CEN/TS 927-8:2020

SLOVENSKI STANDARD
01-april-2020
Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo - 8.
del: Določevanje oprijema na vlažnem lesu z uporabo dvojnega križnega reza
Paints and varnishes - Coating materials and coating systems for exterior wood - Part 8:
Determination of the adhesion on wood after water exposure by a double-X-cut test
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im
Außenbereich - Teil 8: Bestimmung der Haftfestigkeit auf Holz durch Doppel-
Kreuzschnittprüfung nach Wasserbeanspruchung
Peintures et vernis - Produits de peinture et systèmes de peinture pour le bois en
extérieur - Partie 8 : Détermination de l’adhésion sur le bois après une exposition à l’eau
lors d’un essai avec double incision en X
Ta slovenski standard je istoveten z: CEN/TS 927-8:2020
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
87.040 Barve in laki Paints and varnishes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 927-8
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
February 2020
TECHNISCHE SPEZIFIKATION
ICS 87.040
English Version
Paints and varnishes - Coating materials and coating
systems for exterior wood - Part 8: Determination of the
adhesion on wood after water exposure by a double-X-cut
test
Peintures et vernis - Produits de peinture et systèmes Beschichtungsstoffe - Beschichtungsstoffe und
de peinture pour le bois en extérieur - Partie 8 : Beschichtungssysteme für Holz im Außenbereich - Teil
Détermination de l'adhésion sur le bois après une 8: Bestimmung der Haftfestigkeit auf Holz durch
exposition à l'eau lors d'un essai avec double incision Doppel-Kreuzschnittprüfung nach
en X Wasserbeanspruchung
This Technical Specification (CEN/TS) was approved by CEN on 21 October 2019 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, 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, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 927-8:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Apparatus and materials . 5
6 Samples . 6
7 Procedure. 6
7.1 Cleaning of test surface . 6
7.2 Making a double-X-cut . 6
7.3 Application and removal of the tape (dry conditions) . 7
7.4 Application and removal of the tape after wetting (wet conditions) . 7
8 Results . 7
9 Test report . 12
Annex A (normative) Requirements for field testing . 14
Annex B (normative) Testing the tape - Determination of adhesive strength of tape on test
surface . 15
Bibliography . 16

European foreword
This document (CEN/TS 927-8:2020) 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 shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: 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, Turkey and the
United Kingdom.
Introduction
This Technical Specification (CEN/TS 927-8) is one of two methods for assessing the resistance of a
coating system to removal by external forces provided by either double-X-cutting or direct pull-off
(CEN/TS 927-9). Two existing ISO Standards (EN ISO 2409 and EN ISO 4624) specify test methods for
dry substrates in general, but make no provision for wet conditions, where wood coatings are known to
be particularly vulnerable. Both CEN methods (CEN/TS 927-8 and CEN/TS 927-9) take into account the
special nature of wood as a substrate because as well wet conditions as the selection of the substrate
are considered.
The adhesion of a coating system to a wood substrate can be reduced by high moisture content
particularly at the wood/coating interface. Water can access this interface either from the outside
because the coating film itself is permeable or through film defects. Water can also come from the wood
substrate, and thus reach the coating film from the rear. The described method is applicable for testing
the adhesion of a coating system to wood or wood based substrates under both dry and wet conditions.
1 Scope
This document describes the method for assessing the resistance of paint coatings to separation from
substrates when a double-X pattern is cut into the coating, penetrating through to the substrate and
using a tape.
Where a m
...