généralités
La plupart des AMS disponibles dans le commerce fonctionnent selon l'un des trois principes suivants: pression
différentielle, taux de déperdition de chaleur et variation de la vitesse d'une onde sonore. Une brève description de
chaque type courant d'AMS ainsi que les avantages et les inconvénients de chacun sont présentés ci-dessous.
Avant toute décision d'achat d'un type particulier d'AMS, il faut établir les caractéristiques du profil de débit à
l'endroit de la conduite où l'AMS sera installé (voir l’article A.2). Il convient de ne pas utiliser les AMS de mesurage
du débit-volume dans les conduites où l'écoulement est non uniforme, asymétrique, non stabilisé, rotationnel et/ou
stratifié.
4.2 Sonde de pression différentielle
4.2.1 Méthode du tube de Pitot simple
L'ISO 10780, la méthode manuelle de référence pour le mesurage de la vitesse et du débit-volume dans les
conduites, utilise des tubes de Pitot qui sont des moyens traditionnels servant à déterminer le profil de vitesse de
l'écoulement dans les conduites. Il existe un certain nombre de tubes de Pitot, mais les tubes de Pitot de type S et
de type L, spécifiés dans l'ISO 10780, sont ceux utilisés pour la grande majorité des mesurages de débit dans les
conduites. Certains AMS basés sur le tube de Pitot combinent simplement des dispositifs enregistrant en continu la
pression différentielle et la température dans la conduite, un système automatique de réduction des données, tel
qu'un enregistreur de données ou un ordinateur, et un tube de Pitot pour obtenir un mesurage en continu du débit.
Les tubes de Pitot utilisent la température du flux gazeux et la différence de pression mesurée en deux points ou
plus de la surface du tube de Pitot pour déterminer la vitesse du flux de gaz en des points particuliers de la section
transversale de la conduite. Le débit-volume est alors déterminé en multipliant la vitesse moyenne sur la section
transversale par l'aire de cette section.
Ces systèmes sont simples et relativement économiques à installer, à faire fonctionner et à entretenir, mais ils sont
sujets aux mêmes erreurs que les tubes de Pitot décrits à l'article 6 de l'ISO 10780:1994. À moins de prendre des
précautions particulières, les tubes de Pitot peuvent, par exemple, donner des résultats erronés lors de leur
utilisation pour le mesurage de flux de gaz se trouvant dans l'une des conditions suivantes:
a) nombres de Reynolds inférieurs à 1 200;
b) vitesses inférieures à 5 m/s ou supérieures à 50 m/s;
c) écoulement rotationnel ou angulai
...
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