SIST EN 302-3:2023

SLOVENSKI STANDARD
01-april-2023
Lepila za nosilne lesene konstrukcije - Preskusne metode - 3. del: Ugotavljanje
vpliva kislinskih poškodb lesnih vlaken, nastalih zaradi cikličnih obremenitev s
temperaturo in vlago, na prečno natezno trdnost
Adhesives for load-bearing timber structures - Test methods - Part 3: Determination of
the effect of acid damage to wood fibres by temperature and humidity cycling on the
transverse tensile strength
Klebstoffe für tragende Holzbauteile - Prüfverfahren - Teil 3: Bestimmung des Einflusses
von Säureschädigung der Holzfasern durch Temperatur- und Feuchtezyklen auf die
Querzugfestigkeit
Adhésifs pour structures portantes en bois - Méthodes d’essai - Partie 3 : Détermination
de l’influence de l’attaque d’acide des fibres de bois, résultant de traitements cycliques
en température et humidité sur la résistance à la traction transversale
Ta slovenski standard je istoveten z: EN 302-3:2023
ICS:
83.180 Lepila Adhesives
91.080.20 Lesene konstrukcije Timber structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 302-3
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2023
EUROPÄISCHE NORM
ICS 83.180 Supersedes EN 302-3:2017
English Version
Adhesives for load-bearing timber structures - Test
methods - Part 3: Determination of the effect of acid
damage to wood fibres by temperature and humidity
cycling on the transverse tensile strength
Adhésifs pour structures portantes en bois - Méthodes Klebstoffe für tragende Holzbauteile - Prüfverfahren -
d'essai - Partie 3 : Détermination de l'influence de Teil 3: Bestimmung des Einflusses von
l'attaque d'acide des fibres de bois, résultant de Säureschädigung der Holzfasern durch Temperatur-
traitements cycliques en température et humidité sur und Feuchtezyklen auf die Querzugfestigkeit
la résistance à la traction transversale
This European Standard was approved by CEN on 18 December 2022.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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, Türkiye 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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 302-3:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols . 7
5 Principle . 7
6 Apparatus . 7
7 Method . 7
7.1 Selection of timber . 7
7.2 Preparation of the bonded assemblies . 8
7.3 Preparation of the test pieces . 9
7.4 Number of test pieces .10
7.5 Climatic and cyclic storage conditions .10
7.6 Test procedure .10
8 Expression of results .11
9 Test report .11
9.1 The adhesive .11
9.2 Preparation of test pieces and testing procedures .11
9.3 Test results .12

European foreword
This document (EN 302-3:2023) has been prepared by Technical Committee CEN/TC 193 “Adhesives”,
the secretariat of which is held by UNE.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2023, and conflicting national standards shall be
withdrawn at the latest by August 2023.
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.
This document supersedes EN 302-3:2017.
The main changes compared to the previous edition are listed below:
a) two new standards, EN 17334 and EN 17418, have been included in the list of standards in the
Introduction;
b) two new Clauses (Terms and definitions and Symbols) have been introduced.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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 the United
Kingdom.
Introduction
This document is one of a series dealing with adhesives for use with timber structures, and is published
in support of the EN 1995 series, Eurocode 5: Design of timber structures. The series consists of five
classification and performance requirements for adhesives for load-bearing timber structures, phenolic
and aminoplastic adhesives (EN 301), one component polyurethane adhesives (EN 15425), emulsion
polymer isocyanate adhesives (EN 16254), two component epoxy and polyurethane adhesives for glued
in rods (EN 17334) and for on-site repair of cracked timber structures (EN 17418), and all together
twelve test methods (EN 302-1, EN 302-2, EN 302-3, EN 302-4, EN 302-5, EN 302-6, EN 302-7, EN 302-8,
EN 15416-1, EN 15416-3, EN 15416-4 and EN 15416-5).
These European standards have the following titles.
EN 301, Adhesives, phenolic and aminoplastic, for load-bearing timber structures — Classification and
performance requirements
EN 302, Adhesives for load-bearing timber structures — Test methods:
— Part 1: Determination of longitudinal tensile shear strength
— Part 2: Determination of resistance to delamination
— Part 3: Determination of the effect of acid damage to wood fibres by temperature and humidity cycling
on the transverse tensile strength
— Part 4: Determination of the effects of wood shrinkage on the shear strength
— Part 5: Determination of maximum assembly time under referenced conditions
— Part 6: Determination of the minimum pressing time under referenced conditions
— Part 7: Determination of the working life under referenced conditions
— Part 8: Static load test of multiple bond line specimens in compression shear
EN 15416, Adhesives for load bearing timber structures other than phenolic and aminoplastic — Test
methods:
— Part 1: Long-term tension load test perpendicular to the bond line at varying climate conditions with
specimens perpendicular to the glue line (Glass house test)
— Part 3: Creep deformation test at cyclic climate conditions with specimens loaded in bending shear
— Part 4: Determination of open assembly time under referenced conditions
— Part 5: Determination of minimum pressing time under referenced conditions
EN 15425, Adhesives — One component polyurethane (PUR) for load-bearing timber structures —
Classification and performance requirements
EN 16254, Adhesives — Emulsion polymer isocyanate (EPI) for load-bearing timber structures —
Classification and performance requirements
EN 17334, Glued-in rods in glued structural timber products — Testing, requirements and bond shear
strength classification
EN 17418, Two-component epoxy and polyurethane adhesives for on-site repair of cracked timber
structures — Testing, requirements and repair strength verification
Safety statement
Persons using this document should be familiar with the normal laboratory practice, if applicable. This
document cannot address all of the safety problems, if any, associated with its use. It is the responsibility
of the user to establish appropriate safety and health practices and to ensure compliance with any
regulatory conditions.
Environmental statement
It is understood that some of the material permitted in this standard can have a negative environmental
impact. As technological advantages lead to better alternatives for these materials, they will be eliminated
from this document to the greatest extent possible.
At the end of the test, it is recommended that the users of the standard take care to carry out an
appropriate disposal of the wastes, according to local regulations.
1 Scope
This document specifies a method for determining the effect on bond strength of damage to wood fibres
caused by the action of acids from the adhesive or primer used in the gluing process during climatic
cycling.
It is applicable to the following applications:
a) for assessing the compliance of adhesives with EN 301, EN 15425 and EN 16254;
b) for assessing the suitability and quality of adhesives for load-bearing timber structures;
c) for determining if the adhesive after bonding has a damaging influence on the strength of the wood
due to chemical action.
This test is intended primarily to obtain performance data for the classification of adhesives for load-
bearing timber structures according to their suitability for use in defined climatic environments. This test
is carried out on Norway spruce (Picea abies L.) or Beech (Fagus sylvatica L.).
This method is not intended to provide data for structural design and does not necessarily represent the
performance of the bonded member in service.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes require
...