Non-destructive testing - Ultrasonic thickness measurement (ISO 16809:2017)

ISO 16809:2017 specifies the principles for ultrasonic thickness measurement of metallic and non-metallic materials by direct contact, based on measurement of time of flight of ultrasonic pulses only.

Zerstörungsfreie Prüfung - Dickenmessung mit Ultraschall (ISO 16809:2017)

Dieses Dokument legt die Grundlagen für die Messung der Dicke metallischer und nicht metallischer Werkstoffe mit Ultraschall durch unmittelbaren Kontakt mit dem Prüfgegenstand fest, ausschließlich basierend auf der Messung der Laufzeit von Ultraschallimpulsen.

Essais non destructifs - Mesurage de l'épaisseur par ultrasons (ISO 16809:2017)

Le présent document spécifie les principes pour le mesurage de l'épaisseur par ultrasons de matériaux métalliques et non métalliques par contact direct, exclusivement basés sur la mesure du temps de vol d'impulsions ultrasonores.

Neporušitvene preiskave - Ultrazvočno merjenje debeline (ISO 16809:2017)

Standard ISO 16809:2017 določa načela za ultrazvočno merjenje debeline kovinskih in nekovinskih materialov z neposrednim stikom, in sicer samo na podlagi merjenja časa preleta ultrazvočnih impulzov.

General Information

Status
Published
Publication Date
04-Jun-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
05-Jun-2019
Completion Date
05-Jun-2019

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SLOVENSKI STANDARD
SIST EN ISO 16809:2019
01-november-2019
Nadomešča:
SIST EN 14127:2011
Neporušitvene preiskave - Ultrazvočno merjenje debeline (ISO 16809:2017)
Non-destructive testing - Ultrasonic thickness measurement (ISO 16809:2017)
Zerstörungsfreie Prüfung - Dickenmessung mit Ultraschall (ISO 16809:2017)
Essais non destructifs - Mesurage de l'épaisseur par ultrasons (ISO 16809:2017)
Ta slovenski standard je istoveten z: EN ISO 16809:2019
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
SIST EN ISO 16809:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 16809:2019
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SIST EN ISO 16809:2019
EN ISO 16809
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN 14127:2011
English Version
Non-destructive testing - Ultrasonic thickness
measurement (ISO 16809:2017)

Essais non destructifs - Mesurage de l'épaisseur par Zerstörungsfreie Prüfung - Dickenmessung mit

ultrasons (ISO 16809:2017) Ultraschall (ISO 16809:2017)
This European Standard was approved by CEN on 8 April 2019.

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

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16809:2019 E

worldwide for CEN national Members.
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SIST EN ISO 16809:2019
EN ISO 16809:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 16809:2019
EN ISO 16809:2019 (E)
European foreword

The text of ISO 16809:2017 has been prepared by Technical Committee ISO/TC 135 "Non-destructive

testing” of the International Organization for Standardization (ISO) and has been taken over as

EN ISO 16809:2019 by Technical Committee CEN/TC 138 “Non-destructive testing” the secretariat of

which is held by AFNOR.

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 December 2019, and conflicting national standards

shall be withdrawn at the latest by December 2019.

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 14127:2011.

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 16809:2017 has been approved by CEN as EN ISO 16809:2019 without any modification.

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SIST EN ISO 16809:2019
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SIST EN ISO 16809:2019
INTERNATIONAL ISO
STANDARD 16809
Second edition
2017-11
Non-destructive testing — Ultrasonic
thickness measurement
Essais non destructifs — Mesurage de l'épaisseur par ultrasons
Reference number
ISO 16809:2017(E)
ISO 2017
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SIST EN ISO 16809:2019
ISO 16809:2017(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 16809:2019
ISO 16809:2017(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Measurement modes ........................................................................................................................................................................................ 1

5 General requirements ..................................................................................................................................................................................... 3

5.1 Instruments ............................................................................................................................................................................................... 3

5.2 Probes ............................................................................................................................................................................................................. 3

5.3 Couplant ........................................................................................................................................................................................................ 3

5.4 Reference blocks .................................................................................................................................................................................... 3

5.5 Test objects ................................................................................................................................................................................................. 3

5.6 Qualification of personnel ............................................................................................................................................................. 4

6 Application of the technique .................................................................................................................................................................... 4

6.1 Surface conditions and surface preparation ................................................................................................................. 4

6.2 Technique .................................................................................................................................................................................................... 4

6.2.1 General...................................................................................................................................................................................... 4

6.2.2 Measurement during manufacture .................................................................................................................. 5

6.2.3 In-service measurement of residual wall thickness .......................................................................... 5

6.3 Selection of probe ................................................................................................................................................................................. 6

6.4 Selection of instrument ................................................................................................................................................................... 6

6.5 Materials different from the reference material ........................................................................................................ 6

6.6 Special measuring conditions .................................................................................................................................................... 7

6.6.1 General...................................................................................................................................................................................... 7

6.6.2 Measurements at temperatures below 0 °C ............................................................................................. 7

6.6.3 Measurements at elevated temperatures ................................................................................................... 7

6.6.4 Hazardous atmospheres ........................................................................................................................................... . 7

7 Instrument setting .............................................................................................................................................................................................. 7

7.1 General ........................................................................................................................................................................................................... 7

7.2 Methods of setting ................................................................................................................................................................................ 8

7.2.1 General...................................................................................................................................................................................... 8

7.2.2 Digital thickness instruments ............................................................................................................................... 8

7.2.3 A-scan instrument .......................................................................................................................................................... 8

7.3 Checks of settings ................................................................................................................................................................................. 9

8 Influence on accuracy ...................................................................................................................................................................................10

8.1 Operational conditions..................................................................................................................................................................10

8.1.1 Surface conditions .......................................................................................................................................................10

8.1.2 Surface temperature ..................................................................................................................................................10

8.1.3 Metallic coating ..............................................................................................................................................................11

8.1.4 Non-metallic coating .................................................................................................................................................11

8.1.5 Geometry .............................................................................................................................................................................12

8.2 Equipment ................................................................................................................................................................................................12

8.2.1 Resolution ...........................................................................................................................................................................12

8.2.2 Range ......................................................................................................................................................................................13

8.3 Evaluation of accuracy ...................................................................................................................................................................13

8.3.1 General...................................................................................................................................................................................13

8.3.2 Influencing parameters ...........................................................................................................................................14

8.3.3 Method of calculation ...............................................................................................................................................14

9 Influence of materials ..................................................................................................................................................................................14

9.1 General ........................................................................................................................................................................................................14

9.2 Inhomogeneity .....................................................................................................................................................................................14

9.3 Anisotropy ...............................................................................................................................................................................................14

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9.4 Attenuation .............................................................................................................................................................................................14

9.5 Surface conditions .............................................................................................................................................................................14

9.5.1 General...................................................................................................................................................................................14

9.5.2 Contact surface ...............................................................................................................................................................15

9.5.3 Reflecting surface .........................................................................................................................................................15

9.5.4 Corrosion and erosion ........................................................................................................................................... ...15

10 Test report ................................................................................................................................................................................................................16

10.1 General ........................................................................................................................................................................................................16

10.2 General information ........................................................................................................................................................................16

10.3 Measurement data ............................................................................................................................................................................17

Annex A (informative) Corrosion in vessels and piping ................................................................................................................18

Annex B (informative) Instrument settings ...............................................................................................................................................23

Annex C (informative) Parameters influencing accuracy ............................................................................................................26

Annex D (informative) Selection of measuring technique ..........................................................................................................32

Bibliography .............................................................................................................................................................................................................................37

iv © ISO 2017 – All rights reserved
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ISO 16809:2017(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 135, Non-destructive testing,

Subcommittee SC 3, Ultrasonic testing.

This second edition cancels and replaces the first edition (ISO 16809:2012), which has been technically

revised. The main changes compared to the previous edition are as follows:
— editorial improvements have been made;
— the terminology has been adapted to the latest edition of ISO 5577;
— Formulae (5) and (6) have been corrected.
© ISO 2017 – All rights reserved v
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SIST EN ISO 16809:2019
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SIST EN ISO 16809:2019
INTERNATIONAL STANDARD ISO 16809:2017(E)
Non-destructive testing — Ultrasonic thickness
measurement
1 Scope

This document specifies the principles for ultrasonic thickness measurement of metallic and non-

metallic materials by direct contact, based on measurement of time of flight of ultrasonic pulses only.

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 5577, Non-destructive testing — Ultrasonic testing — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5577 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 Measurement modes

The thickness of a part or structure is determined by accurately measuring the time required for a

short ultrasonic pulse generated by a transducer to travel through the thickness of the material once,

twice or several times.

The material thickness is calculated by multiplying the known sound velocity of the material with the

transit time and dividing by the number of times the pulse transits the material wall.

This principle can be accomplished by applying one of the following modes, see Figure 1.

1) Mode 1: Measure the transit time from an initial excitation pulse to a first returning echo, minus a

zero correction to account for the thickness of the probe's wear plate and the couplant layer (single-

echo mode).

2) Mode 2: Measure the transit time from the end of a delay line to the first back wall echo (single-

echo delay line mode).

3) Mode 3: Measure the transit time between back wall echoes (multiple-echo mode).

4) Mode 4: Measure the transit time for a pulse travelling from the transmitter to a receiver in contact

with the back wall (through-transmission mode).
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SIST EN ISO 16809:2019
ISO 16809:2017(E)
Mode 1 Mode 2
Mode 3 Mode 4
Key
A transmit/receive probe D transmission pulse indication
A1 transmit probe E1 to E3 back wall echoes
A2 receive probe F interface echo
A3 dual-element probe G delay path
B test object H received pulse
C sound path travel time
Figure 1 — Measurement modes
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SIST EN ISO 16809:2019
ISO 16809:2017(E)
5 General requirements
5.1 Instruments

The following types of instruments shall be used to achieve thickness measurement:

a) dedicated ultrasonic thickness measurement instruments with numerical display showing the

measured value;

b) dedicated ultrasonic thickness measurement instruments with numerical display showing the

measured value and A-scan presentation (waveform display);

c) instruments designed primarily for the detection of discontinuities with A-scan presentation of

signals. This type of instrument can also include numerical display of thickness values.

See 6.4.
5.2 Probes

The following types of probes shall be used; these are generally longitudinal wave probes:

— dual-element probes;
— single-element probes.
See 6.3.
5.3 Couplant

Acoustic contact between probe (probes) and material shall be provided, normally by application of a

fluid or gel.

The couplant shall not have any adverse effect on the test object, the equipment or represent a health

hazard to the operator.
For the use of the couplant in special measuring conditions, see 6.6.

The coupling medium should be chosen to suit the surface conditions and the irregularities of the

surface to ensure adequate coupling.
5.4 Reference blocks

The measuring system shall be calibrated on one or more samples or reference blocks representative of

the object to be measured, i.e. having comparable dimensions, material and structure. The thickness of

the blocks or the steps should cover the range of thickness to be measured. Either the thickness or the

sound velocity of the reference blocks shall be known.
5.5 Test objects
The object to be measured shall allow for ultrasonic wave propagation.
There shall be free access to each individual area to be measured.

The surface of the area to be measured shall be free of all dirt, grease, lint, scale, welding flux and

spatter, oil or other extraneous matter that could interfere with the testing.

If the surface is coated, the coating shall have good adhesion to the material. Otherwise it shall be

removed.
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When measuring through coating its thickness and sound velocity need to be known unless mode 3

is used.
For further details, see Clause 8.
5.6 Qualification of personnel

An operator performing ultrasonic thickness measurement according to this document shall have

a basic knowledge of the physics of ultrasound, and a detailed understanding and training related to

ultrasonic thickness measurements. In addition, the operator shall have knowledge of the product and

material to be tested.

It is assumed that ultrasonic thickness testing is performed by qualified and capable personnel. In order

to prove this qualification, it is recommended that personnel be qualified in accordance with ISO 9712

or equivalent.

NOTE For categories III and IV according to Pressure Equipment Directive 97/23/EC, Annex I, 3.1.3, there is

a requirement for personnel to be approved by a third-party organization recognized by a member state.

6 Application of the technique
6.1 Surface conditions and surface preparation

Using the pulse-echo method means that the ultrasonic pulse needs to pass the contact surface between

test object and the probe at least twice: when entering the object and when leaving it.

Therefore, a clean and even contact area with at least twice the probe's diameter is preferred. Poor

contact will result in loss of energy, distortion of signals and sound path.

To enable sound propagation all loose parts and non-adherent coatings shall be removed by brushing or

grinding.

Attached layers, like colour coating, plating, enamels, may stay on the object, but only a few thickness

meters are able to exclude these layers from being measured.

Very often, thickness measurements need to be done on corroded surfaces, e.g. storage tanks and

pipelines. To increase measuring accuracy the contact surface should be ground within an area at least

two times the probe's diameter. This area should be clean from corrosion products.

Care should be taken not to reduce the thickness below the minimum acceptable value.

6.2 Technique
6.2.1 General

The task of ultrasonic thickness measurements can be separated into two application areas:

— measurement during manufacture;
— in-service measurements of residual wall thickness.

Each area has its own special conditions which require special measuring techniques.

Using a knowledge of the material, geometry and thickness to be measured and the required accuracy,

the most suitable measuring equipment and mode shall be selected as follows (Annex D gives guidance):

a) depending on the thickness and the material, frequencies from 100 kHz with through-transmission

on highly attenuative materials up to 50 MHz on thin metal sheets shall be used;

b) if dual-element probes are used, then compensation for V-path error is required;

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c) on curved objects, the diameter of the probe contact area shall be significantly smaller than the

diameter of the test object.

The accuracy of the thickness measurement depends on how accurate the time of flight can be measured,

on the mode of time-measuring (zero crossing, flank-to-flank, peak-to-peak), on the mode chosen (with

multiple echoes, mode 3, the accuracy is higher than with modes 1 and 2), and on the frequencies which

can be used (higher frequencies provide higher accuracy than lower frequencies because of the more

accurate time measurement).

Ultrasonic thickness measurement is often required over an area of the component to be measured.

Where this is the case, consideration should be given to the spacing between each

...

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