prEN ISO 23279

• Abstract:

  ISO 23279:2017 specifies how to characterize indications from discontinuities by classifying them as originating from planar or non-planar embedded discontinuities.; This procedure is also suitable for indications from discontinuities that break the surface after removal of the weld reinforcement.

• Status: Not Published
• Publication Date: 02-Apr-2028
• ICS: 25.160.40 - Welded joints and welds
• Technical Committee: CEN/TC 121 - Welding
• Drafting Committee: CEN/TC 121/WG 21 - Testing of welds
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 10-Sep-2026
• Completion Date: 10-Sep-2026
• Ref Project: oSIST prEN ISO 23279:2026 - Non-destructive testing of welds - Ultrasonic testing - Characterization of discontinuities in welds (ISO/DIS 23279:2026)

• Revises: EN ISO 23279:2017 - Non-destructive testing of welds - Ultrasonic testing - Characterization of discontinuities in welds (ISO 23279:2017)
• Effective Date: 27-Nov-2024

Overview

prEN ISO 23279:2026 specifies procedures for the non-destructive testing of welds using ultrasonic testing methods, with a focus on the characterization of discontinuities in welds. This standard, developed under CEN and based on ISO/DIS 23279:2026, provides guidelines for classifying ultrasonic indications as either planar or non-planar embedded discontinuities.

The standard ensures uniformity and repeatability in evaluating weld integrity by establishing clear criteria and procedures for the classification of discontinuities. It is applicable to both internal discontinuities and those breaking the surface after weld reinforcement removal. By following these procedures, industries can achieve higher reliability in weld inspection and quality assurance.

Key Topics

• Classification of Discontinuities: The core of the standard is the systematic approach to characterizing ultrasonic indications:

  • Planar vs. Non-planar: Procedures for distinguishing between planar discontinuities (such as cracks or lack of fusion) and non-planar discontinuities (such as inclusions or porosity).
  • Parameters for Classification: Utilizes several key parameters, including:
    • Maximum echo amplitude
    • Directional reflectivity
    • Static echo pattern (A-scan)
    • Dynamic echo pattern (envelope)
    • Welding technique and location of discontinuity

• Flowchart-Based Approach: The classification process is organized into a stepwise flowchart, ensuring that each indication is evaluated consistently by applying a set of discriminatory criteria in stages.

• Echo Amplitude Thresholds:

  • Low amplitude indications below a specified evaluation level are not classified.
  • High amplitude indications above a certain reference are typically associated with planar discontinuities.

• Directional Reflectivity: Criteria based on the amplitude difference when testing from different directions are used to differentiate types of discontinuities, particularly lack of fusion.

• Pattern Recognition: Analysis of both static and dynamic echo patterns provides further characterization, including differentiating single, smooth patterns from clusters or complex signals.

• Complementary Testing: In cases of ambiguity, other ultrasonic techniques or alternative non-destructive testing methods, such as radiography, may be recommended.

Applications

prEN ISO 23279:2026 is widely utilized in industries where the reliability and mechanical integrity of welded joints are critical, including:

• Structural Steelwork: Ensures weld safety in construction, bridges, and heavy manufacturing.
• Oil & Gas and Petrochemical: Used during pipeline fabrication and plant maintenance for critical pressure-retaining welds.
• Shipbuilding and Offshore Platforms: Supports the inspection of high-strength welds exposed to harsh environments.
• Aerospace, Rail, and Automotive: Applied in the evaluation of safety-critical welded components.

This standard facilitates:

• Consistent weld quality assessment
• Early detection of critical defects
• Improved traceability and documentation of inspection results
• Compliance with contractual and regulatory requirements for welded structures

Related Standards

prEN ISO 23279:2026 is closely aligned with the following non-destructive testing (NDT) standards, which provide complementary requirements and guidance:

• ISO 17640: Non-destructive testing of welds - Ultrasonic testing - Techniques, testing levels, and assessment
• ISO 11666: Non-destructive testing of welds - Ultrasonic testing - Acceptance levels
• ISO 5577: Non-destructive testing - Ultrasonic testing - Vocabulary

Integration with these standards helps ensure a comprehensive approach to weld inspection, supporting best practices in ultrasonic testing and enhancing overall weld quality management.

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For organizations and professionals engaged in weld inspection, adopting prEN ISO 23279:2026 strengthens process control, boosts customer confidence, and supports international trade by aligning with globally recognized non-destructive testing standards.

SLOVENSKI STANDARD
01-oktober-2026
Neporušitveno preskušanje zvarnih spojev - Ultrazvočno preskušanje -
Karakterizacija nehomogenosti v zvarnih spojih (ISO/DIS 23279:2026)
Non-destructive testing of welds - Ultrasonic testing - Characterization of discontinuities
in welds (ISO/DIS 23279:2026)
Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung -
Charakterisierung von Inhomogenitäten in Schweißnähten (ISO/DIS 23279:2026)
Essais non destructifs des assemblages soudés - Contrôle par ultrasons -
Caractérisation des discontinuités dans les assemblages soudés (ISO/DIS 23279:2026)
Ta slovenski standard je istoveten z: prEN ISO 23279
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 23279
ISO/TC 44/SC 5
Non-destructive testing of
Secretariat: AFNOR
welds — Ultrasonic testing —
Voting begins on:
Characterization of discontinuities
2026-09-07
in welds
Voting terminates on:
2026-11-30
Essais non destructifs des assemblages soudés — Contrôle
par ultrasons — Caractérisation des discontinuités dans les
assemblages soudés
ICS: 25.160.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 23279:2026(en)
DRAFT
ISO/DIS 23279:2026(en)
International
Standard
ISO/DIS 23279
ISO/TC 44/SC 5
Non-destructive testing of
Secretariat: AFNOR
welds — Ultrasonic testing —
Voting begins on:
Characterization of discontinuities
in welds
Voting terminates on:
Essais non destructifs des assemblages soudés — Contrôle
par ultrasons — Caractérisation des discontinuités dans les
assemblages soudés
ICS: 25.160.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 23279:2026(en)
ii
ISO/DIS 23279:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle of classification . 1
5 Criteria for classification . 2
5.1 General .2
5.2 Maximum echo amplitude (stages 1 and 2) .3
5.2.1 Low amplitudes (stage 1) .3
5.2.2 High amplitudes (stage 2) .3
5.3 Directional reflectivity (stage 3) .3
5.3.1 Applicability based on length .3
5.3.2 Application conditions .3
5.3.3 Directional reflectivity criteria .3
5.3.4 Result .4
5.4 Static echo pattern (stage 4) .4
5.5 Transverse dynamic echo pattern (stage 5) .4
5.6 Complementary testing .4
Annex A (normative) Classification of indications from internal discontinuities in welds —
Flowchart procedure . 5
Annex B (informative) Directional reflectivity . 9
Annex C (informative) Basic dynamic echo patterns of reflectors .11

iii
ISO/DIS 23279:2026(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 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 44, Welding and allied processes, Subcommittee
SC 5, Testing and inspection of welds.
This fourth edition cancels and replaces the third edition (ISO 23279:2017), which has been technically
revised.
Requests for official interpretations of any aspect of this document should be directed to the Secretariat
of ISO/TC 44/SC 5 via your national standards body. A complete listing of these bodies can be found at
www.iso.org.
iv
DRAFT International Standard ISO/DIS 23279:2026(en)
Non-destructive testing of welds — Ultrasonic testing —
Characterization of discontinuities in welds
1 Scope
This document specifies how to characterize indications from discontinuities by classifying them as
originating from planar or non-planar embedded discontinuities.
This procedure is also suitable for indications from discontinuities that break the surface after removal of
the weld reinforcement.
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
ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and assessment
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:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Principle of classification
Classification of discontinuities as planar or non-planar is based on several parameters:
a) welding techniques;
b) geometrical position of the discontinuity;
c) maximum echo amplitude;
d) directional reflectivity;
e) static echo pattern (i.e. A-scan);
f) dynamic echo pattern (envelope).
The process of classification involves examining each of the parameters against all the others in order to
arrive at an accurate conclusion.
For guidance, Figure A.1 gives the classification of indications from internal weld discontinuities suitable for
general applications.
ISO/DIS 23279:2026(en)
Figure A.1 shall be applied in conjunction with the two parameters a) and b) listed above and not taken in
isolation.
The classification procedure specified in this document is also suitable for indications that come from
surface breaking discontinuities after removal of the weld reinforcement (see Figure 1).
Dimensions in millimetres
Key
A ground weld
Figure 1 — Origin of indications from a weld
5 Criteria for classification
5.1 General
The classification is carried out by the successive application of several discriminatory criteria to:
a) maximum echo amplitude;
b) directional reflectivity;
c) static echo pattern (A-scan);
d) dynamic echo pattern (envelope).
These criteria shall be applied using the flowchart procedure according to Annex A and as described in
Clause 5.
It is recommended that the same probes be used for detection and for classification of discontinuities. The
flowchart procedure standardizes a system of classification.
...