EN ISO 15971:2014
(Main)Natural gas - Measurement of properties - Calorific value and Wobbe index (ISO 15971:2008)
Natural gas - Measurement of properties - Calorific value and Wobbe index (ISO 15971:2008)
ISO 15971:2008 concerns the measurement of calorific value of natural gas and natural gas substitutes by non‑separative methods, i.e. methods that do not involve the determination of the gas composition, nor calculations from it. ISO 15971:2008 describes the principles of operation of a variety of instruments in use for this purpose, and provides guidelines for the selection, evaluation, performance assessment, installation and operation of these.
Calorific values can be expressed on a mass basis, a molar basis or, more commonly, a volume basis. The working range for superior calorific value of natural gas, on the volume basis, is usually between 30 MJ/m3 and 45 MJ/m3 at standard reference conditions (see ISO 13443). The corresponding range for the Wobbe index is usually between 40 MJ/m3 and 60 MJ/m3.
ISO 15971:2008 neither endorses nor disputes the claims of any commercial manufacturer for the performance of an instrument. Its central thesis is that fitness-for-purpose in any particular application (defined in terms of a set of specific operational requirements) can be assessed only by means of a well-designed programme of experimental tests. Guidelines are provided for the proper content of these tests.
Erdgas - Messung der Eigenschaften - Wärmewerte und Wobbe-Index (ISO 15971:2008)
Gaz naturel - Mesurage des propriétés - Pouvoir calorifique et indice de Wobbe (ISO 15971:2008)
L'ISO 15971:2008 concerne le mesurage du pouvoir calorifique du gaz naturel et de produits de substitution du gaz naturel par des méthodes non séparatives, c'est-à-dire des méthodes qui n'impliquent pas la détermination de la composition du gaz, ni le calcul à partir de celle-ci. Elle décrit les principes de fonctionnement d'une diversité d'instruments utilisés à cet effet, et elle fournit des lignes directrices pour leur sélection, évaluation, évaluation de performance, installation et fonctionnement.
Les pouvoirs calorifiques peuvent être exprimés sur une base massique, molaire ou, plus communément, volumique. La plage de travail pour le pouvoir calorifique supérieur du gaz naturel, sur une base volumique, est généralement comprise entre 30 MJ/m3 et 45 MJ/m3 dans les conditions de référence standard (voir l'ISO 13443). La plage correspondante de l'indice de Wobbe est généralement comprise entre 40 MJ/m3 et 60 MJ/m3.
L'ISO 15971:2008 ne cautionne ni ne conteste les revendications d'un quelconque constructeur commercial pour la performance d'un instrument. Sa thèse centrale est que l'adaptation à un usage dans une quelconque application particulière (définie en termes d'un ensemble d'exigences opérationnelles spécifiques) ne peut être évaluée qu'au moyen d'un programme bien conçu d'essais expérimentaux. Des lignes directrices sont fournies pour le contenu correct de ces essais.
Zemeljski plin - Merjenje njegovih lastnosti - Kalorična vrednost in Wobbejev indeks (ISO 15971:2008)
Standard EN-ISO 15971 obravnava na merjenje kalorične vrednosti zemeljskega plina in nadomestkov zemeljskega plina z neseparacijskimi metodami, ki ne vključujejo določevanja sestave plina ali izračuna, ki iz tega izhaja. Opisuje načela delovanja različnih instrumentov, ki se uporabljajo v ta namen, in zagotavlja smernice za njihovo izbiro, vrednotenje, oceno učinka, namestitev in delovanje. Kalorične vrednosti se lahko izrazijo na podlagi mase, števila molov ali, najpogosteje, prostornine. Delovno območje za boljšo kalorično vrednost zemeljskega plina na podlagi prostornine je pri standardnih referenčnih pogojih med 30 in 45 MJ/m3 (glej ISO 13443). Ustrezen razpon za Wobbejev indeks je običajno med 40 in 60 MJ/m3. Ta mednarodni standard niti ne podpira in niti ne ugovarja trditvam katerega koli proizvajalca o zmogljivosti inštrumentov. Njegova osrednja teza je, da je primernost za uporabo za kateri koli namen (opredeljen z vidika nabora posebnih obratovalnih zahtev) lahko ocenjena le z dobro zasnovanim programom poskusnih preskusov. Na voljo so smernice za pravilno izvajanje teh preskusov.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2014
=HPHOMVNLSOLQ0HUMHQMHQMHJRYLKODVWQRVWL.DORULþQDYUHGQRVWLQ:REEHMHY
LQGHNV ,62
Natural gas - Measurement of properties - Calorific value and Wobbe index (ISO
15971:2008)
Erdgas - Messung der Eigenschaften - Wärmewerte und Wobbe-Index (ISO 15971:2008)
Gaz naturel - Mesurage des propriétés - Pouvoir calorifique et indice de Wobbe (ISO
15971:2008)
Ta slovenski standard je istoveten z: EN ISO 15971:2014
ICS:
75.060 Zemeljski plin Natural gas
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 15971
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2014
ICS 75.060
English Version
Natural gas - Measurement of properties - Calorific value and
Wobbe index (ISO 15971:2008)
Gaz naturel - Mesurage des propriétés - Pouvoir calorifique Erdgas - Messung der Eigenschaften - Wärmewerte und
et indice de Wobbe (ISO 15971:2008) Wobbe-Index (ISO 15971:2008)
This European Standard was approved by CEN on 16 February 2014.
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, 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
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15971:2014 E
worldwide for CEN national Members.
Contents Page
Foreword .3
Foreword
The text of ISO 15971:2008 has been prepared by Technical Committee ISO/TC 193 “Natural gas” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 15971:2014.
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 September 2014, and conflicting national standards shall be
withdrawn at the latest by September 2014.
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.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 15971:2008 has been approved by CEN as EN ISO 15971:2014 without any modification.
INTERNATIONAL ISO
STANDARD 15971
First edition
2008-12-15
Natural gas — Measurement of
properties — Calorific value and Wobbe
index
Gaz naturel — Mesurage des propriétés — Pouvoir calorifique et indice
de Wobbe
Reference number
ISO 15971:2008(E)
©
ISO 2008
ISO 15971:2008(E)
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ii © ISO 2008 – All rights reserved
ISO 15971:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
3.1 Calorific value and Wobbe index . 1
3.2 Water content of gas . 2
3.3 Performance classification . 2
3.4 Terms from metrology. 3
4 Principles of measurement. 4
4.1 Introduction . 4
4.2 Direct combustion calorimetry. 5
4.3 Indirect methods. 5
4.4 Inferential methods. 6
5 Performance assessment and acceptance tests. 7
5.1 Performance assessment for instrument selection. 7
5.2 Factory and site acceptance tests . 20
6 Sampling and installation guidelines . 21
6.1 Sampling. 21
6.2 Installation guidelines . 22
7 Calibration . 25
7.1 Calibration procedures. 25
7.2 Calibration gases. 26
8 Verification . 27
8.1 Verification procedures. 27
8.2 Verification gases . 28
9 Maintenance . 29
9.1 Preventive maintenance. 29
9.2 Corrective maintenance . 29
10 Quality control. 29
10.1 General. 29
10.2 Environmental parameters and ancillary equipment. 31
10.3 Instrumental factors . 32
Annex A (normative) Symbols and units. 33
Annex B (informative) Examples of type-approval and technical specifications. 34
Annex C (informative) Class 0 mass-basis calorimetry . 36
Annex D (informative) Direct combustion calorimetry. 40
Annex E (informative) Stoichiometric combustion devices. 43
Annex F (informative) Effect of non-alkane gases on stoichiometric combustion devices. 47
Annex G (informative) Measurement of Wobbe index. 48
Bibliography . 49
ISO 15971:2008(E)
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
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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 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15971 was prepared by Technical Committee ISO/TC 193, Natural gas.
iv © ISO 2008 – All rights reserved
ISO 15971:2008(E)
Introduction
The amount of energy delivered by a flowing natural gas is often determined as the product of the volume
delivered and the calorific value per unit volume of the gas. It is, therefore, important to have available
standardized methods of determining the calorific value. In many cases, it is possible to calculate the calorific
value of natural gas, with sufficient accuracy, given the composition (see ISO 6976). However, it is also
possible, and sometimes a preferred alternative, to measure calorific value using any one of several
techniques that do not require a compositional analysis. The methods currently in use, and
...
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