SIST EN 302-8:2023+A1:2026
(Main + Amendment)Adhesives for load-bearing timber structures - Test methods - Part 8: Static load test of multiple bond line specimens in compression shear
- Abstract
This document specifies a method of determining the ability of adhesive bonds to resist static load. It is applicable to adhesives used in load bearing timber structures.
It is applicable for the following applications:
a) for assessing the compliance of adhesives according to EN 301, EN 15425, EN 16254, EN 17334 and EN 17418;
b) for assessing the suitability and quality of adhesives for load-bearing timber structures;
c) for assessing the effect on the bond strength resulting from constant load at different climate conditions.
This method 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 method is not intended to provide data for structural design and does not necessarily represent the performance of the bonded member in service.
- Status
- Published
- Publication Date
- 17-Jun-2026
- Technical Committee
- IPMA - Polimer materials and products
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 11-Jun-2026
- Due Date
- 16-Aug-2026
- Completion Date
- 18-Jun-2026
SIST EN 302-8:2023+A1:2026 is the Slovenian adoption of EN 302-8:2023+A1:2026 from CEN. It specifies a laboratory method for checking how adhesive bonds in load-bearing timber structures resist a static load in compression shear under defined climate conditions. Manufacturers, test laboratories, and certification or quality teams use it to assess adhesive compliance, suitability, and performance data for timber-structure applications.
What does SIST EN 302-8:2023+A1:2026 specify?
SIST EN 302-8:2023+A1:2026 specifies one test method and the specimen preparation needed for it. The method is used on adhesives for load-bearing timber structures, mainly to compare adhesive performance under constant load in different climates.
| Clause | What it covers |
|---|---|
| 1 | Scope and intended use |
| 2 | Normative references |
| 3 | Terms and definitions |
| 4 | Principle of the test |
| 5 | Apparatus |
| 6 | Test specimens |
| 7 | Test procedure |
| 8 | Test report |
The standard is intended for assessing compliance with EN 301, EN 15425, EN 16254, EN 17334 and EN 17418, and for judging adhesive suitability and quality. It is not intended for structural design calculations, and the results do not necessarily represent service performance of a bonded member.
What are the key requirements of SIST EN 302-8:2023+A1:2026?
The core requirement in SIST EN 302-8:2023+A1:2026 is that bonded specimens are loaded in compression shear and then exposed to a sequence of controlled climates. The test records failures and deformation, so the reader gets an indication of how the adhesive bond behaves when load and environment act together.
Test principle and apparatus
Clause 4 states that the specimens are held under constant compression shear load through three climate stages. This matters because the test is aimed at durability under sustained stress, not short-term bond strength alone.
Clause 5 requires a test jig, climate-control equipment, and a testing machine capable of applying compression load. The jig geometry and spring arrangement are defined in figures, so labs need to build or verify the fixture carefully to get comparable results. If the jig or climate chamber is not suitable, the comparison between adhesives becomes unreliable.
Specimen material and preparation
Clause 6 requires untreated beech wood, Fagus sylvatica L., with the specified density at 12 % moisture content, straight grain, and no major wood defects. The annual ring angle to the bonded surface is also controlled. In practice, this limits wood-related variation so the adhesive is what the test is measuring.
The standard covers both close contact glue lines and thick glue lines. For close contact glue lines, the wood is conditioned in climate [20/65], planed shortly before gluing, and assembled into laminated members that are later trimmed into six test specimens. For thick glue lines, two production routes are given:
- Method A uses a middle layer built from alternating wood pieces and removable spacers.
- Method B uses a solid wood middle layer, a two-step bonding operation, and grooving before the second bond.
Method B also calls for a PRF adhesive of type to EN 301-I-90-GP-0,6-M in the second bonding step. For the reader, this means the specimen build-up is not arbitrary - the method fixes the way the thick bond line is created and stabilized before testing.
Load application and climate cycle
Clause 7 requires the specimens to be loaded in the jig and brought to the total load within a defined short time, then held in the climatic chamber. The loaded specimens are exposed to one of the high-temperature low-humidity climate cycles 1a to 1d, followed by climate 2 and climate 3.
The sequence and timing matter because the method is looking at bond performance after sustained load in changing climates. The standard also requires the climate treatment to start soon after loading, and any transfer between climates to avoid shock or vibration.
Measurement and evaluation
Clause 7 requires weekly checks for failures and, after the full test period, unloading and measurement of slippage if enough specimens remain intact. Slippage is measured across razor-blade marks to the nearest 0,01 mm and averaged. In practice, this gives a repeatable deformation measure that shows how much the adhesive bond moved under load.
Reporting
Clause 8 requires the report to identify the adhesive, the wood, the bonding procedure, the conditioning times, the nominal glue-line thickness, the climate in which failure occurred, the slippage results, the measurement method, and any other factor that may have influenced the outcome. This is what allows the test to be compared, audited, or used in qualification work.
What terms does SIST EN 302-8:2023+A1:2026 define?
- Glue line - The adhesive layer between the wood members.
- Thick glue line - A glue line with nominal thickness in the range of 0,5 mm to 2,0 mm at the time of bonding; it is used to study adhesive behavior in thicker joints.
- Close contact glue line - A glue line with a thickness of at most 0,1 mm; it represents a very tight bond line made without added spacers.
- Slippage - The deformation measured across the blade marks after unloading; it is the main output used to judge bond movement under the test load.
Who uses SIST EN 302-8:2023+A1:2026?
SIST EN 302-8:2023+A1:2026 is used by adhesive manufacturers, testing laboratories, certification bodies, and quality managers working with load-bearing timber structures. It is relevant where adhesives must be checked for compliance with EN 301, EN 15425, EN 16254, EN 17334, or EN 17418, or where performance data are needed for classification in climatic environments. It also supports work linked to the EN 1995 series, Eurocode 5: Design of timber structures.
What changed in SIST EN 302-8:2023+A1:2026 from the previous edition?
The foreword states that EN 302-8:2023, compared with EN 302-8:2017, added testing of test pieces with bond line thicknesses of 0,5 mm, 1 mm and 2 mm. It also states that Clause 8 Test report and the Bibliography were deleted in that 2023 edition.
Which standards are used with SIST EN 302-8:2023+A1:2026?
| Standard | What it contributes |
|---|---|
| EN 923 | Terms and definitions for adhesives |
| EN 384:2016+A2:2022 | Wood density and moisture content information used in reporting |
| EN 301 | Classification and performance requirements for phenolic and aminoplastic adhesives; also the reference family for a climate cycle and the PRF adhesive type used in Method B |
| EN 15425 | Classification and performance requirements for one component polyurethane adhesives |
| EN 16254 | Classification and performance requirements for emulsion polymer isocyanate adhesives |
| EN 17334 | Testing, requirements and bond shear strength classification for glued-in rods |
| EN 17418 | Testing, requirements and repair strength verification for on-site repair adhesives |
| EN 302-1 to EN 302-7 | Other adhesive test methods in the same EN 302 series |
| EN 15416-1, EN 15416-3, EN 15416-4, EN 15416-5 | Related test methods for other adhesive classes used with timber structures |
What does the SIST EN 302-8:2023+A1:2026 document contain?
The document contains the test principle, fixture and machine requirements, specimen preparation routes, climate-conditioning requirements, and the loading and evaluation procedure. It also includes figures for the jig, specimen build-up, spacer frames, grooving and final specimen shape, plus a table for the climate treatment cycle. For users, these visuals are what make the method reproducible in a lab, from specimen manufacture through to measurement of slippage and failure.
Relations
- Effective Date
- 18-Mar-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 24-Jun-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
- Effective Date
- 18-Mar-2026
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Frequently Asked Questions
SIST EN 302-8:2023+A1:2026 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Adhesives for load-bearing timber structures - Test methods - Part 8: Static load test of multiple bond line specimens in compression shear". This standard covers: This document specifies a method of determining the ability of adhesive bonds to resist static load. It is applicable to adhesives used in load bearing timber structures. It is applicable for the following applications: a) for assessing the compliance of adhesives according to EN 301, EN 15425, EN 16254, EN 17334 and EN 17418; b) for assessing the suitability and quality of adhesives for load-bearing timber structures; c) for assessing the effect on the bond strength resulting from constant load at different climate conditions. This method 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 method is not intended to provide data for structural design and does not necessarily represent the performance of the bonded member in service.
This document specifies a method of determining the ability of adhesive bonds to resist static load. It is applicable to adhesives used in load bearing timber structures. It is applicable for the following applications: a) for assessing the compliance of adhesives according to EN 301, EN 15425, EN 16254, EN 17334 and EN 17418; b) for assessing the suitability and quality of adhesives for load-bearing timber structures; c) for assessing the effect on the bond strength resulting from constant load at different climate conditions. This method 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 method is not intended to provide data for structural design and does not necessarily represent the performance of the bonded member in service.
SIST EN 302-8:2023+A1:2026 is classified under the following ICS (International Classification for Standards) categories: 83.180 - Adhesives; 91.080.20 - Timber structures. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 302-8:2023+A1:2026 has the following relationships with other standards: It is inter standard links to SIST EN 302-8:2023, SIST EN 301:2023+A1:2026, SIST EN 15425:2023+A1:2026, SIST EN 384:2016+A2:2022, SIST EN 923:2016, SIST EN 16254:2014, SIST EN 17334:2021, SIST EN 16254:2014+A1:2016, SIST EN 17418:2021, SIST EN 15425:2009, SIST EN 15425:2023, SIST EN 16254:2023, SIST EN 301:2023, SIST EN 301:2018. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
SIST EN 302-8:2023+A1:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2026
Lepila za nosilne lesene konstrukcije - Preskusne metode - 8. del: Preskus statične
obremenitve preskušancev z več lepljenimi spoji pri tlačni strižni obremenitvi
(vključno z dopolnilom A1)
Adhesives for load-bearing timber structures - Test methods - Part 8: Static load test of
multiple bond line specimens in compression shear
Klebstoffe für tragende Holzbauteile - Prüfverfahren - Teil 8: Statische
Belastungsprüfung an Prüfkörpern mit mehreren Klebfugen bei Druck-
Scherbeanspruchung
Adhésifs pour structures portantes en bois - Méthodes d'essai - Partie 8 : Essai de
charge statique d'éprouvettes à joints de colle multiples en cisaillement par compression
Ta slovenski standard je istoveten z: EN 302-8:2023+A1:2026
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 302-8:2023+A1
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 83.180 Supersedes EN 302-8:2023
English Version
Adhesives for load-bearing timber structures - Test
methods - Part 8: Static load test of multiple bond line
specimens in compression shear
Adhésifs pour structures portantes en bois - Méthodes Klebstoffe für tragende Holzbauteile - Prüfverfahren -
d'essai - Partie 8 : Essai de charge statique Teil 8: Statische Belastungsprüfung an Prüfkörpern mit
d'éprouvettes à joints de colle multiples en cisaillement mehreren Klebfugen bei Druck-Scherbeanspruchung
par compression
This European Standard was approved by CEN on 18 December 2022 and includes Amendment 1 approved by CEN on 3 April
2026.
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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 302-8:2023+A1:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Principle . 7
5 Apparatus . 7
5.1 Test jig . 7
5.2 Equipment for climate control . 10
5.3 Testing machine . 10
6 Test specimens . 10
6.1 Selection of wood . 10
6.2 Preparation of the laminated members . 10
6.2.1 Test pieces with close contact glue line . 10
6.3 Preparation of test specimens . 17
7 Test procedure . 18
7.1 Application of load . 18
7.2 Test climates . 19
7.3 Measurements and evaluation of result . 19
8 Test report . 19
8.1 The adhesives . 19
8.2 Preparation of test pieces and testing procedure . 20
8.3 Test results . 20
European foreword
This document (EN 302-8:2023+A1:2026) 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 December 2026, and conflicting national standards
shall be withdrawn at the latest by December 2026.
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 includes Amendment 1 approved by CEN on 3 April 2026.
This document supersedes !EN 302-8:2023".
The start and finish of text introduced or altered by amendment is indicated in the text by tags !".
The main changes in EN 302-8:2023 compared to the previous edition EN 302-8:2017 are listed below:
a) test of test pieces with bond line thickness 0,5 mm, 1 mm and 2 mm has been included in the
document;
b) Clause 8 Test report has been deleted;
c) the Bibliography has been deleted.
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 document may have negative environmental
impact. As technological advantages lead to better alternatives for these materials, they will be
eliminated from this document to the extent possible.
At the end of the test, it is recommended that the users of this document take care to carry out an
appropriate disposal of the wastes, according to local regulation.
1 Scope
This document specifies a method of determining the ability of adhesive bonds to resist static load. It is
applicable to adhesives used in load bearing timber structures.
It is applicable for the following applications:
a) for assessing the compliance of adhesives according to EN 301, EN 15425, EN 16254, EN 17334 and
EN 17418;
b) for assessing the suitability and quality of adhesives for load-bearing timber structures;
c) for assessing the effect on the bond strength resulting from constant load at different climate
conditions.
This method 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 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 requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 301, Adhesives, phenolic and aminoplastic, for load-bearing timber structures — Classification and
performance requirements
EN 384:2016+A2:2022, Structural timber — Determination of characteristic values of mechanical
properties and density
EN 923, Adhesives — Terms and definitions
EN 15425, Adhesives — One component polyurethane (PUR) for load-bearing timber structures —
Classification and performance requirements
EN 16254, Adhesives — Emulsion polymerized 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
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 923 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
glue line
adhesive layer between the wood members
3.2
thick glue line
glue line of nominal thickness in the range of 0,5 mm to 2,0 mm at the time of bonding
Note 1 to entry: Thick glue lines are achieved by using spacers, grooves or similar devices when two plain
members are glued together.
3.3
close contact glue line
glue line of thickness maximum 0,1 mm
Note 1 to entry: Close contact glue line can be achieved by pressing together two plane wood members with a
clamping pressure of (0,8 ± 0,1) N/mm without additional grooves, spacers or similar devices.
4 Principle
Bonded test pieces are subjected to a constant compression shear load under a series of three different
climates. Number of failures and the amount of deformation is measured after the end of the last
climate cycle.
5 Apparatus
5.1 Test jig
The test equipment is shown in Figure 1 and Figure 2.
Dimensions in millimetres
Key
1 top plate
2 spacer plate
3 base plate
4 tension rod
5 centre rod
Figure 1 — Test jig
Dimensions in millimetres
Key
1 top plate 4 tension rod (the given lengths are minimum values)
2 spacer plate 5 centre rod (the given length is a minimum value)
3 base plate
Figure 2 — Nominal dimensions of plates and rods
If longer rods are used, distance blocks need to be placed on top and/or under the specimen. The
distance blocks shall be prepared in such a way that the two contact surfaces, between the distance
block and the jig and between the distance block and the specimen, are parallel. Dimension of distance
blocks: at least 48 mm × 51 mm × 10 mm.
NOTE 1 Blocks produced from several pieces of plywood bonded together have been found suitable.
The spring shall have the following characteristics:
— outside diameter (unloaded): 105 mm;
— end fix: both ends fixed and grounded;
— free length: 320 mm;
— compre
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