oSIST prEN 12480:2010

Gas meters - Rotary displacement meters

This European Standard 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 European Standard applies to rotary displacement gas meters used to measure the volume of at least fuel gases of the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437, 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 standard applies to meters that are installed in locations with vibration and shocks of low significance (class M1 according to MID) and in
-   closed locations (indoor or outdoor with protection as specified by the manufacturer) with condensing or with non-condensing humidity
or, if specified by the manufacturer,
-   open locations (outdoor without any covering) with condensing humidity or with non-condensing humidity.
For use in open location, the meters shall fulfil the specification in annex G
and in locations with electromagnetic disturbances.
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 standard also applies to meters with a maximum allowable pressure PS and the volume V of less than 6 000 bar ž litres or with a product of PS and DN of less than 3 000 bar, as defined by EU directive 97/23/EC.  
The risk philosophy adopted in this standard is based on the analysis of hazards on account of pressure. The standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated appropriate protection measures are specified.
Any residual hazard identified has to be communicated to the user where appropriate.
Depending on the installation situation additional requirements may apply to cover the risks arising from traffic, wind, earthqua

Compteurs de gaz - Compteurs de gaz à déplacement rotatif

Diese Europäische Norm legt den Einsatzbereich, den Bau, den Betrieb, die Ausgabecharakteristiken und die
Prüfung von Drehkolbengaszählern (nachfolgend RD-Zähler oder einfach nur Zähler genannt) für die Gasvolumenmessung
fest.
Diese Europäische Norm gilt für Drehkolbengaszähler, die wenigstens für die Volumenmessung von Brenngasen
der 1., 2. und 3. Gasfamilie, deren Zusammensetzung in EN 437 beschrieben ist, bei einem maximalen
Betriebsdruck bis einschließlich 20 bar in einem Umgebungs- und Gastemperaturbereich von mindestens
−10 °C bis +40 °C eingesetzt werden.
Die vorliegende Norm gilt für Zähler, die an Standorten eingebaut sind, an denen unbedeutende Schwingungen
und Erschütterungen auftreten können (Kategorie M1 nach MID), sowie an
⎯ geschlossenen Standorten (innen oder außen mit dem vom Hersteller vorgeschriebenen Schutz) mit oder
ohne Betauung,
oder, bei entsprechender Angabe durch den Hersteller,
⎯ offenen Standorten (außen ohne Abdeckung) mit oder ohne Betauung,
Für die Verwendung an offenen Standorten müssen die Zähler die Anforderungen in Anhang G erfüllen
sowie an Standorten mit elektromagnetischen Störungen.
Soweit in dieser Norm nicht anders angegeben:
⎯ sind alle dargestellten Drücke als Überdrücke zu verstehen;
⎯ werden alle Einflussgrößen außer der geprüften Einflussgröße relativ konstant bei ihrem Referenzwert
gehalten.
Diese Norm gilt auch für Zähler mit einem maximal zulässigen Druck PS und Volumen V von weniger als
6 000 bar ⋅ Liter oder mit einem Produkt aus PS und DN von weniger als 3 000 bar, wie in der EU-Richtlinie
97/23/EG festgelegt.

Compteurs de gaz - Compteurs à pistons rotatifs

La présente Norme européenne spécifie les gammes, construction, performances, caractéristiques de sortie et essais des compteurs de mesure de volume de gaz à pistons rotatifs (appelés ci-après simplement compteurs).
La présente Norme européenne s'applique aux compteurs de gaz à pistons rotatifs utilisés pour mesurer au moins le volume de gaz des 1ère, 2ème et 3ème familles, dont la composition est spécifiée dans l’EN 437, à une pression d'utilisation maximum jusqu’à 20 bar et pour une gamme de température ambiante et de température du gaz au moins comprise entre - 10 °C et + 40 °C.
La présente norme s'applique aux compteurs installés dans des endroits soumis à des vibrations et chocs peu significatifs (catégorie M1 conformément à la directive sur les instruments de mesure) et dans
-   des lieux fermés (intérieur ou extérieur avec une protection spécifiée par le fabricant) avec ou sans condensation de l'humidité
ou, en cas de spécification du fabricant,
-   des lieux ouverts (extérieur sans protection) avec ou sans condensation de l'humidité.
Lorsqu'ils sont utilisés dans des lieux ouverts, les compteurs doivent satisfaire aux spécifications de l'Annexe G
et dans des lieux présentant des perturbations électromagnétiques.
Sauf indications contraires spécifiées dans la présente norme :
-   toutes les pressions utilisées sont des pressions relatives ;
-   toutes les quantités influentes, à l’exception de celle soumise à l’essai, sont maintenues relativement constantes par rapport à la valeur de référence.
La présente norme s’applique également aux compteurs dont le produit de la pression maximale admissible PS par le volume V est inférieur à 6 000 bar litres ou dont le produit PS.DN est inférieur à 3 000 bar, conformément à la définition donnée par la Directive UE 97/23/CE.
La philosophie du risque adoptée dans la présente norme s’appuie sur l’analyse des dangers représentés par la pression.

Plinomeri - Rotacijski plinomeri

General Information

• Status: Not Published
• Public Enquiry End Date: 19-Jan-2011
• ICS: 91.140.40 - Gas supply systems
• Technical Committee: DPL - Gas supply
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 14-Mar-2014
• Due Date: 19-Mar-2014
• Completion Date: 14-Mar-2014
• Directive: 2004/22/EC - Directive 2004/22/EC of the European Parliament and of the Council of 31 March 2004 on measuring instruments
• Directive: 97/23/EC - Directive 97/23/EC of the European Parliament and of the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Mandate: M/347 - Programming mandate to CEN, CENELEX and ETSI relating to measuring instruments
• Ref Project: prEN 12480 - Gas meters - Rotary displacement meters

Relations

• Revised: SIST EN 12480:2004 - Gas meters - Rotary displacement gas meters
• Effective Date: 08-Jun-2022
• Revised: SIST EN 12480:2004 - Gas meters - Rotary displacement gas meters
• Effective Date: 01-Dec-2010

Overview

prEN 12480 (CEN) defines the requirements for rotary displacement (RD) gas meters used to measure gas volume. The standard specifies ranges, construction, performance, output characteristics and testing for RD meters intended for fuel gases of the 1st, 2nd and 3rd gas families as defined in EN 437. It covers meters rated for a maximum working pressure up to and including 20 bar and for use across an ambient and gas temperature range of at least -10 °C to +40 °C.

The standard addresses installation environments with low-significance vibration and shocks (class M1 according to MID) and includes provisions for both closed (indoor/outdoor with manufacturer-specified protection) and, when declared by the manufacturer, open locations (outdoor without covering). Additional tests for open-location use are given in Annex G. The document also aligns with EU requirements for pressure equipment where applicable (products with PS·V < 6000 bar·litres or PS·DN < 3000 bar per Directive 97/23/EC).

Key Topics

• Scope and applicability: Gas families per EN 437, pressure and temperature ranges, installation classes.
• Metrological performance: Error of indication, pressure loss, repeatability, bidirectional operation and influence factors.
• Design and manufacturing: Materials for pressurized parts, corrosion resistance, strength of housings and robustness against internal/external stresses.
• Output and interfaces: Indexing, magnetic coupling, mechanical indicating devices, pulse generators and electrical connections.
• Testing and conformity: Type and individual meter tests, conformity assessment (Annex A, B), durability and non-destructive testing (Annex E).
• Safety and risk philosophy: Pressure-related hazard analysis, elimination/reduction measures and communication of residual hazards to users.

Applications

prEN 12480 is intended for manufacturers, testing laboratories, regulators and system integrators involved with:

• Selection and certification of rotary displacement gas meters for commercial and industrial gas measurement.
• Type approval and conformity assessment for meters installed in indoor and protected outdoor locations.
• Integrating meter outputs (pulses, mechanical indexes) into energy management and billing systems while ensuring metrological traceability.
• Assessing suitability of meters for installations subject to electromagnetic disturbances, weather exposure (open locations) and routine durability requirements.

Benefits include improved metrological accuracy, consistent testing protocols, enhanced safety through hazard analysis, and clearer requirements for installation environments.

Related Standards

• EN 437 - classification of fuel gases (referenced gas families)
• EU Directive 97/23/EC - pressure equipment considerations referenced in the scope
• Measuring instrument directives and MID classifications (referenced for vibration/shock class M1)

For implementation, consult the full prEN 12480 text and manufacturer documentation for declared operating ranges, annex-specific tests (e.g., Annex G) and conformity procedures.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2010
Plinomeri - Rotacijski plinomeri
Gas meters - Rotary displacement meters
Compteurs de gaz - Compteurs de gaz à déplacement rotatif
Compteurs de gaz - Compteurs à pistons rotatifs
Ta slovenski standard je istoveten z: prEN 12480
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.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2010
ICS 91.140.40 Will supersede EN 12480:2002
English Version
Gas meters - Rotary displacement meters
Compteurs de gaz - Compteurs à pistons rotatifs Compteurs de gaz - Compteurs de gaz à déplacement
rotatif
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 237.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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 Management Centre has the
same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12480 rev:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .5
1 SCOPE .5
2 NORMATIVE REFERENCES .6
3 TERMINOLOGY .7
3.1 Terms and definitions .7
3.2 Symbols .9
4 WORKING RANGE . 10
4.1 General . 10
4.2 Flow rate range . 10
4.3 Pressure range . 11
4.4 Temperature range . 11
5 METROLOGICAL PERFORMANCE . 11
5.1 Error of indication . 11
5.1.1 Requirements . 11
5.1.2 Test . 13
5.2 Pressure loss . 13
5.2.1 Requirements . 13
5.2.2 Test . 13
5.3 Metrological repeatability . 14
5.3.1 Requirements . 14
5.3.2 Test . 14
5.4 Working pressure . 14
5.4.1 Requirements . 14
5.4.2 Conformity assessment . 14
5.4.3 Individual test . 14
5.5 Working temperature range . 15
5.6 Condensing ambient conditions . 16
5.6.1 Requirements . 16
5.6.2 Test . 16
5.7 Bidirectional meters . 16
5.7.1 Requirements . 16
5.7.2 Conformity assessment . 16
5.8 Influence of oil filling . 16
5.8.1 Requirements . 16
5.8.2 Tests . 16
6 DESIGN AND MANUFACTURING . 17
6.1 General . 17
6.2 Material . 17
6.2.1 General . 17
6.2.2 Resistance to external corrosion . 17
6.2.3 Penetration resistance . 17
6.2.4 Adhesion of the protective coating. 19
6.2.5 Materials for pressurized parts . 19
6.2.6 Strength of housings . 20
6.3 Robustness . 21
6.3.1 Resistance to internal pressure . 21
6.3.2 Fire resistance . 23
6.3.3 External leak tightness . 23
6.3.4 Overload . 23
6.3.5 Bending and torsional moment . 24
6.4 Transportation and storage . 26
6.4.1 Protection against foreign matter . 26
6.4.2 Protection against damage. 26
6.5 Connections . 27
6.6 Pressure and temperature tappings . 28
6.6.1 Pressure tappings . 28
6.6.2 Temperature tappings . 28
6.7 Manufacturing . 28
7 METER OUTPUT . 29
7.1 Index . 29
7.1.1 General . 29
7.1.2 Magnetic coupling . 29
7.1.3 Mechanical indicating device . 30
7.1.4 Test element . 30
7.2 Index window . 31
7.2.1 General . 31
7.2.2 Requirements . 31
7.2.3 Tests . 32
7.3 Output drive shafts . 32
7.3.1 Requirements . 32
7.3.2 Tests . 34
7.4 Pulse generators . 34
7.4.1 General . 34
7.4.2 Specification for low frequency pulse generator . 35
7.4.3 Specification for high frequency pulse generator . 35
7.4.4 Electrical Connection . 35
8 DURABILITY . 35
8.1 Requirements . 35
8.2 Tests . 36
9 MARKING. 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 Indelibility test . 37
10 DOCUMENTATION . 37
10.1 Documentation related to the manufacturer's tests . 37
10.2 Declaration of conformity . 37
10.3 Instruction manual . 37
Annex A (normative)  Conformity assessment tests . 39
Annex B (normative)  Individual meter testing . 42
Annex C (normative) Resistance to high temperature (optional) . 43
C.1 Requirements . 43
C.2 Test . 43
C.2.1 Apparatus . 43
C.2.2 Test conditions . 43
C.2.3 Test procedure . 44
C.3 Marking . 45
Annex D (informative) Compliance evaluation for gas meters . 46
D.1 Quality Management System. 46
D.1.1 General . 46
D.1.2 Requirement . 46
D.1.3 Final assessment . 46
Annex E (normative) Non destructive testing (NDT) . 47
Annex F (informative) Materials for pressurized parts . 50
Annex G (normative) Additional tests for meters to be used in open locations . 58
G.1 Weathering . 58
G.1.1 Requirements . 58
G.1.2 Test . 58
Annex H (normative) Meter family . 59
H.1 Definition of meter family . 59
Annex ZA (informative) Relationship to MID . 60
Annex ZB (informative) Relationship to PED . 65
Bibliography . 70

Foreword
This document (prEN 12480:2010) has been prepared by Technical Committee CEN/TC 237 “Gas meters”,
the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12480:2002.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directives, see informative Annex ZA and ZB, which are an integral part of this
document.
1 SCOPE
This European Standard 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 European Standard applies to rotary displacement gas meters used to measure the volume of at least
fuel gases of the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437, 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 standard applies to meters that are installed in locations with vibration and shocks of low significance
(class M1 according to MID) and in
 closed locations (indoor or outdoor with protection as specified by the manufacturer) with
condensing or with non-condensing humidity
or, if specified by the manufacturer,
 open locations (outdoor without any covering) with condensing humidity or with non-condensing
humidity.
For use in open location, the meters shall fulfil the specification in annex G
and in locations with electromagnetic disturbances.
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 standard also applies to meters with a maximum allowable pressure PS and the volume V of less than
6 000 bar x litres or with a product of PS and DN of less than 3 000 bar, as defined by EU directive 97/23/EC.
The risk philosophy adopted in this standard is based on the analysis of hazards on account of pressure. The
standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated
appropriate protection measures are specified.
Any residual hazard identified has to be communicated to the user where appropriate.
Depending on the installation situation additional requirements may apply to cover the risks arising from
traffic, wind, earthquake loading and external fire.
This European Standard is primarily written to address metrological aspects and conformity assessment of
RD meters. This standard clearly identifies in annex ZA and ZB which clauses are specific to the metrological
or pressure containing requirements, or those that are applicable to both. As well as providing conformity
assessment requirements, this standard provides requirements that shall be fulfilled prior to delivery of the
product, i.e. Individual meter testing.
2 NORMATIVE REFERENCES
This European Standard incorporates by dated or undated references provisions from other publications.
These normative references are cited at the appropriate places in the text, and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European Standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies (including amendments).
EN 437, Test gas - Test pressures – Appliance categories
EN 10204, Metallic products - Types of inspection documents
EN 12405, Gas-volume electronic conversion devices
EN 12156-3, Valves – Shell design strength – Part 3: Experimental method
EN 60079-0:2007, Electrical apparatus for explosive gas atmospheres - General requirements
EN 60079-11:2007, Equipment protection by intrinsic safety "i"
EN 60947-5-6, Low voltage switchgear and controlgear – Part 5-6: Control circuit devices and switching
elements – DC interface for proximity sensors and switching amplifiers (NAMUR) (IEC 60947-5-6:1999)
EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)
EN 60730-1:1995, Automatic electrical controls for household and similar use - Part 1: General requirements
(IEC 60730-1:1993, modified)
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads - Part 1: Dimension,
tolerances and designation
ISO 834-1, Fire resistance tests – Elements of building construction – Part 1: General requirements
ISO 1518: 2009, Paints and varnishes — Scratch test
ISO 2768-1, General tolerances – Part 1: Tolerances for linear and angular dimensions without individual
tolerance indications
ISO 7005-1, Metallic flanges - Part1: Steel flanges
ISO 7005-2, Metallic flanges - Part2: Cast iron flanges
3 TERMINOLOGY
3.1 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply:
3.1.1 actual flow rate
flow, at the pressure and temperature conditions prevailing in the gas distribution line in which the meter is
fitted
3.1.2 Accuracy class 1,0
meter which has an error of indication between –2 % and + 2 % for flow rates Q where Q ≤ Q < Q , and
min t
between –1 % and +1 % for flow rates Q where Q ≤ Q ≤ Q
t max
3.1.3 base conditions
fixed conditions to which a volume of gas is converted, having been initially measured at prevailing
metering conditions
3.1.4 cyclic volume
volume of the gas measured by one complete revolution of the element(s)

3.1.5 density of gas
the mass of gas divided by the volume

3.1.6 design temperature range (TS)
range of temperatures for which the meter is designed as specified by the manufacturer and marked on the
meter
3.1.7 diameter
nominal size of diameter
3.1.8 error of indication
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 :
where
−
V V
i c
E = ⋅ 100
V
c
V is the indicated volume and V is the volume which has actually flowed through the meter
i c
a pressure of (1 013,25 ±100) mbar and temperature of (20 ±0.5) °C
3.1.9 maximum allowable pressure (PS)
maximum pressure for which the meter is designed as specified by the manufacturer

3.1.10 minimum flow rate Qmin
lowest flowrate at which the gas meter provides indications that satisfy the requirements regarding
maximum permissible error (MPE)
3.1.11 maximum flowrate Qmax
highest flow rate at which the gas meter provides indications that satisfy the requirements regarding
maximum permissible error (MPE)
3.1.12 meter family
A meter family in respect to the conformity assessment is a group of meters of different sizes but with similar
construction (see Annex H). By specifying a meter family it is possible to reduce the number of tests and
documents during assessment
3.1.13 metering conditions
conditions of the gas prevailing at the point of measurement
3.1.14 metering pressure (p )
m
absolute pressure at which the volume of the gas is measured
3.1.15 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
3.1.16 operating pressure range
limits of working pressure, as marked on the meter, for which the meter will continue to operate within its
metrological characteristics as declared by the manufacturer
3.1.17 operating temperature range
range of temperatures for which the meter satisfies the metrological requirements of this standard
3.1.18 overload flowrate Q
r
the  highest  flowrate  at  which  the  meter  operates  for  a  short  period  of  time  without
deteriorating
3.1.19 pressure loss
non-recoverable pressure drop caused by the presence of the meter in the pipeline
3.1.20 rotary displacement meter (RD meter)

gas volume meter in which a rigid measuring compartment is formed between the walls of a stationary
chamber and rotating element or elements. 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
3.1.21 specified conditions
condition of the gas at which the performance specifications of the meter are given
3.1.22 storage temperature range
range of temperatures at which the meter can be stored without being adversely affected
3.1.23 transitional flowrate Q
t
transitional flowrate, the flowrate occurring between the maximum and minimum flowrates at which the
flowrate range is divided into two zones, the upper zone and the lower zone. Each zone has a characteristic
MPE
3.1.24 volume of meter
internal volume of meter excluding the volume of internal parts
3.1.25 working pressure
pressure of the gas at the inlet of the meter
3.1.26 limit pressure pl
pressure at which yielding becomes apparent in any component of the meter or its fixtures

3.1.27 MPE
Maximum permissible error
3.1.28 WME
Weighted mean error
3.1.29 safety factor body Sb
ratio of the limit pressure pl to the maximum allowable pressure PS applied to the meter body
3.1.30 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
Table 1 — Symbols
3 chapter Represented quantity Symbol SI Unit
actual flow rate Q m³/h
3.1.1
Accuracy class 1,0 meter
3.1.2
base conditions
3.1.3
cyclic volume Vcyc dm³
3.1.4
-
Density of gas
3.1.5 ρ kg⋅m ³
Design temperature range TS °C
3.1.6
Diameter DN dimensionless
3.1.7
error of indication E %
3.1.8
Maximum allowable pressure PS bar
3.1.9
Q
Minimum flow rate m³/h
3.1.10 min
Maximum flow rate Q m³/h
3.1.11
max
Meter family
3.1.12
metering conditions
3.1.13
metering pressure p bar
3.1.14 m
3.1.15
Normal conditions of use
3.1.16
Operating pressure range p bar
3.1.17
Operating temperature range t °C
3.1.18
Overload flow rate Q m³/h
3.1.19
r
Pressure loss mbar
3.1.20
Rotary displacement meter
3.1.21
Specified conditions
3.1.22
3.1.23 storage temperature range ts °C
Transitional flow rate Q m³/h
3.1.24 t
Volume of meter V dm³
3.1.25
Working pressure bar
3.1.26
Limit pressure pl bar
3.1.27
MPE %
3.1.28
WME %
3.1.29
Safety factor body Sb dimensionless
3.1.30
Safety factor others S dimensionless
3.1.31
SUBSCRIPTS:
Metering conditions of the gas m
Base conditions b
minimum min
Transitional t
maximum max
actual c
indicated i
4 WORKING RANGE
4.1 General
Gas meters shall be classified according 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 specified by the purchaser, the values of the maximum and minimum flowrate of rotary displacement
gas meters are:
Qmax (m³/h): 100, 160, 250, 400, 650
Qmin (m³/h): 10, 13, 16, 20, 25, 32, 40, 50, 65, 80

With Qmax ≥ 20 Qmin
In addition, decimal multiples and sub-multiples of the values given can be used.
4.3 Pressure range
The pressure range shall be from zero to the maximum allowable working pressure stated by manufacturer
and shall be marked on the meter.
4.4 Temperature range
All meters shall be capable of meeting the requirements described in the appropriate tests for the gas
temperature range, the ambient temperature range and the storage temperature range.
The manufacturer shall specify the temperature ranges:
• a minimum ambient temperature range of –10 °C to +40 °C (the manufacturer may declare a wider
ambient temperature range using a minimum temperature of –10 °C, –25 °C, or –40 °C and a
maximum temperature of 40 °C, 55 °C, or 70 °C)
• a minimum gas temperature range of 40°C (the gas temperature range shall be within the ambient
temperature range)
• a minimum storage temperature range of –20 °C to + 60 °C (see 6.3.4).(the storage temperature
range may be wider than or equal to the ambient temperature range)
5 METROLOGICAL PERFORMANCE
Uncertainty of test rig (best measurement capability) shall be at maximum 1/5 of MPE for conformity
assessment (module B) and at maximum 1/3 of MPE for conformity assessment (modules D and F, including
final product inspection of module H1).
5.1 Error of indication
5.1.1 Requirements
When tested in accordance with 5.1.2, 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
m³/h
Q ≤ Q < Q ± 2 %
min t
± 1 %
Q ≤ Q ≤ Q
t  max
.
Transitional flow rate values, Q , are given in Table 3
t
Table 3 — transitional flow rate values
Qmax/Qmin: Q
t
Qmax/Qmin <30 0,20 Q
max
Qmax/Qmin = 30 0,15 Q
max
Qmax/Qmin >30
≤ 0,10 Q
max
The gas meter shall not exploit the MPEs or systematically favour any party.
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.
The WME shall have a value between -0,4 % and +0,4 %.
The WME is calculated as follows:
∑ (Q / Q ) ⋅
E
i
i max
WME =
∑ ( / )
Q Q
i max
Where:
Q /Q is a weighting factor;
i max
E is the error of indication at the flow rate Q given as a percentage.
i I
When Q = Q a weighting factor of 0,4 instead of 1 shall be used.
i max
5.1.2 Test
The test is carried out using air (density 1,2 kg m-³), or gas specified in the scope, at normal ambient
conditions if not otherwise specified for other tests (for example 5.4 and 5.5). The meter is tested at the
following flow rates (± 10 %):
a) conformity assessment:
1) For meters with flowrate range between 1:20 to 1:30:
Q ; 0,05 Q ; 0,1 Q (when these values are larger than Q ); 0,25 Q ; 0,4 Q ;
min max max min max max
0,7 Q ; Q .
max max
2) for meters with a flowrate range ≥ 1:50:
Q ; 0,05 Q ; 0,15 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 flowrates indicated in
Table 4:
When requested by the customer, the error of indication test can be carried out at
specified conditions (close to the expected operational conditions).
If the test point is equal to Qt, the tighter limit of the error of indication has to be
applied.
Table 4 — test points for individual meter testing
Qmax/Qmin Q min 0,015 Q max 0,05 Q max 0, 25 Q max Q max
X  X X
20 ≤ Qmax/Qmin < 30
X X X X
30 ≤ Qmax/Qmin < 160
X X X X X
Qmax/Qmin ≥160
5.2 Pressure loss
5.2.1 Requirements
The maximum pressure loss at Q , when using air with density 1,2 kg m-³, shall be declared by the
max
manufacturer.
5.2.2 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.
5.3 Metrological repeatability
5.3.1 Requirements
In the flow range Qmin - Qmax the variation of error of indication at each flowrate shall stay within the range:
Qmin ≤ Q < Qt  1/3 MPE
Qt < Q ≤ Qmax 1/5 MPE
5.3.2 Test
The error of indication of the meter shall be determined at Qmin, the flow shall then be increased to at least
Qt, and then returned to Qmin and the error of indication determined.
This process shall be repeated and the error of indication at Qmin determined again.
Check that the three resulting errors of indication at Qmin are within 0.33MPE.
This test may be combined with the test described below for determining the reproducibility from Qt to Qmax,
i.e. take readings Qmin, Qt, Qmax, Qt, Qmax, etc.
The error of indication of the meter is determined at two flow rates in the following order: Q , Q , Q , Q , Q ,
t max t max t
Q , where the change from Q to Q is done via 1,10 Q , in order to approach Q from a higher flow
max t max max max
rate.
At each flow rate the error is determined three times without changing the flow rate. The cycle is repeated
three times. The test shall be carried out with air, or gas, at atmospheric conditions ( ± 100 mbar).
Check that the nine 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.
5.4 Working pressure
The manufacturer should indicate for which pressure range the meter could be used with or without additional
high-pressure calibration tests.
5.4.1 Requirements
When tested in accordance with 5.4.2, the meter could be used without high-pressure calibration within the
specified pressure range.
5.4.2 Conformity assessment
One meter of each meter family is tested following 5.1.2 a) and adjusted following 5.1.1.
A high pressure test is performed at least for 10 different flow rates equally distributed between Q and Q max
t
with a pressure which is the highest pressure for which the manufacturer will claim this meter to be used
without an additional high pressure test (see MPE requirement 5.1.1)
5.4.3 Individual test
For use of the meter inside of the Working pressure range for which this meter type is approved, no additional
individual high pressure test is required.
For use of the meter at a pressure above the Working pressure range for which this meter type is approved,
the error of indication test shall be carried out at specified conditions (close to the operational conditions).
When requested by the customer, the error of indication test can be carried out at specified conditions (close
to the operational conditions) even where the pressure is inside of the pressure range for this meter type.
5.5 Working temperature range
A meter of a meter family with the highest expected temperature dependency shall be type tested as follows:
The meter shall be tested at the upper specified gas temperature and at the lower specified gas
temperature.
The gas temperature and ambient temperature shall be equal and not differ more then 2°C from the
specified temperatures.
The error of indication shall be determined at both temperatures for the flow rates which are specified in
5.1.2 a). All errors of indication shall be within the MPE.
As an alternative, the gas meter may be tested at one temperature limit or both limits at all test flow rates
according to 5.1.2a except 0.7 Q and Q (or except Q only). The measured errors of indications shall
max max max
be within the MPE.
For all test flow rates larger or equal to Q , the differences to the measured errors of indication at normal
t
ambient conditions (see 5.1.2a) shall be calculated. These differences shall not vary by more than 0.2 %.
Furthermore, the average difference shall be calculated. Assuming that this average difference is valid for the
flow rates which have not been tested, the errors of indication at these flow rates range shall be within the
MPE, too.
c) minimum operational temperature
 cool the meter down to minimum operational temperature, until stabilized ;
 start the meter at a flow rate not exceeding Q with air (or equivalent medium) at ambient
min
temperature.
The meter shall start to rotate at a flow rate not exceeding Q , and continue to rotate for not less than one
min
complete revolution with a pressure loss not exceeding 0,1 mbar.
d) maximum operational temperature
 heat the meter at maximum operational temperature, until stabilized ;
 start the meter at a flow rate not exceeding Q with air (or equivalent medium) at ambient
min
temperature.
The meter shall start to rotate at a flow rate not exceeding Q , and continue to rotate for not less of one
min
complete revolution with a pressure loss not exceeding 0,1 mbar.
e) storage temperature range
 cool the meter to the minimum storage temperature, until stabilized ;
 take the meter back to ambient temperature, until stabilized;
 perform again the error of indication test as indicated in 5.1.2 a and carry out a visual inspection.
 The error of indication shall be within the maximum permissible error, shall not display a shift in
excess of 0,4 %, and the meter shall not show signs of deterioration.
 heat the meter to the maximum storage temperature, until stabilized ;
 take the meter back to ambient temperature, until stabilized;
 perform again the error of indication test as indicated in 5.1.2 a and carry out a visual inspection.
The error of indication shall be within the maximum permissible error, and the meter shall not show signs of
deterioration.
5.6 Condensing ambient conditions
5.6.1 Requirements
After testing in accordance with 5.6.2 the error of indication shall remain within the initial maximum
permissible error limits specified in Table 2 and the index and markings shall remain legible.
5.6.2 Test
One meter shall be tested for error of indication in accordance with 5.1.2 a) and shall then be tested in
accordance with EN ISO 6270-1 for a duration of 340 hours. The meter shall then be re-tested for error
of indication in accordance with 5.1.2 a) and shall be visually inspected for legibility of the index and the
markings.
5.7 Bidirectional meters
5.7.1 Requirements
Meters designed for both flow directions shall conform to the metrological performances described in
5.1.1 for both directions.
5.7.2 Conformity assessment
The test meter is tested following 5.1.2 a), adjusted following 5.1.1. The meter is turned in the opposite
flow direction and tested again following 5.1.2 a.)
5.8 Influence of oil filling
For meters designed for operating with oil filling
5.8.1 Requirements
After testing in accordance with 5.8.2 the influence of oil filling is lower than 1/3 of MPE. For meters
meeting this requirement the individual meter calibration, 1.5.2b may be performed without oil filling.
5.8.2 Tests
At least one meter from one meter family shall be tested for error of indication in accordance with 5.1.2 a
with oil filling. The same meter shall be tested with the oil drained: Check that the MPE differences
between the two tests doesn’t exceed 1/3 of the MPE for each tested flow rate
6 DESIGN AND MANUFACTURING
6.1 General
A gas meter shall be designed, manufactured and checked, with the manufacturer providing instructions on
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