kSIST FprEN 927-14:2022
(Main)Paints and varnishes - Coating materials and coating systems for exterior wood - Determination of tensile properties of coating films
Paints and varnishes - Coating materials and coating systems for exterior wood - Determination of tensile properties of coating films
This standard is directed at the investigation of the mechanical and tensile properties of free
coating films. It is similar to ISO 5273 and ISO 37 for the testing of plastic and rubber materials
but with particular focus on test sample preparation from free coating films. Typical parameters
for the mechanical behaviour are the modulus of elasticity, the tensile strength and the
elongation at break/elongation at rupture during stretching of a free coating film with constant
speed.
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im Außenbereich - Bestimmung der Zugeigenschaften von Beschichtungsfilmen
Dieses Dokument beschreibt ein Verfahren zur Bestimmung der Eigenschaften bei Zugbelastung von freien Beschichtungsfilmen für Holz im Außenbereich. Typische Parameter für das mechanische Verhalten sind der Elastizitätsmodul, die Zugfestigkeit und die Bruchdehnung während der Ausdehnung eines freien Beschichtungsfilms bei konstanter Prüfgeschwindigkeit. Die in diesem Dokument beschriebenen Prüfverfahren sind auf Beschichtungen anwendbar, aus denen freie Filme hergestellt werden können.
Peintures et vernis - Produits de peinture et systèmes de peinture pour le bois en extérieur - Partie 14 : Détermination des propriétés en traction des films de revêtement
Le présent document décrit une méthode permettant de déterminer les propriétés en traction des feuils de peinture libres pour le bois en extérieur. Les paramètres caractéristiques du comportement mécanique sont le module d’élasticité, la résistance à la traction et l’allongement à la rupture lors de l’étirage d’un feuil de peinture libre à une vitesse d’essai constante. Les méthodes d’essai décrites dans le présent document sont applicables aux revêtements à partir desquels peuvent être fabriqués des feuils libres.
Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo - Določanje nateznih lastnostii premaznih filmov
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 927-14:2021
01-december-2021
Barve in laki - Premazi in premazni sistemi za zaščito lesa za zunanjo uporabo -
Določanje nateznih lastnosti premaznih filmov
Paints and varnishes - Coating materials and coating systems for exterior wood -
Determination of tensile properties of coating films
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im
Außenbereich - Bestimmung der Zugeigenschaften von Beschichtungsfilmen
Ta slovenski standard je istoveten z: prEN 927-14
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
87.040 Barve in laki Paints and varnishes
oSIST prEN 927-14:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 927-14:2021
DRAFT
EUROPEAN STANDARD
prEN 927-14
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2021
ICS 87.040
English Version
Paints and varnishes - Coating materials and coating
systems for exterior wood - Determination of tensile
properties of coating films
Beschichtungsstoffe - Beschichtungsstoffe und
Beschichtungssysteme für Holz im Außenbereich -
Bestimmung der Zugeigenschaften von
Beschichtungsfilmen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 139.If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.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.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 European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 927-14:2021 E
worldwide for CEN national Members.---------------------- Page: 3 ----------------------
oSIST prEN 927-14:2021
prEN 927-14:2021
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 .............................................................................................................................. 6
5.1 Film application device ................................................................................................................................. 6
5.2 Test apparatus.................................................................................................................................................. 6
5.3 Coating thickness gauge................................................................................................................................ 6
6 Test specimens ................................................................................................................................................. 6
6.1 Sampling of coating products ..................................................................................................................... 6
6.2 Preparation of test specimens .................................................................................................................... 6
6.3 Shape and size .................................................................................................................................................. 7
6.4 Thickness ........................................................................................................................................................... 8
6.5 Conditioning ...................................................................................................................................................... 8
6.6 Cutting of test specimens .............................................................................................................................. 8
7 Test procedure ................................................................................................................................................. 9
7.1 General ................................................................................................................................................................ 9
7.2 Measurement of test specimens ................................................................................................................ 9
7.3 Clamping of samples ...................................................................................................................................... 9
7.4 Determination of tensile properties ........................................................................................................ 9
7.5 Determination of the tensile strength .................................................................................................. 11
7.6 Determination of the tensile strain at break ..................................................................................... 12
7.7 Determination of the tensile modulus of elasticity ......................................................................... 13
8 Test report ...................................................................................................................................................... 14
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prEN 927-14:2021
European foreword
This document (prEN 927-14:2021) has been prepared by Technical Committee CEN/TC 139 “Paints and
varnishes”, the secretariat of which is held by DIN.This document is currently submitted to the CEN Enquiry.
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Introduction
Wood as a natural construction material may be protected against rain, sunlight and microorganisms
attack by a coating film to keep its appearance and mechanical integrity if used outdoors. Humidity will
cause swelling of wood, as drying will cause shrinking. These movements are different in the three main
directions of wood (longitudinal < radial < tangential) that leads to different stresses in the surface
coating. The coating however should stay intact over time to protect the wood substrate. A coating
material that is too rigid and brittle will crack and fail. Water can penetrate the wood through defects
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1 Scope
This document describes a method to determine the tensile properties of free coating films for wood in
exterior application. Typical parameters for the mechanical behaviour are the modulus of elasticity, the
tensile strength and the elongation at break during stretching of a free coating film at constant test speed.
The test methods described in this document are applicable to coatings from which free films can be
made.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 927-1:2013, Paints and varnishes - Coating materials and coating systems for exterior wood - Part 1:
Classification and selectionEN ISO 527-1:2019, Plastics - Determination of tensile properties - Part 1: General principles (ISO 527-
1:2019)EN ISO 527-3, Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets (ISO
527-3)EN ISO 4618, Paints and varnishes - Terms and definitions (ISO 4618)
EN ISO 15528, Paints, varnishes and raw materials for paints and varnishes - Sampling (ISO 15528)
ISO 4593, Plastics — Film and sheeting — Determination of thickness by mechanical scanning
ISO 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
3 Terms and definitionsFor the purposes of this document, the terms and definitions given in EN ISO 4618 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
4 Principle
Tensile test specimens are prepared from free coating films and subjected to a tensile test under defined
conditions until they fail. During this procedure, the load sustained by the sample and the elongation
behaviour are recorded.This document is similar to EN ISO 527-3 and ISO 37 for the testing of plastic and rubber materials but
focusses on the sample preparation and specific testing of free films of wood coatings.
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5 Apparatus and materials
5.1 Film application device
Coating films can be prepared by casting the liquid coating material in moulds or by applying it to a
suitable non-adhering substrate by manual procedure or using an automatic film applicator, see 5.3.
NOTE Automatic application devices are preferred as they move at constant speed and deliver a more uniform
final coating film.5.2 Test apparatus
The tensile test machine shall comply with the requirements of EN ISO 527-1:2019, 5.1, where applicable.
It should be equipped with selectable speed control (typical range: 10 mm/min to 200 mm/min), load
and strain indicator and temperature control unit. The strain indicator can either use crosshead travel
measurement or extensometer measurement. If an extensometer is used, an optical measurement device
is preferred as it does not touch and influence the specimen.5.3 Coating thickness gauge
For film thickness measurement, all devices using mechanical scanning according to ISO 4593 or
equivalent methods are applicable.6 Test specimens
6.1 Sampling of coating products
Take a representative sample of the liquid coating material to be tested as specified in EN ISO 15528.
Deaerating of the coating material should be considered (e.g. in a centrifuge or in a high speed vacuum
mixer).6.2 Preparation of test specimens
Prepare the test specimens by casting the liquid coating material into shallow (e.g. silicone rubber-based)
moulds (in case of low viscosity coating materials) or by drawing the (more viscous) coating material as
a wet film on a flat support (e.g. on a PTFE coated metal plate, POM or some inert foil, e.g. based on
untreated PP or PE) with a broad film applicator. The substrate shall be well levelled horizontally before
applying the coating material.The substrate shall allow the dry film to be removed easily without the need for additional wetting or
pre-stressing it. For cast films, apply the proper amount of (wet) coating material to produce the
requested dry film thickness.In the case of inert foils as substrate it is recommended to attach them to the levelled flat support
(typically a glass plate) by wetting the backside with oil or water, avoiding entrapped air bubbles. The
wet coating film should preferably be applied on the foil with an automatic film applicator at an
appropriate speed.The coating films to gain the final test specimens shall be prepared at controlled conditions in a standard
atmosphere [(23 ± 2) °C, (50 ± 10) % relative humidity or (20 ± 2) °C, (65 ± 10) % relative humidity]. The
cured coating films shall be free from cracks, bubbles or other defects.Pre-treatment e.g. by heat, or immersion in water to ease the removal of coating films from the substrate
shall not be used as it may strongly influence the mechanical film properties. Pre-treatments potentially
cause thermal change of film morphology or leaching of water-soluble ingredients in an uncontrolled
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6.3 Shape and size
To determine tensile performance, two different sample geometries are applicable and shall be agreed
upon among the contracting partners.Figure 1 shows the dimensions and tolerances of t
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