SIST EN ISO 6416:2018

SLOVENSKI STANDARD
SIST EN ISO 6416:2018
01-februar-2018
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SIST EN ISO 6416:2005
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Hydrometry - Measurement of discharge by the ultrasonic transit time (time of flight)
method (ISO 6416:2017)
Hydrometrie - Messung des Durchflusses mit dem Ultraschall-Laufzeitverfahren (Transit-
time-/Time-of-flight-Verfahren) (ISO 6416:2017)
Hydrométrie - Mesure du débit par le temps de transit ultrasonique (temps de vol)
méthode (ISO 6416:2017)
Ta slovenski standard je istoveten z: EN ISO 6416:2017
ICS:
17.120.20 Pretok v odprtih kanalih Flow in open channels
SIST EN ISO 6416:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 6416:2018

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SIST EN ISO 6416:2018


EN ISO 6416
EUROPEAN STANDARD

NORME EUROPÉENNE

November 2017
EUROPÄISCHE NORM
ICS 17.120.20 Supersedes EN ISO 6416:2005
English Version

Hydrometry - Measurement of discharge by the ultrasonic
transit time (time of flight) method (ISO 6416:2017)
Hydrométrie - Mesure du débit par la méthode du Hydrometrie - Messung des Durchflusses mit dem
temps de transit ultrasonique (temps de vol) (ISO Ultraschall-Laufzeitverfahren (Transit-time-/Time-of-
6416:2017) flight-Verfahren) (ISO 6416:2017)
This European Standard was approved by CEN on 22 August 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey 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
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6416:2017 E
worldwide for CEN national Members.

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SIST EN ISO 6416:2018
EN ISO 6416:2017 (E)
Contents Page
European foreword . 3
2

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SIST EN ISO 6416:2018
EN ISO 6416:2017 (E)
European foreword
This document (EN ISO 6416:2017) has been prepared by Technical Committee ISO/TC 113
“Hydrometry” in collaboration with Technical Committee CEN/TC 318 “Hydrometry” the secretariat of
which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2018, and conflicting national standards shall be
withdrawn at the latest by May 2018.
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 6416:2005.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 6416:2017 has been approved by CEN as EN ISO 6416:2017 without any modification.

3

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SIST EN ISO 6416:2018

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SIST EN ISO 6416:2018
INTERNATIONAL ISO
STANDARD 6416
Fourth edition
2017-10
Hydrometry — Measurement of
discharge by the ultrasonic transit
time (time of flight) method
Hydrométrie — Mesure du débit par la méthode du temps de transit
ultrasonique (temps de vol)
Reference number
ISO 6416:2017(E)
©
ISO 2017

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SIST EN ISO 6416:2018
ISO 6416:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

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SIST EN ISO 6416:2018
ISO 6416:2017(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Applications . 1
4.1 Types of applications . 1
4.2 Attributes and limitations . 2
5 Method of measurement . 2
5.1 Discharge . 2
5.2 Calculation of discharge from the transit-time measurement . 3
6 Flow velocity determination by the ultrasonic (transit time) method .3
6.1 Principle . 3
6.2 Sound propagation in water . 5
6.2.1 General. 5
6.2.2 Speed of sound in water . 6
6.2.3 Propagation losses . 6
6.2.4 Signal path bending . 8
6.2.5 Reflection . . 9
7 Gauge configuration .10
7.1 General .10
7.2 Single-path systems .10
7.3 Multi-path systems .11
7.4 Crossed-path systems .11
7.5 Reflected-path systems .13
7.6 Systems using transponders .14
7.7 Wireless systems (if a cable crossing is not possible) .15
7.8 Systems using divided cross-sections .16
7.9 Sloping paths .16
8 Determination of discharge .17
8.1 Single-path systems .17
8.2 Multi-path systems .18
8.2.1 General.18
8.2.2 Mid-section method .19
8.2.3 Mean-section method .20
8.3 Systems with transducers in the channel .21
9 System verification and calibration .22
10 Site selection .23
11 Site survey — Before design and construction .23
11.1 General .23
11.2 Visual survey .23
11.3 Survey of the cross-section .24
11.4 Survey of velocity distribution .24
11.5 Survey of signal propagation .24
12 Operational measurement requirements .24
12.1 General .24
12.2 Basic components of flow determination .25
12.3 Water velocity determination .25
12.4 Determination of water stage or depth .25
12.5 Determination of mean bed level .26
12.6 Channel width .27
© ISO 2017 – All rights reserved iii

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SIST EN ISO 6416:2018
ISO 6416:2017(E)

13 Gauging station equipment .27
13.1 General .27
13.2 Design and construction of equipment .28
13.2.1 Transducers.28
13.2.2 Transducer cables .29
13.3 Reflectors .29
13.4 Civil engineering works .32
13.5 Signal timing and processing .32
13.5.1 General.32
13.5.2 Signal-to-noise ratio .32
13.5.3 Signal maintenance (gain control) .33
13.5.4 Signal detection . .33
13.5.5 Post-detection filtering .34
13.6 System self-checking .34
13.7 Site-specific data (or site parameters) .35
13.8 Clock and calendar .35
13.9 System performance criteria .35
13.9.1 General.35
13.9.2 Operating environment .36
13.9.3 Water environment.36
13.9.4 Mechanical environment .36
13.9.5 Extreme environmental conditions .36
13.9.6 Power source .36
13.9.7 Measurement uncertainty .36
13.10 System output .37
13.10.1 Local display .37
13.10.2 Local record .37
13.10.3 Remote record .37
13.10.4 Diagnostic information .37
13.11 Installation .37
13.12 Commissioning .38
13.13 Operating manual .38
13.14 Maintenance .39
14 Measurement uncertainties .40
14.1 General .40
14.2 Definition of uncertainty .40
14.3 Uncertainty in discharge .41
14.3.1 Uncertainty equation .41
14.3.2 Effective number of paths .42
14.3.3 Uncertainty in the line velocity, U .
lv 42
14.3.4 Uncertainty in the channel width estimation, U .42
w
14.3.5 Examples of uncertainty estimation .43
14.3.6 Uncertainty estimate at low flow .44
14.3.7 Uncertainty estimate at high flow .45
Annex A (informative) Principle of measurement uncertainty .47
Annex B (informative) Performance guide for hydrometric equipment for use in technical
standard examples .54
Bibliography .58
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SIST EN ISO 6416:2018
ISO 6416:2017(E)

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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 1,
Velocity area methods.
This fourth edition cancels and replaces the third edition (ISO 6416:2004), which has been technically
revised. The main changes from the previous edition are:
— the title has been changed;
— a new subclause (7.7) on wireless systems has been added;
— former subclauses 9.2 and 11.6 have been removed;
— Clause 10 on site selection has been revised;
— Annex A (Principle of measurement uncertainty) and Annex B (Performance guide for hydrometric
equipment for use in technical standards) have been added.
© ISO 2017 – All rights reserved v

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SIST EN ISO 6416:2018

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SIST EN ISO 6416:2018
INTERNATIONAL STANDARD ISO 6416:2017(E)
Hydrometry — Measurement of discharge by the ultrasonic
transit time (time of flight) method
1 Scope
This document describes the establishment and operation of an ultrasonic (transit-time) gauging
station for the continuous measurement of discharge in a river, an open channel or a closed conduit.
It also describes the basic principles on which the method is based, the operation and performance of
associated instrumentation and procedures for commissioning.
It is limited to the “transit time of ultrasonic pulses” technique, and is not applicable to systems that
make use of the “Doppler shift” or “correlation” or “level-to-flow” techniques.
This document is not applicable to measurement in rivers with ice.
NOTE This document focuses on open channel flow measurement. IEC 60041 covers the use of the technique
for full pipe flow measurement.
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 772, Hydrometry — Vocabulary and symbols
ISO 4373, Hydrometry — Water level measuring devices
ISO/TS 25377, Hydrometric uncertainty guidance (HUG)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 772 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
4 Applications
4.1 Types of applications
a) Open channels
b) Multiple channels
c) Closed conduits
This method does not need a man-made or natural control, as it does not rely upon the establishment of
a unique relationship between water level and discharge.
© ISO 2017 – All rights reserved 1

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SIST EN ISO 6416:2018
ISO 6416:2017(E)

4.2 Attributes and limitations
The following attributes and limitations shall be considered when deploying this measuring system.
Attributes
1. Potential for high accuracy
2. Tolerant of back water effects
3. Able to measure multiple channels and combine results to give total flow
4. Capable of determining individual velocities at distinct heights within the water column
5. Visually unobtrusive
6. Fish friendly
7. Mains power supply not essential
8. Intrinsically safe systems available for use in explosive atmospheres
9. No obstru
...