M/347 - Measuring instruments

This European Standard specifies the requirements and tests for the construction, performance, safety and production of class 1,5 diaphragm gas meters (referred to as meters) having co-axial single pipe, or two pipe connections, used to measure volumes of fuel gases of the 1st, 2nd and 3rd families in accordance with EN 437:2003+A1:2009, at maximum working pressures not exceeding 0,5 bar and maximum actual flow rates not exceeding 160 m3/h over a minimum ambient and gas temperature range of −10 °C to +40 °C.
This standard applies to meters with and without built-in temperature conversion that are installed in locations with vibration and shocks of low significance 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
-   in locations with electromagnetic disturbances corresponding to those likely to be found in residential, commercial and light industrial buildings.
Unless otherwise stated, all pressures given in this document are gauge pressure.
Clauses 1 to 9 and Annex B and Annex D are for design and type testing only.
Requirements for electronic indexes, batteries, valves incorporated in the meter and additional functionalities are given in EN 16314.
NOTE   The content of OIML Publications 'International Recommendation R 137' has been taken into account in the drafting of this standard.
Significant changes from previous editions include:
   conformity with the MID 2009/137/EC regarding declared errors of the same sign and testing Qmin at the minimum and maximum declared gas temperatures;
-   corrosion protection restructured;
-   endurance testing revised to reflect more accurately current operating conditions;
-   requirements for non-metallic meters for external use added to take account of different material characteristics;
-   provision for meters with electronic indexes and integrated shut-off valves;
-   adhesion testing of labels;
Annex A has been restructured to give additional requirements for meters provided with a built-in gas temperature conversion device.
If no specific requirements are given for test equipment, the instruments used should be traceable to a national or international reference standard and the uncertainty (2s) should be better than 1/5 of the maximum value of the parameter to be tested. For differential results the repeatability (2s)/resolution should be better than 1/5 of the maximum value of the issue to be tested.

This European Standard specifies the requirements and tests for the construction, performance, safety and production of class 1,5 diaphragm gas meters (referred to as meters). This applies to meters with co-axial single pipe, or two pipe connections, that are used to measure volumes of fuel gases, which are within the limits of test gases of the 1st, 2nd and 3rd families described in EN 437. The meters have maximum working pressures not exceeding 0,5 bar and maximum actual flow rates not exceeding 160 m3.h−1 over a minimum ambient temperature range of −10 °C to 40 °C and a gas temperature range as specified by the manufacturer with a minimum range of 40 K.
This standard applies to meters with and without built-in temperature conversion that are installed in locations with vibration and shocks of low significance (see MID Annex 1 Chapter 1.3.2 (a), class M1). It also applies to meters in:
-   closed locations (indoor or outdoor with protection as specified by the manufacturer) both with condensing humidity or with non-condensing humidity;
or, if specified by the manufacturer:
-   open locations (outdoor without any covering) both with condensing humidity and with non-condensing humidity;
-   in locations with electromagnetic disturbances corresponding to those likely to be found in residential, commercial and light industrial buildings (see MID Annex 1 Chapter 1.3.3 (a), class E1).
Unless otherwise stated, all pressures given in this document are gauge pressure.
Requirements for electronic indexes, batteries, valves incorporated in the meter and other additional functionalities are given in EN 16314.
Unless otherwise stated in a particular test, the tests are carried out on meters that include additional functionality devices intended by the manufacturer.
Clauses 1 to 9 and Annexes B and C are for design and type testing only.
NOTE   The content of OIML Publication 'International Recommendation R 137' has been taken into account in the drafting of this standard.
If no specific requirements are given for test equipment, the instruments used should be traceable to a national or international reference standard and the uncertainty (2σ) should be better than 1/5 of the maximum value of the parameter to be tested. For differential results the repeatability (2σ)/resolution should be better than 1/5 of the maximum value of the parameter to be tested.

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

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

This European Standard specifies initial verification tests and applies to heat meters, that is to instruments intended for measuring the heat which, in a heat-exchange circuit, is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units. Electrical safety requirements are not covered by this European Standard. Pressure safety requirements are not covered by this European Standard. Surface mounted temperature sensors are not covered by this European Standard. This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies installation, commissioning, operational monitoring and maintenance and applies to heat meters, that is to instruments intended for measuring the heat which, in a heat-exchange circuit, is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units. Electrical safety requirements are not covered by this European Standard. Pressure safety requirements are not covered by this European Standard. Surface mounted temperature sensors are not covered by this European Standard. This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies initial verification tests and applies to heat meters. Heat meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units.
Electrical safety requirements are not covered by this European Standard.
Pressure safety requirements are not covered by this European Standard.
Surface mounted temperature sensors are not covered by this European Standard.
This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies commissioning, operational monitoring and maintenance and applies to heat meters. Heat meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units.
Electrical safety requirements are not covered by this European Standard.
Pressure safety requirements are not covered by this European Standard.
Surface mounted temperature sensors are not covered by this European Standard.
This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies the general requirements and applies to heat meters, that is to instruments intended for measuring the heat which, in a heat-exchange circuit, is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units. Electrical safety requirements are not covered by this European Standard. Pressure safety requirements are not covered by this European Standard. Surface mounted temperature sensors are not covered by this European Standard. This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies pattern approval tests and applies to heat meters, that is to instruments intended for measuring the heat which, in a heat-exchange circuit, is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units. Electrical safety requirements are not covered by this European Standard. Pressure safety requirements are not covered by this European Standard. Surface mounted temperature sensors are not covered by this European Standard. This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies the constructional requirements and applies to heat meters, that is to instruments intended for measuring the heat which, in a heatexchange circuit, is absorbed (cooling) or given up (heating) by a liquid called the heatconveying liquid. The heat meter indicates the quantity of heat in legal units. Electrical safety requirements are not covered by this European Standard. Pressure safety requirements are not covered by this European Standard. Surface mounted temperature sensors are not covered by this European Standard. This standard covers meters for closed systems only, where the differential pressure over the thermal load is
limited.

This European Standard specifies pattern approval tests and applies to heat meters. Heat meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units.
Electrical safety requirements are not covered by this European Standard.
Pressure safety requirements are not covered by this European Standard.
Surface mounted temperature sensors are not covered by this European Standard.
This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies the constructional requirements and applies to heat meters. Heat meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units.
Electrical safety requirements are not covered by this European Standard.
Pressure safety requirements are not covered by this European Standard.
Surface mounted temperature sensors are not covered by this European Standard.
This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies the general requirements and applies to heat meters. Heat meters are instruments intended for measuring the energy which in a heat-exchange circuit is absorbed (cooling) or given up (heating) by a liquid called the heat-conveying liquid. The heat meter indicates the quantity of heat in legal units.
Electrical safety requirements are not covered by this European Standard.
Pressure safety requirements are not covered by this European Standard.
Surface mounted temperature sensors are not covered by this European Standard.
This standard covers meters for closed systems only, where the differential pressure over the thermal load is limited.

This European Standard specifies the requirements and tests for the construction, performance, safety and conformity of gas-volume electronic conversion devices associated to gas meters, used to measure volumes of fuel gases of the 1st and 2nd families according to EN 437. This European Standard is intended for type testing, the detailed relevant provisions of which are given in Annex A. Only three kinds of conversion are treated in this European Standard: conversion as a function of temperature only (called T conversion); conversion as a function of the pressure and of the temperature with constant compression factor (called PT conversion); conversion as a function of the pressure, the temperature and taking into account the compression factor (called PTZ conversion).

This European Standard specifies requirements and tests for the construction, performance and safety of class 1,0 and class 1,5 battery powered ultrasonic gas meters (hereinafter referred to as meters), having co-axial single pipe, or two pipe connections, used to measure volumes of distributed fuel gases of the second and/or third family, as given in EN 437, at maximum working pressures not exceeding 0,5 bar ) and maximum actual flow rates of up to 10 m3/h over a minimum ambient temperature range of -10 °C to +40 °C, and minimum gas temperature span of 40 K, for domestic applications. This European Standard applies to meters where the measuring element and the register(s) are enclosed in the same case.
This European Standard applies to meters with and without built-in temperature conversion, that are installed in locations with vibration and shocks of low significance 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
and in locations with electromagnetic disturbances.
Unless otherwise stated, all pressures given in this European Standard are gauge pressures.
When more than one meter type is submitted for testing, then each meter type is required to be tested against this European Standard.
Clauses 1 to 15 and Annex C are for design and type testing only.
NOTE   See Annex A for production requirements.

This European Standard specifies the requirements and tests for the construction, performance, safety and conformity of gas volume electronic conversion devices associated to gas meters, used to measure volumes of fuel gases of the 1st and 2nd families according to EN 437.
This European Standard is intended for type testing, the detailed relevant provisions of which are given in Annex A.
Only three kinds of conversion are treated in this European Standard:
   conversion as a function of temperature only (called T conversion);
   conversion as a function of the pressure and of the temperature with constant compression factor (called PT conversion);
   conversion as a function of the pressure, the temperature and taking into account the compression factor (called PTZ conversion).
!This document is not relevant to temperature conversion integrated into gas meters which only indicate the converted volume."
EN 12405-2 for energy conversion is in preparation.
Gas-volume conversion devices consist of a calculator and a temperature transducer or a calculator, a temperature transducer and a pressure transducer locally installed.
For application of this European Standard, a conversion device may be, as a choice of the manufacturer, considered as a complete instrument (Type 1) or made of separate elements (Type 2), according to the definitions given in 3.1.18.1 and 3.1.18.2.
In this last case, the provisions concerning pressure transducers, temperature sensors and temperature transducers are given in Annexes B, C and D respectively.
Any conversion device can provide an error curve correction for a gas meter.
NOTE   When rendering an account to an end user the readings from the conversion device can be used in conjunction with the readings from a gas meter conforming to EN 1359, EN 12480, or EN 12261, as appropriate, or to any other appropriate and relevant international or national standard for gas meters, without prejudice of national regulations.

This European Standard specifies requirements and tests for the construction, performance and safety of class 1,0 and class 1,5 battery powered ultrasonic gas meters (hereinafter referred to as meters), having co-axial single pipe, or two pipe connections, used to measure volumes of distributed fuel gases of the second and/or third family, as given in EN 437, at maximum working pressures not exceeding 0,5 bar ) and maximum actual flow rates of up to 10 m3/h over a minimum ambient temperature range of -10 °C to +40 °C, and minimum gas temperature span of 40 K, for domestic applications. This European Standard applies to meters where the measuring element and the register(s) are enclosed in the same case.
This European Standard applies to meters with and without built-in temperature conversion, that are installed in locations with vibration and shocks of low significance 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
and in locations with electromagnetic disturbances.
Unless otherwise stated, all pressures given in this European Standard are gauge pressures.
When more than one meter type is submitted for testing, then each meter type is required to be tested against this European Standard.
Clauses 1 to 15 and Annex C are for design and type testing only.
NOTE   See Annex A for production requirements.

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 fuel gases of at least the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437+A1:2009, 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 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 fuel gases of at least the 1st, 2nd and 3rd gas families, the composition of which is specified in EN 437:2003+A1:2009, 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 European Standard applies to meters that are installed in locations with vibration and shocks of low significance 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;
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 European Standard also applies to meters with a maximum allowable pressure PS and the volume V of less than 6 000 bar • litres or with a product of PS and DN of less than 3 000 bar.
NOTE   These limits are the same as in EU directive 97/23/EC.
This European Standard can 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 on account of pressure. The standard applies principles to eliminate or reduce hazards. Where these hazards cannot be eliminated appropriate protection measures are specified.

This document specifies criteria for selection of water meters, installation requirements and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter.
In applications where a water meter is legally required to conform to the requirements of the Measuring Instruments Directive, this document may be used to demonstrate conformity.
Where legal national requirements exist they shall in all cases take precedence over or supplement the specifications given in this part of this document.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the test parameters and the test methods for water meters, irrespective of the design technologies, as specified in EN 14154-1:2005+A2, used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
In the case where water meters having a value of Q3 > 160 m3/h, the test schedule may make provisions for modification of the Reference Conditions, to meet individual test laboratory limitations, when testing specifically for endurance or for performance under Influence Quantities.
Meters thus tested shall be marked so as to unambiguously indicate part compliance with this document. To augment this marking the meter manufacturer shall, in addition, be obliged to fully disclose the specific non compliance(s) due to the test laboratory limitations.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the requirements and certification procedures for water meters, irrespective of the design technologies used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
This document also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to meter the actual volume flow of cold potable water or heated water. It provides metrological requirements for electronic ancillary devices when they are subject to metrological control. As a rule the ancillary devices are optional. However national or international regulations make some ancillary devices mandatory in relation to the utilisation of the water meter.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the requirements and certification procedures for water meters, irrespective of the design technologies used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
This document also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to meter the actual volume flow of cold potable water or heated water. It provides metrological requirements for electronic ancillary devices when they are subject to metrological control. As a rule the ancillary devices are optional. However national or international regulations make some ancillary devices mandatory in relation to the utilisation of the water meter.

This document specifies criteria for selection of water meters, installation requirements and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter.
In applications where a water meter is legally required to conform to the requirements of the Measuring Instruments Directive, this document may be used to demonstrate conformity.
Where legal national requirements exist they shall in all cases take precedence over or supplement the specifications given in this part of this document.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the test parameters and the test methods for water meters, irrespective of the design technologies, as specified in EN 14154-1:2005+A2, used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
In the case where water meters having a value of Q3 > 160 m3/h, the test schedule may make provisions for modification of the Reference Conditions, to meet individual test laboratory limitations, when testing specifically for endurance or for performance under Influence Quantities.
Meters thus tested shall be marked so as to unambiguously indicate part compliance with this document. To augment this marking the meter manufacturer shall, in addition, be obliged to fully disclose the specific non compliance(s) due to the test laboratory limitations.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the requirements and certification procedures for water meters, irrespective of the design technologies used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
This document also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to meter the actual volume flow of cold potable water or heated water. It provides metrological requirements for electronic ancillary devices when they are subject to metrological control. As a rule the ancillary devices are optional. However national or international regulations make some ancillary devices mandatory in relation to the utilisation of the water meter.

This document specifies criteria for selection of water meters, installation requirements and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter.
In applications where a water meter is legally required to conform to the requirements of the Measuring Instruments Directive, this document may be used to demonstrate conformity.
Where legal national requirements exist they shall in all cases take precedence over or supplement the specifications given in this part of this document.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the test parameters and the test methods for water meters, irrespective of the design technologies, as specified in EN 14154-1:2005+A1, used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
In the case where water meters having a value of Q3 > 160 m3/h, the test schedule may make provisions for modification of the Reference Conditions, to meet individual test laboratory limitations, when testing specifically for endurance or for performance under Influence Quantities.
Meters thus tested shall be marked so as to unambiguously indicate part compliance with this document. To augment this marking the meter manufacturer shall, in addition, be obliged to fully disclose the specific non compliance(s)due to the test laboratory limitations.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the test parameters and the test methods for water meters, irrespective of the design technologies, as specified in EN 14154-1:2005+A1, used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
In the case where water meters having a value of Q3 > 160 m3/h, the test schedule may make provisions for modification of the Reference Conditions, to meet individual test laboratory limitations, when testing specifically for endurance or for performance under Influence Quantities.
Meters thus tested shall be marked so as to unambiguously indicate part compliance with this document. To augment this marking the meter manufacturer shall, in addition, be obliged to fully disclose the specific non compliance(s)due to the test laboratory limitations.

This document applies to water meters intended for residential, commercial, light industrial and industrial use, and specifies the requirements and certification procedures for water meters, irrespective of the design technologies used to meter the actual volume of clean cold potable water or heated water, flowing through a fully charged, closed conduit. These water meters shall incorporate devices, which indicate the integrated volume.
This document also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to meter the actual volume flow of cold potable water or heated water. It provides metrological requirements for electronic ancillary devices when they are subject to metrological control. As a rule the ancillary devices are optional. However national or international regulations make some ancillary devices mandatory in relation to the utilisation of the water meter.

This document specifies criteria for selection of water meters, installation requirements and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter.
In applications where a water meter is legally required to conform to the requirements of the Measuring Instruments Directive, this document may be used to demonstrate conformity.
Where legal national requirements exist they shall in all cases take precedence over or supplement the specifications given in this part of this document.