SIST EN ISO 22479:2022

Corrosion of metals and alloys - Sulfur dioxide test in a humid atmosphere (fixed gas method) (ISO 22479:2019)

This document specifies a method for assessing the resistance of materials or products to a humid atmosphere containing sulfur dioxide.
This method is applicable to testing metals and alloys, metallic and non-organic coatings and organic coatings.

Korrosion von Metallen und Legierungen - Prüfung mit Schwefeldioxid in feuchter Atmosphäre (Verfahren mit festem Gasvolumen) (ISO 22479:2019)

Dieses Dokument legt ein Verfahren zur Beurteilung der Beständigkeit von Materialien oder Produkten gegenüber einer feuchten Atmosphäre, die Schwefeldioxid enthält, fest.
Dieses Verfahren ist anwendbar für die Prüfung von Metallen und Legierungen, metallenen und nicht-organischen Beschichtungen sowie organischen Beschichtungen.
WARNUNG — Dieses Dokument beansprucht nicht, alle damit verbundenen Sicherheitsprobleme, falls vorhanden, zu behandeln. Es liegt in der Verantwortung des Anwenders dieses Dokuments, geeignete Sicherheits- und Gesundheitsschutzpraktiken umzusetzen.

Corrosion des métaux et alliages - Essai au dioxyde de soufre en atmosphère humide (méthode avec volume fixe de gaz) (ISO 22479:2019)

Le présent document spécifie une méthode d’estimation de la résistance de matériaux ou de produits à une atmosphère humide contenant du dioxyde de soufre.
Cette méthode est applicable aux essais de métaux et d’alliages, de revêtements métalliques et non organiques, ainsi que de revêtements organiques.

Korozija kovin in zlitin - Korozijski preskus s SO2 v vlažni atmosferi (metoda s stalno (fiksno) koncentracijo plina) (ISO 22479:2019)

Ta dokument določa metodo za ocenjevanje odpornosti materialov ali izdelkov na vlažno
atmosfero, ki vsebuje žveplov dioksid.
Ta metoda se uporablja za preskušanje kovin in zlitin, kovinskih in neorganskih premazov ter organskih
premazov.

General Information

• Status: Published
• Public Enquiry End Date: 17-May-2022
• Publication Date: 11-Jul-2022
• ICS: 77.060 - Corrosion of metals
• Technical Committee: IPKZ - Protection of metals against corrosion
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jul-2022
• Due Date: 05-Sep-2022
• Completion Date: 12-Jul-2022
• Ref Project: EN ISO 22479:2022 - Corrosion of metals and alloys - Sulfur dioxide test in a humid atmosphere (fixed gas method) (ISO 22479:2019)

Relations

• Replaces: SIST EN ISO 3231:1998 - Paints and varnishes - Determination of resistance to humid atmospheres containing sulfur dioxide (ISO 3231:1993)
• Effective Date: 01-Sep-2022
• Replaces: SIST EN ISO 6988:1999 - Metallic and other non-organic coatings - Sulfur dioxide test with general condensation of moisture (ISO 6988:1985)
• Effective Date: 29-Jun-2022

Overview

EN ISO 22479:2022 (ISO 22479:2019) specifies a laboratory method - the sulfur dioxide test in a humid atmosphere (fixed gas method) - for assessing the corrosion resistance of metals, alloys and their coatings. Adopted by CEN and identical to ISO 22479:2019, this standard defines how to expose test specimens to a humid SO2-containing atmosphere so that SO2 dissolved in condensed moisture accelerates corrosion for comparative testing, quality control and materials evaluation.

Key topics and technical requirements

• Scope and applicability: Applies to metals and alloys, metallic and non‑organic coatings, and organic coatings for evaluation of resistance to humid atmospheres containing sulfur dioxide.
• Principle: A fixed volume of sulfur dioxide is introduced into a cabinet of fixed volume; moisture condenses on specimens and the dissolved SO2 causes corrosion.
• Test cabinet and components: Components contacting SO2 must be corrosion‑resistant and inert (must not emit vapours that influence results). Preferred cabinet capacity is (300 ± 10) L; alternative sizes are permitted if specimen arrangement, gas volume and water quantity are adjusted accordingly.
• Specimen preparation and arrangement: Standard references for panels and film thickness are cited (ISO 1514, ISO 2808). The standard covers specimen dimensions, preparation, and mounting to avoid cross‑contamination between different protection systems.
• Test cycles and duration: ISO 22479 defines required test cycles, durations and procedures for introducing water and SO2, heating the cabinet, replacing reagents, cleaning specimens after test, and performing performance checks. (Specific cycle parameters are given in the full standard.)
• Evaluation and reporting: Procedures for post‑test cleaning, assessment of corrosion damage, and required information for the test report are specified. Normative terms reference ISO 8044 (corrosion terminology).

Applications and who uses it

• Corrosion test laboratories performing standardized SO2/humidity exposure tests.
• Coatings and surface‑treatment manufacturers for product development and quality control.
• Materials engineers and R&D teams comparing corrosion resistance of alloys or coatings.
• Specification writers, purchasers and compliance officers who need standardized test evidence for materials intended for service where SO2 and humidity are concerns.
• Regulatory and standards bodies referencing harmonized test methods in procurement or product standards.

Related standards

• ISO 1514 - Standard panels for testing (paints and varnishes)
• ISO 2808 - Determination of film thickness (paints and varnishes)
• ISO 8044 - Corrosion of metals and alloys - Basic terms and definitions
• EN ISO 22479:2022 supersedes EN ISO 3231 and EN ISO 6988 (combined and revised into this edition)

Keywords: corrosion, sulfur dioxide test, humid atmosphere, fixed gas method, EN ISO 22479:2022, ISO 22479:2019, corrosion testing, metals and alloys, coatings, test cabinet.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2022
Nadomešča:
SIST EN ISO 3231:1998
SIST EN ISO 6988:1999
Korozija kovin in zlitin - Korozijski preskus s SO2 v vlažni atmosferi (metoda s
stalno (fiksno) koncentracijo plina) (ISO 22479:2019)
Corrosion of metals and alloys - Sulfur dioxide test in a humid atmosphere (fixed gas
method) (ISO 22479:2019)
Korrosion von Metallen und Legierungen - Prüfung mit Schwefeldioxid in feuchter
Atmosphäre (Verfahren mit festem Gasvolumen) (ISO 22479:2019)
Corrosion des métaux et alliages - Essai au dioxyde de soufre en atmosphère humide
(méthode avec volume fixe de gaz) (ISO 22479:2019)
Ta slovenski standard je istoveten z: EN ISO 22479:2022
ICS:
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22479
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2022
EUROPÄISCHE NORM
ICS 77.060 Supersedes EN ISO 3231:1997, EN ISO 6988:1994
English Version
Corrosion of metals and alloys - Sulfur dioxide test in a
humid atmosphere (fixed gas method) (ISO 22479:2019)
Corrosion des métaux et alliages - Essai au dioxyde de Korrosion von Metallen und Legierungen - Prüfung mit
soufre en atmosphère humide (méthode avec volume Schwefeldioxid in feuchter Atmosphäre (fixed gas
fixe de gaz) (ISO 22479:2019) method) (ISO 22479:2019)
This European Standard was approved by CEN on 20 June 2022.

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, 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22479:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 22479:2019 has been prepared by Technical Committee ISO/TC 156 "Corrosion of
metals and alloys” of the International Organization for Standardization (ISO) and has been taken over
as EN ISO 22479:2022 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings,
including for corrosion protection and corrosion testing of metals and alloys” 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 December 2022, and conflicting national standards
shall be withdrawn at the latest by December 2022.
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 3231:1997 and EN ISO 6988:1994.
Any feedback and questions on this document should be directed to the users’ national standards body.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 22479:2019 has been approved by CEN as EN ISO 22479:2022 without any modification.

INTERNATIONAL ISO
STANDARD 22479
First edition
2019-05
Corrosion of metals and alloys —
Sulfur dioxide test in a humid
atmosphere (fixed gas method)
Corrosion des métaux et alliages — Essai au dioxyde de soufre en
atmosphère humide (méthode avec volume fixe de gaz)
Reference number
ISO 22479:2019(E)
©
ISO 2019
ISO 22479:2019(E)
© ISO 2019
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]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 22479:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Test specimens. 3
6.1 General . 3
6.2 Dimensions . 3
6.3 Preparation . 3
6.3.1 Metals and alloys . 3
6.3.2 Paints and varnishes . 3
6.4 Arrangement of the test specimens . 4
7 Test conditions . 4
7.1 Test cycles . 4
7.2 Test duration . 5
8 Procedure. 6
8.1 Introduction of water . 6
8.2 Arrangement of the test specimens . 6
8.3 Introduction of sulfur dioxide . 6
8.4 Heating the test cabinet. 6
8.5 Introduction of standard atmosphere . 6
8.6 Replacement of water and sulfur dioxide . 6
8.7 Cleaning of test specimens after test . 6
8.7.1 General. 6
8.7.2 Metals and alloys, metallic and non-organic coating test specimens . 6
8.7.3 Organic coating test specimens . 7
8.8 Performance check . 7
9 Evaluation . 7
10 Test report . 7
Annex A (informative) Another example of a test cabinet . 9
Annex B (informative) Performance check .10
Annex C (informative) Supplemental information .12
Bibliography .14
ISO 22479:2019(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 156, Corrosion of metals and alloys.
This first edition of ISO 22479 cancels and replaces ISO 3231:1993 and ISO 6988:1985, which have been
combined and technically revised. The main changes compared with the previous edition are as follows:
— the method of generating sulfur dioxide from reagents has been deleted because of the risk of
exposure to toxic chemicals.
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 2019 – All rights reserved

ISO 22479:2019(E)
Introduction
A humid atmosphere containing sulfur dioxide induces corrosion of many metals.
The results obtained in this document should not be regarded as a direct guide to the corrosion
resistance of the tested materials in all environments where these materials may be used. Similarly,
performances of different materials in this document should not be taken as a direct guide to the
relative corrosion resistance of these materials in service.
It is appropriate to test only the same corrosion protection systems at the same time in one test
procedure, because an interaction between samples can't be prevented. When testing different
corrosion protection systems with different materials, it should be taken into account that the influence
of sulfur dioxide often can be different.
The term “fixed gas method” means that at the beginning of the test a fixed volume of gas is introduced
into a cabinet of fixed volume.
INTERNATIONAL STANDARD ISO 22479:2019(E)
Corrosion of metals and alloys — Sulfur dioxide test in a
humid atmosphere (fixed gas method)
WARNING — This document does not purport to address all of the safety concerns, if any,
associated with its use. It is the responsibility of the user of this document to establish
appropriate safety and health practices.
1 Scope
This document specifies a method for assessing the resistance of materials or products to a humid
atmosphere containing sulfur dioxide.
This method is applicable to testing metals and alloys, metallic and non-organic coatings and organic
coatings.
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 1514, Paints and varnishes — Standard panels for testing
ISO 2808, Paints and varnishes — Determination of film thickness
ISO 8044, Corrosion of metals and alloys — Basic terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 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 Principle
The test specimens are exposed to a humid atmosphere containing sulfur dioxide. The sulfur dioxide
dissolved by the moisture condenses on the test specimen surface and causes corrosion.
5 Apparatus
5.1 Component protection.
All components in contact with sulfur dioxide in a humid atmosphere shall be made of corrosion
resistant materials, and shall themselves not emit any gas or vapour likely to influence corrosion of the
test specimens.
ISO 22479:2019(E)
5.2 Test cabinet.
The preferred capacity of the test cabinet is (300 ± 10) l. When agreed between the interested parties,
other capacities may be used. In these cases, the size and/or number of test specimens, the volume of
gas and the quantity of water shall be properly arranged in accordance with the capacity of the test
cabinet.
The upper part of the cabinet shall be designed so that drops of condensed water formed on its surface
do not fall on the test specimens being tested. An inclination of the upper part of the test cabinet of about
12° or more to the horizontal plane provides a suitable safeguard. The test specimens may be placed at
different levels within the cabinet, as long as the solution does not drip from the test specimens or their
supports at one level onto other test specimens placed below.
The temperature in the test cabinet is controlled by heating the floor and lower part of the side walls
of the test cabinet. The temperature shall be measured at least 250 mm from the side walls and at least
150 mm below the upper part (lid).
A gas inlet port shall be less than 50 mm above the water surface. The test cabinet shall be hermetically
leak-tight.
A pressure relief valve shall be placed in or near the upper part of the test cabinet.
The exhaust gas and the released gas from the pressure relief valve shall be treated as appropriate.
NOTE Relevant regulatory limitations can apply.
A drain port shall be provided in the test cabinet.
A typical test cabinet is shown in Figure 1. Another example of test cabinet is shown in Figure A.1.
The test cabinet shall be installed in a room free from dust, draughts, corrosive gas and direct solar
radiation, at a room temperature of (23 ± 5) °C and at a relative humidity of less than 75 %.
Key
1 lid 5 gas inlet port 9 heater
2 test specimens 6 flowmeter 10 drain port
3 specimen supports 7 source of sulfur dioxide 11 pressure relief valve
4 water inside the cabinet 8 water tank 12 temperature measurement
Figure 1 — Typical test cabinet
2 © ISO 2019 – All rights reserved

SIST
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