SIST EN ISO 29601:2026

Paints and varnishes - Corrosion protection by protective paint systems - Assessment of porosity in a dry film (ISO 29601:2026)

This document specifies procedures for detecting the presence of porosity in a protective paint system of any thickness on a steel or other metallic substrate. The procedures given in this document are based on methods using two different types of test equipment, the choice of equipment depending on the dry-film thickness. These procedures are only applicable to the testing of electrically non-conductive parts of a paint system.
The test methods specified are mainly intended for use with new coatings, but can also be used for coatings which have been in service for some time. In the latter case, it is important to bear in mind that the coating can have been penetrated by substances in contact with the coating during service.

Beschichtungsstoffe - Korrosionsschutz durch Beschichtungssysteme - Beurteilung der Porosität einer trockenen Beschichtung (ISO 29601:2026)

Diese Internationale Norm legt Verfahren zur Feststellung von Porosität in Beschichtungssystemen jeder
Schichtdicke für den Korrosionsschutz auf einem Stahlsubstrat oder anderen Substraten aus Metall fest. Die
in dieser Internationalen Norm angegebenen Vorgehensweisen basieren auf Verfahren, die zwei
verschiedene Prüfgerätetypen verwenden. Die Auswahl des Gerätes richtet sich nach der
Trockenschichtdicke. Diese Verfahren sind nur für die Prüfung elektrisch nichtleitender Schichten eines
Beschichtungssystems anwendbar.
Die festgelegten Prüfverfahren werden hauptsächlich für neue Beschichtungen angewendet, sie können
jedoch auch für Beschichtungen angewendet werden, die bereits in der Praxis gebraucht wurden. Im letzteren
Fall ist zu beachten, dass in das Beschichtungssystem Substanzen während der Lagerung eingedrungen sein
könnten.

Peintures et vernis Anticorrosion par systèmes de peinture - Évaluation de la porosité d'un feuil sec (ISO 29601:2026)

L'ISO 29601:2011 spécifie des modes opératoires permettant de détecter l'existence de porosité dans un système de revêtement de peinture, quelle qu'en soit l'épaisseur, appliqué sur un subjectile en acier ou sur tout autre métal. Les modes opératoires fournis dans la présente Norme internationale sont basés sur des méthodes faisant appel à deux types d'équipement d'essai, le choix de l'équipement étant fonction de l'épaisseur du feuil sec. Ces modes opératoires ne s'appliquent qu'aux essais des couches électriquement non conductrices d'un système de peinture.
Les méthodes d'essai spécifiées sont destinées principalement aux revêtements neufs mais peuvent aussi être employées pour les revêtements déjà mis en service. Dans ce dernier cas, il est important de garder à l'esprit le fait que des substances en contact avec le revêtement ont pu y pénétrer pendant la période en service.

Barve in laki - Korozijska zaščita z zaščitnimi premaznimi sistemi - Ocenjevanje poroznosti suhega filma (ISO 29601:2026)

Ta dokument določa postopke za zaznavanje prisotnosti poroznosti v zaščitnem barvnem sistemu katere koli debeline na jekleni ali drugi kovinski podlagi. Postopki, navedeni v tem dokumentu, temeljijo na metodah, ki uporabljajo dve različni vrsti preskusne opreme, izbira opreme pa je odvisna od debeline suhega filma. Ti postopki so uporabni le za preskušanje električno neprevodnih delov barvnega sistema.
Določene preskusne metode so namenjene predvsem uporabi z novimi premazi, lahko pa se uporabljajo tudi za premaze, ki so v uporabi že nekaj časa. V slednjem primeru je pomembno upoštevati, da lahko premaz med uporabo preidejo snovi, ki so bile v stiku s premazom.

General Information

• Status: Published
• Public Enquiry End Date: 31-May-2025
• Publication Date: 17-May-2026
• ICS: 25.220.20 - Surface treatment
• ICS: 87.020 - Paint coating processes
• ICS: 87.040 - Paints and varnishes
• Technical Committee: IBLP - Paints and varnishes
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-May-2026
• Due Date: 12-Jul-2026
• Completion Date: 18-May-2026
• Ref Project: EN ISO 29601:2026 - Paints and varnishes - Corrosion protection by protective paint systems - Assessment of porosity in a dry film (ISO 29601:2026)

Relations

• Replaces: SIST EN ISO 29601:2012 - Paints and varnishes - Corrosion protection by protective paint systems - Assessment of porosity in a dry film (ISO 29601:2011)
• Effective Date: 01-Jun-2026
• Referred By: SIST EN ISO 13506-1:2024 - Protective clothing against heat and flame - Part 1: Test method for complete garments - Measurement of transferred energy using an instrumented manikin (ISO 13506-1:2024)
• Effective Date: 28-Jan-2026

Overview

kSIST FprEN ISO 29601:2026, titled Paints and varnishes - Corrosion protection by protective paint systems - Assessment of porosity in a dry film, is a European standard developed by CEN. This standard defines procedures for detecting porosity in protective paint and varnish systems on steel or other metallic substrates. Porosity assessment is essential in ensuring the long-term corrosion protection provided by coatings applied in demanding industrial and infrastructure environments.

The standard applies to paint systems of any thickness, provided they contain electrically non-conductive components. It details two principal testing methods - the use of low-voltage pinhole detectors and high-voltage holiday detectors - to suit different dry film thicknesses. The guidance is relevant for both newly applied coatings and, with care, coatings that have been in service.

Key Topics

Porosity Detection Methods

• Low-voltage pinhole detectors: Typically used for coatings up to 500 µm. These use a wetted sponge and battery-powered device to detect discontinuities.
• High-voltage holiday detectors: Required for dry film thickness above 500 µm. These systems generate a spark to reveal defects, using a probe and calibrated voltage settings.

Test Procedure Highlights

• Test method selection depends on dry film thickness.
• Proper surface preparation and grounding are critical for accurate results.
• Test voltages must be set according to film thickness for reliable detection.
• Results are reported as the number of discontinuities found in the inspection area.

Applications

kSIST FprEN ISO 29601:2026 serves a range of sectors where corrosion protection of metals is crucial, including:

• Industrial Infrastructure: Bridges, storage tanks, pipelines, and offshore platforms rely on protective coating systems to prevent corrosion-related failures.
• Manufacturing and Maintenance: New installations and maintenance operations benefit from quality assurance through porosity assessment.
• Quality Control: Paint manufacturers, applicators, and inspection agencies use these methods to verify the integrity of protective coatings before and after deployment.
• Regulatory Compliance: Reference in national and project specifications ensures coatings meet required performance standards.

Practical use of this standard helps identify holidays, pinholes, cracks, voids, and other discontinuities that can compromise corrosion protection, thus supporting durability and reducing lifecycle costs.

Related Standards

kSIST FprEN ISO 29601:2026 complements several international and European standards for protective paint and varnish systems:

• ISO 12944 series: Addresses all aspects of corrosion protection by paint systems, including design, implementation, and maintenance.
• ISO 19840: Specifies measurement and acceptance criteria for dry film thickness of protective paints on rough surfaces.
• ISO 16276-1/2: Covers assessment and acceptance criteria for the adhesion/cohesion strength of coatings.
• ISO 4628 series: Provides methods for evaluating degradation of coatings, such as blistering, rusting, and cracking.
• ISO 2808: Outlines methods for determining coating film thickness.

Referencing these standards in combination ensures comprehensive and standardized evaluation of protective coating performance, from surface preparation through to long-term inspection.

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Keywords: kSIST FprEN ISO 29601:2026, porosity assessment, protective paint systems, corrosion protection, dry film testing, pinhole detector, holiday detector, industrial coatings, quality control, paint and varnish standards, steel protection.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2026
Nadomešča:
SIST EN ISO 29601:2012
Barve in laki - Korozijska zaščita z zaščitnimi premaznimi sistemi - Ocenjevanje
poroznosti suhega filma (ISO 29601:2026)
Paints and varnishes - Corrosion protection by protective paint systems - Assessment of
porosity in a dry film (ISO 29601:2026)
Beschichtungsstoffe - Korrosionsschutz durch Beschichtungssysteme - Beurteilung der
Porosität einer trockenen Beschichtung (ISO 29601:2026)
Peintures et vernis Anticorrosion par systèmes de peinture - Évaluation de la porosité
d'un feuil sec (ISO 29601:2026)
Ta slovenski standard je istoveten z: EN ISO 29601:2026
ICS:
25.220.20 Površinska obdelava Surface treatment
87.040 Barve in laki Paints and varnishes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 29601
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2026
EUROPÄISCHE NORM
ICS 87.020 Supersedes EN ISO 29601:2011
English Version
Paints and varnishes - Corrosion protection by protective
paint systems - Assessment of porosity in a dry film (ISO
29601:2026)
Peintures et vernis Anticorrosion par systèmes de Beschichtungsstoffe - Korrosionsschutz durch
peinture - Évaluation de la porosité d'un feuil sec (ISO Beschichtungssysteme - Beurteilung der Porosität
29601:2026) einer trockenen Beschichtung (ISO 29601:2026)
This European Standard was approved by CEN on 27 April 2026.

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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 29601:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 29601:2026) has been prepared by Technical Committee ISO/TC 35 "Paints and
varnishes" in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the
secretariat of which is held by DIN.
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 October 2026, and conflicting national standards shall
be withdrawn at the latest by October 2026.
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 29601:2011.
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 29601:2026 has been approved by CEN as EN ISO 29601:2026 without any modification.

International
Standard
ISO 29601
Second edition
Paints and varnishes — Corrosion
2026-04
protection by protective paint
systems — Assessment of porosity
in a dry film
Peintures et vernis — Anticorrosion par systèmes de peinture —
Évaluation de la porosité d'un feuil sec
Reference number
ISO 29601:2026(en) © ISO 2026
ISO 29601:2026(en)
© ISO 2026
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 29601:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Test equipment . 2
5.1 Low-voltage pinhole detectors .2
5.1.1 General .2
5.1.2 Electric path .2
5.1.3 Sensitivity and alarm .2
5.1.4 Conductive liquid .2
5.2 High-voltage holiday detectors .3
5.2.1 General .3
5.2.2 Electrical source .3
5.2.3 Electrical path .3
5.2.4 Alarm .3
5.2.5 Controlled output voltage.3
6 Procedure . 3
6.1 Selection of test method .3
6.2 Low-voltage pinhole detection .4
6.2.1 Test voltage.4
6.2.2 Paint conditions before testing .4
6.2.3 Wetting agent .4
6.2.4 Preparation before testing .4
6.2.5 Testing .4
6.3 High-voltage holiday detection .4
6.3.1 Paint conditions before testing .4
6.3.2 Test voltage settings and calculation .5
6.3.3 Output voltage verification .5
6.3.4 Preparation before testing .5
6.3.5 Testing .5
7 Expression of results . 5
8 Test report . 5
Annex A (normative) Mean dry-film thicknesses and corresponding test voltages . 7
Bibliography . 9

iii
ISO 29601:2026(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 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 35, Paints and varnishes, Subcommittee
SC 14, Protective paint systems for steel structures, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 139, Paints and varnishes, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 29601:2011), which has been technically
revised.
The main changes are as follows:
— general (editorial) update of terminology;
— update on cleaning procedure before measurement;
— update on verification of test equipment;
— update on voltage calculation;
— low voltage measurement was confirmed.
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.

iv
ISO 29601:2026(en)
Introduction
This document supplements the ISO 12944 series with regard to the detection of porosity in a dry film. If
specified or agreed, this document can also be used for other applications.
The objective of this document is to achieve uniformity of practice for the detection of porosity in a dry film.
The methods chosen entail the detection of porosity using one of two types of equipment, a low-voltage
pinhole detector or a high-voltage holiday detector.
This document complements the following International Standards:
— ISO 19840, which concerns the measurement of the thickness of dry films on rough surfaces;
— ISO 16276-1, which concerns the measurement of the adhesion of a coating by pull-off testing;
— ISO 16276-2, which concerns the measurement of the adhesion by cross-cut and X-cut testing.

v
International Standard ISO 29601:2026(en)
Paints and varnishes — Corrosion protection by protective
paint systems — Assessment of porosity in a dry film
1 Scope
This document specifies procedures for detecting the presence of porosity in a protective paint system of
any thickness on a steel or other metallic substrate. The procedures given in this document are based on
methods using two different types of test equipment, the choice of equipment depending on the dry-film
thickness. These procedures are only applicable to the testing of electrically non-conductive parts of a paint
system.
The test methods specified are mainly intended for use with new coatings, but
...