SIST EN ISO 4064-1:2025

SLOVENSKI STANDARD
01-maj-2025
Nadomešča:
SIST EN ISO 4064-1:2017/A11:2023
Vodomeri za merjenje hladne pitne vode in vroče vode - 1. del: Metrološke in
tehnične zahteve (ISO 4064-1:2024)
Water meters for cold potable water and hot water - Part 1: Metrological and technical
requirements (ISO 4064-1:2024)
Wasserzähler zum Messen von kaltem Trinkwasser und heißem Wasser - Teil 1:
Metrologische und technische Anforderungen (ISO 4064-1:2024)
Compteurs d'eau potable froide et d'eau chaude - Partie 1: Exigences métrologiques et
techniques (ISO 4064-1:2024)
Ta slovenski standard je istoveten z: EN ISO 4064-1:2025
ICS:
17.120.10 Pretok v zaprtih vodih Flow in closed conduits
91.140.60 Sistemi za oskrbo z vodo Water supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 4064-1
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2025
EUROPÄISCHE NORM
ICS 91.140.60 Supersedes EN ISO 4064-1:2017
English Version
Water meters for cold potable water and hot water - Part
1: Metrological and technical requirements (ISO 4064-
1:2024)
Compteurs d'eau potable froide et d'eau chaude - Wasserzähler zum Messen von kaltem Trinkwasser
Partie 1: Exigences métrologiques et techniques (ISO und heißem Wasser - Teil 1: Metrologische und
4064-1:2024) technische Anforderungen (ISO 4064-1:2024)
This European Standard was approved by CEN on 23 September 2024.

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 ISO 4064-1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/32/EU aimed to be covered . 4

European foreword
This document (EN ISO 4064-1:2025) has been prepared by Technical Committee ISO/TC 30
"Measurement of fluid flow in closed conduits" in collaboration with Technical Committee CEN/TC 92
“Water meters” the secretariat of which is held by SNV.
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 August 2025, and conflicting national standards shall
be withdrawn at the latest by August 2025.
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 ISO 4064-1:2017.
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, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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.
Endorsement notice
The text of ISO 4064-1:2024 has been approved by CEN as EN ISO 4064-1:2025 without any
modification.
Annex ZA
(informative)
Relationship between this European Standard and the essential
requirements of Directive 2014/32/EU aimed to be covered
This European Standard has been prepared under a Commission’s standardization request Mandate to
CEN and CENELEC for standardisation in the field of measuring instruments “M/541 EN” to provide one
voluntary means of conforming to essential requirements of Directive 2014/32/EU of the European
Parliament and the Council of 26 February 2014 on measuring instruments.
Once this standard is cited in the Official Journal of the European Union under that Directive
2014/32/EU, compliance with the normative clauses of this standard given in Table ZA.1 and
application of the edition of the normatively referenced standards as given in Table ZA.2 confers, within
the limits of the scope of this standard, a presumption of conformity with the corresponding essential
requirements of that Directive 2014/32/EU, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Annex I of Directive
2014/32/EU.
Essential Requirements (ERs) of Directive
32/2014/EU Clause(s)/sub-clause(s) Qualifying remarks/
Annex I Essential Requirements
of this EN Notes
Note: Amended by Directive 2015/13/EU
4.2.1
4.2.2
I.1.1 and 1.2 Allowable errors, Rated
4.2.3
operating conditions
4.2.8
6.4
6.4
I.1.3.1 Climatic environments, temperature
A.2
limits
A.5
A.2
I.1.3.2 Mechanical environments
A.5
A.3
I.1.3.3 Electromagnetic environments
A.5
7.2.12.2.2
I.1.3.4 Other influences
Annex A table A.1
7.1
I.1.4.1 Basic rules for testing
A.1
8.4
I.1.4.2 Ambient humidity
Annex A.5 table A.1
I.2 Reproducibility 7.2.9.3
I.3 Repeatability 7.2.4
6.7.2
I.4 Discrimination and sensitivity
6.7.3.2
4.2
I.5 Durability
7.2.6
I.6 Reliability 6.1
6.1.7
I.7.1 Fraudulent use
6.8
6.1.8
I.7.2 Suitable for use 6.7.1
6.4
6.1.9
I.7.3 Unduly biasing
6.2
I.7.5 Robustness and suitability of materials 6.1
4.3.4
5.1.3
I.7.6 Allow for control after placing on the

market and put into use
6.7.1
Annex B
4.3.4
5.1.1
I.8.1 Not to be influenced in any admissible
6.3
way
6.8.2.2.
6.8.2.3
I.8.2 Securing of hardware components 6.8
I.8.3 Securing and identification of software 6.8
I.8.4 Measurement data adequately protected
6.8
against corruption
I.8.5 Total quantity supplied not to be reset 6.8
I.9.1 Inscriptions 6.6
I.9.2 Marking of packaging and documents 6.6
6.3
I.9.3 Information on operation
6.6
6.7. 3.2.1
I.9.5 Scale interval for the measurand
6.7.3.2.3
I.9.7 Unit of measurement 6.7.1.2
6.6.1
I.9.8 Marking properties
6.6.2
I.10.1 Display or hard copy 6.7.2
I.10.2 Reading properties 6.7.1.1
I.10.5 Properties of display for remote
6.1.8
reading
3.6
I.12 Conformity evaluation
7.2
MI.1 Values of flow rate range
4.1
Note: addresses amendment of Directive
6.4
2015/13/EU
Clause(s)/subclause(s)
Specific Requirements of Annex III for Qualifying
of this European
WATER METERS (MI-001) remarks/Notes
Standard
4.2.4
MI.2 Temperature range of the water
6.4
4.2.8
MI.3 Relative pressure of the water
6.4
MI.4 Nominal value of AC voltage supply and
5.2
limits of DC supply
MI.5 MPE ±2 % for water temperature ≤
30 °C for flow rate between Q2 (included) 4.2.3
and Q4
MI.5 MPE ±3 % for water temperature >
30 °C for flow rate between Q2 (included) 4.2.3
and Q4
MI.6 MPE ±5 % for any water temperature
4.2.3
for flow rate between Q1 and Q2 (excluded)
4.3.3
6.1.9
MI.6 Non exploitation of MPE 6.2.1
7.2.3
7.3.6
MI.7.1.1 Electromagnetic immunity A.3
5.1.1
MI.7.1.2 Condition after electromagnetic
A.3
disturbance
A.5
5.1.2
MI 7.1.3 Critical change value
A.3
MI 7.2.1 Variation of measurement after
7.2.6.3
durability
MI 7.2.2 Error of indication after durability 7.2.6.3
MI.8.1 Meter able to be installed in defined
7.2.3
position
MI.8.2 Meter is not designed to measure
4.2.7
reverse flow
MI.9 Cubic metre 6.7.1.2
Table ZA.2 — Normative references from Clause 2 of this document and their corresponding
European publications
Column 1 Column 2 Column 3 Column 4
Reference in International
Title Corresponding European
Clause 2 Standard Edition
Standard Edition
ISO 4064- ISO 4064- Water meters for cold EN ISO 4064-2:2025
2:2024¦OIML R 2:2024¦OIML R 49- potable water and hot
49-2:2024 2:2024 water — Part 2: Test
methods
The documents listed in the Column 1 of Table [ZA.2], in whole or in part, are normatively referenced in
this document, i.e. are indispensable for its application. The achievement of the presumption of
conformity is subject to the application of the edition of Standards as listed in Column 4 or, if no
European Standard Edition exists, the International Standard Edition given in Column 2 of Table [ZA.2].
WARNING 1 Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 Other Union legislation may be applicable to the product(s) falling within the scope of this
standard.
International
Standard
ISO 4064-1
Fifth edition
Water meters for cold potable water
2024-12
and hot water —
Part 1:
Metrological and technical
requirements
Compteurs d'eau potable froide et d'eau chaude —
Partie 1: Exigences métrologiques et techniques
Reference number
ISO 4064-1:2024(en) © ISO 2024

ISO 4064-1:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 4064-1:2024(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Water meter and its constituents .2
3.2 Metrological characteristics .5
3.3 Operating conditions .7
3.4 Test conditions .8
3.5 Electronic and electrical equipment .10
4 Metrological requirements . .11
4.1 Values of Q , Q , Q , and Q .11
1 2 3 4
4.2 Accuracy class and maximum permissible error . 12
4.2.1 General . 12
4.2.2 Accuracy class 1 water meters . 12
4.2.3 Accuracy class 2 water meters . 12
4.2.4 Meter temperature classes . 12
4.2.5 Water meters with separable calculator and measurement transducer . 13
4.2.6 Relative error of indication . 13
4.2.7 Reverse flow . 13
4.2.8 Water temperature and water pressure . 13
4.2.9 Absence of flow or of water . 13
4.2.10 Static pressure . 13
4.3 Requirements for meters and ancillary devices . 13
4.3.1 Connections between electronic parts . 13
4.3.2 Adjustment device .14
4.3.3 Correction device .14
4.3.4 Calculator .14
4.3.5 Indicating device .14
4.3.6 Ancillary devices .14
5 Water meters equipped with electronic devices .15
5.1 General requirements . 15
5.2 Power supply .16
5.2.1 General .16
5.2.2 External power supply .16
5.2.3 Non-replaceable battery .16
5.2.4 Replaceable battery .17
6 Technical requirements . 17
6.1 Materials and construction of water meters .17
6.2 Adjustment and correction . .18
6.3 Installation conditions .18
6.4 Rated operating conditions .19
6.5 Pressure loss .19
6.6 Marks and inscriptions . 20
6.7 Indicating device . .21
6.7.1 General requirements .21
6.7.2 Types of indicating device . 22
6.7.3 Verification devices — First element of an indicating device — Verification
scale interval . 23
6.8 Protection devices .24
6.8.1 General .24
6.8.2 Electronic sealing devices .24
7 Metrological controls .25
7.1 Reference conditions . 25

iii
ISO 4064-1:2024(en)
7.2 Type evaluation and approval . 25
7.2.1 External examination . 25
7.2.2 Number of samples . 25
7.2.3 Errors (of indication) . 26
7.2.4 Repeatability . 26
7.2.5 Overload water temperature . 26
7.2.6 Durability . 26
7.2.7 Interchange error .27
7.2.8 Static magnetic field .27
7.2.9 Documentation.27
7.2.10 Type approval certificate . 28
7.2.11 Modification of an approved type . 28
7.2.12 Type evaluation of a water meter with electronic devices . 29
7.3 Initial verification . 29
Annex A (normative) Performance tests for water meters with electronic devices .31
Annex B (informative) Checking facilities.33
Annex C (informative) Permissible errors in service and subsequent verification .37
Annex D (normative) Requirements for software-controlled water meters .38
Bibliography .46

iv
ISO 4064-1:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 30, Measurement of fluid flow in closed
conduits, Subcommittee SC 7, Volume methods including water meters and OIML Technical Subcommittee
TC 8/SC 5, Water meters, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 92, Water meters, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
This fifth edition of ISO 4064-1 cancels and replaces the fourth edition (ISO 4064-1:2014), which has been
technically revised.
The main changes are as follows:
— a few editorial and technical changes were done throughout the document.
This edition of ISO 4064-1 is identical to the corresponding edition of OIML R 49-1, which has been issued
concurrently. OIML R 49-1 was approved for final publication by the International Committee of Legal
Metrology at its 59th meeting in October 2024. It will be submitted to the International Conference on Legal
Metrology in 2025 for formal sanction.
A list of all parts in the ISO 4064 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
International Standard ISO 4064-1:2024(en)
Water meters for cold potable water and hot water —
Part 1:
Metrological and technical requirements
1 Scope
This document specifies the metrological and technical requirements for water meters for cold potable
water and hot water flowing through a fully charged, closed conduit. These water meters incorporate
devices which indicate the accumulated volume.
In addition to water meters based on mechanical principles, this document applies to devices based on
electrical or electronic principles, and mechanical principles incorporating electronic devices, used to
measure the volume of cold potable water and hot water.
This document also applies to electronic ancillary devices. Ancillary devices are optional. However, it is
possible for national or regional regulations to render some ancillary devices mandatory in relation to the
utilization of water meters.
NOTE Any national regulations apply in the country of use.
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. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 4064-2:2024|OIML R 49-2:2024, Water meters for cold potable water and hot water — Part 2: Test methods
3 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:
— ISO Online browsing platform: available at https:// www. iso. org/o bp
— IEC Electropedia: available at https:// www.e lectropedia. org/
[1] [8]
NOTE 1 This terminology conforms to that used in ISO/IEC Guide 99:2007|OIML V 2-200:2012 , OIML V 1 and
[9]
OIML D 11 . Modified versions of some terms defined in References [1], [8] and [9] are listed here.
NOTE 2 The following terms are referenced in the other parts of the ISO 4064| OIML R 49 series but are not
cited within the main body of this document: tariff control device (3.1.9), pre-setting device (3.1.10), meter for two
constant partners (3.1.12), in-line meter (3.1.13), cartridge meter connection interface (3.1.21), meter with exchangeable
metrological module (3.1.22), connection interface for meters with exchangeable metrological modules (3.1.24), non-
adjustable water meter (3.1.25), adjustable water meter (3.1.26), initial intrinsic error (3.2.7), resolution of a displaying
device (3.2.14), overload flow rate (3.3.3), transitional flow rate (3.3.4), combination meter changeover flow rate (3.3.6),
minimum admissible temperature (3.3.7), maximum admissible temperature (3.3.8), working pressure (3.3.11), test
flow rate (3.3.13), nominal diameter (3.3.14), temperature stability (3.4.8), preconditioning (3.4.9), recovery (3.4.11),
automatic checking facility (3.5.5), permanent automatic checking facility type P automatic checking facility (3.5.6),
intermittent automatic checking facility type I automatic checking facility (3.5.7), non-automatic checking facility type N
checking facility (3.5.8).
ISO 4064-1:2024(en)
NOTE 3 Attention is drawn to the fact that the term "verification" or "initial verification" is equivalent to the term
"conformity assessment" in the context of application of the European Measuring Instruments Directive.
3.1 Water meter and its constituents
3.1.1
water meter
instrument intended to measure, memorize, and display the volume of water passing through the
measurement transducer (3.1.2) at metering conditions (3.2.11)
Note 1 to entry: A water meter includes at least a measurement transducer, a calculator (including adjustment or
correction devices, if present) and an indicating device. These three devices can be in different housings.
Note 2 to entry: A water meter may be a combination meter (see 3.1.16).
Note 3 to entry: In this International Standard, a water meter is also referred to as a “meter”.
3.1.2
measurement transducer
part of the meter that transforms the flow rate (3.3.1) or volume of water to be measured into signals which
are passed to the calculator (3.1.4) and includes the sensor (3.1.3)
Note 1 to entry: The measurement transducer may function autonomously or use an external power source and may
be based on a mechanical, electrical or electronic principle.
3.1.3
sensor
element of a meter that is directly affected by a phenomenon, body or substance carrying a quantity to be
measured
[SOURCE: ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 3.8, modified — "meter" replaces "measuring
system"; original note to entry removed; original examples removed, “Note 1 to entry” added.]
Note 1 to entry: For a water meter, the sensor may be a disc, piston, wheel or turbine element, the electrodes on an
electromagnetic meter, or another element. The element senses the flow rate or volume of water passing through the
meter and is referred to as a "flow sensor" or "volume sensor".
3.1.4
calculator
part of the meter that transforms the output signals from the measurement transducer(s) (3.1.2) and, possibly,
from associated measuring instruments and stores the results in memory until they are used
Note 1 to entry: The gearing is considered to be the calculator in a mechanical meter.
Note 2 to entry: The calculator may be capable of communicating both ways with ancillary devices.
3.1.5
indicating device
part of the meter that provides an indication corresponding to the volume of water passing through the meter
Note 1 to entry: For the definition of the term “indication”, see ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 4.1.
Note 2 to entry: In this International Standard, the volume of water passing through the meter refers to the
accumulated volume.
3.1.6
adjustment device
part of the meter that allows an adjustment of the meter such that the error curve of the meter is generally
shifted parallel to itself to fit in the envelope of the maximum permissible error(s) (3.2.5)
Note 1 to entry: For the definition of the term “adjustment of a measuring system”, see ISO/IEC Guide 99:2007|OIML V
2-200:2012 (VIM), 3.11.
ISO 4064-1:2024(en)
3.1.7
correction device
device connected to or incorporated in the meter for automatic correction of the volume of water at metering
conditions (3.2.11), by taking into account the flow rate (3.3.1) and/or the characteristics of the water to be
measured and the pre-established calibration curves
Note 1 to entry: For the definition of the term “correction”, see ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 2.53.
3.1.8
ancillary device
device intended to perform a specific function, directly involved in elaborating, transmitting or displaying
measured values
Note 1 to entry: For the definition of “measured value”, see ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 2.10.
Note 2 to entry: The main ancillary devices are:
a) zero-setting device;
b) price-indicating device;
c) repeating indicating device;
d) printing device;
e) memory device;
f) tariff control device;
g) pre-setting device;
h) self-service device;
i) flow sensor movement detector (for detecting movement of the flow sensor before this is clearly visible on the
indicating device);
j) remote or automatic reading device (which may be incorporated permanently or added temporarily).
Note 3 to entry: Depending on national regulations, ancillary devices may be subject to legal metrological control.
3.1.9
tariff control device
device that allocates measured values into different registers depending on tariff or other criteria, each
register having the possibility to be read individually
3.1.10
pre-setting device
device that permits the selection of the quantity of water to be measured and which automatically stops the
flow of water after the selected quantity has been measured
3.1.11
associated measuring instrument
instrument connected to the calculator (3.1.4) or the correction device (3.1.7) for measuring a quantity,
characteristic of water, with a view to making a correction and/or a conversion
3.1.12
meter for two constant partners
meter that is permanently installed and only used for deliveries from one supplier to one customer
3.1.13
in-line meter
type of meter that is fitted into a closed conduit by means of the meter end connections provided
Note 1 to entry: The end connections may be flanged or threaded.

ISO 4064-1:2024(en)
3.1.14
complete meter
meter whose measurement transducer (3.1.2), calculator (3.1.4), and indicating device (3.1.5) are not separable
3.1.15
combined meter
meter whose measurement transducer (3.1.2), calculator (3.1.4), and indicating device (3.1.5) are separable
3.1.16
combination meter
meter comprising one large meter, one small meter, and a changeover device that, depending on the
magnitude of the flow rate (3.3.1) passing through the meter, automatically directs the flow through either
the small or the large meter, or both
Note 1 to entry: The meter reading is obtained from two independent totalizers, or from one totalizer which adds up
the values from both meters.
3.1.17
equipment under test
EUT
complete meter (3.1.14), sub-assembly or ancillary device (3.1.8) that is subjected to a test
3.1.18
concentric meter
type of meter that is fitted into a closed conduit by means of a manifold
Note 1 to entry: The inlet and outlet passages of the meter and the manifold are coaxial at the interface between them.
3.1.19
concentric meter manifold
pipe fitting specific to the connection of a concentric meter (3.1.18)
3.1.20
cartridge meter
type of meter that is fitted into a closed conduit by means of an intermediate fitting called a connection
interface
Note 1 to entry: The inlet and outlet passages of the meter and the connection interface are either concentric or axial
[5]
as specified in ISO 4064-4 .
3.1.21
cartridge meter connection interface
pipe fitting specific to the connection of an axial or concentric cartridge meter (3.1.20)
3.1.22
meter with exchangeable metrological module
meter comprising a connection interface and an exchangeable metrological module (3.1.23) from the same
type approval (3.4.13)
3.1.23
exchangeable metrological module
self-contained module comprising a measurement transducer (3.1.2), a calculator (3.1.4) and an indicating
device (3.1.5)
3.1.24
connection interface for meters with exchangeable metrological modules
pipe fitting specific to the connection of exchangeable metrological modules

ISO 4064-1:2024(en)
3.1.25
non-adjustable water meter
water meter (3.1.1) whose indication cannot be altered in any way (e.g. without changing the internal
dimensions and/or method of operation), and which has no adjustment device (3.1.6) or correction device
(3.1.7).
Note 1 to entry: This category should also include mechanical meters with an internal adjustment device where the
adjustment cannot be altered at initial verification stage as the meter would need to be dismantled.
Note 2 to entry: The meter should not have a correction device, i.e. the indicating device of the meter should either be
purely mechanical or be electronic but with a constant multiplying factor applied to the indication and set to the same
value for all meters (such as a device which counts the number of rotations of the shaft and multiplies by a fixed value
to give total volume passed).
3.1.26
adjustable water meter
water meter (3.1.1) that is connected to or incorporates an adjustment and/or correction device (3.1.7)
3.1.27
software-controlled water meter
water meter (3.1.1) that incorporates and utilizes legally relevant software modules
3.2 Metrological characteristics
3.2.1
actual volume
V
a
total volume of water passing through the meter, disregarding the time taken
Note 1 to entry: This is the measurand.
Note 2 to entry: The actual volume is calculated from a reference volume as determined by a suitable measurement
standard, taking into account differences in metering conditions, as appropriate.
3.2.2
indicated volume
V
i
volume of water indicated by the meter, corresponding to the actual volume
3.2.3
primary indication
indication which is subject to legal metrological control
3.2.4
error
measured quantity value minus a reference quantity value
[SOURCE: ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 2.16, modified — “error” replaces “measurement
error”; original notes to entry removed; “Note 1 to entry” added, “Note 2 to entry” added.]
Note 1 to entry: For the application of this part of ISO 4064|OIML R 49, the indicated volume is considered as the
measured quantity value and the actual volume as the reference quantity value. The difference between indicated
volume and actual volume is referred to as: error (of indication).
Note 2 to entry: In this International Standard, the error (of indication) is expressed as a percentage of the actual
()VV−
ia
volume, and is equal to: ×100%
V
a
ISO 4064-1:2024(en)
3.2.5
maximum permissible error
MPE
extreme value of measurement error (3.2.4), with respect to a known reference quantity value, permitted by
specifications or regulations for a given meter
[SOURCE: ISO/IEC Guide 99:2007|OIML V 2-200:2012 (VIM), 4.26, modified — "meter" replaces
"measurement, measuring instrument, or measuring system"; original notes removed]
3.2.6
intrinsic error
error (3.2.4) of a meter determined under reference condition(s) (3.4.5)
[SOURCE: OIML D 11:2013, 3.8, modified — "a meter" replaces "indication"]
3.2.7
initial intrinsic error
intrinsic error (3.2.6) of a meter as determined prior to performance test(s) (3.4.6) and durability (3.2.10)
evaluations
[SOURCE: OIML D 11:2013, 3.9, modified — "meter" replaces "measuring instrument"]
3.2.8
fault
difference between the error (3.2.4) (of indication) and the intrinsic error (3.2.6) of a meter
[SOURCE: OIML D 11:2013, 3.10, modified — "of indication" placed in parentheses; "meter" replaces
...