ISO/TS 19392-2:2018

TECHNICAL ISO/TS
SPECIFICATION 19392-2
First edition
2018-04
Paints and varnishes — Coating
systems for wind-turbine rotor
blades —
Part 2:
Determination and evaluation of
resistance to rain erosion using
rotating arm
Peintures et vernis — Matériaux de revêtement pour pales de turbines
éoliennes —
Partie 2: Détermination et évaluation de la résistance à l'érosion
causée par la pluie au moyen d'un bras rotatif
Reference number
©
ISO 2018
© ISO 2018
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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Apparatus . 3
6 Sampling . 3
7 Test specimens. 4
7.1 Substrate . 4
7.2 Preparation . 4
7.3 Conditioning . 4
7.4 Thickness of coating . 5
8 Procedure. 5
8.1 Number of determinations . 5
8.2 Examination before exposure . 5
8.3 Calibration . 5
8.4 Exposure to simulation of rain erosion. 5
8.5 Examination after exposure. 6
9 Evaluation . 6
10 Precision . 7
11 Test report . 7
Annex A (normative) Details of test methods . 8
BIbliography .10
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 on 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 the following
URL: 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.
A list of all parts in the ISO 19392 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved

Introduction
In the wind energy industry, coatings are applied to rotor blades surface to protect the glass fibre
reinforced polymer composite substrate. Rain drops and hailstones can damage these coatings in such
a way that individual layers come off or the whole coating delaminates from the substrate.
ISO/TS 19392-1 describes the minimum requirements and weathering of the coating system. Rain
erosion can be simulated by means of high speed water jets or water droplets impinging on the
specimen surface. This document describes a method which simulates rain erosion by accelerating one
or more coated panels, attached to the end of rotating arms, through a simulated rain field at a constant
rotational velocity. ISO/TS 19392-3 describes a method where a water jet or a series of water jets at
defined pressure hits the surface of the specimen.
TECHNICAL SPECIFICATION ISO/TS 19392-2:2018(E)
Paints and varnishes — Coating systems for wind-turbine
rotor blades —
Part 2:
Determination and evaluation of resistance to rain erosion
using rotating arm
1 Scope
This document specifies a test method for the determination of resistance of coating systems or tape
for wind-turbine rotor blades to rain erosion by using the rotating arm test.
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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 1513, Paints and varnishes — Examination and preparation of test samples
ISO 2808, Paints and varnishes — Determination of film thickness
ISO 4618, Paints and varnishes — Terms and definitions
ISO 4628-1:2016, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and
designation system
ISO 4628-2, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of
blistering
ISO 4628-4, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 4: Assessment of degree of
cracking
ISO 4628-5, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and
size of defects, and of intensity of uniform changes in appearance — Part 5: Assessment of degree of flaking
ISO 4628-6, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 6: Assessment of degree of
chalking by tape method
ISO 13076, Paints and varnishes — Lighting and procedure for visual assessments of coatings
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 19403-2, Paints and varnishes — Wettability — Part 2: Determination of the surface free energy of
solid surfaces by measuring the contact angle
ASTM G73-10, Standard Test Method for Liquid Impingement Erosion Using Rotating Apparatus
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 terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
exposed area
exposed surface
area which has contact with the water droplets
4 Principle
A method for simulating rain erosion is to accelerate one or more coated panels, attached to the end
of rotating arms, through a simulated rain field at a constant rotational velocity. As the rain droplets
impinge on the surface of the specimen, an impact force is transferred to the coated sample panel. Over
time, this causes degradation of the coating and underlying composite structure, and the coating is
thereby removed.
The degree of erosion is determined by visual or microscopic inspection at defined intervals. The test
is finished as soon as the composite substrate is exposed. The evaluation enables pass or fail decision
as well as a comparison with different coating systems in the same conditions in the same test rig. Also
possible is the investigation of the course of the damage starting from initiation until complete failure.
2 © ISO 2018 – All rights reserved

5 Apparatus
Ordinary laboratory apparatus, together with the following.
5.1 Testing device with rotating arm, an example of which is shown in Figure 1.
Dimensions in metres
a) Side view b) Top view
Key
1 rain generator
2 rotating disk
3 specimen holder
a
Water flow.
Figure 1 — Schematic illustration of an example of a test device with vertical axis of rotation
There are a number of different apparatus designs available with different testing parameters –
and even some with the same apparatus design which have different testing parameters. As these
differences can give different results, the user is advised to use caution when comparing results from
different facilities and different parameters.
6 Sampling
Take a representative sample of the product to be tested (or of each product in case of a multi-coat
system), as described in ISO 15528.
Examine and prepare each sample for testing, as described in ISO 1513.
7 Test specimens
7.1 Substrate
Test specimens are made from
...