EN 18070:2025

Performance of wood adhesives exposed to high temperatures with regard to behaviour of load-bearing timber structures in fire - Test method, evaluation and classification

This document specifies a test method for comparing the compression shear strength of adhesive bonds in wood and solid wood after exposure to a target temperature for a specified duration of time.
This document is applicable to adhesives used in load bearing timber structures.
This document is not applicable to Epoxy- and two component Polyurethane-adhesives.
This method is intended to obtain data for the performance of wood adhesives at very high temperatures. The result of this comparison can be used to classify the adhesive with regard to the behaviour of load-bearing timber structures in fire.

Leistungsfähigkeit von hohen Temperaturen ausgesetzten Holzklebstoffen in Bezug auf das Verhalten tragender Holzbauteile im Brandfall - Prüfverfahren, Bewertung und Klassifizierung

Dieses Dokument legt ein Prüfverfahren zum Vergleich der Druck-Scherfestigkeit von Klebfugen in Holz und Vollholz nach der Einwirkung einer Solltemperatur für eine festgelegte Zeitspanne fest.
Dieses Dokument ist anwendbar für Klebstoffe, die für tragende Holzbauteile verwendet werden.
Dieses Dokument ist nicht anwendbar für Epoxid- und Zwei-Komponenten-Polyurethan-Klebstoffe.
Dieses Verfahren ist dafür vorgesehen, Leistungsdaten von Holzklebstoffen bei stark erhöhten Temperaturen zu erhalten. Das Ergebnis dieses Vergleichs kann zur Klassifizierung des Klebstoffs im Hinblick auf das Verhalten tragender Holzbauteile im Brandfall verwendet werden.

Performance des adhésifs pour bois exposés à des températures élevées en ce qui concerne le comportement des structures porteuses en bois en situation d’incendie - Méthode d’essai, évaluation et classification

Le présent document spécifie une méthode d'essai visant à comparer la résistance au cisaillement par compression de joints de colle dans du bois et du bois massif après exposition à une température cible pendant une durée spécifiée.
Ce document s'applique aux adhésifs utilisés sur des structures portantes en bois.
Il n’est pas applicable aux adhésifs époxy ni aux adhésifs polyuréthane bicomposants.
Cette méthode vise à obtenir des données relatives aux performances des adhésifs pour bois à des températures très élevées. Le résultat de cette comparaison peut être utilisé pour attribuer à l’adhésif une classe concernant le comportement des structures porteuses en bois en situation d’incendie.

Delovanje lepil za les pri visokih temperaturah in požaru - Preskusne metode, vrednotenje in razvrščanje

Ta dokument določa preskusno metodo za primerjavo tlačne strižne trdnosti sprijetih lepil v lesu in masivnega lesa po izpostavljenosti ciljni temperaturi za določen čas. Ta dokument se uporablja za lepila za nosilne lesene konstrukcije. Ne uporablja se za epoksi lepila in dvokomponentna poliuretanska lepila. Ta metoda je namenjena pridobivanju podatkov o učinkovitosti lepil za les pri zelo visokih temperaturah. Rezultat te primerjave je mogoče uporabiti za razvrščanje lepila glede na obnašanje nosilnih lesenih konstrukcij v primeru požara.

General Information

• Status: Published
• Publication Date: 29-Jul-2025
• ICS: 79.040 - Wood, sawlogs and sawn timber
• ICS: 79.060.99 - Other wood-based panels
• ICS: 83.180 - Adhesives
• Technical Committee: CEN/TC 193 - Adhesives
• Drafting Committee: CEN/TC 193/SC 1/WG 13 - Fire behaviour
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 30-Jul-2025
• Due Date: 06-Mar-2026
• Completion Date: 30-Jul-2025
• Ref Project: SIST EN 18070:2025 - Performance of wood adhesives at high temperatures and fire - Test methods, evaluation and classification.

Overview

EN 18070:2025 is a European standard developed by CEN that specifies a test method to assess the performance of wood adhesives under high-temperature exposure, with a focus on their behavior in load-bearing timber structures during fire incidents. This standard provides a systematic approach for evaluating the compression shear strength of adhesive bonds in wood after exposure to elevated temperatures. It excludes epoxy and two-component polyurethane adhesives and targets adhesives used specifically in structural timber applications. The results of testing according to this standard enable classification of adhesives based on their fire performance, supporting safe and reliable construction practices.

Key Topics

• Test Methodology
  The standard defines a compression shear strength test for bonded timber samples exposed to specified high temperatures for defined durations. Test pieces consist of both solid wood and adhesive-bonded wood blocks, allowing comparative evaluation.

• Temperature Classes
  Adhesives are assessed at predetermined test temperatures-200°C, 220°C, 232°C, and 270°C-enabling classification according to their suitability and performance at these thermal stresses.

• Test Piece Preparation
  Test blocks are prepared from Norway spruce with controlled density and moisture content to ensure consistency. The adhesive bonding process follows strict preparation protocols including conditioning, planing, and precise lamination to replicate realistic timber structure conditions.

• Measurement and Instruments
  The standard specifies the use of climate chambers or ovens with precise temperature control (±2°C), thermocouples placed directly in the bond line or solid wood center for accurate temperature monitoring, and testing machines capable of block shear testing with ±1% load accuracy.

• Evaluation and Classification
  Data from shear tests on heated bonded and solid wood pieces are used to calculate the relative compression shear strength. This ratio serves as a basis for classifying adhesives in relation to their fire resistance in structural timber applications.

Applications

EN 18070:2025 is essential for manufacturers, testers, and engineers involved in the design, production, and certification of wood adhesives used in load-bearing timber structures. Key practical applications include:

• Fire Safety Assessment
  Testing adhesives per EN 18070 offers critical data to predict and improve timber structure performance under fire conditions, helping architects and engineers design safer buildings.

• Quality Control
  Adhesive producers utilize this standard to develop formulations optimized for high-temperature durability and to assure consistent product quality in fire-resistant applications.

• Regulatory Compliance
  The classification of adhesives according to this standard supports compliance with European regulations on fire safety in construction materials and aids in meeting national building codes.

• Material Selection Guidance
  Construction professionals rely on EN 18070 results to choose adhesives that maintain structural integrity in fire scenarios, thus enhancing the overall fire resilience of timber structures.

Related Standards

• EN 923: Adhesives - Terms and Definitions
  Provides foundational terminology relevant to wood adhesive testing and classification.

• EN 14080:2013: Timber Structures - Glued Laminated Timber and Glued Solid Timber - Requirements
  Details requirements and test methods for glued timber, including the block shear test referenced in EN 18070.

• Additional Fire Safety Standards for Timber Structures
  EN 18070 complements other European fire safety regulations and standards related to structural timber, helping create an integrated safety framework for wood building components.

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By applying EN 18070:2025, stakeholders in the wood construction industry ensure that adhesives used in load-bearing timber meet rigorous fire performance criteria. This enhances structural safety, supports regulatory adherence, and promotes confidence in wood as a sustainable and resilient building material.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2025
Delovanje lepil za les pri visokih temperaturah in požaru - Preskusne metode,
vrednotenje in razvrščanje
Performance of wood adhesives at high temperatures and fire - Test methods,
evaluation and classification.
Leistungseigenschaften von Holzklebstoffen bei hohen Temperaturen und im Brandfall -
Prüfverfahren, Bewertung und Klassifizierung
Performances des adhésifs pour bois à hautes températures et au feu - Méthodes
d’essai, évaluation et classification
Ta slovenski standard je istoveten z: EN 18070:2025
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
83.180 Lepila Adhesives
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 18070
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2025
EUROPÄISCHE NORM
ICS 79.040; 83.180
English Version
Performance of wood adhesives exposed to high
temperatures with regard to behaviour of load-bearing
timber structures in fire - Test method, evaluation and
classification
Performance des adhésifs pour bois exposés à des Leistungsfähigkeit von hohen Temperaturen
températures élevées en ce qui concerne le ausgesetzten Holzklebstoffen in Bezug auf das
comportement des structures porteuses en bois en Verhalten tragender Holzbauteile im Brandfall -
situation d'incendie - Méthode d'essai, évaluation et Prüfverfahren, Bewertung und Klassifizierung
classification
This European Standard was approved by CEN on 23 June 2025.

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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 18070:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Apparatus . 5
5.1 Test jig . 5
5.2 Climate chamber or oven . 5
5.3 Thermocouples . 5
5.4 Testing machine . 6
6 Test pieces . 6
6.1 Selection of wood . 6
6.2 Preparation of test pieces . 6
7 Procedure . 9
7.1 Number of test pieces . 9
7.2 Test temperature . 9
7.3 Temperature treatment before the shear test . 9
7.4 Performance of the shear tests . 10
7.5 Evaluation of result . 10
8 Requirements . 11
9 Test report . 11
Bibliography . 12

European foreword
This document (EN 18070:2025) 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 January 2026, and conflicting national standards shall
be withdrawn at the latest by January 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.
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
Safety statement
Persons using this document are to 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 can 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, the user of the document should take care to carry out an appropriate disposal of
the wastes, see local regulation for additional guidance.
1 Scope
This document specifies a test method for comparing the compression shear strength of adhesive bonds
in wood and solid wood after exposure to a target temperature for a specified duration of time.
This document is applicable to adhesives used in load bearing timber structures.
This document is not applicable to Epoxy- and two component Polyurethane-adhesives.
This method is intended to obtain data for the performance of wood adhesives at very high
temperatures. The result of this comparison can be used to classify the adhesive with regard to the
behaviour of load-bearing timber structures in fire.
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 923, Adhesives - Terms and definitions
EN 14080:2013, Timber structures - Glued laminated timber and glued solid timber - Requirements
3 Terms and definitions
For the purposes of this document the terms and definitions given in EN 923 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/
4 Principle
Adhesively bonded test pieces and solid wood test pieces are prepared. Both types of test pieces are
tested in a compression shear test according to EN 14080:2013, Annex D, after exposure to a test
temperature T. The ratio of compression shear strength of the adhesively bonded test pieces and the
solid wood test pieces is evaluated.
5 Apparatus
5.1 Test jig
Test equipment as specified in EN 14080:2013, Annex D for the performance of the shear test.
5.2 Climate chamber or oven
A climate chamber or oven for the heating of the test pieces, capable of maintaining the test
temperature T in the test piece within ±2 °C and having a sufficient air circulation to provide the
required temperature within the oven volume.
5.3 Thermocouples
Thermocouples capable of measuring the temperature in the test pieces to within ±2 °C. The recording
equipment shall have the same or smaller tolerances.
5.4 Testing machine
A testing machine with an accuracy of ±1 % of the load, capable of performing the block shear test
specified in EN 14080:2013, Annex D.
6 Test pieces
6.1 Selection of wood
Norway spruce (Picea abies L.) with a density of (450 ± 15) kg/m at 12 % moisture content shall be
used.
The material shall be straight-grained and preferably free from knots, reaction wood, machining defects
(such as chipped grain, dubbed ends, feed roll polish, coarse knife marks and feed roll compression) and
any drying defects such as case hardening, collapse, splits or checks. The raw material for the
preparation of the test pieces shall have dimensions of at least 60 mm (width) × 50 mm (height) and a
length of at least 800 mm.
The angle of the annual rings to the surface, as measured from the wide face, shall be between 45° and
90°.
6.2 Preparation of test pieces
The wood shall be conditioned at (20 ± 2) °C and a relative humidity of (65 ± 5) % until a moisture
content of (12 ± 1) % has been obtained.
Plane each lamination not more than 8 h before the bonding of the test pieces.
Solid wood block shear test pieces and adhesively bonded block shear test pieces shall be produced. To
ensure that all test pieces have a comparable wood quality, the solid wood test pieces and the
adh
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