Paints and varnishes - Coating materials and coating systems for exterior wood - Assessment of tannin staining

This Technical Specification specifies a test method for assessing the discoloration of coatings on wood by tannin staining due to wood extractives. The method uses an extract from Merbau wood as an indicator. Bleeding of wood extractives is assessed at two specified stages firstly after coating application and secondly after cyclic climate exposure. A qualification of colour differences that can be attributed to three different causes, bleeding of extractives, low opacity of the coating film or general yellowing in climate exposure, is included. This document does not specify acceptance values for colour differences that can be tolerated and it is not applicable to staining caused by knots for which there is a different test method (e. g. CEN/TS 16359).

Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im Außenbereich - Beurteilung von unerwünschten Verfärbungen aufgrund von Holzinhaltsstoffen

Diese Technische Spezifikation legt ein Prüfverfahren zum Beurteilen der Verfärbung von Beschichtungssystemen auf Holz durch Tannine als Bestandteil von Holzinhaltsstoffen fest. Ein Extrakt aus Merbau-Holz wird bei diesem Verfahren als Indikator verwendet. Das Ausbluten von Holzinhaltsstoffen wird in zwei festgelegten Phasen, zunächst nach dem Auftragen des Beschichtungsstoffes und anschließend nach Beanspruchung durch Wechselklima, beurteilt. Bei der Bestimmung von Farbabständen nach dieser Methode sind die drei unterschiedlichen Ursachen von Verfärbungen, Ausbluten von Inhaltsstoffen, geringem Deckvermögen der Beschichtung oder einer Vergilbung infolge klimatischer Einflüsse berücksichtigt. Dieses Dokument legt keine Grenzwerte für Farbabstände fest, die toleriert werden können, und ist nicht anwendbar zur Beurteilung von Fleckenbildung bzw. Verfärbungen durch Äste, für die ein anderes Prüfverfahren (z. B. CEN/TS 16359) verfügbar ist.

Peintures et vernis - Produits de peinture et systèmes de peinture pour le bois en extérieur - Évaluation des taches de tanin

Cette Spécification technique spécifie une méthode d’essai permettant d’évaluer la décoloration des revêtements du bois par des taches de tanin dues aux matières extractibles du bois. La méthode utilise un extrait de bois de merbau comme indicateur. La migration des matières extractibles est évaluée à deux étapes spécifiques, premièrement après l’application du revêtement, deuxièmement après une exposition climatique cyclique. La qualification porte sur les écarts de couleur pouvant être attribués à trois raisons différentes, à la migration des matières extractibles, à une faible opacité du feuil ou à un jaunissement général lors de l’exposition climatique. Le présent document ne spécifie pas l’acceptation des valeurs pour les écarts de couleur pouvant être tolérées et il ne s’applique pas aux taches provoquées par les nœuds pour lesquelles il y a une méthode d’essai différente (par exemple CEN/TS 16359).

Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo - Ocenjevanje odpornosti premazov proti obarvanju zaradi lesnih taninov

General Information

Status
Published
Public Enquiry End Date
19-Dec-2012
Publication Date
20-Jan-2014
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
23-Dec-2013
Due Date
27-Feb-2014
Completion Date
21-Jan-2014

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SLOVENSKI STANDARD
SIST-TS CEN/TS 16498:2014
01-februar-2014
%DUYHLQODNL3UHPD]LLQSUHPD]QLVLVWHPL]D]DãþLWROHVD]D]XQDQMRXSRUDER
2FHQMHYDQMHRGSRUQRVWLSUHPD]RYSURWLREDUYDQMX]DUDGLOHVQLKWDQLQRY
Paints and varnishes - Coating materials and coating systems for exterior wood -
Assessment of tannin staining
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im
Außenbereich - Beurteilung von unerwünschten Verfärbungen aufgrund von
Holzinhaltsstoffen

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

extérieur - Évaluation des taches de tanin
Ta slovenski standard je istoveten z: CEN/TS 16498:2013
ICS:
71.100.50 .HPLNDOLMH]D]DãþLWROHVD Wood-protecting chemicals
87.040 Barve in laki Paints and varnishes
SIST-TS CEN/TS 16498:2014 en,fr,de

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

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SIST-TS CEN/TS 16498:2014
---------------------- Page: 2 ----------------------
SIST-TS CEN/TS 16498:2014
TECHNICAL SPECIFICATION
CEN/TS 16498
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
November 2013
ICS 87.040
English Version
Paints and varnishes - Coating materials and coating systems
for exterior wood - Assessment of tannin staining

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

peinture pour le bois en extérieur - Évaluation des taches Beschichtungssysteme für Holz im Außenbereich -

de tanin Beurteilung von unerwünschten Verfärbungen aufgrund von
Holzinhaltsstoffen

This Technical Specification (CEN/TS) was approved by CEN on 12 February 2013 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their

comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available

promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)

until the final decision about the possible conversion of the CEN/TS into an EN is reached.

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

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 16498:2013: E

worldwide for CEN national Members.
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SIST-TS CEN/TS 16498:2014
CEN/TS 16498:2013 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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

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

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

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

4 Apparatus and materials .......................................................................................................................5

5 Procedure ...............................................................................................................................................6

5.1 Preparation of wood extract .................................................................................................................6

5.2 Wood panels, extract application and sealing ....................................................................................7

5.3 Coating application................................................................................................................................8

5.4 Colour measurements after coating application ................................................................................8

5.5 Cyclic climate exposure ........................................................................................................................9

5.6 Colour measurements after cyclic climate exposure ........................................................................9

5.7 Calculation and assessment of colour differences ............................................................................9

6 Test report ........................................................................................................................................... 10

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

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SIST-TS CEN/TS 16498:2014
CEN/TS 16498:2013 (E)
Foreword

This document (CEN/TS 16498:2013) has been prepared by Technical Committee CEN/TC 139 “Paints and

varnishes”, the secretariat of which is held by DIN.

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

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,

Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

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SIST-TS CEN/TS 16498:2014
CEN/TS 16498:2013 (E)
Introduction

Coatings on exterior wood surfaces have both decorative and protective functions. A valued function of the

coating system is to protect against discoloration caused by the presence of wood extractives in the coating

migrating from the wood material. Bleeding of extractives can occur at different stages, including shortly after

coating application and at a later stages in use, when driving forces like fluctuating humidity are present.

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SIST-TS CEN/TS 16498:2014
CEN/TS 16498:2013 (E)
1 Scope

This Technical Specification specifies a test method for assessing the discoloration of coatings on wood by

tannin staining due to wood extractives. The method uses an extract from Merbau wood as an indicator.

Bleeding of wood extractives is assessed at two specified stages firstly after coating application and secondly

after cyclic climate exposure. A qualification of colour differences that can be attributed to three different

causes, bleeding of extractives, low opacity of the coating film or general yellowing in climate exposure, is

included. This document does not specify acceptance values for colour differences that can be tolerated and it

is not applicable to staining caused by knots for which there is a different test method (e. g. CEN/TS 16359).

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 927-5, Paints and varnishes - Coating materials and coating systems for exterior wood - Part 5:

Assessment of the liquid water permeability
ISO 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 3131, Wood — Determination of density for physical and mechanical tests
ISO 7724-2, Paints and varnishes — Colorimetry — Part 2: Colour measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
tannin staining

appearance of discoloration on coated surfaces caused by wood extractives in the substrate

3.2
knot staining

appearance of discoloration on coated surfaces caused by wood extractives in knots

3.3
wood extractives
low-molecular weight wood components soluble in organic solvents or water
4 Apparatus and materials
4.1 1 l measuring cylinder.
4.2 Balance, with an accuracy of 0,01 g.

4.3 CIELAB Spectrophotometer, with d/8 geometry, D65 light source and 10° standard observer.

4.4 Chips of Merbau wood (Intsia sp.), produced by drilling.
4.5 1 l round bottom flask with a water cooled condenser.
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SIST-TS CEN/TS 16498:2014
CEN/TS 16498:2013 (E)
4.6 Round bottom heater.
4.7 Coating applicator, with a 60 µm gap and 40 mm to 100 mm width.
4.8 Equipment fo
...

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