SIST EN 12480:2026
(Main)Gas meters - Rotary displacement gas meters
Gas meters - Rotary displacement gas meters
This document specifies ranges, construction, performances, output characteristics and testing of rotary displacement gas meters (hereinafter referred to as RD meters or simply meters) for gas volume measurement.
This document applies to rotary displacement gas meters used to measure the volume of fuel gases of at least the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437:2021, at a maximum working pressure up to and including 20 bar over an ambient and gas temperature range of at least −10 °C to +40 °C.
This document applies to meters that are installed in locations with vibration and shocks of low significance (class M1) and in
- closed locations (indoor or outdoor with protection) with condensing or with non-condensing humidity
or,
- open locations (outdoor without any covering) with condensing humidity or with non-condensing humidity,
and in locations with electromagnetic disturbances (class E1 and E2). The standard applies to mechanical meters with mechanical index, electronic devices are not covered by this standard.
Unless otherwise specified in this standard:
- all pressures used are gauge;
- all influence quantities, except the one under test, are kept relatively constant at their reference value.
This document applies to meters with a maximum allowable pressure PS and the volume V of less than 6 000 bar · L or with a product of PS and DN of less than 3 000 bar.
This document is to be used for both pattern approval and individual meter testing. Cross-reference tables are given in:
- Annex A for the tests that need to be undertaken for pattern approval;
- Annex B for individual meter testing.
Some parts of this standard cover meters with mechanical index only.
The risk philosophy adopted in this standard is based on the analysis of hazards including pressure. The standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated appropriate protection measures are specified.
Gaszähler - Drehkolbengaszähler
Dieses Dokument legt den Einsatzbereich, die Bauart, den Betrieb, die Ausgabecharakteristiken und die Prüfung von Drehkolbengaszählern (nachfolgend RD Zähler oder einfach nur Zähler genannt) für die Gasvolumenmessung fest.
Dieses Dokument gilt für Drehkolbengaszähler, die bei einem maximalen Betriebsdruck bis einschließlich 20 bar in einem Umgebungs- und Gastemperaturbereich von mindestens −10 °C bis +40 °C für die Volumenmessung von Brenngasen von mindestens der 1., 2. und 3. Gasfamilie eingesetzt werden, deren Zusammensetzung in EN 437:2021 beschrieben ist.
Dieses Dokument gilt für Zähler, die an Standorten eingebaut sind, an denen unbedeutende Schwingungen und Erschütterungen (Klasse M1) auftreten können und die an
- geschlossenen Standorten (innen oder außen mit Schutz) mit oder ohne Betauung
oder an
- offenen Standorten (außen ohne Abdeckung) mit oder ohne Betauung
und an Standorten mit elektromagnetischen Störungen (Klasse E1 und E2) eingesetzt werden. Die Normen gelten für mechanische Zähler mit mechanischem Zählwerk. Elektronische Zähler fallen nicht unter dieses Dokument.
Soweit in diesem Dokument nicht anders angegeben:
- sind alle dargestellten Drücke als Überdrücke zu verstehen;
- werden alle Einflussgrößen außer der geprüften Einflussgröße relativ konstant bei ihrem Referenzwert gehalten.
Dieses Dokument gilt auch für Zähler mit einem maximal zulässigen Druck PS und Volumen V von weniger als 6 000 bar·l oder mit einem Produkt aus PS und DN von weniger als 3 000 bar.
Dieses Dokument kann für die Musterzulassungsprüfung und die Einzelzählerprüfung angewendet werden. Verweistabellen sind in den folgenden Abschnitten aufgeführt:
- Anhang A für die Prüfungen, die zur Musterzulassung vorgenommen werden müssen;
- Anhang B für die Einzelzählerprüfung.
Einige Abschnitte dieses Dokuments behandeln ausschließlich Zähler mit einem mechanischen Zählwerk.
Die in diesem Dokument angewendete Risikophilosophie beruht auf einer Gefahrenanalyse, die Druck einschließt. In diesem Dokument werden Grundsätze angewendet, mit denen Gefahren beseitigt oder verringert werden. Dort, wo diese Gefahren nicht beseitigt werden können, werden angemessene Schutzmaßnahmen festgelegt.
Compteurs de gaz - Compteurs de gaz à déplacement rotatif
Le présent document spécifie les plages, construction, performances, caractéristiques de sortie et essais des compteurs de mesure de volume de gaz à pistons rotatifs (appelés ci après simplement compteurs).
Le présent document s’applique aux compteurs de gaz à pistons rotatifs utilisés pour mesurer le volume de gaz au moins des 1re, 2e et 3e familles, dont la composition est spécifiée dans l’EN 437:2021, à une pression de service maximale jusqu’à 20 bar pour une gamme de température ambiante et de température du gaz d’au moins -10 °C à +40 °C.
Le présent document s’applique aux compteurs installés dans des endroits où les vibrations et les chocs sont peu importants (classe M1) et :
— dans des endroits fermés (à l’intérieur ou à l’extérieur avec la protection spécifiée par le fabricant) avec ou sans condensation d’humidité ;
ou, si le constructeur le spécifie,
— dans des endroits ouverts (à l’extérieur sans protection) avec ou sans condensation d’humidité ;
et dans des endroits avec des perturbations électromagnétiques (classe E1 et E2). La norme s’applique aux compteurs mécaniques avec index mécanique ; les dispositifs électroniques ne sont pas couverts par le présent document.
Sauf spécification contraire dans le présent document :
— toutes les pressions sont des pressions relatives ;
— toutes les grandeurs d’influence, sauf celle qui est soumise à l’essai, sont maintenues constantes à leur valeur de référence.
Le présent document s’applique également aux compteurs avec une pression maximale admissible, PS, et un volume, V, de moins de 6 000 bar · L ou avec un produit de PS et DN inférieur à 3 000 bar.
Le présent document peut être utilisé aussi bien pour l’approbation de modèle que pour des essais individuels de compteurs. Des tableaux de correspondance sont donnés à :
— l’Annexe A pour les essais qu’il est nécessaire d’effectuer pour l’approbation de modèle ;
— l’Annexe B pour les essais individuels de compteurs.
Certaines parties du présent document couvrent les compteurs disposant uniquement d’un index mécanique.
L’approche du risque adoptée dans le présent document repose sur l’analyse des dangers, notamment la pression. Les principes appliqués par le document visent à éliminer ou réduire les dangers. Lorsque ces dangers ne peuvent pas être éliminés, des mesures de protection appropriées sont spécifiées.
Plinomeri - Rotacijski plinomeri
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2026
Nadomešča:
SIST EN 12480:2018
Plinomeri - Rotacijski plinomeri
Gas meters - Rotary displacement gas meters
Gaszähler - Drehkolbengaszähler
Compteurs de gaz - Compteurs de gaz à déplacement rotatif
Ta slovenski standard je istoveten z: EN 12480:2025
ICS:
91.140.40 Sistemi za oskrbo s plinom Gas supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 12480
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2025
EUROPÄISCHE NORM
ICS 91.140.40 Supersedes EN 12480:2018
English Version
Gas meters - Rotary displacement gas meters
Compteurs de gaz - Compteurs de gaz à déplacement Gaszähler - Drehkolbengaszähler
rotatif
This European Standard was approved by CEN on 8 September 2025.
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12480:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 5
1 Scope . 6
2 Normative references . 7
3 Terms, definitions, symbols and abbreviations . 9
3.1 Terms and definitions . 9
3.2 Symbols and abbreviations . 12
4 Operating range . 13
4.1 General . 13
4.2 Flow rate range . 13
4.3 Operating pressure range . 13
4.4 Operating temperature range . 14
5 Metrological performance . 14
5.1 General . 14
5.2 Error of indication . 14
5.2.1 Requirements . 14
5.2.2 Test . 15
5.3 Pressure loss . 15
5.3.1 Requirements . 15
5.3.2 Test . 16
5.4 Metrological repeatability . 16
5.4.1 Requirements . 16
5.4.2 Test . 16
5.5 Operating pressure . 16
5.5.1 General . 16
5.5.2 Requirements . 16
5.5.3 Pattern approval test . 17
5.5.4 Individual test . 17
5.6 Temperature ranges . 17
5.6.1 General . 17
5.6.2 Minimum operational temperature . 17
5.6.3 Maximum operational temperature . 18
5.6.4 Storage temperature range . 18
5.7 Condensing ambient conditions . 18
5.7.1 Requirements . 18
5.7.2 Test . 18
5.8 Bidirectional meters . 19
5.8.1 Requirements . 19
5.8.2 Test . 19
5.9 Influence of oil filling . 19
5.9.1 Requirements . 19
5.9.2 Tests . 19
6 Design, manufacturing and materials . 19
6.1 General . 19
6.2 Design . 20
6.2.1 General . 20
6.2.2 Design method . 20
6.3 Material . 21
6.3.1 General . 21
6.3.2 Resistance to external corrosion . 21
6.3.3 Penetration resistance. 21
6.3.4 Adhesion of the protective coating . 22
6.3.5 Materials for pressurized parts . 23
6.4 Adequate strength . 23
6.4.1 Resistance to internal pressure . 23
6.4.2 Fire resistance . 24
6.4.3 External leak tightness . 24
6.4.4 Overload . 25
6.4.5 Bending and torsional moment . 25
6.5 Transportation and storage . 27
6.5.1 Protection against foreign matter . 27
6.5.2 Protection against damage . 27
6.6 Connections . 28
6.7 Pressure and temperature tappings . 28
6.7.1 Pressure tappings . 28
6.7.2 Temperature tappings . 29
6.8 Manufacturing. 29
7 Meter output . 30
7.1 Index . 30
7.1.1 General . 30
7.1.2 Magnetic coupling. 30
7.1.3 Mechanical indicating device . 30
7.1.4 Test element . 31
7.2 Index window . 31
7.2.1 Requirements . 31
7.2.2 Tests . 32
7.3 Output drive shafts. 33
7.3.1 Requirements . 33
7.3.2 Tests . 34
7.4 Pulse generators . 35
7.4.1 General . 35
7.4.2 Specification for low frequency pulse generator . 35
7.4.3 Specification for high frequency pulse generator . 36
7.4.4 Electrical connection . 36
8 Durability . 36
8.1 Requirements . 36
8.2 Tests . 36
9 Marking, labelling and packaging . 36
9.1 General . 36
9.2 Direction of flow . 37
9.3 Pressure tappings . 37
9.4 Durability and legibility of marking . 37
9.4.1 Requirements . 37
9.4.2 Test . 37
10 Documentation . 38
10.1 Documentation related to the product tests . 38
10.2 Instruction manual . 38
Annex A (normative) Pattern approval . 39
Annex B (normative) Individual meter testing . 41
Annex C (normative) Resistance to high temperature . 42
C.1 General . 42
C.2 Requirements . 42
C.3 Test . 42
C.3.1 Apparatus . 42
C.3.2 Test conditions . 43
C.3.3 Test procedure . 43
C.4 Marking . 44
Annex D (normative) Compliance evaluation for gas meters . 45
D.1 General . 45
D.2 Quality Management System . 45
D.2.1 General . 45
D.2.2 Compliance evaluation . 45
D.2.3 Issue of the certificate of compliance with EN 12480 . 45
Annex E (normative) Non-destructive testing (NDT) . 46
Annex F (informative) Materials for pressurized parts . 48
Annex G (normative) Additional tests for meters to be used in open locations . 60
G.1 General . 60
G.2 Weathering . 60
G.2.1 Requirements . 60
G.2.2 Test . 60
Annex H (normative) Meter family . 61
H.1 Definition of meter family . 61
H.2 Criteria for grouping meters together in order to form a family . 61
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/32/EU aimed to be covered . 62
Annex ZB (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/68/EU aimed to be covered . 67
Bibliography . 69
European foreword
This document (EN 12480:2025) has been prepared by Technical Committee CEN/TC 237 “Gas meters”,
the secretariat of which is held by BSI.
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 May 2026, and conflicting national standards shall be
withdrawn at the latest by May 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12480:2018.
The main goal of this revision was to be harmonized with 2014/32/EU (Measuring Instruments
Directive) and 2014/68/EU Pressure Equipment Directive.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, and Annex ZB, which are integral
parts of this document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
1 Scope
This document specifies ranges, construction, performances, output characteristics and testing of rotary
displacement gas meters (hereinafter referred to as RD meters or simply meters) for gas volume
measurement.
This document applies to rotary displacement gas meters used to measure the volume of fuel gases of at
least the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437:2021, at a
maximum working pressure up to and including 20 bar over an ambient and gas temperature range of at
least −10 °C to +40 °C.
This document applies to meters that are installed in locations with vibration and shocks of low
significance (class M1) and in
— closed locations (indoor or outdoor with protection) with condensing or with non-condensing
humidity
or,
— open locations (outdoor without any covering) with condensing humidity or with non-condensing
humidity,
and in locations with electromagnetic disturbances (class E1 and E2). The standard applies to mechanical
meters with mechanical index, electronic devices are not covered by this standard.
Unless otherwise specified in this standard:
— all pressures used are gauge;
— all influence quantities, except the one under test, are kept relatively constant at their reference
value.
This document applies to meters with a maximum allowable pressure PS and the volume V of less than
6 000 bar · L or with a product of PS and DN of less than 3 000 bar.
This document is to be used for both pattern approval and individual meter testing. Cross-reference
tables are given in:
— Annex A for the tests that need to be undertaken for pattern approval;
— Annex B for individual meter testing.
Some parts of this standard cover meters with mechanical index only.
The risk philosophy adopted in this standard is based on the analysis of hazards including pressure. The
standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated
appropriate protection measures are specified.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
EN 1092-1:2018, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 1: Steel flanges
EN 1092-2:2023, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 2: Cast iron flanges
EN 1092-3:2003, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 3: Copper alloy flanges
EN 1092-4:2002, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 4: Aluminium alloy flanges
EN 1759-1:2004, Flanges and their joint — Circular flanges for pipes, valves, fittings and accessories, Class
designated — Part 1: Steel flanges, NPS 1/2 to 24
EN 1759-3:2003, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, Class
designated — Part 3: Copper alloy flanges
EN 1759-4:2003, Flanges and their joint — Circular flanges for pipes, valves, fittings and accessories, class
designated — Part 4: Aluminium alloy flanges
EN 10204:2004, Metallic products — Types of inspection documents
EN 12516-2:2014+A1:2021, Industrial valves — Shell design strength — Part 2: Calculation method for
steel valve shells
EN 12516-3:2002, Valves — Shell design strength — Part 3: Experimental method
EN 12516-4:2014+A1:2018, Industrial valves — Shell design strength — Part 4: Calculation method for
valve shells manufactured in metallic materials other than steel
EN 60529:1991, Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989)
EN 60079-11:2012, Explosive atmospheres — Part 11: Equipment protection by intrinsic safety "i"
(IEC 60079-11:2011 + Cor.:2012)
EN IEC 60730-1:2024, Automatic electrical controls — Part 1: General requirements (IEC 60730-1:2022)
EN IEC 60079-0:2018, Explosive atmospheres — Part 0: Equipment — General requirements (IEC 60079-
0:2017)
As impacted by EN 60529:1991/A1:2000, EN 60529:1991/A2:2013, EN 60529:1991/AC:2016-12 and
EN 60529:1991/A2:2013/AC:2019-02.
As impacted by EN IEC 60079-0:2018/AC:2020-02 and EN IEC 60079-0:2018/A11:2024.
EN IEC 61000-6-1:2019, Electromagnetic compatibility (EMC) — Part 6-1: Generic standards — Immunity
standard for residential, commercial and light-industrial environments (IEC 61000-6-1:2016)
EN IEC 61000-6-2:2019, Electromagnetic compatibility (EMC) — Part 6-2: Generic standards — Immunity
standard for industrial environments (IEC 61000-6-2:2016)
EN IEC 61000-6-3:2021, Electromagnetic compatibility (EMC) — Part 6-3: Generic standards — Emission
standard for equipment in residential environments (IEC 61000-6-3:2020)
EN IEC 61000-6-4:2019, Electromagnetic compatibility (EMC) — Part 6-4: Generic standards — Emission
standard for industrial environments (IEC 61000-6-4:2018)
EN 61000-6-5:2015, Electromagnetic compatibility (EMC) — Part 6-5: Generic standards — Immunity for
equipment used in power station and substation environment (IEC 61000-6-5:2015)
EN 61000-6-7:2015, Electromagnetic compatibility (EMC) — Part 6-7: Generic standards — Immunity
requirements for equipment intended to perform functions in a safety-related system (functional safety) in
industrial locations (IEC 61000-6-7:2014)
EN IEC 61000-6-8:2020, Electromagnetic compatibility (EMC) — Part 6-8: Generic standards — Emission
standard for professional equipment in commercial and light-industrial locations (IEC 61000-6-8:2020)
EN ISO 6270-2:2025, Paints and varnishes — Determination of resistance to humidity — Part 2:
Condensation (in-cabinet exposure with heated water reservoir) (ISO 6270-2:2025)
EN ISO 9606-1:2017, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1:2012
including Cor 1:2012 and Cor 2:2013)
EN ISO 9606-2:2004, Qualification test of welders — Fusion welding — Part 2: Aluminium and aluminium
alloys (ISO 9606-2:2004)
EN ISO 9712:2022, Non-destructive testing — Qualification and certification of NDT personnel
(ISO 9712:2021)
EN ISO 14732:2025, Welding personnel — Qualification testing of welding operators and weld setters for
mechanized and automatic welding of metallic materials (ISO 14732:2025)
EN ISO 15607:2019, Specification and qualification of welding procedures for metallic materials — General
rules (ISO 15607:2019)
EN ISO 15609-1:2019, Specification and qualification of welding procedures for metallic materials —
Welding procedure specification — Part 1: Arc welding (ISO 15609-1:2019)
EN ISO 15614-1:2017, Specification and qualification of welding procedures for metallic materials —
Welding procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
(ISO 15614-1:2017, Corrected version 2017-10-01)
EN ISO 15614-2:2025, Specification and qualification of welding procedures for metallic materials —
Welding procedure test — Part 2: Arc welding of aluminium and its alloys (ISO 15614-2:2025)
As impacted by EN 61000-6-5:2015/AC:2018-01.
EN ISO/CIE 11664-4:2019, Colorimetry — Part 4: CIE 1976 L*a*b* colour space (ISO/CIE 11664-4:2019)
ISO 834-1:2025, Fire-resistance tests — Elements of building construction — Part 1: General requirements
ISO 7005-1:2011, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
ISO 7005-2:1988, Metallic flanges — Part 2: Cast iron flanges
ISO 14782:2021, Plastics — Determination of haze for transparent materials
ISO 17663:2023, Welding — Quality requirements for heat treatment in connection with welding and allied
processes
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
accuracy class 1,0
Q,
accuracy achieved by a meter, which has an error of indication between −2 % and +2 % for flow rates
Q Q,
where Q ≤ < Q , and an error of indication between −1 % and +1 % for flow rates where
min t
Q ≤ Q ≤ Q
t max
3.1.2
cyclic volume
V
cyc
volume of the gas measured by one complete revolution of the element(s)
3.1.3
density of gas
ρ
mass of gas divided by the volume
3.1.4
allowable design temperature range
TS
range of gas temperatures (minimum to maximum) for which the meter is designed as declared and
marked on the meter
3.1.5
diameter
DN
alphanumeric designation of size for components of a pipework system, which is used for reference
purposes
Note 1 to entry: It comprises the letters DN followed by a dimensionless whole number which is indirectly
related to the physical size, in millimetres, of the bore or outside diameter of the end connections
3.1.6
error of indication
E
value which shows the relationship in percentage terms of the difference between the volume indicated
by the meter and the volume which has actually flowed through the meter, to the latter value:
VV−
ic
E ⋅ 100
V
c
where
V is the indicated volume and V is the volume which has actually flowed through the meter
i c
3.1.7
maximum allowable pressure
PS
maximum pressure for which the meter is designed
3.1.8
minimum flow rate
Q
min
lowest flow rate at which the gas meter provides indications that satisfy the requirements regarding
maximum permissible error (MPE)
3.1.9
maximum flow rate
Q
max
highest flow rate at which the gas meter provides indications that satisfy the requirements regarding
maximum permissible error (MPE)
3.1.10
meter family
group of meters of different sizes but with similar construction (see Annex H)
Note 1 to entry: By specifying a meter family it is possible to reduce the number of tests and documents during
assessment.
3.1.11
metering condition
condition of the gas prevailing at the point of measurement
=
3.1.12
metering pressure
p
m
absolute pressure at which the volume of the gas is measured
3.1.13
normal conditions of use
conditions referring to the meter operating:
— within the range of working pressure;
— within the operational temperature and gas temperature range;
— with the distributed gas
3.1.14
operating pressure range
p
limits of working pressure for which the meter will continue to operate within its metrological
characteristics
3.1.15
operating temperature range
t
range of gas and ambient temperatures for which the meter satisfies the metrological requirements of
this standard
3.1.16
overload flow rate
Q
r
highest flow rate at which the meter operates for a short period of time without deteriorating
3.1.17
pressure loss
non-recoverable pressure drop caused by the presence of the meter in the pipeline
3.1.18
rotary displacement meter
gas volume meter in which a rigid measuring compartment is formed between the walls of a stationary
chamber and rotating element or elements
Note 1 to entry: Each rotation of the element(s) displaces a fixed volume of gas which is cumulatively registered
and indicated by an indicating device. It is designed to measure, memorize and display the volume of a fuel gas that
has passed through it.
3.1.19
storage temperature range
ts
range of temperatures at which the meter is stored without being adversely affected
3.1.20
transitional flow rate
Q
t
flow rate occurring between the maximum and minimum flow rates at which the flow rate range is
divided into two zones, the upper zone and the lower zone, each zone having a characteristic MPE
3.1.21
volume of meter
V
internal volume of meter excluding the volume of internal parts
3.1.22
working pressure
pressure of the gas at the inlet of the meter
3.1.23
limit pressure
pl
pressure at which yielding becomes apparent in any component of the meter or its fixtures
3.1.24
safety factor body
Sb
ratio of the limit pressure pl to the maximum allowable pressure PS applied to the meter body
3.1.25
safety factor others
S
ratio of the limit pressure pl to the maximum allowable pressure PS applied to other pressure containing
parts of the meter
3.2 Symbols and abbreviations
Table 1 — Symbols
Symbol Represented quantity Unit
V cyclic volume
dm
cyc
-3
ρ Density of gas
kg⋅m
TS Allowable design temperature range °C
DN Diameter Dimensionless
E Error of indication %
MPE Maximum permissible error %
WME Weighted mean error %
PS Maximum allowable pressure bar
Q flow rate
m /h
p Metering pressure bar
m
p Operating pressure range bar
Symbol Represented quantity Unit
t Operating temperature range °C
Q Overload flow rate
r m /h
ts Storage temperature range °C
Q Transitional flow rate
m /h
t
V Volume of meter in litres
dm
pl Limit pressure bar
S Safety factor body Dimensionless
b
S Safety factor others Dimensionless
tr Revolution Dimensionless
Subscripts
m Metering conditions of the gas
min Minimum
max Maximum
i Indicated
t Transitional
4 Operating range
4.1 General
Gas meters shall be classified according to accuracy class 1,0. The values of maximum flow rates and the
corresponding values of the upper limits of the minimum flow rates shall be one of those given in 4.2,
when the meter is tested with air of density approximately 1,2 kg/m .
4.2 Flow rate range
Unless covered in the E.U. type examination certificate, the values of the maximum and minimum flow
rates of rotary displacement gas meters shall be decimal multiples and sub-multiples of these values, with
≥ 20 Q . For example, for one decade:
Q
max min
Q (m /h): 100, 160, 250, 400, 650
max
(m /h): 10, 13, 16, 20, 25, 32, 40, 50, 65, 80
Q
min
4.3 Operating pressure range
The upper limit of the operating pressure range shall not exceed the maximum allowable pressure PS.
The operating pressure range shall be marked on the meter.
4.4 Operating temperature range
All meters shall be capable of meeting the requirements in 5.6 for the following: gas; ambient; storage;
design temperature ranges:
— a minimum ambient temperature range of –10 °C to 40 °C;
If a wider ambient temperature range is required, then these values shall be chosen using a maximum
temperature of 40 °C, 55 °C, or 70 °C and a lower temperature limit of –10 °C, –25 °C, or –40 °C.
— a minimum gas temperature range of 40 K (the gas temperature range shall be within the ambient
temperature range);
— a minimum storage temperature range of –20 °C to 60 °C (see 5.6) (the storage temperature range
shall be wider than or equal to the ambient temperature range).
The operating temperature range shall be inside the limits of the allowable design temperature range.
The operating temperature range shall be marked on the meter.
5 Metrological performance
5.1 General
The uncertainty of the test rig (best measurement capability) shall be at a maximum of 1/5 of the MPE
for the initial pattern approval test and at a maximum of 1/3 of the MPE for the individual meter testing.
Meters family shall be applied according to Annex H.
5.2 Error of indication
5.2.1 Requirements
When tested in accordance with 5.2.2, the meter error of indication shall be within the limits specified in
Table 2.
Table 2 — Limits of maximum permissible errors
Flow rate Q Maximum permissible errors
m /h
Q ±2 %
Q ≤ < Q
min t
±1 %
Q
Q ≤ ≤ Q
t max
Transitional flow rate values, Q , shall be taken from Table 3.
t
Table 3 — Transitional flow rate values
Q / Q Q
max min t
20 ≤ Q / Q ≤ 30 0,20 Q
max min max
Q / Q > 30 ≤ 0,10 Q
max min max
Each meter shall be adjusted so that the weighted mean error (WME) is as close to zero as the adjustment
and the maximum permissible errors allow, without systematically favouring any party.
The WME shall have a value between −0,4 % and +0,4 %.
The WME is calculated as follows:
Σ (/Q Q )⋅ E
i max i
WME=
Σ (/Q Q )
i max
where
Q / Q is a weighting factor;
i max
E is the error of indication at the flow rate QI given as a percentage.
i
When Q = Q , a weighting factor of 0,4 instead of 1 shall be used.
i max
5.2.2 Test
-3
The test is carried out using air (density 1,2 kg⋅m ), or gas specified in the scope, at normal ambient
conditions. The meter is tested at the following flow rates (±10 %):
a) pattern approval:
1) For meters with flow rate range between 1:20 to 1:30:
Q ; 0,05 Q (when this value is larger than Q ) ; 0,1 Q ; 0,2 Q ; 0,4 Q ; 0,7 Q ;
min max min max max max max
Q .
max
2) for meters with a flow rate range ≥ 1:50:
Q ; 0,05 Q ; 0,10 Q ; 0,25 Q ; 0,40 Q ; 0,70 Q ; Q .
min max max max max max max
b) individual factory testing for error of indication (every meter shall be tested) at the flow rates
indicated in Table 4.
If the test point is equal to Q , the tighter limit of the error of indication has to be applied.
t
Table 4 — Test points for individual meter testing
Q / Q Q 0,015 Q 0,1 Q 0,2 Q Q
max min min max max max max
20 ≤ Q / Q ≤ 30 X X X
max min
30 < Q / Q < 160 X X X X
max min
Q / Q ≥ 160 X X X X X
max min
5.3 Pressure loss
5.3.1 Requirements
When tested in accordance with 5.3.2, the maximum pressure loss at Q , when using air with density
max
-3
1,2 kg⋅m , shall be declared.
5.3.2 Test
The pressure loss shall be measured between a point 1 DN upstream and a point 1 DN downstream of the
meter, on piping of the same DN as the meter.
Care shall be taken on selection and manufacturing of the pressure tappings to ensure that flow pattern
distortions do not affect the pressure readings.
5.4 Metrological repeatability
5.4.1 Requirements
When tested in accordance with 5.4.2, in the flow range Q – Q the variation of error of indication
min max
at each flow rate shall stay within the range:
Q
Q ≤ < Q : 1/3 MPE;
min t
Q
Q ≤ ≤ Q : 1/5 MPE.
t max
5.4.2 Test
The error of indication of the meter shall be determined at Q , the flow shall then be increased to at
min
least Q , and then returned to Q and the error of indication determined.
t min
This process shall be repeated and the error of indication at Q determined again.
min
Check that the three successive errors of indication at Q are within the MPE given in 5.4.1.
min
It is possible to combine this test with the test described below for determining the repeatability from Q
t
to Q .
max
The error of indication of the meter is determined at two flow rates in the following order: Q , Q , where
t max
the change from Q to Q is done via 1,10 Q , in order to approach Q from a higher flow rate.
t max max max
The cycle is repeated six times. The test shall be carried out with air, or gas, at atmospheric conditions
(±100 mbar).
Check that the six resulting errors of indication at each flow rate are within a span of 0,2 %, excluding
any interaction between the meter and the test bench.
5.5 Operating pressure
5.5.1 General
The maximum operating pressure for which the meter is useable without additional high-pressure
calibration shall be declared. Above this declared pressure, additional high pressure calibration shall be
undertaken.
5.5.2 Requirements
a) For pattern approval, when tested in accordance with 5.5.3 a), the meter shall comply with 5.2.1.
b) Using the same meter as in a) above, when tested in accordance with 5.5.3 b), at the declared
maximum operating pressure it shall be confirmed that the meter complies with 5.2.1.
c) For individual test, when tested in accordance with 5.5.4, the declared maximum operating pressure
shall be confirmed.
5.5.3 Pattern approval test
a) One meter of each meter family is tested f
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