kSIST-TS FprCEN/TS 927-12:2023

Paints and varnishes - Coating materials and coating systems for exterior wood - Part 12: Ultraviolet and visible radiation transmittance

This Technical Specification describes 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 exterior wood. From the spectral transmittance the transmittance of UV, VIS and the UV plus VIS wavelength range can be calculated.
It is applicable to free coatings films or coatings applied on a UV-transparent substrate.

Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im Außenbereich - Teil 12: Durchlässigkeit für ultraviolette und sichtbare Strahlung

Peintures et vernis - Produits de peinture et systèmes de peinture pour le bois extérieur - Partie 12: Transmission du rayonnement ultraviolet et visible

Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo - 12. del: Prepustnost ultravijoličnih in vidnih žarkov

General Information

• Status: Not Published
• Public Enquiry End Date: 02-Feb-2023
• ICS: 71.100.50 - Wood-protecting chemicals
• ICS: 87.040 - Paints and varnishes
• Technical Committee: POH - Furniture
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 07-Dec-2022
• Due Date: 25-Jan-2023
• Completion Date: 15-Feb-2023
• Ref Project: FprCEN/TS 927-12 - Paints and varnishes - Coating materials and coating systems for exterior wood - Part 12: Ultraviolet and visible radiation transmittance

Standards Content (Sample)

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 927-12:2023
01-januar-2023

Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo - 12.

del: Prepustnost ultravijoličnih in vidnih žarkov

Paints and varnishes - Coating materials and coating systems for exterior wood - Part

12: Ultraviolet and visible radiation transmittance
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im

Außenbereich - Teil 12: Durchlässigkeit für ultraviolette und sichtbare Strahlung

Peintures et vernis - Produits de peinture et systèmes de peinture pour le bois extérieur -

Partie 12: Transmission du rayonnement ultraviolet et visible
Ta slovenski standard je istoveten z: FprCEN/TS 927-12
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
87.040 Barve in laki Paints and varnishes
kSIST-TS FprCEN/TS 927-12:2023 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TS FprCEN/TS 927-12:2023
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kSIST-TS FprCEN/TS 927-12:2023
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 927-12
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2022
ICS 87.040
English Version
Paints and varnishes - Coating materials and coating
systems for exterior wood - Part 12: Ultraviolet and visible
radiation transmittance

Peintures et vernis - Produits de peinture et systèmes Beschichtungsstoffe - Beschichtungsstoffe und

de peinture pour le bois extérieur - Partie 12: Beschichtungssysteme für Holz im Außenbereich - Teil

Transmission du rayonnement ultraviolet et visible 12: Durchlässigkeit für ultraviolette und sichtbare

Strahlung

This draft Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee

CEN/TC 139.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and

United Kingdom.

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.

Warning : This document is not a Technical Specification. It is distributed for review and comments. It is subject to change

without notice and shall not be referred to as a Technical Specification.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 927-12:2022 E

worldwide for CEN national Members.
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kSIST-TS FprCEN/TS 927-12:2023
FprCEN/TS 927-12:2022 (E)
Contents Page

European foreword ............................................................................................................................................ 3

Introduction .......................................................................................................................................................... 4

1 Scope .......................................................................................................................................................... 5

2 Normative references .......................................................................................................................... 5

3 Terms and definitions ......................................................................................................................... 5

4 Abbreviations ......................................................................................................................................... 5

5 Principle ................................................................................................................................................... 6

6 Apparatus and materials .................................................................................................................... 6

6.1 Film applicator for coating material .............................................................................................. 6

6.2 Substrate for free coating film preparation ................................................................................ 6

6.2.1 Preparation of free film and test specimen ................................................................................. 6

6.2.2 Coating application .............................................................................................................................. 6

6.3 Film thickness measurement ........................................................................................................... 7

6.4 UV/VIS spectrophotometer ............................................................................................................... 7

6.5 Long-pass filter specification for check ........................................................................................ 8

7 Test procedure ....................................................................................................................................... 8

7.1 Test procedure with spectrophotometer ..................................................................................... 8

7.2 Check of spectrophotometer with long-pass filter ................................................................... 9

7.3 Spectral transmittance of the specimen (film) .......................................................................... 9

7.4 Calculation of transmittance........................................................................................................... 10

8 Precision ................................................................................................................................................ 10

9 Test report ............................................................................................................................................. 10

Annex A (normative) Spectral transmittance of long-pass filter .................................................... 12

Annex B (informative) Application and evaluation references ..................................................... 13

Bibliography ....................................................................................................................................................... 14

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kSIST-TS FprCEN/TS 927-12:2023
FprCEN/TS 927-12:2022 (E)
European foreword

This document (FprCEN/TS 927-12:2022) has been prepared by Technical Committee CEN/TC 139

“Paints and varnishes — Coating materials and coating systems for exterior wood — Ultraviolet and

visible radiation transmittance”, the secretariat of which is held by DIN.
This document is currently submitted to the Vote on TS.
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kSIST-TS FprCEN/TS 927-12:2023
FprCEN/TS 927-12:2022 (E)
Introduction

Wood is a natural material that must be protected against solar radiation, heat, rain, and microorganisms

to maintain its appearance and mechanical integrity when used outdoors. Wood and its components

(especially lignin) are sensitive to photo oxidation and must therefore be protected by suitable coatings,

particularly against ultraviolet (UV) and visible (VIS) radiation in the violet and blue region.

Clear and transparent coating films may be modified by fine sized transparent (mostly yellow or red

ferrous oxide-based) pigments and more or less colourless, organic and inorganic UV-absorbers to reduce

the harmful part of solar radiation. As these additives are not visible, there is a demand for a test method

to determine their efficiency.

The transmittance in a specific wavelength range allows to evaluate the UV and VIS radiation protection

of a coating film.
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kSIST-TS FprCEN/TS 927-12:2023
FprCEN/TS 927-12:2022 (E)
1 Scope

This document describes 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 exterior wood. 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 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.

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

For the purposes of this document, the terms and definitions given in EN ISO 4618 and the following

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
transmittance
quotient of transmitted radiant flux, Φ , and incident radiant flux, Φ
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
Note 4 to entry: The transmittance has unit one.
[SOURCE: CIE S 017:2020]
4 Abbreviations
UV ultraviolet radiation in the wavelength range from 280 nm to 400 nm
VIS visible radiation in the wavelength range from 400 nm to 700 nm
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5 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 (Ulbricht sphere), and a

spectroradiometer with a diffraction element and a detector.

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 Φ (λ)

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

t t m

spectral transmittance τ(λ). 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 7.4.

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.
6 Apparatus and materials
6.1 Film applicator for coating material

A suitable doctor blade to apply coatings films of defined wet layer thickness shall be used. As an example

for high build wood stains a dry film thickness of approximately 90 µm to 120 µm should be achieved.

6.2 Substrate for free coating film preparation
6.2.1 Preparation of free film and test specimen

A clean and plane substrate shall be used to apply the wet coating materials to prepare the free coating

films of correct uniform layer thickness. Ideal as substrate to separate later the coating film without

damage is a PTFE coated smooth metal plate or a PE-, PP-foil, or silicone paper fixed on e.g. a smooth

glass or metal plate. In case of low viscosity coatings silicone rubber rings can be used after balancing

them horizontally, on e.g. a glass plate to fill in the liquid coating material. The coating material normally

is sufficiently dry after a minimum of 7 days or better of 28 days at (23 ± 2) °C at (50 ± 5)

...