prEN ISO 8502-2
(Main)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)
- 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
- Publication Date
- 01-Feb-2028
- Technical Committee
- CEN/TC 139 - Paints and varnishes
- Drafting Committee
- CEN/TC 139 - Paints and varnishes
- Current Stage
- 4020 - Submission to enquiry - Enquiry
- Start Date
- 13-Aug-2026
- Completion Date
- 13-Aug-2026
prEN ISO 8502-2 is a CEN draft standard for preparation of steel substrates before painting and related coating processes. It specifies a swabbing method for extracting water-soluble contaminants from a defined steel surface so the collected extract can be analysed, especially for chloride-containing salts. In practice, it is used when a team needs a repeatable way to check surface cleanliness before coating, after cleaning, or on coated surfaces between coating operations.
What does prEN ISO 8502-2 specify?
prEN ISO 8502-2 specifies how to remove soluble contaminants from a steel surface by controlled swabbing with water and how to prepare the extracted sample for analysis. The method applies to steel surfaces before and after cleaning, and also to coated surfaces between coating steps.
The document is organized into:
- Clause 1 - Scope
- Clause 2 - Normative references
- Clause 3 - Terms and definitions
- Clause 4 - Principle
- Clause 5 - Apparatus and materials
- Clause 6 - Procedure
- Clause 7 - Test report
The structure matters because it moves from what the method is for, to what equipment is needed, to how the sampling is performed, and finally to what must be recorded for traceability.
What are the key requirements of prEN ISO 8502-2?
Sampling principle and limits
prEN ISO 8502-2 removes a portion of the water-soluble chlorides from a test area by washing or swabbing with water, then analyses the extract for chloride ion concentration. The method gives average values over the sampled area, so local contamination can still be missed. That means it is useful for general cleanliness checks, but not for mapping very small isolated contamination spots.
The document also notes that swabbing may not remove deep-seated contaminants such as iron(II) salts. For localized impurities, the text points users to the closed-cell approach described in ISO 8502-6.
Apparatus, water and test area
prEN ISO 8502-2 requires clean glassware, water of at least ISO 3696 grade 3, clean gloves, chloride-free absorbent cotton pads, and measuring equipment including a contact thermometer. The water quality matters because the test is looking for very small amounts of soluble contaminants, so the rinse water itself must not add salts.
The surface area to be tested is defined by agreement between the interested parties and marked off before swabbing. The method gives practical options for marking the area, such as masking tape, a magnet sheet frame, a plastic frame with double-sided tape, or a drawn frame line.
Blank test before sampling
prEN ISO 8502-2 requires a blank test for each batch of absorbent cotton pads. This checks whether the pads themselves contribute contamination to the extract. In practice, the blank value must be taken into account when the later analysis is interpreted.
Swabbing procedure
prEN ISO 8502-2 uses a defined swabbing pattern with repeated passes over the marked area. The procedure calls for gloves to avoid hand contamination, a measured water volume, and separate handling of beakers used for moistening the pad and collecting used pads. The text specifies downward and horizontal strokes and a sequence of pad use so the whole test area is sampled in a consistent way.
The surface temperature must be measured with the stated accuracy, and the surface must stay above +5 °C. This matters because the method is intended to work under field conditions, but not where ice can form on the surface.
Analysis options
prEN ISO 8502-2 allows several ways to analyse the extract. These include the ion detection tube method in ISO 8502-5, ion chromatography in ISO 10304-1, and other suitable devices such as salt concentration meters or conductometric methods. The choice affects how the laboratory or field team measures the contamination level after extraction.
Test report
prEN ISO 8502-2 requires the report to identify the tested surface, cite the standard, state the solvent and its volume, record the swabbing pattern and number of passes, note the surface temperature, list any deviations, and give the test date. This is what makes the result usable in quality records, comparisons, and audits.
What changed in prEN ISO 8502-2 from the previous edition?
prEN ISO 8502-2 replaces ISO 8502-2:2017. The foreword states that Clauses 4, 5 and 6 were technically revised, and former Clauses 7 and 8 were deleted. The foreword also says that methods for analysing water-soluble contaminants are now described in ISO 8502-5, ISO 8502-9 and ISO 10304-1.
Which standards are used with prEN ISO 8502-2?
prEN ISO 8502-2 refers to these standards:
- ISO 3696 - specifies laboratory water quality used for the extraction water.
- ISO 8502-5 - gives the ion detection tube method for chloride measurement.
- ISO 8502-9 - gives the field conductometric method for soluble salts.
- ISO 10304-1 - gives ion chromatography for chloride, nitrate and sulfate.
- ISO 8502-6 - is named in the principle as the closed-cell method for extracting localized contaminants.
What does the prEN ISO 8502-2 document contain?
prEN ISO 8502-2 contains a defined swabbing method, a list of required apparatus and materials, and step-by-step instructions for blank testing, marking the test area, wet swabbing, collecting the extract, and checking surface temperature. It also includes a figure showing the swabbing pattern and direction.
The document further gives the allowed analysis routes for the collected extract and a reporting checklist for traceability. In practice, that makes it a working procedure for surface-preparation control, field inspection, laboratory follow-up, and documentation of cleanliness before coating.
Relations
- Effective Date
- 19-Jun-2024
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Frequently Asked Questions
prEN ISO 8502-2 is a draft published by the European Committee for Standardization (CEN). Its full title is "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)". This standard covers: 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.
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.
prEN ISO 8502-2 is classified under the following ICS (International Classification for Standards) categories: 25.220.10 - Surface preparation. The ICS classification helps identify the subject area and facilitates finding related standards.
prEN ISO 8502-2 has the following relationships with other standards: It is inter standard links to EN ISO 8502-2:2017. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
prEN ISO 8502-2 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
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.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
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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
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NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
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RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
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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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
...