EN 12405-3:2015

Gas meters - Conversion devices - Part 3: Flow computer

Part 3 of this European Standard specifies the requirements and tests for the construction, performance, safety and conformity of flow computers (FCs) used to meet the metrological and technical requirements of a high accuracy volume conversion device.
They are used to determine volume of fuel gases, including those of the first and second families according to EN 437.
For the purpose of this European Standard, only flow computers that are intended to operate with ultrasonic meters according to ISO 17089 1 or gas turbine meters conforming to EN 12261 are considered.
For the purpose of this European Standard only classification classes E2 and M1 are considered for the flow computer calculator.
FCs are equipped with external separate transducers for pressure and temperature which may be approved separately.
The provisions concerning pressure and temperature transducers are given in Annex B and C.
Requirements and tests are given for energy calculator in EN 12405 2.

Gaszähler - Umwerter - Teil 3: Flowcomputer

Teil 3 dieser Europäischen Norm legt die Anforderungen und Prüfungen an den Bau, die Leistungsfähigkeit, die Sicherheit und die Konformität von Flowcomputern (FC) fest, die zur Erfüllung metrologischer und technischer Anforderungen eines Volumenumwerters mit hoher Genauigkeit verwendet werden.
Sie werden zur Bestimmung des Volumens von Brenngasen einschließlich der Brenngase der ersten und zweiten Familie nach EN 437 verwendet.
Für die Anwendung dieser Europäischen Norm werden ausschließlich Flowcomputer betrachtet, die für den Betrieb mit Ultraschallzählern nach ISO 17089 1 oder Turbinenradgaszählern nach EN 12261 vorgesehen sind.
Für die Anwendung dieser Europäischen Norm werden für Rechner von Flowcomputern ausschließlich die Klassifizierungsklassen E2 und M1 berücksichtigt.
Die Flowcomputer sind mit externen gesonderten Messumformern für Druck und Temperatur ausgestattet, die separat genehmigt werden dürfen.
Die Festlegungen hinsichtlich der Druck- und Temperatur-Messumformer sind in Anhang B und C enthalten.
Die Anforderungen und Prüfungen für den Energierechner sind in EN 12405-2 angegeben.

Compteurs de gaz - Dispositifs de conversion - Partie 3: Calculateurs de débit

La partie 3 de la présente Norme européenne définit les exigences et les essais pour la fabrication, les performances, la sécurité et la conformité des calculateurs de débit (FC) utilisés pour satisfaire aux exigences métrologiques et techniques d'un dispositif de conversion de volume de grande exactitude.
Ils sont utilisés pour déterminer le volume des gaz combustibles, y compris ceux de première et deuxième famille conformément à l'EN 437.
Pour les besoins de la présente Norme européenne, seuls les calculateurs de débit qui sont prévus pour fonctionner avec des compteurs à ultrasons conformément à l'ISO 17089-1 ou avec des compteurs de gaz à turbine conformément à l'EN 12261 sont pris en compte.
Pour les besoins de la présente Norme européenne, seules les classes E2 et M1 sont prises en compte pour le calculateur de débit.
Les FC doivent être équipés de transducteurs externes distincts pour la pression et la température, qui peuvent être homologués séparément.
Les dispositions relatives aux transducteurs de pression et de température sont données aux Annexes B et C.
Pour les calculateurs d'énergie, les exigences et les essais sont donnés dans l'EN 12405-2.

Plinomeri - Korektorji - 3. del: Računalnik pretoka

Del 3 tega standarda določa zahteve in preskuse za izgradnjo, delovanje, varnost in skladnost računalnikov pretoka, ki se uporabljajo za izpolnjevanje meroslovnih in tehničnih zahtev visokonatančne naprave za prostorninsko konverzijo.

General Information

• Status: Published
• Publication Date: 01-Dec-2015
• ICS: 91.140.40 - Gas supply systems
• Technical Committee: CEN/TC 237 - Gas meters
• Drafting Committee: CEN/TC 237/WG 4 - Associated conversion devices
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 10-Jun-2021
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 12405-3:2016 - Gas meters - Conversion devices - Part 3: Flow computer

Overview

EN 12405-3:2015 - Gas meters - Conversion devices - Part 3: Flow computer - specifies the requirements and tests for the construction, performance, safety and conformity of flow computers (FCs) used for high‑accuracy volume conversion of fuel gases. The standard addresses FCs that operate with ultrasonic meters (ISO 17089‑1) or gas turbine meters (EN 12261) and focuses on metrological and technical requirements for accurate gas volume determination for gases of the first and second families defined in EN 437.

Key topics and technical requirements

• Scope and intended use: Flow computers for high‑accuracy volume conversion in gas metering systems; only calculator classification classes E2 and M1 are considered.
• Construction requirements: Mechanical, electrical and environmental design criteria including casings, sealing and time‑measuring functions (clock and intervals).
• Inputs and transducers: FCs are equipped with external, separately mounted pressure and temperature transducers; transducers may be approved independently. Provisions for these transducers are given in Annex B (pressure) and Annex C (temperature).
• Measurement principles and correction functions: Volume conversion correction algorithms (temperature, pressure and body‑dimension corrections for ultrasonic meters), and requirements for handling gas characteristics and base conditions.
• Performance and metrology: Rated operating conditions, maximum permissible errors, influence factors, repeatability, durability and calibration/adjustment of transducers.
• Monitoring and safety features: Alarms, meter health checks (USM integrity and turbine meter checks), cut‑off functions, handling of maintenance conditions and memorization of metrological data.
• Data and security: Long‑term data storage requirements (categories, triggers, time stamps) and security measures (physical, electronic, software).
• Tests and conformity: Type tests, environmental (temperature, humidity, vibration, shocks), electrical immunity and performance tests to verify conformity; detailed test regimes are specified in Annex A.
• Installation, marking and documentation: Installation instructions, marking requirements and required operating documentation.

Practical applications and users

This standard is essential for:

• Flow computer manufacturers designing FCs for ultrasonic or turbine gas meters.
• Gas meter integrators and OEMs assembling metering skids and custody‑transfer systems.
• Utilities and gas distribution companies specifying metering equipment for billing and custody transfer.
• Testing and calibration laboratories performing type tests and conformity assessments.
• Regulators and metrology authorities ensuring compliance with high‑accuracy metering requirements.

Related standards

• EN 12405‑2 - Energy calculator requirements (referenced for energy calculation aspects)
• ISO 17089‑1 - Ultrasonic gas meters (USM) - specified meter types compatible with FCs
• EN 12261 - Gas turbine meters - compatible meter type
• EN 437 - Gas families and gas properties (gases of first and second families)

SIST EN 12405‑3:2016 provides the technical and metrological framework to ensure accurate, safe and conforming flow computer operation in modern gas metering systems.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Gaszähler - Umwerter - Teil 3: Ergänzendes ElementCompteurs de gaz - Dispositifs de conversion - Partie 3 : Calculateurs de débitGas meters - Conversion devices - Part 3: Flow computer91.140.40Sistemi za oskrbo s plinomGas supply systemsICS:Ta slovenski standard je istoveten z:EN 12405-3:2015SIST EN 12405-3:2016en,fr,de01-februar-2016SIST EN 12405-3:2016SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12405-3
December
t r s w ICS
{ sä s v rä v r English Version
Gas meters æ Conversion devices æ Part
uã Flow computer Compteurs de gaz æ Dispositifs de conversion æ Partie
uã Calculateurs de débit
Gaszähler æ Umwerter æ Teil
uã Flowcomputer This European Standard was approved by CEN on
s { September
t r s wä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey andUnited Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
t r s w CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s t v r wæ uã t r s w ESIST EN 12405-3:2016

Type test . 52 A.1 General conditions . 52 A.2 Accuracy tests under reference conditions . 54 SIST EN 12405-3:2016

Pressure transducers . 65 B.1 Scope . 65 B.2 Rated operating conditions . 65 B.3 Construction requirements . 65 B.4 Performances . 66 B.5 Tests of conformity . 67 B.6 Marking . 67 Annex C (normative)
Temperature transducers . 68 C.1 Scope . 68 C.2 Rated operating conditions . 68 C.3 Construction requirements . 68 C.4 Performances . 69 C.5 Tests of conformity . 70 C.6 Marking . 70 Annex D (normative)
Requirements and testing of meter error correction . 71 D.1 General . 71 D.2 Verification of the volumetric flow rate determination. 71 D.3 Verification of the gas density calculation procedure . 71 D.4 Verification of the gas viscosity calculation procedures . 72 D.5 Verification of the error transposition from e(Qi) to e(Rei) . 72 D.6 Verification of the error function
or
interpolation or approximation . 73 D.7 Verification of correction factor F(Q) or F(Re), corrected flow rate and corrected volume determination. 73 D.8 Verification of the activation and deactivation of error correction calculations on limits of its application . 73 Annex E (informative)
Range of application of meter error correction with functions:
e(Q) or e (Re) . 74 E.1 General . 74 E.2 Range of application . 74 E.3 Example for turbine meters working at pop nearly constant . 75 Bibliography . 77
Figure 1 — Description of the functionalities of the flow computer calculator Modular and global approaches In the modular approach, the flow computer is an assembly of separate associated measuring instruments and a calculator, which are verified separately. Each instrument is verified according to its testing procedure, using the indication available on the calculator or on the associated measuring instrument itself. In this case, the indication shall correspond to the indication of that measuring instrument, which is directly performing volume conversion. The verification of the functions consists in verifying the calculation concerning each characteristic quantity of the gas and/or the calculation for the volume conversion. In case of external communication, sufficient resolution of required data is ensured during data transmission. The associated measuring instruments are validated for or with a type calculator in order to ensure the interoperability of the association. CVDD is covered in EN 12405-2. In the global approach, the flow computer is tested as a package including the calculator and its associated measuring instruments and functions. The testing procedures are given in Annex A. SIST EN 12405-3:2016

EN 12405-3:201
...