oSIST prEN ISO 8502-2:2026

• Abstract:

  ISO 8502-2:2017 describes a method for the determination of chloride-containing salts that are readily soluble in water and are present on a steel surface. The method is also applicable to previously coated surfaces. ISO 8502-2:2017 includes a method, applicable in the field or in the laboratory, for washing off the surface while several methods are referred to for chloride analyses.

• Status: Not Published
• Public Enquiry End Date: 01-Nov-2026
• ICS: 25.220.10 - Surface preparation
• ICS: 87.020 - Paint coating processes
• Technical Committee: IBLP - Paints and varnishes
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 19-Aug-2026
• Due Date: 06-Jan-2027
• Ref Project: prEN ISO 8502-2 - Preparation of steel substrates before application of paints and related products - Tests for the assessment of surface cleanliness - Part 2: Extraction of water-soluble contaminants for analysis by swabbing method (ISO/DIS 8502‑2:2026)

• Revises: SIST EN ISO 8502-2:2017 - Preparation of steel substrates before application of paints and related products - Tests for the assessment of surface cleanliness - Part 2: Laboratory determination of chloride on cleaned surfaces (ISO 8502-2:2017)
• Effective Date: 01-Oct-2026

Overview

oSIST prEN ISO 8502-2:2026 specifies a practical method for extracting and analyzing water-soluble contaminants from steel surfaces, using the swabbing method prior to the application of paints and related products. Published by the Slovenian Institute for Standardization (SIST), this standard provides guidance for evaluating surface cleanliness-a critical factor impacting the performance and longevity of protective coatings on steel. The method is applicable both before and after cleaning processes, as well as on coated surfaces between layers.

Ensuring the surface cleanliness of steel prior to coating prevents premature coating failure due to the presence of contaminants such as chlorides, nitrates, and sulfates. ISO 8502-2:2026 outlines the standardized procedure for sampling, extracting, and documenting these soluble impurities.

Key Topics

• Sampling and Extraction:

  • Swabbing method for removing water-soluble contaminants.
  • Use of absorbent cotton pads, deionized water, and specific marking/containment techniques for defining test areas.

• Applicable Surfaces:

  • Bare steel surfaces, both pre- and post-cleaning.
  • Coated steel surfaces between coating applications.

• Analytical Methods:

  • Measurement of extracted contaminants using ion detection tubes (ISO 8502-5), ion chromatography (ISO 10304-1), or conductive measurement devices (ISO 8502-9).

• Test Procedure and Integrity:

  • Specifications for preparing apparatus and maintaining cleanliness (e.g., blank tests for absorbent materials).
  • Requirements for test reporting, including details of the steel surface, extraction methods, solvent details, and environmental conditions.

Applications

This standard has widespread relevance in industries where corrosion protection and durable paint finishes on steel are essential. Key applications include:

• Industrial Coatings and Paints: For manufacturers and applicators preparing steel substrates prior to applying coatings in sectors such as marine, infrastructure, automotive, and construction.
• Quality Control and Inspection: Used by testing laboratories or site inspectors to assess the surface cleanliness and ensure compliance with project specifications and international requirements.
• Maintenance and Asset Management: For periodic inspection of coated steel structures, helping identify potential risks due to residual contaminants, thereby optimizing maintenance intervals and costs.
• Procurement and Contract Specifications: Contractors and asset owners reference this standard to ensure consistent cleaning and surface preparation practices, improving overall coating reliability.

Proper adherence to ISO 8502-2 procedures helps reduce the risks of coating failure, minimizes surface rework, and extends the service life of steel structures by systematically monitoring and controlling soluble surface salts.

Related Standards

To achieve comprehensive surface preparation and cleanliness assessment, the following ISO and EN standards are commonly used alongside oSIST prEN ISO 8502-2:2026:

• ISO 8502-5: Measurement of chloride on steel surfaces prepared for painting using the ion detection tube method.
• ISO 8502-9: Field method for the conductometric determination of water-soluble salts.
• ISO 10304-1: Determination of dissolved anions (e.g., bromide, chloride, nitrate, sulfate) by ion chromatography.
• ISO 3696: Specifications for laboratory-grade water used in analysis.
• ISO 8502-6: Alternative procedures for extracting deep-seated contaminants using closed-cell methods.
• Other parts of ISO 8502: Cover additional test methods for a thorough assessment of steel substrate cleanliness.

Adopting ISO 8502-2:2026 ensures that surface preparation practices are reliable, repeatable, and aligned with global expectations for quality and performance-all crucial for competitive, high-value steel protection and coating projects.

SLOVENSKI STANDARD
01-oktober-2026
Priprava jeklenih podlag pred nanašanjem barv in sorodnih premazov - Preskusi
za ocenjevanje čistosti površine - 2. del: Ekstrakcija v vodi topnih onesnaževal za
analizo z metodo brisanja (s tamponi) (ISO/DIS 8502-2:2026)
Preparation of steel substrates before application of paints and related products - Tests
for the assessment of surface cleanliness - Part 2: Extraction of water-soluble
contaminants for analysis by swabbing method (ISO/DIS 8502-2:2026)
Vorbereitung von Stahluntergründen vor dem Auftragen von Beschichtungsstoffen und
verwandten Produkten - Prüfungen zur Beurteilung der Oberflächenreinheit - Teil 2:
Laborbestimmung von Chlorid auf gereinigten Oberflächen (ISO/DIS 8502-2:2026)
Préparation des subjectiles d'acier avant application de peintures et de produits
assimilés - Essais pour apprécier la propreté d'une surface - Partie 2: Extraction des
contaminants solubles dans l'eau pour analyse à l'aide de la méthode par tamponnage
(ISO/DIS 8502-2:2026)
Ta slovenski standard je istoveten z: prEN ISO 8502-2
ICS:
25.220.10 Priprava površine Surface preparation
87.020 Postopki za nanašanje Paint coating processes
barvnih premazov
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 8502-2
ISO/TC 35/SC 12
Preparation of steel substrates
Secretariat: BSI
before application of paints and
Voting begins on:
related products — Tests for the
2026-08-14
assessment of surface cleanliness —
Voting terminates on:
2026-11-06
Part 2:
Extraction of water-soluble
contaminants for analysis by
swabbing method
ICS: 25.220.10
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.
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STANDARDS MAY ON OCCASION HAVE TO
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Reference number
ISO/DIS 8502-2:2026(en)
DRAFT
ISO/DIS 8502-2:2026(en)
International
Standard
ISO/DIS 8502-2
ISO/TC 35/SC 12
Preparation of steel substrates
Secretariat: BSI
before application of paints and
Voting begins on:
related products — Tests for the
assessment of surface cleanliness —
Voting terminates on:
Part 2:
Extraction of water-soluble
contaminants for analysis by
swabbing method
ICS: 25.220.10
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
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or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
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RECIPIENTS OF THIS DRAFT ARE INVITED
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TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
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Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 8502-2:2026(en)
ii
ISO/DIS 8502-2:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus and materials . 2
5.1 General .2
5.2 Water .2
5.3 Marking options .2
5.4 Graduated beaker .2
5.5 Gloves .2
5.6 Absorbent cotton pads.2
5.7 Measuring cylinder .2
5.8 Glass rod .2
5.9 Contact thermometer .3
6 Procedure . 3
6.1 Blank test .3
6.2 Washing the test area .3
6.3 Extraction by swabbing .3
6.4 Soluble deposition concentration measurement method by ion detection tube .3
6.5 Soluble deposition concentration measurement method by ion chromatography .3
6.6 Soluble deposition concentration measurement method by other analysis devices .4
7 Test report . 4

iii
ISO/DIS 8502-2:2026(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 maintenanc
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