ISO/TS 19392-5:2023

Paints and varnishes — Coating systems for wind-turbine rotor blades — Part 5: Measurement of transmittance properties of UV protective coatings

This document specifies a test method to measure the ultraviolet (UV) and visible (VIS) spectral transmittance in the wavelength range from 280 nm to 700 nm of coatings for wind turbine rotor blades. Single and multilayer coatings or coating systems can be tested. From the spectral transmittance the transmittance of UV, VIS and the combined UV and VIS wavelength range can be calculated. It is applicable to free coatings films or coatings applied on a UV-transparent quartz substrate.

Matériaux de revêtement pour pales de turbines éoliennes — Partie 5: Mesurage des propriétés du facteur de transmission des revêtements de protection anti UV

General Information

• Status: Published
• Publication Date: 09-Mar-2023
• ICS: 87.040 - Paints and varnishes
• Technical Committee: ISO/TC 35/SC 9 - General test methods for paints and varnishes
• Drafting Committee: ISO/TC 35/SC 9/WG 32 - Coating materials for wind-turbine rotor blades
• Current Stage: 6060 - International Standard published
• Start Date: 10-Mar-2023
• Due Date: 21-Sep-2024
• Completion Date: 10-Mar-2023

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 19392-5
First edition
2023-03
Paints and varnishes — Coating
systems for wind-turbine rotor
blades —
Part 5:
Measurement of transmittance
properties of UV protective coatings
Matériaux de revêtement pour pales de turbines éoliennes —
Partie 5: Mesurage des propriétés du facteur de transmission des
revêtements de protection anti UV
Reference number
ISO/TS 19392-5:2023(E)
© ISO 2023
---------------------- Page: 1 ----------------------
ISO/TS 19392-5:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023

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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 19392-5:2023(E)
Contents Page

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

Introduction .................................................................................................................................................................................................................................v

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

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

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

4 Principle ........................................................................................................................................................................................................................ 2

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

5.1 Film applicator for coating material ................................................................................................................................... 2

5.2 Substrate for free coating film preparation ................................................................................................................. 2

5.2.1 Preparation of free film and test specimen ................................................................................................ 2

5.2.2 Coating application ........................................................................................................................................... ................ 3

5.3 Film thickness measurement .................................................................................................................................................... 3

5.4 UV/VIS spectrophotometer ......................................................................................................................................................... 3

5.5 Long pass specification for check .......................................................................................................................................... 4

6 Test procedure .......................................................................................................................................................................................................4

6.1 Test procedure with spectrophotometer ........................................................................................................................ 4

6.2 Check of spectrophotometer with long pass filter ................................................................................................. 5

6.3 Spectral transmittance of the specimen (film).......................................................................................................... 6

6.4 Calculation of transmittance ..................................................................................................................................................... 6

7 Precision ....................................................................................................................................................................................................................... 6

8 Test report .................................................................................................................................................................................................................. 6

Annex A (normative) Check of the spectral transmittance of the long pass filter .............................................8

Annex B (informative) Application and evaluation references ............................................................................................... 9

Bibliography .............................................................................................................................................................................................................................11

iii
© ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/TS 19392-5:2023(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 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/TS 19392 series can be found on the ISO website.

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 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 19392-5:2023(E)
Introduction

In the wind energy industry, coatings are applied to rotor blades surface to protect the glass fibre

reinforced polymer composite substrate from environmental stresses. 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. This applies mostly to the leading edge. Glass fibre reinforced polymer composites

and other blade materials can be also sensitive to UV degradation and thus can be damaged during

outdoor operation, if not protected accurately against irradiation by solar radiation. Failure of

protection can lead to delamination and a subsequent failure of the full blade.

An important function of the rotor blade coating is therefore to protect the blade material from UV

radiation. This applies to the leading edge, but also to the other surface areas of the blade.

The damage by solar radiation is mainly induced by the most energetic ultraviolet (UV) radiation, but

also visible (VIS) radiation (e.g. violet or blue radiation) is still energetic enough to have a negative

input on the appearance and durability of the blade.

Pigments and organic or inorganic UV absorbers can be used to reduce the coating film transmittance

against UV (and visible) radiation and cause a positive effect on lifetime and functional aspects of the

blade material. Pigments and UV absorbers can affect the transmittance in the visible range. This may

lead to colour change of the coated blade.

This document, as part of the ISO/TS 19392 series on rotor blade coatings, describes a method to

measure the spectral transmittance or the transmittance in a specific wavelength range. This allows

evaluating the UV and VIS radiation protection quality of a coatings film on the sensitive blade substrate

below. The focus is to avoid damage of the blade by natural solar radiation especially caused by the

most energetic part, the ultraviolet and short wavelength visible radiation.
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 19392-5:2023(E)
Paints and varnishes — Coating systems for wind-turbine
rotor blades —
Part 5:
Measurement of transmittance properties of UV protective
coatings
1 Scope

This document specifies a test method to measure the ultraviolet (UV) and visible (VIS) spectral

transmittance in the wavelength range from 280 nm to 700 nm of coatings for wind turbine rotor

blades. Single and multilayer coatings or coating systems can be tested.

From the spectral transmittance the transmittance of UV, VIS and the combined UV and VIS wavelength

range can be calculated.

It is applicable to free coatings films or coatings applied on a UV-transparent quartz substrate.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 2808, Paints and varnishes — Determination of film thickness

ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning

and testing
ISO 4618, Paints and varnishes — Vocabulary
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
transmittance
quotient of transmitted radiant flux, Φ , and incident radiant flux, Φ , τ =
t m

Note 1 to entry: Transmittance is also defined spectrally in terms of wavelength, in which case, “spectral” is

added before the quantity name.

Note 2 to entry: Due to energy conservation, α + ρ + τ = 1 except when polarized radiation is observed, where α is

absorptance and ρ is reflectance.

Note 3 to entry: Transmittance, τ, is the sum of regular transmittance, τ , and diffuse transmittance, τ : τ = τ + τ .

r d r d
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/TS 19392-5:2023(E)
Note 4 to entry: The transmittance has unit one.
[SOURCE: CIE S 017:2020; 17-24-065]
3.2
ultraviolet radiation
radiation in a wavelength range from 280 nm to 400 nm
3.3
visible radiation
VIS
radiation in a wavelength range from 400 nm to 700 nm
4 Principle

The UV and VIS transmittance through a coating film is measured using an UV/VIS spectrophotometer

equipped with a radiation source, a limiting aperture, an integrating sphere, and a spectroradiometer

with a diffraction element and a detector. See Annex B for application and evaluation references.

A beam of optical radiation, limited by an aperture, with an incident radiant flux, Φ , is directed on a

film specimen. The transmitted radiant flux, Φ , enters an integrating sphere. The sphere is equipped

with the input optics of a spectroradiometer with which spectrally resolved measurements of the

unfiltered radiant flux Φ (λ) and the filtered (transmitted) radiant flux Φ (λ) can be performed. The

m t
quotient Φ (λ)/Φ (λ) is the spectral transmittance τ(λ).
t m

NOTE τ(λ) multiplied by 100 represents the percentage of the transmitted radiant flux at a specific

wavelength or wavelength range passing through the film compared to the incident radiant flux Φ (λ).

From the spectral transmittance, the transmittance in a specific wavelength range can be calculated as

described in 6.4.

The spectral transmittance is recorded in wavelength increments over the entire wavelength range of

280 nm to 700 nm continuously during a wavelength scanning (e.g. in 2 nm to 10 nm steps depending

on the apparatus used and the resolution needed). Depending on the application the transmittance of

the specific wavelength ranges for UV, VIS and UV + VIS can be calculated.
5 Apparatus and materials
5.1 Film applicator for coating material
A suitable blade or spatula to apply coatings fi
...

© ISO 19392-5 – All rights reserved
ISO /DTS 19392--5:2022 (E)
ISO TC 35/SC 9/WG 32
Date: 2022-11-21
Secretariat: DINBSI
ISO/DTS 19392-5, Paints and varnishes — Coating systems for wind-turbine rotor

blades — Part 5: Measurement of transmittance properties of UV- protective rotor blade

coatings/coating systems
DTS stage
Warning for WDs and CDs

This document is not an ISO International Standard. It is distributed for review and comment. It is subject to

change without notice and may not be referred to as an International Standard.

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.

To help you, this guide on writing standards was produced by the ISO/TMB and is available at

https://www.iso.org/iso/how-to-write-standards.pdf

A model manuscript of a draft International Standard (known as “The Rice Model”) is available at

https://www.iso.org/iso/model_document-rice_model.pdf
---------------------- Page: 1 ----------------------
© ISO 2018
---------------------- Page: 2 ----------------------
ISO /DTS 19392-5:2022 (E)
© ISO 2022

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: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
4 © ISO #### – All rights reserved
iv © ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO /DTS 19392-5:2022 (E)
Contents

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

Introduction.................................................................................................................................................................... iv

1 Scope (mandatory) .......................................................................................................................................... 4

2 Normative references (mandatory) .......................................................................................................... 4

3 Terms and definitions (mandatory) ......................................................................................................... 4

4 Clause title autonumber................................................................................................................................ 4

5 Clause title .......................................................................................................................................................... 4

5.1 Subclause autonumber .................................................................................................................................. 4

5.1.1 Subclause autonumber .................................................................................................................................. 4

6 Clause title .......................................................................................................................................................... 4

Annex A (informative) Annex title e.g. Example of a figure and a table .................................................... 4

Bibliography .................................................................................................................................................................... 4

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

Introduction..................................................................................................................................................................... v

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

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

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

4 Principle ............................................................................................................................................................. 2

5 Apparatus and materials .............................................................................................................................. 3

5.1 Film applicator for coating material ........................................................................................................ 3

5.2 Substrate for free coating film preparation ........................................................................................... 3

5.2.1 Preparation of free film and test specimen ........................................................................................... 3

5.2.2 Coating application ......................................................................................................................................... 3

5.3 Film thickness measurement ...................................................................................................................... 3

5.4 UV/VIS spectrophotometer ......................................................................................................................... 3

5.5 Long pass specification for check .............................................................................................................. 5

6 Test procedure ................................................................................................................................................. 6

6.1 Test procedure with spectrophotometer ............................................................................................... 6

6.2 Check of spectrophotometer with long pass filter .............................................................................. 7

6.3 Spectral transmittance of the specimen (film) ..................................................................................... 8

6.4 Calculation of transmittance ....................................................................................................................... 8

7 Precision ............................................................................................................................................................. 8

8 Test report ......................................................................................................................................................... 8

Annex A (normative) Check of the spectral transmittance of the long pass filter ............................. 10

Annex B (informative) Application and evaluation references ................................................................ 11

Bibliography ................................................................................................................................................................. 13

© ISO #### – All rights reserved 5
© ISO 2022 – All rights reserved v
---------------------- Page: 4 ----------------------
ISO /DTS 19392-5:2022 (E)
6 © ISO #### – All rights reserved
vi © ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
ISO /DTS 19392-5:2022 (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/directiveswww.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/patentswww.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.htmlwww.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.

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 #### – All rights reserved 7
© ISO 2022 – All rights reserved vii
---------------------- Page: 6 ----------------------
ISO /DTS 19392-5:2022 (E)
Introduction

In the wind energy industry, coatings are applied to rotor blades surface to protect the glass fibre

reinforced polymer composite substrate from environmental stresses. 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. This applies mostly to the leading edge. Glass fibre reinforced polymer composites

and other blade materials can be also sensitive to UV degradation and thus can be damaged during

outdoor operation, if not protected accurately against irradiation by solar radiation. Failure of protection

can lead to delamination and a subsequent failure of the full blade.

AAn important function of the rotor blade coating is therefore to protect the blade material from UV

radiation. This applies to the leading edge, but also to the other surface areas of the blade.

The damage by solar radiation is mainly induced by the most energetic ultraviolet (UV) radiation, but

also visible (VIS) radiation (e.g. violet or blue radiation) is still energetic enough to have a negative input

on the appearance and durability of the blade.

Pigments and organic or inorganic UV absorbers can be used to reduce the coating film transmittance

against UV (and visible) radiation and cause a positive effect on lifetime and functional aspects of the

blade material. Pigments and UV absorbers can affect the transmittance in the visible range. This

mightmay lead to colour change of the coated blade.

This document, as part of the series ISO/TS 19392 series on rotor blade coatings, describes a method to

measure the spectral transmittance or the transmittance in a specific wavelength range. This allows

evaluating the UV and VIS radiation protection quality of a coatings film on the sensitive blade substrate

below. The focus is to avoid damage of the blade by natural solar radiation especially caused by the most

energetic part, the ultraviolet and short wavelength visible radiation.

This document is harmonized with prEN 927-12: Paints and varnishes — Coating materials and coating

systems for exterior wood — Part 12: Ultraviolet and visible radiation transmittance.

8 © ISO #### – All rights reserved
viii © ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
TECHNICAL SPECIFICATION ISO/DTS 19392-5:2022(E)
Paints and varnishes — Coating systems for wind-turbine rotor
blades — Part 5: Measurement of transmittance properties of UV-
protective rotor blade coatings/coating systems
1 Scope

This document specifies a test method to measure the ultraviolet (UV) and visible (VIS) spectral

transmittance in the wavelength range from 280 nm to 700 nm of coatings for wind turbine rotor blades.

Single and multilayer coatings or coating systems can be tested.

From the spectral transmittance the transmittance of UV, VIS and the combined UV and VIS wavelength

range can be calculated.

It is applicable to free coatings films or coatings applied on a UV-transparent quartz substrate.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning

and testing
EN ISO 2808, Paints and varnishes — Determination of film thickness (ISO 2808)
EN ISO 4618, Paints and varnishes — Terms and definitions

CIE S 017, ILV: International Lighting Vocabulary, 2nd Edition (technical content harmonized with IEC

60050-845)
3 Terms and definitions

For the purposes of this document, the terms according toand definitions given in ISO 4618 and the

following terms and definitions apply.

ISO and IEC maintain terminologicalterminology databases for use in standardization at the following

addresses:

— ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp

— IEC Electropedia: available at http://www.electropedia.org/https://www.electropedia.org/

3.1
transmittance
© ISO 2022 – All rights reserved 1
---------------------- Page: 8 ----------------------
ISO/DTS 19392-5:2022(E)

quotient of transmitted radiant flux, 𝜱 , radiant flux, Φ , and incident radiant flux, 𝜱 , 𝝉= radiant

𝒕 𝒎
flux, Φ ,  =

Note 1 to entry: Transmittance is also defined spectrally in terms of wavelength, wavelength, in which case,

"“spectral"” is added before the quantity name.

Note 2 to entry: Due to energy conservation, α + ρ + τ = 1 except when polarized radiation polarized radiation is

observed, where α is absorptance and ρ is reflectance. reflectance.

Note 3 to entry: Transmittance, τ, is the sum of regular transmittance, regular transmittance, τ , and diffuse

transmittance, diffuse transmittance, τ : τ = τ + τ .
d r d
Note 4 to entry: The transmittance has unit one.
[SOURCE: CIE S 017:2020; 17-24-065]
4 Abbreviations
UV: 3.2
ultraviolet radiation
radiation in thea wavelength range from 280 nm to 400 nm
VIS: 3.3
visible radiation
VIS
radiation in thea wavelength range from 400 nm to 700 nm
54 Principle

The UV and VIS transmittance through a coating film is measured using an UV/VIS spectrophotometer

equipped with a radiation source, a limiting aperture, an integrating sphere, and a spectroradiometer

with a diffraction element and a detector. See Annex B for application and evaluation references.

A beam of optical radiation, limited by an aperture, with an incident radiant flux, Φ , is directed on a film

specimen. The transmitted radiant flux, Φ , enters an integrating sphere. The sphere is equipped with the

input optics of a spectroradiometer with which spectrally resolved measurements of the unfiltered

radiant flux Φ (λ) and the filtered (transmitted) radiant flux Φ (λ) can be performed. The quotient

m t
Φ (λ)/Φ (λ) is the spectral transmittance τ(λ).
t m

NOTE τ(λ) multiplied by 100 represents the percentage of the transmitted radiant flux at a specific

wavelength or wavelength range passing through the film compared to the incident radiant flux Φ (λ).

From the spectral transmittance, the transmittance in a specific wavelength range can be calculated as

described in 76.4.

The spectral transmittance is recorded in wavelength increments over the entire wavelength range of

280 nm to 700 nm continuously during a wavelength scanning (e.g. in 2 nm to 10 nm steps depe

...

FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 19392-5
ISO/TC 35/SC 9
Paints and varnishes — Coating
Secretariat: BSI
systems for wind-turbine rotor
Voting begins on:
2022-12-05 blades —
Voting terminates on:
Part 5:
2023-01-30
Measurement of transmittance
properties of UV protective coatings
Matériaux de revêtement pour pales de turbines éoliennes —
Partie 5: Mesurage des propriétés du facteur de transmission des
revêtements de protection anti UV
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/DTS 19392-5:2022(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/DTS 19392-5:2022(E)
FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 19392-5
ISO/TC 35/SC 9
Paints and varnishes — Coating
Secretariat: BSI
systems for wind-turbine rotor
Voting begins on:
blades —
Voting terminates on:
Part 5:
Measurement of transmittance
properties of UV protective coatings
Matériaux de revêtement pour pales de turbines éoliennes —
Partie 5: Mesurage des propriétés du facteur de transmission des
revêtements de protection anti UV
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/DTS 19392-5:2022(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
© ISO 2022 – All rights reserved
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/DTS 19392-5:2022(E)
Contents Page

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

Introduction .................................................................................................................................................................................................................................v

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

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

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

4 Principle ........................................................................................................................................................................................................................ 2

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

5.1 Film applicator for coating material ................................................................................................................................... 2

5.2 Substrate for free coating film preparation ................................................................................................................. 2

5.2.1 Preparation of free film and test specimen ................................................................................................ 2

5.2.2 Coating application ........................................................................................................................................... ................ 3

5.3 Film thickness measurement .................................................................................................................................................... 3

5.4 UV/VIS spectrophotometer ......................................................................................................................................................... 3

5.5 Long pass specification for check .......................................................................................................................................... 4

6 Test procedure .......................................................................................................................................................................................................4

6.1 Test procedure with spectrophotometer ........................................................................................................................ 4

6.2 Check of spectrophotometer with long pass filter ................................................................................................. 5

6.3 Spectral transmittance of the specimen (film).......................................................................................................... 6

6.4 Calculation of transmittance ..................................................................................................................................................... 6

7 Precision ....................................................................................................................................................................................................................... 6

8 Test report .................................................................................................................................................................................................................. 6

Annex A (normative) Check of the spectral transmittance of the long pass filter .............................................8

Annex B (informative) Application and evaluation references ............................................................................................... 9

Bibliography .............................................................................................................................................................................................................................11

iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/DTS 19392-5:2022(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

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different types of ISO documents should be noted. This document was drafted in accordance with the

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Attention is drawn to the possibility that some of the elements of this document may be the subject of

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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.

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 2022 – All rights reserved
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ISO/DTS 19392-5:2022(E)
Introduction

In the wind energy industry, coatings are applied to rotor blades surface to protect the glass fibre

reinforced polymer composite substrate from environmental stresses. 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. This applies mostly to the leading edge. Glass fibre reinforced polymer composites

and other blade materials can be also sensitive to UV degradation and thus can be damaged during

outdoor operation, if not protected accurately against irradiation by solar radiation. Failure of

protection can lead to delamination and a subsequent failure of the full blade.

An important function of the rotor blade coating is therefore to protect the blade material from UV

radiation. This applies to the leading edge, but also to the other surface areas of the blade.

The damage by solar radiation is mainly induced by the most energetic ultraviolet (UV) radiation, but

also visible (VIS) radiation (e.g. violet or blue radiation) is still energetic enough to have a negative

input on the appearance and durability of the blade.

Pigments and organic or inorganic UV absorbers can be used to reduce the coating film transmittance

against UV (and visible) radiation and cause a positive effect on lifetime and functional aspects of the

blade material. Pigments and UV absorbers can affect the transmittance in the visible range. This may

lead to colour change of the coated blade.

This document, as part of the ISO 19392 series on rotor blade coatings, describes a method to measure

the spectral transmittance or the transmittance in a specific wavelength range. This allows evaluating

the UV and VIS radiation protection quality of a coatings film on the sensitive blade substrate below.

The focus is to avoid damage of the blade by natural solar radiation especially caused by the most

energetic part, the ultraviolet and short wavelength visible radiation.
© ISO 2022 – All rights reserved
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TECHNICAL SPECIFICATION ISO/DTS 19392-5:2022(E)
Paints and varnishes — Coating systems for wind-turbine
rotor blades —
Part 5:
Measurement of transmittance properties of UV protective
coatings
1 Scope

This document specifies a test method to measure the ultraviolet (UV) and visible (VIS) spectral

transmittance in the wavelength range from 280 nm to 700 nm of coatings for wind turbine rotor

blades. Single and multilayer coatings or coating systems can be tested.

From the spectral transmittance the transmittance of UV, VIS and the combined UV and VIS wavelength

range can be calculated.

It is applicable to free coatings films or coatings applied on a UV-transparent quartz substrate.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning

and testing
ISO 2808, Paints and varnishes — Determination of film thickness (ISO 2808)
ISO 4618, Paints and varnishes — Terms and definitions
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
transmittance
Φ t
quotient of transmitted radiant flux, Φ , and incident radiant flux, Φ , τ =
t m

Note 1 to entry: Transmittance is also defined spectrally in terms of wavelength, in which case, “spectral” is

added before the quantity name.

Note 2 to entry: Due to energy conservation, α + ρ + τ = 1 except when polarized radiation is observed, where α is

absorptance and ρ is reflectance.

Note 3 to entry: Transmittance, τ, is the sum of regular transmittance, τ , and diffuse transmittance, τ : τ = τ + τ .

r d r d
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ISO/DTS 19392-5:2022(E)
Note 4 to entry: The transmittance has unit one.
[SOURCE: CIE S 017:2020; 17-24-065]
3.2
ultraviolet radiation
radiation in a wavelength range from 280 nm to 400 nm
3.3
visible radiation
VIS
radiation in a wavelength range from 400 nm to 700 nm
4 Principle

The UV and VIS transmittance through a coating film is measured using an UV/VIS spectrophotometer

equipped with a radiation source, a limiting aperture, an integrating sphere, and a spectroradiometer

with a diffraction element and a detector. See Annex B for application and evaluation references.

A beam of optical radiation, limited by an aperture, with an incident radiant flux, Φ , is directed on a

film specimen. The transmitted radiant flux, Φ , enters an integrating sphere. The sphere is equipped

with the input optics of a spectroradiometer with which spectrally resolved measurements of the

unfiltered radiant flux Φ (λ) and the filtered (transmitted) radiant flux Φ (λ) can be performed. The

m t
quotient Φ (λ)/Φ (λ) is the spectral transmittance τ(λ).
t m
NOTE τ(λ) multiplied by 100 represents the percen
...