EN ISO 6974-2:2012
(Main)Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)
Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)
This part of ISO 6974 describes the process required to determine the uncertainty associated with the mole
fraction for each component from a natural gas analysis in accordance with ISO 6974‑1.
Erdgas - Bestimmung der Zusammensetzung und der zugehörigen Unsicherheit durch Gaschromatographie - Teil 2: Unsicherheitsberechnungen (ISO 6974-2:2012)
Dieser Teil von ISO 6974 beschreibt den erforderlichen Prozess zur Bestimmung der mit der Mol¬fraktion jeder Komponente verbundenen Unsicherheit bei einer Erdgasanalyse nach ISO 6974 1.
Gaz naturel - Détermination de la composition et de l'incertitude associée par chromatographie en phase gazeuse - Partie 2: Calculs d'incertitude (ISO 6974-2:2012)
La présente partie de l'ISO 6974 décrit le processus nécessaire pour déterminer l'incertitude associée à la
fraction molaire de chaque constituant d'une analyse de gaz naturel conformément à l'ISO 6974-1.
Zemeljski plin - Določevanje sestave in pripadajoče negotovosti s plinsko kromatografijo - 2. del: Računanje negotovosti (ISO 6974-2:2012)
Ta del standarda ISO 6974 opisuje postopek za določevanje pripadajoče negotovosti z molsko frakcijo za vsako sestavino iz analize zemeljskega plina v skladu s standardom ISO 6974-1.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2012
1DGRPHãþD
SIST EN ISO 6974-2:2002
=HPHOMVNLSOLQ'RORþHYDQMHVHVWDYHLQSULSDGDMRþHQHJRWRYRVWLVSOLQVNR
NURPDWRJUDILMRGHO 5DþXQDQMHQHJRWRYRVWL ,62
Natural gas - Determination of composition and associated uncertainty by gas
chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)
Erdgas - Bestimmung der Zusammensetzung und der zugehörigen Unsicherheit durch
Gaschromatographie - Teil 2: Unsicherheitsberechnungen (ISO 6974-2:2012)
Gaz naturel - Détermination de la composition avec une incertitude définie par
chromatographie en phase gazeuse - Partie 2: Calculs d'incertitude (ISO 6974-2:2012)
Ta slovenski standard je istoveten z: EN ISO 6974-2:2012
ICS:
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 6974-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2012
ICS 75.060 Supersedes EN ISO 6974-2:2002
English Version
Natural gas - Determination of composition and associated
uncertainty by gas chromatography - Part 2: Uncertainty
calculations (ISO 6974-2:2012)
Gaz naturel - Détermination de la composition et de Erdgas - Bestimmung der Zusammensetzung und der
l'incertitude associée par chromatographie en phase zugehörigen Unsicherheit durch Gaschromatographie - Teil
gazeuse - Partie 2: Calculs d'incertitude (ISO 6974-2:2012) 2: Unsicherheitsberechnungen (ISO 6974-2:2012)
This European Standard was approved by CEN on 14 May 2012.
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, 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
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6974-2:2012: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Foreword
This document (EN ISO 6974-2:2012) has been prepared by Technical Committee ISO/TC 193 "Natural gas".
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 November 2012, and conflicting national standards shall be withdrawn
at the latest by November 2012.
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.
This document supersedes EN ISO 6974-2:2002.
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, 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 6974-2:2012 has been approved by CEN as a EN ISO 6974-2:2012 without any modification.
INTERNATIONAL ISO
STANDARD 6974-2
Second edition
2012-05-15
Natural gas — Determination of
composition and associated uncertainty
by gas chromatography —
Part 2:
Uncertainty calculations
Gaz naturel — Détermination de la composition et de l’incertitude
associée par chromatographie en phase gazeuse — Partie 2: Calculs
d’incertitude
Reference number
ISO 6974-2:2012(E)
©
ISO 2012
ISO 6974-2:2012(E)
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 either ISO at the address below or ISO’s
member body in the country of the requester.
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Published in Switzerland
ii © ISO 2012 – All rights reserved
ISO 6974-2:2012(E)
Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
4.1 Symbols . 1
4.2 Subscripts . 2
5 Calculation of uncertainty . 2
5.1 General considerations . 2
5.2 Principles . 5
5.3 Step 9 — Calculation of uncertainty of mole fractions . 5
5.4 Step 10 — Calculation of the expanded uncertainty of mole fractions . 11
Annex A (informative) Calculation of processed component uncertainties for
the methane-by-difference approach .12
Annex B (normative) Uncertainties of relative response factors .13
Annex C (informative) Alternative calculation of the uncertainty of the value of the unknown .14
Bibliography .16
ISO 6974-2:2012(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
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 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 6974-2 was prepared by Technical Committee ISO/TC 193, Natural Gas, Subcommittee SC 1, Analysis
of natural gas.
This second edition of ISO 6974-2, together with ISO 6974-1:2012, cancels and replaces ISO 6974-1:2000 and
ISO 6974-2:2001, which have been technically revised.
ISO 6974 consists of the following parts, under the general title Natural Gas — Determination of composition
and associated uncertainty by gas chromatography:
— Part 1: General guidelines and calculation of composition
— Part 2: Uncertainty calculations
— Part 3: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and hydrocarbons up to C
using two packed columns
— Part 4: Determination of nitrogen, carbon dioxide and C to C and C hydrocarbons for a laboratory and
1 5 6+
on-line measuring system using two columns
— Part 5: Determination of nitrogen, carbon dioxide and C to C and C hydrocarbons for a laboratory and
1 5 6+
on-line process application using three columns
— Part 6: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and C to C hydrocarbons
1 8
using three capillary columns
Future subsequent parts of ISO 6974 are planned.
iv © ISO 2012 – All rights reserved
ISO 6974-2:2012(E)
Introduction
ISO 6974 describes methods of analysis of natural gas and methods for calculating component mole fractions and
uncertainties. ISO 6974 (all parts) is intended for the measurement of H , He, O , N , CO and hydrocarbons, either
2 2 2 2
as individual components or as a group, for example all hydrocarbons above C , defined as C . This approach is
5 6+
suitable for a range of end applications, including calibrating gas mixtures and providing natural gas composition
and uncertainty data to be used in the calculation of calorific value and other additive physical properties of the
gas. Details of these end applications are provided in ISO 6974-3 and subsequent parts of ISO 6974.
ISO 6974-1 gives guidelines for calculating the mole composition of natural gas, determined using one of the
gas chromatographic methods described in ISO 6974-3 and subsequent parts of ISO 6974. ISO 6974-1 also
describes all the essential steps for setting up an analysis, including outlining the structure of the analysis,
defining the working ranges and establishing the analytical procedure.
This part of ISO 6974 describes the steps required to calculate the uncertainty of the component mole fractions
of natural gas determined using gas chromatography.
ISO 6974-3 and subsequent parts of ISO 6974 describe different gas chromatographic methods. These
methods cover both daily practice in the laboratory and on-line field applications. ISO 6974-1:2012, Annex A,
provides a comparison of the characteristics of the analytical methods described in ISO 6974-3 and subsequent
parts of ISO 6974.
It is intended that this part of ISO 6974 be used in conjunction with ISO 6974-1 and a method of analysis, e.g.
ISO 6974-3 or subsequent parts of ISO 6974.
ISO 6974-1:2012, 5.5, describes the conventional normalization approach for calculating processed mole
fractions from raw mole fractions. When conventional normalization is used for multiple operation methods
without bridging, the uncertainties of the calculated mole fractions will be conservative. If a more accurate
assessment of uncertainty is required, an alternative approach to normalization, using the generalized least
squares (GLS) method, can be used; this is described in ISO 6974-1:2012, Annex B. Further alternative
approaches are available for calculating processed mole fractions, including methane-by-difference (see
ISO 6974-1:2012, Annex C) and data harmonization (see Reference [1]).
INTERNATIONAL STANDARD ISO 6974-2:2012(E)
Natural gas — Determination of composition and associated
uncertainty by gas chromatography —
Part 2:
Uncertainty calculations
1 Scope
This part of ISO 6974 describes the process required to determine the uncertainty associated with the mole
fraction for each component from a natural gas analysis in accordance with ISO 6974-1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 6974-1:2012, Natural gas — Deter
...
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