prEN ISO 11998

Paints and varnishes - Determination of wet-scrub resistance of coatings (ISO/DIS 11998:2025)

The ability of coatings to withstand wear caused by repeated cleaning operations and to withstand penetration by soiling agents is an important consideration both from a practical point of view and when comparing and rating such coatings. ISO 11998:2006 describes an accelerated method for the determination of wet-scrub resistance. With regard to the cleanability of coatings, only the method itself and not the soiling agents are specified.

Beschichtungsstoffe - Bestimmung der Nassabriebbeständigkeit von Beschichtungen (ISO/DIS 11998:2025)

Peintures et vernis - Détermination de la résistance au frottement humide des revêtements (ISO/DIS 11998:2025)

La capacité des revêtements (produits de peinture) à résister à l'usure provoquée par des opérations de nettoyage répétées et à la pénétration de salissures est un critère important, tant d'un point de vue pratique que lors de la comparaison et de l'évaluation de ces produits. L'ISO 11998:2006 décrit une méthode accélérée de détermination de la résistance au frottement humide. En ce qui concerne l'aptitude au nettoyage des revêtements, seule la méthode elle-même est spécifiée, non les salissures.

Barve in laki - Določanje odpornosti proti mokremu drgnjenju premazov (ISO/DIS 11998:2025)

General Information

• Status: Not Published
• Publication Date: 04-Apr-2027
• ICS: 87.040 - Paints and varnishes
• Technical Committee: CEN/TC 139 - Paints and varnishes
• Drafting Committee: CEN/TC 139 - Paints and varnishes
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 03-Dec-2025
• Completion Date: 03-Dec-2025
• Ref Project: oSIST prEN ISO 11998:2025 - Paints and varnishes - Determination of wet-scrub resistance of coatings (ISO/DIS 11998:2025)

Relations

• Revises: EN ISO 11998:2006 - Paints and varnishes - Determination of wet-scrub resistance and cleanability of coatings (ISO 11998:2006)
• Effective Date: 12-Jun-2024

Overview

prEN ISO 11998 (ISO/DIS 11998:2025) specifies an accelerated laboratory method for the determination of wet-scrub resistance of coatings. Published as a CEN parallel draft and circulated by ISO/TC 35/SC 9, this document replaces ISO 11998:2006 and focuses solely on the abrasion resistance of dry coating films under defined wet-scrub conditions. The draft is subject to change until final publication; it does not cover cleanability or soiling agents.

Key topics and technical requirements

• Scope and principle: Apply a coating to a defined substrate, dry and condition it, weigh, subject the panel to a set number of wet-scrub cycles, then reweigh to calculate mass loss and mean loss in film thickness.
• Test specimen and substrate: PVC film free of migration-susceptible plasticizers (nominal 0.25 mm) or alternative substrates if solvents affect PVC.
• Film application: Use a film applicator (automatic preferred) at 10–15 mm/s with a doctor blade of appropriate gap; gap width ≥ 60 mm.
• Wet-scrub tester: Reciprocating scrub machine with stroke length (300 ± 10) mm and operating at approximately (37 ± 2) scrub cycles/min; a counter for cycles is required.
• Scrub pad and holder: Technical non-woven abrasive pads (90.0 ± 0.5 mm × 39.0 ± 0.5 mm). New pad per test; scrub pad holder mass pressing on panel = (135 ± 1) g. Batch quality control and acceptance procedures are covered in Annex B and C.
• Reagents and measurements: Washing liquid is 2.5 g/L sodium n‑dodecylbenzenesulfonate in grade 3 water (ISO 3696). Analytical balance resolution to 0.1 mg is required.
• Results and statistics: Calculation of loss per unit area and mean film-thickness loss, with classification by agreed limits. The 2025 draft updates repeatability and reproducibility statistics vs. the 2006 edition.
• Annexes: Include procedures for dry-film density, abrasive quality control, reference paint formulation, and interlaboratory comparison details.

Applications and users

This standard is targeted at:

• Paint and varnish manufacturers for product development and quality control.
• Independent testing laboratories conducting standardized abrasion testing.
• Specification writers and procurement teams who need objective wet-scrub performance data.
• Certification bodies and regulatory authorities requiring harmonized test methods. Practical uses include comparative ranking of coatings, supporting claims of scrub resistance, formulation optimization, and compliance with classification standards (e.g., where fewer cycles might be specified in EN 13300).

Related standards

Normative and referenced documents include: ISO 1513, ISO 1524, ISO 3270, ISO 3696, ISO 4618, ISO 5725-2 and ISO 15528. The draft was prepared in collaboration with CEN/TC 139 (Vienna Agreement).

Keywords: ISO 11998, wet-scrub resistance, paints and varnishes, coatings test method, wet scrub tester, non-woven abrasive, film applicator, repeatability, reproducibility.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2025
Barve in laki - Določanje odpornosti proti mokremu drgnjenju premazov (ISO/DIS
11998:2025)
Paints and varnishes - Determination of wet-scrub resistance of coatings (ISO/DIS
11998:2025)
Beschichtungsstoffe - Bestimmung der Nassabriebbeständigkeit von Beschichtungen
(ISO/DIS 11998:2025)
Peintures et vernis - Détermination de la résistance au frottement humide des
revêtements (ISO/DIS 11998:2025)
Ta slovenski standard je istoveten z: prEN ISO 11998
ICS:
87.040 Barve in laki Paints and varnishes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 11998
ISO/TC 35/SC 9
Paints and varnishes —
Secretariat: BSI
Determination of wet-scrub
Voting begins on:
resistance of coatings
2025-09-10
ICS: 87.040
Voting terminates on:
2025-12-03
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 11998:2025(en)
DRAFT
ISO/DIS 11998:2025(en)
International
Standard
ISO/DIS 11998
ISO/TC 35/SC 9
Paints and varnishes —
Secretariat: BSI
Determination of wet-scrub
Voting begins on:
resistance of coatings
ICS: 87.040
Voting terminates on:
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 2025
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 11998:2025(en)
ii
ISO/DIS 11998:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling . 4
8 Procedure . 4
8.1 Film application .4
8.2 Wet-scrub resistance .4
9 Expression of results . 7
9.1 Calculation of the loss in coating mass per unit area .7
9.1.1 Area traversed by the scrub pad .7
9.1.2 Loss in coating mass per unit area .7
9.2 Calculation of mean loss in film thickness .7
9.3 Assessment of wet-scrub resistance .7
10 Precision . 7
10.1 General .7
10.2 Repeatability .8
10.3 Reproducibility . .8
11 Test report . 8
Annex A (normative) Determination of dry-film density of the coating . 9
Annex B (normative) Quality control of the non-woven abrasive .12
Annex C (normative) Acceptance of new non-woven abrasive .13
Annex D (normative) Preparation and formulation of reference paint . 14
Annex E (informative) Example of reference paint .16
Annex F (informative) Details on interlaboratory comparison .18
Bibliography . 19

iii
ISO/DIS 11998:2025(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).
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 9, General test methods for paints and varnishes, 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 third edition cancels and replaces the second edition (ISO 11998:2006), which has been technically
revised.
The main changes are as follows:
— the title has been changed;
— cleanability has been deleted completely;
— the abrasive pad has been changed;
— the statistical data on reproducibility and repeatability have been updated.
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
DRAFT International Standard ISO/DIS 11998:2025(en)
Paints and varnishes — Determination of wet-scrub
resistance of coatings
1 Scope
This document specifies an accelerated method for the determination of wet-scrub resistance. The
determination of cleanability is not covered in the scope of this document.
NOTE The ability of coatings to withstand wear caused by repeated cleaning operations is an important
consideration both from a practical point of view and when comparing and rating such coatings. Since wet-scrub
resistance depends not only on the quality of a coating but also on the substrate, the method of application, the drying
conditions and other factors, the results obtained are not directly transferable to actual practice. In this document the
evaluation of the coating is based on a defined substrate, a fixed application method, specified drying conditions and a
defined method of wet scrubbing.
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 1524, Paints, varnishes and printing inks — Determination of fineness of grind
ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning and testing
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4618, Paints and varnishes — Vocabulary
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for
the determination of repeatability and reproducibility of a standard measurement method
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
scrub cycle
one reciprocal movement of the scrub pad over the scrub length in both directions
3.2
scrub length
stroke length plus the length of the pad

ISO/DIS 11998:2025(en)
3.3
stroke length
distance traversed by one stroke of the apparatus
3.4
wet-scrub resistance
ability of a dry coating film to sustain less than a specified loss in film thickness, averaged over a defined
area, when exposed to a defined number of wet-scrub cycles
4 Principle
The test coating is applied to a test panel using a film applicator at the appropriate gap clearance. After
drying and conditioning, the coated panel is weighed and subjected to a defined number of wet-scrub cycles
in a scrub testing machine as described in 8.2.
NOTE Some classification standards, e. g. EN 13300, require fewer scrub cycles.
It is then washed, dried and weighed again to determine its loss in mass, from which the mean loss in film
thickness is calculated.
Through comparison of the mean loss in film thickness with a specified value, as agreed between interested
parties, the coating can be rated in wet-scrub resistance classes.
5 Reagents
®1)
5.1 Washingliquid. Use a 2,5 g/l solution of sodium n-dodecylbenzenesulfonate (CAS-Nr 25155-30-0)
in water conforming to the requirements of grade 3 of ISO 3696. Allow the solution to stand before use until
all air-bubbles and foam have dissipated.
6 Apparatus
6.1 Test panel, made of PVC film free of migration-susceptible chemical plasticizers, of sufficient rigidity
to ensure a flat surface, impervious to and unaffected by water or aliphatic organic solvents and of nominal
thickness 0,25 mm, approximately 430 mm long and not less than 80 mm wide.
Other types of plastics film may be used where the coating contains solvent which might adversely affect the
PVC film. If the coating delaminates before or during the test, another, more suitable, substrate shall be used.
6.2 Film applicator, preferably an automatic film applicator, used at an application speed of 10 mm/s to
15 mm/s and fitted with a doctor blade with an appropriate gap clearance and a gap width of at least 60 mm.
6.3 Wet-scrub tester apparatus, consisting of a reciprocating scrub testing machine with a stroke length
of (300 ± 10) mm and operating at approximately (37 ± 2) scrub cycles per minute. A counter for recording
the number of scrub cycles shall be provided.
6.4 Scrub pad holder, consisting of a metal plate fitted with pins to hold the abrasive pad. A mounting
device with elongated holes is loosely fitted on the top of the plate (see Figure 1 and Figure 2). Alternatively
other scrub pad holders, e. g. with hook-and-loop fastener, can be used. The mass of the scrub pad holder
which exerts a downward force on the test panel shall be (135 ± 1) g.

1) CAS Registry Number® is a trademark of the American Chemical Society (ACS). This information is given for the
convenience of users of this document and does not constitute an endorsement by ISO of the product named. Equivalent
products may be used if they can be shown to lead to the same results.

ISO/DIS 11998:2025(en)
Figure 1 — Mounting device
Dimensions in millimetres
Key
1 pins
Figure 2 — Scrub pad holder
2)
6.5 Technical non-woven abrasive , a non-woven pad, consisting of a plastics material, with embedded
abrasive, measuring (90,0 ± 0,5) mm × (39,0 ± 0,5) mm. A new abrasive pad shall be used for every test.

2) For information about a suitable technical non-woven abrasive, please contact the DIN Normenausschuss
Beschichtungsstoffe und Beschichtungen (NAB), Burggrafenstraße 6, 10787 Berlin, Germany.

ISO/DIS 11998:2025(en)
Batch control of suitable technical non-woven pads: The quality of the technical non-woven abrasive has a
direct impact on the test result. Therefore, the quality of each batch shall be proven according to Annex B of
this document.
New technical non-woven abrasives should be proven according to Annex C in a round robin test.
6.6 Analytical balance, shielded from draughts, capable of weighing the test panel with applied coating
to the nearest 0,1 mg.
6.7 Straight-edge ruler, with 0,5 mm divisions.
7 Sampling
Take a representative sample of the coating to be tested, as specified in ISO 15528.
Examine and prepare the sample as specified in ISO 1513.
8 Procedure
8.1 Film application
Using the film applicator, make a draw-down of the prepared sample of coating material on the plastics film
to achieve an even film at least 10 mm longer than the scrub length. Prepare one or more coated plastics
film to be able to create enough test panels for threefold testing according to 8.2. Cut the coated plastics
film(s) in three stripes according to dimension requirements given in 6.1 and 6.3. Ensure the gap clearance
is sufficient that the resulting dry film is of such a thickness that, after the defined number of wet-scrub
cycles, the substrate is not exposed.
For the determination of wet-scrub resistance, dry the film at a temperature of (23 ± 2) °C and a relative
humidity of (50 ± 5) % for the required period. The drying time is specified by the customer on basis of
classification standards, legislations or technical soundness and shall be recorded during the test procedure.
Weigh the test panel with the dried coating film to the nearest 0,1 mg.
NOTE 1 Duplicate panels are best prepared by using a standard panel measuring (165 × 430) mm and making a
draw-down approximately 150 mm wide. After drying, the panel can then be cut in half lengthwise.
NOTE 2 For interior wall paints a drying period for 28 days is suitable for classification according to EN 13300.
8.2 Wet-scrub resistance
Ensure that the pad-displacing system is parallel to the surface of the test panel and that the mounting
device is not in contact with the scrub pad holder (see Figure 3). Place the test panel with the applied coating
film in the base pan of the
...