SIST EN ISO 20769-2:2019

SLOVENSKI STANDARD
SIST EN ISO 20769-2:2019
01-marec-2019
1DGRPHãþD
SIST EN 16407-2:2014
Neporušitvene preiskave - Radiografski pregled korozije in nanosov v ceveh z
rentgenskimi žarki in žarki gama - 2. del: Radiografski pregled preko dveh sten
(ISO 20769-2:2018)
Non-destructive testing -- Radiographic inspection of corrosion and deposits in pipes by
X- and gamma rays - Part 2: Double wall radiographic inspection (ISO 20769-2:2018)
Zerstörungsfreie Prüfung - Durchstrahlungsprüfung auf Korrosion und Ablagerungen in
Rohren mit Röntgen - und Gammastrahlen - Teil 2: Doppelwand-Durchstrahlungsprüfung
(ISO 20769-2:2018)
Essais non destructifs - Examen radiographique de la corrosion et des dépôts dans les
canalisations, par rayons X et rayons gamma - Partie 2: Examen radiographique double
paroi (ISO 20769-2:2018)
Ta slovenski standard je istoveten z: EN ISO 20769-2:2018
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
SIST EN ISO 20769-2:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 20769-2:2019

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SIST EN ISO 20769-2:2019


EN ISO 20769-2
EUROPEAN STANDARD

NORME EUROPÉENNE

October 2018
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN 16407-2:2014
English Version

Non-destructive testing - Radiographic inspection of
corrosion and deposits in pipes by X- and gamma rays -
Part 2: Double wall radiographic inspection (ISO 20769-
2:2018)
Essais non destructifs - Examen radiographique de la Zerstörungsfreie Prüfung - Durchstrahlungsprüfung
corrosion et des dépôts dans les canalisations, par auf Korrosion und Ablagerungen in Rohren mit
rayons X et rayons gamma - Partie 2: Examen Röntgen - und Gammastrahlen - Teil 2: Doppelwand-
radiographique double paroi (ISO 20769-2:2018) Durchstrahlungsprüfung (ISO 20769-2:2018)
This European Standard was approved by CEN on 9 August 2018.

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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20769-2:2018 E
worldwide for CEN national Members.

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SIST EN ISO 20769-2:2019
EN ISO 20769-2:2018 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 20769-2:2019
EN ISO 20769-2:2018 (E)
European foreword
This document (EN ISO 20769-2:2018) has been prepared by Technical Committee ISO/TC 135 "Non-
destructive testing" in collaboration with 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 April 2019, and conflicting national standards shall be
withdrawn at the latest by April 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 16407-2:2014.
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 20769-2:2018 has been approved by CEN as EN ISO 20769-2:2018 without any
modification.

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SIST EN ISO 20769-2:2019

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SIST EN ISO 20769-2:2019
INTERNATIONAL ISO
STANDARD 20769-2
First edition
2018-09
Non-destructive testing —
Radiographic inspection of corrosion
and deposits in pipes by X- and
gamma rays —
Part 2:
Double wall radiographic inspection
Essais non destructifs — Examen radiographique de la corrosion et
des dépôts dans les canalisations, par rayons X et rayons gamma —
Partie 2: Examen radiographique double paroi
Reference number
ISO 20769-2:2018(E)
©
ISO 2018

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SIST EN ISO 20769-2:2019
ISO 20769-2:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

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SIST EN ISO 20769-2:2019
ISO 20769-2:2018(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification of radiographic techniques . 3
5 General . 3
5.1 Protection against ionizing radiation . 3
5.2 Personnel qualification . 4
5.3 Identification of radiographs . 4
5.4 Marking . 4
5.5 Overlap of films or digital images . 4
5.6 Types and positions of image quality indicators (IQI) . 4
5.6.1 Single wire IQI . 4
5.6.2 Duplex wire IQI (digital radiographs) . 5
6 Recommended techniques for making radiographs . 5
6.1 Test arrangements . 5
6.1.1 General. 5
6.1.2 Double wall single image (DWSI) . 5
6.1.3 Double wall double image (DWDI) . 7
6.1.4 Alignment of beam and film/detector . 9
6.2 Choice of radiation source . . 9
6.3 Film systems and screens .10
6.4 Screens and shielding for imaging plates (computed radiography only).11
6.5 Reduction of scattered radiation .13
6.5.1 Filters and collimators .13
6.5.2 Interception of back scattered radiation .13
6.6 Source-to-detector distance .13
6.6.1 Double wall single image .13
6.6.2 Double wall double image .14
6.7 Axial coverage and overlap .14
6.8 Circumference coverage .15
6.8.1 General.15
6.8.2 DWSI .16
6.8.3 DWDI .16
6.9 Selection of digital radiographic equipment .16
6.9.1 General.16
6.9.2 CR systems .17
6.9.3 DDA systems .17
7 Radiograph/digital image sensitivity, quality and evaluation.17
7.1 Minimum image quality values .17
7.1.1 Wire image quality indicators .17
7.1.2 Duplex wire IQIs (digital radiographs) .17
7.1.3 Minimum normalized signal to noise ratio (digital radiographs) .17
7.2 Density of film radiographs . .18
7.3 Film processing.18
7.4 Film viewing conditions .18
8 Measurement of differences in penetrated thickness .18
8.1 Principle of technique .18
8.2 Measurement of attenuation coefficient .19
8.3 Source and detector positioning .19
8.4 Image grey level profiles .19
8.5 Validation .19
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8.6 Key points .20
9 Digital image recording, storage, processing and viewing .20
9.1 Scan and read out of image .20
9.2 Calibration of DDAs .20
9.3 Bad pixel interpolation .20
9.4 Image processing .21
9.5 Digital image recording and storage .21
9.6 Monitor viewing conditions .21
10 Test report .21
Annex A (normative) Minimum image quality values .23
Annex B (normative) Penetrated thickness measurements from image grey levels .25
Annex C (normative) Determination of basic spatial resolution .27
Bibliography .30
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SIST EN ISO 20769-2:2019
ISO 20769-2:2018(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 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 135 Non-destructive testing, Subcommittee
SC 5 Radiographic testing.
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.
A list of all parts in the ISO 20769 series can be found on the ISO website.
© ISO 2018 – All rights reserved v

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SIST EN ISO 20769-2:2019
INTERNATIONAL STANDARD ISO 20769-2:2018(E)
Non-destructive testing — Radiographic inspection of
corrosion and deposits in pipes by X- and gamma rays —
Part 2:
Double wall radiographic inspection
1 Scope
This document specifies fundamental techniques of film and digital radiography with the object of
enabling satisfactory and repeatable results to be obtained economically. The techniques are based on
generally recognized practice and fundamental theory of the subject.
This document applies to the radiographic examination of pipes in metallic materials for service
induced flaws such as corrosion pitting, generalized corrosion and erosion. Besides its conventional
meaning, “pipe” as used in this document is understood to cover other cylindrical bodies such as tubes,
penstocks, boiler drums and pressure vessels.
Weld inspection for typical welding process induced flaws is not covered, but weld inspection is
included for corrosion/erosion type flaws.
The pipes can be insulated or not, and can be assessed where loss of material due, for example, to
corrosion or erosion is suspected either internally or externally.
This document covers double wall inspection techniques for detection of wall loss, including double
wall single image (DWSI) and double wall double image (DWDI).
Note that the DWDI technique described in this document is often combined with the tangential
technique covered in ISO 20769-1.
This document applies to in-service double wall radiographic inspection using industrial radiographic
film techniques, computed digital radiography (CR) and digital detector arrays (DDA).
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 11699-1, Non-destructive testing — Industrial radiographic film — Part 1: Classification of film
systems for industrial radiography
ISO 11699-2, Non-destructive testing — Industrial radiographic films — Part 2: Control of film processing
by means of reference values
ISO 17636-2, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray
techniques with digital detectors
ISO 19232-1, Non-destructive testing — Image quality of radiographs — Part 1: Determination of the
image quality value using wire-type image quality indicators
ISO 19232-5, Non-destructive testing — Image quality of radiographs — Part 5: Determination of the
image unsharpness value using duplex wire-type image quality indicators
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ISO 20769-2:2018(E)

ISO 20769-1, Non-destructive testing of welds — Radiographic inspection of corrosion and deposits in pipes
by X- and gamma rays — Part 1: Tangential radiographic inspection
EN 14784-1, Non-destructive testing — Industrial computed radiography with storage phosphor imaging
plates — Part 1: Classification of systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20769-1 and the following 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/
3.1
digital detector array system
DDA system
electronic device converting ionizing or penetrating radiation into a discrete array of analogue
signals which are subsequently digitized and transferred to a computer for display as a digital image
corresponding to the radiologic energy pattern imparted upon the input region of the device
3.2
double wall double image technique
DWDI
technique where the radiation source is located outside and away from the pipe, with the detector on
the opposite side of the pipe and where the radiograph shows details from both the pipe walls on the
detector and source sides of the pipe
Note 1 to entry: See Figure 3.
3.3
double wall single image technique
DWSI
technique where the radiation source is located outside the pipe and close to the pipe wall, with the
detector on the opposite side of the pipe and where the radiograph shows only detail from the pipe wall
on the detector side
Note 1 to entry: See Figure 1.
3.4
object-to-detector distance
b
distance between the radiation side of the test object and the detector surface measured along the
central axis of the radiation beam
3.5
penetrated thickness
w
thickness of material in the direction of the radiation beam calculated on the basis of the nominal
thickness
Note 1 to entry: For double wall radiographic inspection of a pipe, the minimum value for w is twice the pipe wall
thickness. For multiple wall techniques (pipes in pipe or liners), the penetrated thickness is calculated from the
nominal wall thicknesses t.
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3.6
source-to-object distance
f
distance between the source of radiation and the source side of the test object measured along the
central axis of the radiation beam
3.7
total effective penetrated thickness
w
tot
total equivalent thickness of metallic material in the direction of the radiation beam calculated on the
basis of the nominal thickness, with allowance for any liquid or other material present in the pipe and
any insulation
4 Classification of radiographic techniques
The double wall radiographic techniques are divided into two classes:
— basic techniques DWA;
— improved techniques DWB.
The basic techniques are intended for double wall radiography of generalized and localized wall loss.
For the basic techniques, DWA, when using Ir 192 sources for pipes with penetrated thicknesses
between 15 mm and 35 mm, the sensitivity for detection is high for imperfections, provided their
diameters are greater than or equal to 2 mm and the material loss is typically greater than or equal to
5 % of the pipe penetrated thickness, in the absence of liquid or other products in the pipe. When using
Se 75, the corresponding detection sensitivity is high for 2 mm diameter or larger imperfections with
material loss greater than or equal to 4 % of the pipe penetrated thickness. The detection sensitivity
is improved for flaws with larger diameters, whereas the presence of liquid or other products, and
external insulation, can reduce the sensitivity for material loss depending on their properties. Different
detection sensitivities may apply for penetrated thicknesses less than 15 mm and greater than 35 mm.
The presence of external corrosion product can reduce the techniques sensitivity to corrosion due to
the increased radiation attenuation in the product, which can even exceed the reduced attenuation
caused by the loss of steel. Build-up of internal solid material (e.g. scale) in pipes can similarly reduce
sensitivity to internal degradation.
These techniques can also be used for detection of deposits inside the pipe.
The improved techniques should be used where higher sensitivity is required such as for radiography
of fine, localized corrosion pitting.
Further improvements, beyond the improved techniques described herein, are possible and may be
agreed between the contracting parties by specification of all appropriate test parameters.
The choice of radiographic technique shall be agreed between the concerned parties.
5 General
5.1 Protection against ionizing radiation
WARNING — Exposure of any part of the human body to X-rays or gamma-rays can be highly
injurious to health. Wherever X-ray equipment or radioactive sources are in use, appropriate
measures shall be taken to ensure the safety and health of personnel.
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5.2 Personnel qualification
Testing shall be carried out by proficient, suitably trained and qualified personnel and, where
applicable, shall be supervised by competent personnel nominated by the employer or, by delegation of
the employer, the inspection company in charge of testing. To demonstrate appropriate qualification, it
is recommended that personnel be certified according to ISO 9712 or an equivalent formalized syst
...