Paints and varnishes -- Determination of the resistance of coatings to pressure water-jetting

This document specifies a test method for the evaluation of the resistance of coatings to pressure water-jetting. The test method simulates the effects pressure water-jetting has on a coating.

Peintures et vernis -- Détermination de la résistance des revêtements à un jet d'eau sous pression

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Status
Published
Publication Date
09-Dec-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
17-Nov-2021
Completion Date
14-Dec-2021
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ISO 16925:2021 - Paints and varnishes -- Determination of the resistance of coatings to pressure water-jetting
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INTERNATIONAL ISO
STANDARD 16925
Second edition
2021-12
Paints and varnishes — Determination
of the resistance of coatings to
pressure water-jetting
Peintures et vernis — Détermination de la résistance des revêtements
à un jet d'eau sous pression
Reference number
ISO 16925:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 16925:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
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Published in Switzerland
© ISO 2021 – All rights reserved
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ISO 16925:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Apparatus and materials ............................................................................................................................................................................2

6 Sampling ....................................................................................................................................................................................................................... 3

7 Preparation of test specimens .............................................................................................................................................................. 4

7.1 Test specimens........................................................................................................................................................................................ 4

7.2 Preparation and coating ................................................................................................................................................................ 4

7.3 Thickness of coating .......................................................................................................................................................................... 4

8 Procedure ....................................................................................................................................................................................................................4

8.1 Introducing the cut or the scribe ......... .................................................................................................................................. . 4

8.2 Testing ............................................................................................................................................................................................................ 5

9 Evaluation ................................................................................................................................................................................................................... 6

9.1 General ........................................................................................................................................................................................................... 6

9.2 Evaluation with illustrations to compare ...................................................................................................................... 6

10 Precision ....................................................................................................................................................................................................................13

10.1 General ........................................................................................................................................................................................................13

10.2 Repeatability limit (r) .................................................................................................................................................................... 13

10.3 Reproducibility limit (R) ............................................................................................................................................................. 13

11 Designation .............................................................................................................................................................................................................13

12 Test report ...............................................................................................................................................................................................................14

Annex A (normative) Calibration of the test apparatus ...............................................................................................................15

iii
© ISO 2021 – All rights reserved
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ISO 16925:2021(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 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 second edition cancels and replaces the first edition (ISO 16925:2014), which has been technically

revised.
The main changes are as follows:

— the definitions “fracture strength”, “adhesion” and “cohesion” have been deleted from Clause 3

because they are not used in this document;

— in 5.1 and in A.2.4 the data for the adjustment of the mass flow rate have been updated;

— in 8.2 and in the test report the agreement of the mass flow rate has been deleted because it is given

by the test method and need not to be agreed;
— the volumetric flow rate has been changed to mass flow rate in several places;

— the normative references have been updated and the text has been editorially revised.

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.
© ISO 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO 16925:2021(E)
Paints and varnishes — Determination of the resistance of
coatings to pressure water-jetting
1 Scope

This document specifies a test method for the evaluation of the resistance of coatings to pressure

water-jetting. The test method simulates the effects pressure water-jetting has on a coating.

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 2808, Paints and varnishes — Determination of film thickness
ISO 4618, Paints and varnishes — Terms and definitions

ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling

ISO 17872, Paints and varnishes — Guidelines for the introduction of scribe marks through coatings on

metallic panels for corrosion testing
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4618 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/
4 Principle

The resistance of a coated test specimen to the loss of adhesive strength is tested by means of defined

pressure water-jetting.

The extent of the damage of the test specimen primarily depends on, besides the adhesive strength,

the space between nozzle and test piece, the mass flow rate, the test time, the geometry of the nozzle,

the impact area, the angle of impact, and the water temperature of the jet, as well as the cutting and

scribing tool.

The evaluation is carried out by means of a visual comparison of pictures, in which characteristic values

are related to the peeled-off areas.

The parting line (plane) of the peeling shall be indicated in the test report (e.g. substrate/priming coat).

© ISO 2021 – All rights reserved
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ISO 16925:2021(E)
5 Apparatus and materials
Ordinary laboratory apparatus, together with the following.
5.1 Pressure water-jet, consisting of a high-pressure pump and a nozzle.

A high-pressure pump conveys the water from a storage bin. To avoid influences from variations in

pressure, it is necessary that the pressure and the mass flow rate be adjustable at the nozzle described

below.
The water temperature shall be adjustable to ±2 °C.

The temperature shall be adjusted in accordance with Annex A. Necessary safety devices on the pressure

side of the unit, e.g. pressure relief valve and by-pass valve, shall exist. If the jetting is unsteady, a flow

calming section may be installed in front of the nozzle. A pulsation of the water jet at the opening of the

pump is inadmissible. In order to reach a reproducible result, the nozzle shall be solidly mechanically

fixed and the test specimen shall be secured against slipping. For the adjustment of the mass flow rate,

a nozzle with a jet angle of 40° and a mass flow rate of 6 kg/min at 2 MPa (20 bar) is required (see

Annex A).
The following technical data should be attainable:
— mass flow rate: 8 kg/min to 14 kg/min
— pressure: 4 MPa (40 bar) to 13 MPa (130 bar)
— temperature: 20 °C to 80 °C
— jetting time: 10 s to 300 s

Figure 1 shows the schematic construction of a pressure water-jet apparatus which is specially built for

these tests.
© ISO 2021 – All rights reserved
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ISO 16925:2021(E)
Key
1 flow calming section 8 heating
2 high-pressure valve, height adjustable 9 base frame, moveable
3 test specimen 10 temperature sensor
4 clamping element 11 high-pressure pump
5 feed tank 12 by-pass valve
6 floating valve with filter 13 pressure relief valve
7 water shortage safeguard 14 pressure transmitter
Figure 1 — Schematic construction of a pressure water-jet apparatus
5.2 Cutting or scribing tool, to be agreed by the interested parties.
The following cutting and scribing to
...

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