SIST-TP CEN/TR 16478:2013
(Main)Surveillance from first commissioning on measuring devices used in natural gas supply to the installations of the activities under the Directive 2003/87/EC establishing a scheme of CO2 emissions trading
Surveillance from first commissioning on measuring devices used in natural gas supply to the installations of the activities under the Directive 2003/87/EC establishing a scheme of CO2 emissions trading
This Technical Report establishes minimum provisions for the surveillance, based on available standards from first commissioning, of devices and systems with measuring function throughout their technical life when used in the activities of the categories listed in the Annex I of the European Directive 2003/87/EC. It does so in order to ensure the compliance with the expected maximum allowable difference of indication. This Technical Report applies to devices/systems with the function to measure: - volumetric or mass amount of natural gas consumption (any type of gas meters), - volumetric amount of natural gas consumption at specified base conditions (conversion devices), - composition of natural gas (gas chromatographs), for calculating, in accordance with the applicable provisions of the guidelines C(2007) 3416, the amount of the CO2 emissions from the source stream of natural gas. Users of this document should be aware that more detailed national recommendations/standards and/or codes of practice as well as national measures possibly approved by National Regulator may exist inside the EU Member States. When national regulations have to be applied, this document should not be considered. Except in the aforementioned case, this Technical Report is intended to be applied in association with applicable national recommendations/standards and/or codes of practice setting out the above mentioned surveillance provisions. In the event of conflict in terms of different requirements in national regulations/standards and in the provisions of this document, the national regulations/standards will take precedence. Referring to the aforesaid Commission's guidelines C(2007) 3416, SFG_I opts for the calculation based method to determine the amount of the CO2 emissions. Regarding commercially traded of natural gas, competent authorities may permit the determination of the annual gas consumption leading to evaluation of CO2 emissions based solely on the invoiced amount of gas without further individual proof of associated uncertainties, provided that national legislation or the documented application of standards ensures that respective uncertainty requirements for activity data are met for commercial transactions (guidelines C(2007) 3416 -annex 1 ?7). Referring to 5.2 and to Chapter 16, annex 1 of guidelines C(2007) 3416, for installations with “de minimis” souce streams and with low emissions respectively, the provisions of this document can be waived.
Überwachung von Messgeräten in der Erdgasversorgung ab der Erstzulassung auf Anlagen von Tätigkeiten, die unter die Richtlinie 2003/87/EG zur Einrichtung eines Systems zum CO2-Emissionshandel fallen
Dieser Technische Bericht stellt auf der Grundlage verfügbarer Normen Mindestfestlegungen für die Überwachung von Geräten und Einrichtungen mit Messfunktion ab deren erster Inbetriebnahme und für deren gesamte technische Lebensdauer auf, wenn diese im Rahmen der Tätigkeitskategorien, die in der EU Richtlinie 2003/87/EG, Anhang I, gelistet sind, verwendet werden. Dadurch soll die Einhaltung der erwartungsgemäßen, zulässigen Höchstabweichung der Anzeige sichergestellt werden.
Dieser Technische Bericht bezieht sich auf Geräte/Einrichtungen mit einer Messfunktion für die:
- volumenbezogene oder massebezogene Menge des Erdgasverbrauchs (jede Art von Gaszähler),
- volumenbezogene Menge des Erdgasverbrauchs bei festgelegten Basisbedingungen (Mengenumwerter),
- Zusammensetzung von Erdgas (Gas-Chromatographen),
zur Berechnung der Menge an CO2-Emissionen des Erdgas-Stoffstroms nach den zutreffenden Festlegungen der Leitlinien C(2007) 3416.
Nutzer dieses Dokuments sollten berücksichtigen, dass es ausführlichere nationale Empfehlungen/Normen und/oder Vorgehensweisen sowie einzelstaatliche, womöglich durch nationale Behörden genehmigte Maßnahmen in den EU-Mitgliedstaaten geben kann.
Sollten einzelstaatliche, gesetzliche Bestimmungen anzuwenden sein, ist dieses Dokument nicht zu berück-sichtigen.
Unter Ausnahme dieses Falles ist dieser Technische Bericht für die Anwendung im Zusammenhang mit den zutreffenden nationalen Empfehlungen/Normen und/oder Vorgehensweisen gedacht, die die vorstehend erwähnten Festlegungen zur Überwachung darlegen.
Im Fall eines Widerspruchs zwischen den verschiedenen Anforderungen in nationalen Bestimmungen/ Normen und den Festlegungen dieses Dokumentes ist den nationalen Bestimmungen/Normen der Vorrang einzuräumen.
Bezüglich der vorstehend erwähnten Leitlinien C(2007) 3416 entscheidet sich CEN Sector Forum Gas Infrastructure für die Bestimmung der CO2-Emissionen auf Grundlage des Berechnungsverfahrens.
Für kommerziell gehandeltes Erdgas können die zuständigen Behörden die Festlegung des jährlichen Gas-verbrauchs zur Bewertung der CO2-Emissionen ohne weitere Einzelprüfung der damit verbundenen Unsicher-heiten allein aufgrund der in Rechnung gestellten Gasmenge zulassen, wenn die nationale Gesetz¬gebung oder die dokumentierte Anwendung der Normen sicherstellt, dass die entsprechenden Unsicherheits¬anforderungen für die Tätigkeitsdaten bei kommerziellen Abwicklungen eingehalten werden (Leitlinien C(2007) 3416, Anhang I, §7).
Nach den Leitlinien C(2007) 3416, Anhang 1), 5.2 und 16, können die Festlegungen dieses Dokumentes bei Einrichtungen für De-Minimis-Stoffströme und für entsprechend geringe Emissionen aufge¬hoben werden.
Surveillance de la mise en service des appareils de mesure utilisés pour la fourniture de gaz naturel aux installations pour les activités sous la Directive 2003/87/CE établissant un schéma d'échange d'émissions de CO2
Le présent Rapport Technique établit les dispositions minimales pour la surveillance, sur la base des normes disponibles, de la première mise en service, sur les dispositifs et systèmes ayant une fonction de mesure au long de leur durée de vie technique lorsqu'ils sont utilisés dans les activités relevant des catégories énumérées à l'Annexe I de la directive européenne 2003/87/EC, afin d'assurer la conformité avec la différence attendue maximale admissible de l'indication.
Le présent Rapport Technique s'applique aux dispositifs / systèmes ayant la fonction de mesurer :
- le volume ou la masse de consommation de gaz naturel (tout type de compteurs de gaz),
- le volume de consommation de gaz naturel à des conditions de base spécifiées (dispositifs de conversion),
- la composition du gaz naturel (chromatographes gazeux),
pour le calcul, conformément aux dispositions applicables des lignes directrices C (2007) 3416, du montant des émissions de CO2 à partir du flux source de gaz naturel.
Les utilisateurs de ce document doivent être conscients que des recommandations/normes et/ou codes de pratique nationaux plus détaillés ainsi que des mesures nationales, éventuellement approuvées par le Régulateur National peuvent exister à l'intérieur des États membres de l'UE.
Lorsque des réglementations nationales doivent être appliquées, ce document ne doit pas être pris en considération.
Sauf dans le cas mentionné ci-dessus, le présent Rapport Technique est destiné à être appliqué en association avec les recommandations/normes et/ou les guides professionnels nationaux applicables énonçant les dispositions de surveillance mentionnées ci-dessus.
Dans le cas de conflits en termes d'exigences différentes dans les réglementations/normes nationales avec les dispositions du présent document, les réglementations/normes nationales priment.
Concernant les lignes directrices précitées de la Commission C (2007) 3416, le SFG_I opte pour la méthode basée sur le calcul afin de déterminer le montant des émissions de CO2.
En ce qui concerne le gaz naturel commercialisé, les autorités compétentes peuvent autoriser la détermination de la consommation annuelle de gaz conduisant à l'évaluation des émissions de CO2 se fondant uniquement sur le montant facturé de gaz sans preuve individuelle supplémentaire des incertitudes associées, à condition que la législation nationale ou l'application documentée de normes garantit que les exigences d'incertitude respectives pour les données d'activité sont remplies pour les transactions commerciales (lignes directrices C (2007) 3416-annexe 1 § 7).
Concernant le 5,2 et le chapitre 16, Annexe 1 des lignes directrices C (2007) 3416, pour les installations avec des flux de source "de minimis" et avec de faibles émissions respectivement, les dispositions de ce document peuvent être levées.
Nadzor nad merilnimi napravami v napeljavah za zemeljski plin od prvega zagona dalje za vzpostavitev sheme za trgovanje z emisijami CO2, skladno z direktivo 2003/87/EC
To tehnično poročilo na podlagi razpoložljivih standardov določa minimalne predpise za nadzor naprav in sistemov z merilno funkcijo od začetka obratovanja in skozi celotno tehnično življenjsko dobo, kadar se uporabljajo pri dejavnostih kategorij iz Priloge I k evropski direktivi 2003/87/ES. Na ta način se zagotavlja skladnost s pričakovano največjo dovoljeno razliko v navedbi. To tehnično sporočilo se uporablja za naprave/sisteme s funkcijo merjenja: – volumetrične ali masne količine porabe zemeljskega plina (vse vrste plinomerov), – volumetričnega zneska porabe naravnega plina pri opredeljenih osnovnih pogojih (korektorji), – sestave zemeljskega plina (plinski kromatografi) za izračun (v skladu z veljavnimi določbami smernic C(2007) 3416) količine emisij CO2 iz toka vira zemeljskega plina. Uporabniki tega dokumenta se morajo zavedati, da lahko v državah članicah EU obstajajo podrobnejša nacionalna priporočila/standardi in/ali kodeksi ravnanja ter tudi nacionalni ukrepi, ki jih je morda odobril nacionalni upravni organ. Kadar je treba ravnati v skladu z nacionalnimi predpisi, naj se ta dokument ne bi upošteval. Razen v navedenem primeru je to tehnično poročilo namenjeno uporabi v povezavi z veljavnimi nacionalnimi priporočili/standardi in/ali kodeksi ravnanja, ki določajo navedene določbe nadzora. Kadar so različne zahteve v nacionalnih predpisih/standardih v nasprotju z določbami tega dokumenta, imajo prednost nacionalni predpisi/standardi. Odbor SFG_I ob sklicevanju na navedene smernice Komisije C(2007) 3416 daje prednost metodi za določanje količine emisij CO2 na podlagi izračuna. Pristojni organi lahko v zvezi s komercialnim trgovanjem z zemeljskim plinom dovolijo določitev letne porabe plina, zaradi česar se emisije CO2 ocenjujejo izključno na podlagi obračunane količine plina brez dodatnega posameznega dokazovanja povezanih negotovosti, če nacionalna zakonodaja ali dokumentirana uporaba standardov zagotavlja, da so za komercialne transakcije izpolnjene ustrezne zahteve glede negotovosti za podatke o dejavnosti (smernice C(2007) 3416 – točka 7 priloge 1). V skladu s točko 5.2 in poglavjem 16 priloge 1 k smernicam C(2007) 3416 za naprave s tokovi vira de minimis in nizkimi emisijami je mogoče odstopiti od določb tega dokumenta.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
kSIST-TP FprCEN/TR 16478:2012
01-september-2012
[Not translated]
Surveillance from first commissioning on measuring devices used in natural gas supply
to the installations of the activities under the Directive 2003/87/EC establishing a scheme
of CO2 emissions trading
Ta slovenski standard je istoveten z: FprCEN/TR 16478
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
kSIST-TP FprCEN/TR 16478:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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kSIST-TP FprCEN/TR 16478:2012
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kSIST-TP FprCEN/TR 16478:2012
TECHNICAL REPORT
FINAL DRAFT
FprCEN/TR 16478
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2012
ICS 75.180.30
English Version
Surveillance from first commissioning on measuring devices
used in natural gas supply to the installations of the activities
under the Directive 2003/87/EC establishing a scheme of CO2
emissions trading
This draft Technical Report is submitted to CEN members for Technical Committee Approval. It has been drawn up by the Technical
Committee CEN/SS S12.
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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a Technical Report.
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. FprCEN/TR 16478:2012: E
worldwide for CEN national Members.
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Contents Page
Foreword . 3
1 Scope . 4
2 Terms and definitions . 4
3 Surveillance . 6
3.1 General . 6
3.2 Activities of the surveillance for conversion devices, gas chromatographs and gas
meters . 6
3.3 Planning of surveillance . 6
3.3.1 General . 6
3.3.2 First commissioning . 7
3.3.3 Specific activities related to warnings from, self-diagnostic means . 7
3.3.4 Periodical visual inspection / verification / re-lubrication . 7
3.4 Recalibration for gas chromatograph . 8
3.4.1 General . 8
3.4.2 Specific requirements for surveillance . 8
3.5 Specific surveillance activities on gas meters and on gas converters . 9
3.5.1 Periodical recalibration . 9
3.5.2 Periodical monitoring of the difference of indication of gas meters. 10
3.5.3 Monitoring of the changing of the difference of indication of gas meters during
operation. 12
4 Proposal for a European scheme related to common provisions and limit values. 14
4.1 General . 14
4.2 Summary of requirements for surveillance on metrological performance . 14
Annex A (informative) National Situations regarding Devices Measuring the Supply of Gas
Natural for the Activities Listed in Annex 1 of ETD . 16
A.1 BELGIUM (devices in own Fluxys'Emission Trading Sites) . 16
A.2 GERMANY. 18
A.3 SPAIN . 20
A.4 FRANCE . 22
A.5 GREECE . 24
A.6 ITALY . 27
A.7 SLOVAKIA . 30
Bibliography . 31
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Foreword
This document (FprCEN/TR 16478:2012) has been prepared by “CEN Sector Forum Gas Infrastructure”, the
secretariat of which is held by CCMC.
This document is submitted to a Technical Committee Approval.
The document C(2007) 3416 COMMISSION DECISION of 18 July 2007 (2007/589/EC) establishing
guidelines for the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of
the European Parliament and of the Council shall be used as common guidelines in the determination of
the greenhouse gas emissions for all categories of activities listed in the Annex I of the Directive itself.
th
In the 5 paragraph of Clause 3, these guidelines establish that “It shall be ensured that the emission
determination is systematically neither over nor under true emissions. Sources of uncertainties shall be
identified and reduced as far as practicable. (…) All metering or other testing equipment used to report
monitoring data shall be appropriately applied, maintained and calibrated, and checked.”
This Technical Report is intended to be used as a guideline in conjunction with the document C(2007) 3416
and to be applied to measuring instrument of natural gas measuring stations based on EN 1776 and possibly
stand alone measuring instruments measuring the natural gas used in the categories of activities listed in the
Annex I of the Directive 2003/87/EC.
As inside European Union, at the time of writing this document, there is not any common guideline dealing
with how to ensure an established difference of indication of a natural gas metering equipment in the use
throughout their technical life; there is the risk to manage the greenhouse gas emissions data declared by
different Member States that are not completely comparable because of their determination by calculations
based on consumption of natural gas data not homogeneous as regard the reliability of the accuracy of their
measurements.
The intent of this Technical Report is to give minimum provisions for surveillance in use of natural gas
measuring equipment in order to ensure the compliance with an established difference of indication, leading
so to comparable greenhouse gas emissions data.
In the same time it is a proposal addressed to the Commission and the Member States to reflect on a
consistent procedure enabling an equivalent determination of the CO amounts of emissions across the EU
2
countries.
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1 Scope
This Technical Report establishes minimum provisions for the surveillance, based on available standards,
from first commissioning, on the devices and systems with measuring function throughout their technical life
when used in the activities of the categories listed in the Annex I of the European Directive 2003/87/EC, in
order to ensure the compliance with the expected maximum allowable difference of indication.
This Technical Report applies to devices / systems with the function to measure:
volumetric or mass amount of natural gas consumption (any type of gas meters),
volumetric amount of natural gas consumption at specified base conditions (conversion devices),
composition of natural gas (gas chromatographs),
for calculating, in accordance with the applicable provisions of the guidelines C(2007) 3416, the amount of
the CO emissions from the source stream of natural gas.
2
Users of this document should be aware that more detailed national recommendations/standards and/or
codes of practice as well as national measures possibly approved by National Regulator may exist inside the
EU Member States.
When national regulations have to be applied, this document should not be considered.
Except in the aforementioned case, this Technical Report is intended to be applied in association with
applicable national recommendations/standards and/or codes of practice setting out the above mentioned
surveillance provisions.
In the event of conflicts in terms of different requirements in national regulations/standards with the
provisions of this document, the national regulations/standards shall take precedence.
Referring to the aforesaid Commission's guidelines C(2007) 3416, SFG_I opts for the calculation based
method to determine the amount of the CO emissions.
2
As regards commercially traded of natural gas, competent Authorities may permit the determination of the
annual gas consumption leading to evaluation of CO emissions based solely on the invoiced amount of gas
2
without further individual proof of associated uncertainties, provided that national legislation or the
documented application of standards ensures that respective uncertainty requirements for activity data are
met for commercial transactions (guidelines C(2007) 3416 -annex 1 §7).
Referring to 5.2 and to Chapter 16, annex 1 of guidelines C(2007) 3416, for installations with “de minimis”
souce streams and with low emissions respectively, the provisions of this document can be waived.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE The pilot terms are listed in alphabetic order. The derived terms from a pilot term, if any, are listed in the
appropriate order just after the relevant pilot term.
2.1
competent person
person who is trained, experienced and approved to perform measuring surveillance activities
Note 1 to entry: Adapted from EN 12186:2000.
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2.2
difference of indication
difference between the indicated value V of a device with measuring function and the one of a reference
m
instrument V for a specific operating datum of the same measurand expressed as percentage of the value
r
measured by the reference instrument:
V −V
m r
D= ×100
V
r
2.3
System Operator
SO
natural or legal person who carries out the function of transmission and/or distribution and is responsible for
operating, ensuring the surveillance of, and, if necessary, developing the transmission and/or distribution
system/s in a given area and, where applicable, their interconnections, and for ensuring the long-term ability
of the system to meet reasonable demands for the transportation and/or distribution of gas
2.4
maximum allowable difference
maximum absolute value of the difference of indication
2.5
measuring device
measuring instrument capable to measure a process datum (e.g. gas meters, pressure transducer, pressure
indicator, temperature transducer, etc.)
2.6
measuring systems
assembly of several measuring devices capable to measure a process datum via several other process data
(e.g. a gas meter + pressure and temperature transducer + conversion device)
[SOURCE: MID, Directive 2004/22/EC of the European Parliament and the Council of 31 March 2004 on
measuring instruments]
2.7
recalibration
activities consisting in the verification that the differences of indication of a device with measuring function
are within the limits specified in the relevant standard and re-alignment of the indication when needed
2.8
self-diagnostic
mean, e.g. software, capable to warn when the measuring device / system is not operating properly
2.9
self-recalibration
recalibration activity carried out automatically by the measuring device itself, e. g. gas chromatograph
2.10
significant parameter
measurable characteristic involved in the measuring process (of the measuring devices / system) which, in
case of drift out from pre-established limits, may imply errors of the measuring process (e.g. when in an
ultrasonic gas meter, the transient times reflect a significant different speed of sound for one of the paths
compared with the average speed of all paths)
Note 1 to entry: This document considers following limits for significant parameter:
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− normal thresholds: the maximum and/or minimum values of a significant parameter identified in the type test
of a measuring device / system for normal operating conditions; when these limits are met it is presumed that
the necessary conditions for proper measurements occur;
− care thresholds: values of a significant parameter still ensuring proper measurement but signalling the risk that
the significant parameter may further drift and reach the alarm level;
− alarm thresholds: values of a significant parameter that imply inacceptable differences of indication of the
measuring process and that, when they occur, require the activation of corrective actions to reestablish the
necessary conditions under which it is presumed that proper measurement process occurs.
2.11
warnings
visible / perceptible signal noticing that malfunctions have occurred in the measuring device / system
3 Surveillance
3.1 General
st
All those activities carried out from the 1 commissioning of measuring devices / systems throughout their
technical life until the last de-commissioning aimed at ensuring that the differences of indication during the
operating life are not higher than the maximum allowable difference.
3.2 Activities of the surveillance for conversion devices, gas chromatographs and gas
meters
The activities of the surveillance should include:
a) First commissioning;
b) Specific activities related to warnings from self-diagnostic means only where applicable;
c) Periodical:
1) visual inspection and
2) verification and
3) re-lubrication where requested as per the relevant maintenance manual
d) Recalibration applicable only to gas chromatograph; periodical recalibration applicable to gas meters and
converters;
e) Periodical monitoring of the difference of indication and, when needed, subsequent recalibration (not
applicable to gas chromatograph).
The System Operator fulfilling activities d) does not need to consider the activities e).
3.3 Planning of surveillance
3.3.1 General
The stability during operation of the metrological performance depends on both the measuring equipment
and the operating conditions. When establishing the surveillance policy, the following should be considered:
the specific composition of fuel gas, the specific location and layout of the measuring system
(e.g. redundancy of measuring devices), the reliability of the historical measured-performance data, the
measuring-reliability of the stations, the impact of the difference of indication on the involved parties
(e.g. global amount of measured gas, uncertainty thresholds requested by the document C(2007) 3416,
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etc.), the need for the continuity of the gas supply, the presence of the auto-diagnosis function and any other
elements that may affect the measuring-performances of any measuring devices / systems.
For the surveillance activities on devices/systems with measuring controls it should be considered that:
the 1st commissioning takes place only at initial start up of a single new measuring device / system /
stations,
the periodical monitoring of the difference of indication should be followed by a subsequent recalibration
only when needed as described in 3.5.2;
and the advantage to combine, for each intervention at site, surveillance activities for other equipment of the
same installation.
3.3.2 First commissioning
st
The 1 commissioning should be carried out in accordance with:
national regulations/standards where available;
codes of practices of System Operator (SO)
but at least according to this guideline in case of lack of national regulations/standards or codes of practice.
st
The task of 1 commissioning should include following verifications:
the conformity of installation with the applicable prescriptions;
compliance with MID or national standards for meters, converters and other measuring devices where
applicable (markings and integrity of the seals);
a self calibration of gas chromatographs (followed by self-recalibrations which take place periodically);
the availability of the relevant user's manual and test certificate according to relevant standard.
3.3.3 Specific activities related to warnings from, self-diagnostic means
Where measuring devices and/or systems provide specific warnings, in case of their activation the
recommended actions detailed in the relevant user’s manual should be implemented within due time in
accordance with the provisions in force.
3.3.4 Periodical visual inspection / verification / re-lubrication
Commonly the periodical specific visual inspections / verifications / re-lubrication activities are listed and
described in the concerned use/maintenance manual.
In general these activities should be carried out in the period between two consecutive recalibrations and/or
monitoring of the difference of indication. The activities listed in Table 1 should be selected by the operator,
where applicable.
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1)
Table 1 — Periodical visual inspection / verification and maintenance (meters + converters)
Description of the activities Equipment concerned Acceptance criteria
No visible damages,
Readable over operating
temperature range
Visual inspection of external conditions
All measuring devices
of indicating device External Surface protection in
normal conditions
No any abnormal corrosion
Measuring devices with mobile No any emission of abnormal
Noise emissions
parts (e.g. turbine gas meters) noise
Verification of:
¾ cleaning,
As per the relevant standard
¾ external aspect and Orifice meters
and user’s manual
¾ dimensions
of orifice plate and other internal parts
Those measuring devices for
Maintenance activities (e.g. lubrication
which the use/maintenance As per relevant
and re-lubrication) as listed in the
manual specifies the need of use/maintenance manual
user's manual
periodical re-lubrication
3.4 Recalibration for gas chromatograph
3.4.1 General
The gas chromatograph is a measuring device that can undertake self-recalibration at periodical interval or
can be calibrated regularly.
For this equipment the self-recalibration or regularly calibration together with the activities outlined in a), b)
and c) of 3.2 should be sufficient to ensure that the specified metrological performances are met.
3.4.2 Specific requirements for surveillance
The planning of surveillance should consider:
a) the frequency of self recalibration should be established on the basis of:
1) national regulations/standards where available,
2) code(s) of practice of System Operator
but at least according to this guideline in case of lack of national regulations/standards.
The above approach should evaluate following pre-conditions:
the installation conditions (temperature, protection, etc.) of the bottles of gas samples should be carried
out as per the recommendations listed in the relevant installation manual;
1) The applicable activities to be complied with should be selected by the operator.
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the replacement of the bottles of gas samples should be done as per the recommendations listed in the
installation manual; the composition of the gas sample should be certified by an accredited test
laboratory;
the electronic memory of gas chromatograph should give evidence of an appropriated number of last
automatic self-recalibration carried out (e.g. 10 last self-recalibrations) as well as the relevant errors of
indication based on a statistical data collection; all these historical data should be periodically examined
by a competent person to evaluate whether there is a need to introduce some corrective actions aimed
to ensure in the time the expected reliability of the metrological performance.
Further it shall be noted that the examination of historical data should comply with national regulations /
standards where available.
3.5 Specific surveillance activities on gas meters and on gas converters
3.5.1 Periodical recalibration
3.5.1.1 General
System Operators carrying out the surveillance on gas meters and on converter according to the method
described in this subclause would not need to consider the method of surveillance described in 3.5.2.
The method of recalibration should be that followed for calibration as per the relevant standard.
The minimum frequency should be established on the basis of:
national regulations/standards where available,
codes of practice of System Operator (SO) in case of lack of national regulations/standards but at least
on the basis of the frequencies showed in Table 2 of this guideline.
3.5.1.2 Specific conditions for a decreasing of the frequency of periodical recalibrations for gas
meters equipped with self-diagnostic means
Where the gas meters are equipped with self-diagnostic means and the periodical recalibration method has
been chosen for the surveillance in use, the System Operator can prolong the pre-established period of time
between two subsequent recalibrations if the self-diagnostic function is capable to detect care threshold and
alarm threshold for significant parameters.
Some gas meters, e.g. the ultrasonic and Coriolis gas meters, are equipped with self-diagnostic software
capable to warn when the necessary conditions for proper measurement are not met. These conditions are
often identified by limiting minimum and maximum values for certain diagnostic functions or parameters.
Practically the warning consists of alarms that notify that some significant measuring parameters are outside
the identified limits.
For example in the ultrasonic meters it is very common to introduce some limits for the differences of the
various speeds of sound calculated for each path from the average speed of sound of all paths. In other
words when these limits are exceeded the cause (dirty, fault, etc.) should be traced and investigated and
appropriate corrective actions implemented.
The self-diagnostic function can detect following two different warnings for a significant measuring
parameter:
a care threshold (e.g. yellow light) or
an alarm threshold (e.g. red light).
9
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Commonly the alarm threshold warns that the limits of the concerned significant measuring parameter have
been exceeded and the care threshold warns that it is expected that the limits of the concerned significant
measuring parameter can be exceeded.
When thresholds are exceeded the following actions should be taken:
in case of care threshold, an investigation by a competent person on the cause of the drift from starting
normal conditions for proper measurements and relevant corrective actions should be implemented
within appropriate time;
in the case of alarm threshold an investigation by a competent person on the cause of the deviation
from necessary conditions for proper measurements and, consequently, the necessary intervention
(e.g. cleaning of transducer faces in ultrasonic meters) to re-establish adequate operating conditions.
3.5.2 Periodical monitoring of the difference of indication of gas meters
3.5.2.1 General
This type of surveillance activity should be considered as an alternative to the surveillance activity described
in 3.5.1.
This method, as alternative to periodical recalibration, is based on the periodical verification at field of the
difference of indication of the measuring device / system and subsequent recalibration where the historical
trend of the difference of indication data reveals that it should be expected that the pre-established
metrological performances will not be met.
The periodical verification of the difference of indication may be carried out either for the end-output data of
the measuring chain (e.g. output data of gas-volume of an electronic conversion device part of a measuring
chain including a gas meter, pressure and temperature transducers) and/or for single unit of the measuring
chain (e.g. gas meter, pressure transducer, etc.). In this second event, the periodical verification of the
difference of indication should involve at least those single units whose malfunction may affect the end-
output measuring data.
The practical method to verify the difference of indication may be for example:
measuring of the same datum by two different independent meters (e.g. two gas meters in series for the
same flowing gas);
any other suitable method capable to quantify the difference of indications of gas meter under
verification for one or more operating conditions within the normal operating range.
The reference instrument may be based on measurement of flow in closed conduits by tracer (dilution or
transit time methods according to the principles of ISO 2975-1).
One of the methods described in 3.5.2.2 and 3.5.3 can be chosen by the System Operator.
3.5.2.2 Measuring of the same datum at the same time by two different independent gas meters
3.5.2.2.1 Monitoring of two gas meters with same or slightly different measurement ranges
connected in-series
This method practically consists in comparing the two values of the same datum measured by two different
gas meters at the same time. At least two couples of measured values within the normal operating range of
both meters should be compared.
The two gas meters may be of differing technologies and may have slightly different full scales. However in
this last case, it is necessary to have suitable overlapping of operating ranges in such a way so as to be able
to compare two couples of measured values of the same datum.
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Where the operating conditions of the installation do not allow carrying out the tests consequently, it is
recommended to take the measured values of the two couples within a 24-hour period.
EXAMPLE
This method should include the following steps:
the measuring of the concerned processing datum by the two different gas meters;
calculation of the deviation between of the two m
...
SLOVENSKI STANDARD
SIST-TP CEN/TR 16478:2013
01-januar-2013
Nadzor nad merilnimi napravami v napeljavah za zemeljski plin od prvega zagona
dalje za vzpostavitev sheme za trgovanje z emisijami CO2, skladno z direktivo
2003/87/EC
Surveillance from first commissioning on measuring devices used in natural gas supply
to the installations of the activities under the Directive 2003/87/EC establishing a scheme
of CO2 emissions trading
Surveillance de la mise en service des appareils de mesure utilisés pour la fourniture de
gaz naturel aux installations pour les activités sous la Directive 2003/87/CE établissant
un schéma d'échange d'émissions de CO2
Ta slovenski standard je istoveten z: CEN/TR 16478:2012
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
SIST-TP CEN/TR 16478:2013 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TP CEN/TR 16478:2013
TECHNICAL REPORT
CEN/TR 16478
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
December 2012
ICS 75.180.30
English Version
Surveillance from first commissioning on measuring devices
used in natural gas supply to the installations of the activities
under the Directive 2003/87/EC establishing a scheme of CO
2
emissions trading
Surveillance de la mise en service des appareils de mesure
utilisés pour la fourniture de gaz naturel aux installations
pour les activités sous la Directive 2003/87/CE établissant
un schéma d'échange d'émissions de CO
2
This Technical Report was approved by CEN on 15 October 2012. It has been drawn up by the Technical Committee CEN/SS S12.
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
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16478:2012: E
worldwide for CEN national Members.
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Contents Page
Foreword . 3
1 Scope . 4
2 Terms and definitions . 4
3 Surveillance . 6
3.1 General . 6
3.2 Activities of the surveillance for conversion devices, gas chromatographs and gas
meters . 6
3.3 Planning of surveillance . 6
3.3.1 General . 6
3.3.2 First commissioning . 7
3.3.3 Specific activities related to warnings from, self-diagnostic means . 7
3.3.4 Periodical visual inspection/verification/re-lubrication . 7
3.4 Recalibration for gas chromatograph . 8
3.4.1 General . 8
3.4.2 Specific requirements for surveillance . 8
3.5 Specific surveillance activities on gas meters and on gas converters . 9
3.5.1 Periodical recalibration . 9
3.5.2 Periodical monitoring of the difference of indication of gas meters. 10
3.5.3 Monitoring of the changing of the difference of indication of gas meters during
operation. 12
4 Proposal for a European scheme related to common provisions and limit values. 14
4.1 General . 14
4.2 Summary of requirements for surveillance on metrological performance . 14
Annex A (informative) National Situations regarding Devices Measuring the Supply of Gas
Natural for the Activities Listed in Annex 1 of ETD . 16
A.1 BELGIUM (devices in own Fluxys'Emission Trading Sites) . 16
A.2 GERMANY. 18
A.3 SPAIN . 20
A.4 FRANCE . 22
A.5 GREECE . 24
A.6 ITALY . 26
A.7 SLOVAKIA . 29
Bibliography . 30
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Foreword
This document (CEN/TR 16478:2012) has been prepared by “CEN Sector Forum Gas Infrastructure”.
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.
The document C(2007) 3416 COMMISSION DECISION of 18 July 2007 (2007/589/EC) establishing
guidelines for the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of
the European Parliament and of the Council [15] will be used as common guidelines in the determination
of the greenhouse gas emissions for all categories of activities listed in the Annex I of the Directive itself.
In the fifth paragraph of Clause 3, these guidelines establish that “It shall be ensured that the emission
determination is systematically neither over nor under true emissions. Sources of uncertainties shall be
identified and reduced as far as practicable. (…) All metering or other testing equipment used to report
monitoring data shall be appropriately applied, maintained and calibrated, and checked.”
This Technical Report is intended to be used as a guideline in conjunction with the document C(2007) 3416
and to be applied to measuring instruments of natural gas measuring stations based on EN 1776, and
possibly stand alone measuring instruments measuring the natural gas used in the categories of activities
listed in the Annex I of the Directive 2003/87/EC.
Within the European Union, at the time of writing, there was no common guideline dealing with how to
ensure an established difference of indication of a natural gas metering equipment in the use throughout
their technical life. The associated risk: to manage the greenhouse gas emissions data declared by different
Member States that are not completely comparable because of their determination by calculations based on
consumption of natural gas data not homogeneous with regard to the reliability of the accuracy of their
measurements.
The intent of this Technical Report is to give minimum provisions for surveillance in the use of natural gas
measuring equipment in order to ensure compliance with an established difference of indication, leading to
comparable greenhouse gas emissions data.
Furthermore, it is a proposal addressed to the Commission and the Member States to reflect on a consistent
procedure that would enable an equivalent determination of the CO amounts of emissions across the EU
2
countries.
3
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1 Scope
This Technical Report establishes minimum provisions for the surveillance, based on available standards
from first commissioning, of devices and systems with measuring function throughout their technical life
when used in the activities of the categories listed in the Annex I of the European Directive 2003/87/EC. It
does so in order to ensure the compliance with the expected maximum allowable difference of indication.
This Technical Report applies to devices/systems with the function to measure:
volumetric or mass amount of natural gas consumption (any type of gas meters),
volumetric amount of natural gas consumption at specified base conditions (conversion devices),
composition of natural gas (gas chromatographs),
for calculating, in accordance with the applicable provisions of the guidelines C(2007) 3416, the amount of
the CO emissions from the source stream of natural gas.
2
Users of this document should be aware that more detailed national recommendations/standards and/or
codes of practice as well as national measures possibly approved by National Regulator may exist inside the
EU Member States.
When national regulations have to be applied, this document should not be considered.
Except in the aforementioned case, this Technical Report is intended to be applied in association with
applicable national recommendations/standards and/or codes of practice setting out the above mentioned
surveillance provisions.
In the event of conflict in terms of different requirements in national regulations/standards and in the
provisions of this document, the national regulations/standards will take precedence.
Referring to the aforesaid Commission's guidelines C(2007) 3416, SFG_I opts for the calculation based
method to determine the amount of the CO emissions.
2
Regarding commercially traded of natural gas, competent authorities may permit the determination of the
annual gas consumption leading to evaluation of CO emissions based solely on the invoiced amount of gas
2
without further individual proof of associated uncertainties, provided that national legislation or the
documented application of standards ensures that respective uncertainty requirements for activity data are
met for commercial transactions (guidelines C(2007) 3416 -annex 1 §7).
Referring to 5.2 and to Chapter 16, annex 1 of guidelines C(2007) 3416, for installations with “de minimis”
souce streams and with low emissions respectively, the provisions of this document can be waived.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE The pilot terms are listed in alphabetic order. The derived terms from a pilot term, if any, are listed in the
appropriate order just after the relevant pilot term.
2.1
competent person
person who is trained, experienced and approved to perform measuring surveillance activities
[SOURCE: EN 12186:2000, modified]
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2.2
difference of indication
difference between the indicated value V of a device with measuring function and the one of a reference
m
instrument V for a specific operating datum of the same measurand expressed as percentage of the value
r
measured by the reference instrument:
V −V
m r
D= ×100
V
r
2.3
maximum allowable difference
maximum absolute value of the difference of indication
2.4
measuring device
measuring instrument capable of measuring a process datum (e.g. gas meters, pressure transducer,
pressure indicator, temperature transducer, etc.)
2.5
measuring systems
assembly of several measuring devices capable of measuring a process datum via several other process
data (e.g. a gas meter + pressure and temperature transducer + conversion device)
[SOURCE: MID, Directive 2004/22/EC of the European Parliament and the Council of 31 March 2004 on
measuring instruments]
2.6
recalibration
activities consisting of the verification that the differences of indication of a device with measuring function
are within the limits specified in the relevant standard and re-alignment of the indication when needed
2.7
self-diagnostic
mean, e.g. software, capable of warning when the measuring device/system is not operating properly
2.8
self-recalibration
recalibration activity carried out automatically by the measuring device itself, e.g. gas chromatograph
2.9
significant parameter
measurable characteristic involved in the measuring process (of the measuring devices/system) which, in
case of drift out from pre-established limits, may imply errors of the measuring process
Note 1 to entry: For example, when in an ultrasonic gas meter, the transient times reflect a significant different speed
of sound for one of the paths compared with the average speed of all paths.
Note 2 to entry: This document considers following limits for significant parameter:
normal thresholds: the maximum and/or minimum values of a significant parameter identified in the type test of a
measuring device/system for normal operating conditions; when these limits are met it is presumed that the
necessary conditions for proper measurements occur;
care thresholds: values of a significant parameter still ensuring proper measurement but signalling the risk that the
significant parameter may further drift and reach the alarm level;
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alarm thresholds: values of a significant parameter that imply inacceptable differences of indication of the
measuring process and that, when they occur, require the activation of corrective actions to reestablish the
necessary conditions under which it is presumed that proper measurement process occurs.
2.10
Gas Measuring System Operator (GMSO)
natural or legal person who is responsible for the operation and maintenance of the measuring system
2.11
warnings
visible/perceptible signal indicating that malfunctions have occurred in the measuring device/system
3 Surveillance
3.1 General
All those activities carried out from the first commissioning of measuring devices/systems throughout their
technical life until the last de-commissioning aimed at ensuring that the differences of indication during the
operating life are not higher than the maximum allowable difference.
3.2 Activities of the surveillance for conversion devices, gas chromatographs and gas
meters
The activities of the surveillance should include:
a) first commissioning;
b) specific activities related to warnings from self-diagnostic means only where applicable;
c) periodical activities:
1) visual inspection, and
2) verification, and
3) re-lubrication where requested as per the relevant maintenance manual.
d) recalibration applicable only to gas chromatograph; periodical recalibration applicable to gas meters and
converters;
e) periodical monitoring of the difference of indication and, when needed, subsequent recalibration (not
applicable to gas chromatograph).
The Gas Measuring System Operator fulfilling activities d) does not need to consider the activities e).
3.3 Planning of surveillance
3.3.1 General
The stability during operation of the metrological performance depends on both the measuring equipment
and the operating conditions. When establishing the surveillance policy, the following should be considered:
a) the specific composition of fuel gas;
b) the specific location and layout of the measuring system (e.g. redundancy of measuring devices);
c) the reliability of the historical measured-performance data;
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d) the measuring-reliability of the stations;
e) the impact of the difference of indication on the involved parties (e.g. global amount of measured gas,
uncertainty thresholds requested by the document C(2007) 3416, etc.);
f) the need for the continuity of the gas supply, the presence of the auto-diagnosis function;
g) any other elements that may affect the measuring-performances of any measuring devices/systems.
For the surveillance activities on devices/systems with measuring controls, it should be considered that:
h) the first commissioning takes place only at initial start up of a single new measuring
device/system/stations,
i) the periodical monitoring of the difference of indication should be followed by a subsequent recalibration
only when needed as described in 3.5.2, and
j) the advantage to combine, for each intervention at site, surveillance activities for other equipment of the
same installation.
3.3.2 First commissioning
The first commissioning should be carried out in accordance with:
national regulations/standards where available,
codes of practices of the Gas Measuring System Operator (GMSO),
but at least according to this guideline in case of lack of national regulations/standards or codes of practice.
The task of first commissioning should include following verifications:
the conformity of installation with the applicable prescriptions;
compliance with MID or national standards for meters, converters and other measuring devices where
applicable (markings and integrity of the seals);
a self calibration of gas chromatographs (followed by self-recalibrations which take place periodically);
the availability of the relevant user's manual and test certificate according to relevant standard.
3.3.3 Specific activities related to warnings from, self-diagnostic means
Where measuring devices and/or systems provide specific warnings, in case of their activation the
recommended actions detailed in the relevant user’s manual should be implemented within due time in
accordance with the provisions in force.
3.3.4 Periodical visual inspection/verification/re-lubrication
The periodical specific visual inspections/verifications/re-lubrication activities are usually listed and described
in the concerned use/maintenance manual.
In general, these activities should be carried out in the period between two consecutive recalibrations and/or
monitoring of the difference of indication. The activities listed in Table 1 should be selected by the operator,
where applicable.
7
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1)
Table 1 — Periodical visual inspection/verification and maintenance (meters + converters)
Description of the activities Equipment concerned Acceptance criteria
No visible damages,
Readable over operating
temperature range
Visual inspection of external conditions
All measuring devices
of indicating device External Surface protection in
normal conditions
No any abnormal corrosion
Measuring devices with mobile No any emission of abnormal
Noise emissions
parts (e.g. turbine gas meters) noise
Verification of:
¾ cleaning,
As per the relevant standard
¾ external aspect and Orifice meters
and user’s manual
¾ dimensions
of orifice plate and other internal parts
Those measuring devices for
Maintenance activities (e.g. lubrication
which the use/maintenance As per relevant
and re-lubrication) as listed in the
manual specifies the need of use/maintenance manual
user's manual
periodical re-lubrication
3.4 Recalibration for gas chromatograph
3.4.1 General
The gas chromatograph is a measuring device that can undertake self-recalibration at periodical intervals or
can be calibrated regularly.
For this equipment, the self-recalibration or regular calibration together with the activities outlined in a), b)
and c) of 3.2 should be sufficient to ensure that the specified metrological performances are met.
3.4.2 Specific requirements for surveillance
The planning of surveillance should consider:
a) The frequency of self recalibration should be established on the basis of:
1) national regulations/standards where available,
2) code(s) of practice of Gas Measuring System Operator,
but at least according to this guideline in case of lack of national regulations/standards.
b) The above approach should evaluate following pre-conditions:
1) the installation conditions (temperature, protection, etc.) of the bottles of gas samples should be
carried out as per the recommendations listed in the relevant installation manual;
1) The applicable activities to be complied with should be selected by the operator.
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2) the replacement of the bottles of gas samples should be done as per the recommendations listed in
the installation manual; the composition of the gas sample should be certified by an accredited test
laboratory;
3) the electronic memory of gas chromatograph should give evidence of an appropriated number of
last automatic self-recalibration carried out (e.g. 10 last self-recalibrations) as well as the relevant
errors of indication based on a statistical data collection. All these historical data should be
periodically examined by a competent person to evaluate whether there is a need to introduce
corrective actions aimed to ensure the expected reliability of the metrological performance.
c) Furthermore, it shall be noted that the examination of historical data should comply with national
regulations/standards where available.
3.5 Specific surveillance activities on gas meters and on gas converters
3.5.1 Periodical recalibration
3.5.1.1 General
Gas Measuring System Operators carrying out the surveillance on gas meters and on converters according
to the method described in this subclause would not need to consider the method of surveillance described
in 3.5.2.
The method of recalibration should be that followed for calibration as per the relevant standard.
The minimum frequency should be established on the basis of:
national regulations/standards where available,
codes of practice of the Gas Measuring System Operator (GMSO) in case of lack of national
regulations/standards but at least on the basis of the frequencies showed in Table 2 of this guideline.
3.5.1.2 Specific conditions for a decreasing of the frequency of periodical recalibrations for gas
meters equipped with self-diagnostic means
Where the gas meters are equipped with self-diagnostic means and the periodical recalibration method has
been chosen for the surveillance in use, the Gas Measuring System Operator can prolong the pre-
established period of time between two subsequent recalibrations if the self-diagnostic function is capable of
detecting care threshold and alarm threshold for significant parameters.
Some gas meters, e.g. the ultrasonic and Coriolis gas meters, are equipped with self-diagnostic software
capable of warning when the necessary conditions for proper measurement are not met. These conditions
are often identified by limiting minimum and maximum values for certain diagnostic functions or parameters.
Practically, the warning consists of alarms that indicate when some significant measuring parameters are
outside the identified limits.
For example, in the ultrasonic meters it is very common to introduce some limits for the differences of the
various speeds of sound calculated for each path from the average speed of sound of all paths. In other
words, when these limits are exceeded, the cause (dirty, fault, etc.) should be traced and investigated and
appropriate corrective actions implemented.
The self-diagnostic function can detect following two different warnings for a significant measuring
parameter:
a care threshold (e.g. yellow light) or
an alarm threshold (e.g. red light).
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Generally, the alarm threshold warns that the limits of the concerned significant measuring parameter have
been exceeded and the care threshold warns that it is expected that the limits of the concerned significant
measuring parameter will be exceeded.
When thresholds are exceeded, the following actions should be taken:
in case of care threshold: an investigation by a competent person into the cause of the drift from starting
normal conditions for proper measurements; relevant corrective actions should be implemented within
appropriate time;
in the case of alarm threshold: an investigation by a competent person into the cause of the deviation
from necessary conditions for proper measurements and, consequently, the necessary intervention
(e.g. cleaning of transducer faces in ultrasonic meters) to re-establish adequate operating conditions.
3.5.2 Periodical monitoring of the difference of indication of gas meters
3.5.2.1 General
This type of surveillance activity should be considered as an alternative to the surveillance activity described
in 3.5.1.
This method, as alternative to periodical recalibration, is based on the periodical verification at field of the
difference of indication of the measuring device/system and subsequent recalibration where the historical
trend of the difference of indication data reveals that it should be expected that the pre-established
metrological performances will not be met.
The periodical verification of the difference of indication may be carried out either for the end-output data of
the measuring chain (e.g. output data of gas-volume of an electronic conversion device part of a measuring
chain including a gas meter, pressure and temperature transducers) and/or for single unit of the measuring
chain (e.g. gas meter, pressure transducer, etc.). In this second event, the periodical verification of the
difference of indication should involve at least those single units whose malfunction may affect the end-
output measuring data.
The practical method to verify the difference of indication may be for example:
measuring of the same datum by two different independent meters (e.g. two gas meters in series for the
same flowing gas);
any other suitable method capable to quantify the difference of indications of gas meter under
verification for one or more operating conditions within the normal operating range.
The reference instrument may be based on measurement of flow in closed conduits by tracer (dilution or
transit time methods according to the principles of ISO 2975-1).
One of the methods described in 3.5.2.2 and 3.5.3 can be chosen by the Gas Measuring System Operator.
3.5.2.2 Measuring of the same datum at the same time by two different independent gas meters
3.5.2.2.1 Monitoring of two gas meters with same or slightly different measurement ranges
connected in-series
This method practically consists of comparing the two values of the same datum measured by two different
gas meters at the same time. At least two couples of measured values within the normal operating range of
both meters should be compared.
The two gas meters may be of differing technologies and may have slightly different full scales. However, in
this last case, it is necessary to have suitable overlapping of operating ranges in such a way so as to be able
to compare two couples of measured values of the same datum.
10
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Where the operating conditions of the installation do not allow carrying out the tests consequently, it is
recommended to take the measured values of the two couples within a 24 h period.
EXAMPLE
This method should include the following steps:
the measuring of the
...
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