FprEN 16254

Adhesives - Emulsion polymer isocyanate (EPI) for load-bearing timber structures - Classification and performance requirements

This document establishes a classification for emulsion polymer isocyanate (EPI) adhesives according to their suitability for use in load-bearing timber products in defined climatic exposure conditions, and specifies performance requirements for such adhesives for the industrial manufacture of load-bearing timber products only.
The performance requirements of this document are applicable to the adhesives only, not to the timber products. This document does not cover the performance of adhesives for on-site gluing (except for factory-like conditions) or the production of wood-based panels, except solid wood panels, or modified and stabilized wood with considerably reduced swelling and shrinkage properties, e.g. acetylated wood, heat treated wood and polymer impregnated wood.
This document is primarily intended for use by adhesive manufacturers and for use in timber products bonded with adhesives, to assess or control the quality of adhesives. This document only specifies the performance of an adhesive for use in an environment corresponding to the defined conditions.
Such an adhesive meeting the requirements of this document for its type is adequate for use in load-bearing timber products, provided that the bonding process has been carried out according to an appropriate product standard.

Klebstoffe - Emulsionspolymerisiertes Isocyanat (EPI) für tragende Holzbauteile - Klassifizierung und Leistungsanforderungen

Dieses Dokument stellt eine Klassifizierung für Klebstoffe aus emulsionspolymerisiertem Isocyanat (EPI) entsprechend ihrer Eignung zur Verwendung für tragende Holzbauteile unter bestimmten Klimabedingungen auf und legt die Leistungsanforderungen für derartige Klebstoffe ausschließlich zur werksmäßigen Herstellung von tragenden Holzbauteilen fest.
Die Leistungsanforderungen in diesem Dokument sind lediglich für den Klebstoff, nicht für das Holzprodukt anzuwenden. Dieses Dokument behandelt weder das Leistungsverhalten von Klebstoffen für die Vor-Ort-Verklebung (ausgenommen bei werksähnlichen Bedingungen) noch die Produktion von Holzwerkstoffen, ausgenommen Massivholzplatten. Es ist nicht für modifiziertes und vergütetes Holz mit beträchtlich verringerten Quellungs- und Schwindungseigenschaften anzuwenden, wie z. B. acetyliertes Holz, wärmebehandeltes Holz und mit Kunstharz imprägniertes Holz.
Dieses Dokument ist in erster Linie für die Verwendung durch die Hersteller der Klebstoffe und der verklebten Holzprodukte bestimmt, um die Qualität von Klebstoffen zu beurteilen oder zu überprüfen. Dieses Dokument legt nur das Leistungsverhalten eines Klebstoffes fest, der in einer Umgebung Verwendung findet, die den festgelegten Bedingungen entspricht.
Klebstoffe, die die Anforderungen dieses Dokuments erfüllen, sind für den Einsatz in tragenden Holzbauteilen geeignet, vorausgesetzt, dass der Verklebungsvorgang nach einer entsprechenden Produktnorm vorgenommen wurde.

Adhésifs - Isocyanate de polymère en émulsion (EPI) pour structures portantes en bois - Classification et exigences de performance

Le présent document établit une classification des adhésifs isocyanate de polymère en émulsion (EPI) en fonction de leur aptitude à l’emploi dans les structures portantes en bois dans des conditions d’exposition climatique définies, et spécifie les exigences de performance applicables à ces adhésifs uniquement lorsqu’ils sont utilisés pour la fabrication en usine de structures portantes en bois, ou dans des conditions semblables à la fabrication en usine.
Les exigences relatives à la performance définies dans le présent document ne s’appliquent qu’aux adhésifs et non aux produits en bois. Le présent document ne couvre pas la performance des adhésifs utilisés pour le collage sur site (à l’exception des conditions semblables à la fabrication en usine) ou pour la fabrication de panneaux à base de bois, à l’exception des panneaux en bois massif, ou pour le bois modifié et stabilisé ayant une propension considérablement réduite au gonflement et au retrait, par exemple le bois acétylé, le bois traité à la chaleur et le bois imprégné de polymère.
Le présent document s’adresse avant tout aux fabricants d’adhésifs pour leur permettre, dans le domaine des produits en bois collés, d’évaluer ou de contrôler la qualité des adhésifs. Le présent document spécifie la performance d’un adhésif uniquement dans l’environnement correspondant aux conditions définies.
Un adhésif répondant aux exigences du présent document relatives à son type peut être utilisé dans des structures portantes en bois, à condition que le processus de collage ait été réalisé conformément à une norme de produit appropriée.

Lepila - Emulzijsko polimerizirani izocianat (EPI) za nosilne lesene konstrukcije - Razvrstitev in zahtevane lastnosti

General Information

• Status: Not Published
• Publication Date: 30-Aug-2023
• ICS: 83.180 - Adhesives
• Technical Committee: CEN/TC 193 - Adhesives
• Drafting Committee: CEN/TC 193/SC 1 - Adhesives for wood and derived timber products
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 18-Dec-2022
• Due Date: 22-Jul-2023
• Completion Date: 18-Dec-2022
• Ref Project: kSIST FprEN 16254:2022 - Adhesives - Emulsion polymerized isocyanate (EPI) for load-bearing timber structures - Classification and performance requirements

Relations

• Revises: EN 16254:2013+A1:2016 - Adhesives - Emulsion polymerized isocyanate (EPI) for load-bearing timber structures - Classification and performance requirements
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 16254:2022
01-marec-2022

Lepila - Emulzijsko polimerizirani izocianat (EPI) za nosilne lesene konstrukcije -

Razvrstitev in zahtevane lastnosti

Adhesives - Emulsion polymerized isocyanate (EPI) for load-bearing timber structures -

Classification and performance requirements

Klebstoffe - Emulsionspolymerisiertes Isocyanat (EPI) für tragende Holzbauteile -

Klassifizierung und Leistungsanforderungen

Adhésifs - Isocyanate polymérisé en émulsion (EPI) pour structures portantes en bois -

Classification et exigences de performance
Ta slovenski standard je istoveten z: prEN 16254
ICS:
83.180 Lepila Adhesives
91.080.20 Lesene konstrukcije Timber structures
oSIST prEN 16254:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 16254:2022
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oSIST prEN 16254:2022
DRAFT
EUROPEAN STANDARD
prEN 16254
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2021
ICS 83.180 Will supersede EN 16254:2013+A1:2016
English Version
Adhesives - Emulsion polymerized isocyanate (EPI) for
load-bearing timber structures - Classification and
performance requirements

Adhésifs - Isocyanate polymérisé en émulsion (EPI) Klebstoffe - Emulsionspolymerisiertes Isocyanat (EPI)

pour structures portantes en bois - Classification et für tragende Holzbauteile - Klassifizierung und

exigences de performance Leistungsanforderungen

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 193.

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 16254:2021 E

worldwide for CEN national Members.
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oSIST prEN 16254:2022
prEN 16254:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 7

4 Classification ..................................................................................................................................................... 8

5 Requirements ................................................................................................................................................ 10

5.1 General ............................................................................................................................................................. 10

5.2 Bond strength in longitudinal tensile shear test .............................................................................. 11

5.3 Resistance to delamination ...................................................................................................................... 12

5.4 Tensile strength perpendicular to the bond line after climatic treatment (acid

damage test) ................................................................................................................................................... 13

5.5 Effect of wood shrinkage on the shear strength................................................................................ 13

5.6 Static load test of multiple bond line specimens in compression shear .................................. 13

5.7 Creep deformation test at cyclic climate conditions with specimens loaded in

bending shear ................................................................................................................................................ 13

5.8 Long term sustained load test at cyclic climate conditions with specimens loaded

perpendicular to the bond line (“Glass house test”) ....................................................................... 13

5.9 Delamination test on finger-jointed test pieces ................................................................................ 13

6 Test methods ................................................................................................................................................. 13

6.1 General ............................................................................................................................................................. 13

6.2 Determination of bond strength in longitudinal tensile shear test ........................................... 13

6.3 Determination of resistance to delamination .................................................................................... 14

6.4 Determination of tensile strength perpendicular to the bond line after climatic

treatment (acid damaged test) ................................................................................................................ 14

6.5 Determination of the effect of wood shrinkage on the shear strength ..................................... 15

6.6 Static load test of multiple bond line specimens in compression shear .................................. 15

6.7 Creep deformation test with specimens loaded in bending shear ............................................. 16

6.8 Long term sustained load test at cyclic climate conditions with specimens loaded

perpendicular to the bond line (“Glass house test”) ....................................................................... 16

6.9 Delamination test on finger-jointed test pieces ................................................................................ 16

7 Working properties of the adhesive ...................................................................................................... 16

7.1 General ............................................................................................................................................................. 16

7.2 Determination of working life under reference conditions ......................................................... 16

7.3 Determination of open assembly time under reference conditions.......................................... 16

7.4 Determination of pressing time under reference conditions ...................................................... 16

8 Marking and labelling ................................................................................................................................. 16

Annex A (normative) Delamination test for bonding of finger-joints .................................................... 17

A.1 Production of the specimens .................................................................................................................... 17

A.2 Testing .............................................................................................................................................................. 18

A.3 Expression of results ................................................................................................................................... 18

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Annex B (informative) Product limitations and glulam production control for beams

produced with Small Dimension adhesives ........................................................................................ 19

B.1 Product limitations ...................................................................................................................................... 19

B.2 Control of the glue line thickness ........................................................................................................... 19

Bibliography ................................................................................................................................................................. 20

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oSIST prEN 16254:2022
prEN 16254:2021 (E)
European foreword

This document (prEN 16254:2021) has been prepared by Technical Committee CEN/TC 193 “Adhesives”,

the secretariat of which is held by UNE.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 16254:2013+A1:2016.
Compared to EN 16254:2013+A1:2016, the following main changes have been made:
a) designation of adhesive types modified and aligned with EN 301 and EN 15425;
b) reference to EN 15426-2 replaced by reference to EN 302-8;

c) for the delamination test according to EN 302-2 with preservative treated wood a test with Scots

pine (Pinus sylvestris) and Silver fir (Abieas alba) covers also Norway spruce (Picea abies L.);

d) for adhesive type FJ the test according to EN 302-2 is required only with short closed assembly time,

and the test according to EN 15416-5 is only required with thin glue line;

e) Annex A on storage treatments for tests according to EN 302-1 deleted and replaced by reference to

EN 302-1, the storage time for the temperature treatment (A6, A7, A8) are therefore reduced from

72 h to 24 h;

f) for bonding of finger joints in additional wood species the test according to EN 302-2 may be replaced

by the delamination test on finger-joints from EN 301 which is specified as new Annex A.

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oSIST prEN 16254:2022
prEN 16254:2021 (E)
Introduction

This document is one of a series dealing with emulsion polymerized isocyanate (EPI) adhesives for use

with timber structures, and is published in support of product standards for bonded load-bearing timber

structures.
The series consists of:
— one standard for classification and performance requirements (EN 16254);

— eight test methods (EN 302-1, EN 302-2, EN 302-3, EN 302-4, EN 302-8, EN 15416-1, EN 15416-3

and the test method given in Annex A of this document (“finger-joint delamination test”) used to

assess the performance of adhesives after specified heat and humidity treatments; and

— three test methods (EN 302-7, EN 15416-4 and EN 15416-5) to characterize the working properties

of the adhesive.
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oSIST prEN 16254:2022
prEN 16254:2021 (E)
1 Scope

This document establishes a classification for emulsion polymerized isocyanate (EPI) adhesives

according to their suitability for use in load-bearing timber products in defined climatic exposure

conditions, and specifies performance requirements for such adhesives for the industrial manufacture of

load-bearing timber products only.

The performance requirements of this document apply to the adhesives only, not to the timber products.

This document does not cover the performance of adhesives for on-site gluing (except for factory-like

conditions) nor the production of wood-based panels, except solid wood panels, or modified and

stabilized wood with considerably reduced swelling and shrinkage properties, e.g. such as acetylated

wood, heat treated wood and polymer impregnated wood.

This document is primarily intended for the use of adhesive manufacturers and for the use in timber

products bonded with adhesives, to assess or control the quality of adhesives. This document only

specifies the performance of an adhesive for use in an environment corresponding to the defined

conditions.

Such an adhesive meeting the requirements of this document for its type is adequate for use in load-

bearing timber products, provided that the bonding process has been carried out according to an

appropriate product standard.
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 302-1, Adhesives for load-bearing timber structures - Test methods - Part 1: Determination of

longitudinal tensile shear strength

EN 302-2, Adhesives for load-bearing timber structures - Test methods - Part 2: Determination of resistance

to delamination

EN 302-3, 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

EN 302-4, Adhesives for load-bearing timber structures - Test methods - Part 4: Determination of the effects

of wood shrinkage on the shear strength

EN 302-7, Adhesives for load-bearing timber structures - Test methods - Part 7: Determination of the

working life under referenced conditions

EN 302-8, Adhesives for load-bearing timber structures - Test methods - Part 8: Static load test of multiple

bond line specimens in compression shear
EN 923:2015, Adhesives - Terms and definitions

EN 13183-2, Moisture content of a piece of sawn timber - Part 2: Estimation by electrical resistance method

EN 13183-3, Moisture content of a piece of sawn timber - Part 3: Estimation by capacitance method

EN 14080, Timber structures - Glued laminated timber and glued solid timber - Requirements

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oSIST prEN 16254:2022
prEN 16254:2021 (E)

EN 15416-1, 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)

EN 15416-3, Adhesives for load bearing timber structures other than phenolic and aminoplastic - Test

methods - Part 3: Creep deformation test at cyclic climate conditions with specimens loaded in bending shear

EN 15416-4, Adhesives for load bearing timber structures other than phenolic and aminoplastic - Test

methods - Part 4: Determination of open assembly time under referenced conditions

EN 15416-5, Adhesives for load bearing timber structures other than phenolic and aminoplastic - Test

methods - Part 5: Determination of minimum pressing time under referenced conditions

3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 923:2015 and the following

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
3.1
emulsion polymerised isocyanate (EPI) adhesive

water based emulsion polymer or a mixture of water based emulsion polymers cross-linked with an

isocyanate as hardener
3.2
service class 1

climatic conditions characterised by a moisture content in the materials corresponding to a temperature

of 20 °C and the relative humidity of the surrounding air only exceeding 65 % for a few weeks per year

[SOURCE: EN 1995-1-1:2004, 2.3.1.3 modified – Indoor conditions added in Note 1 to entry]

Note 1 to entry: In service class 1, which comprises typical indoor conditions, the average moisture content in

most soft-woods will not exceed 12 %.
3.3
service class 2

climatic conditions characterized by a moisture content in the materials corresponding to a temperature

of 20 °C and the relative humidity of the surrounding air only exceeding 85 % for a few weeks per year

Note 1 to entry: In service class 2, to which most covered exterior conditions belong, the average moisture

content in most softwoods will not exceed 20 %.

[SOURCE: EN 1995-1-1:2004, 2.3.1.3, modified – Covered exterior conditions added in Note 1 to entry]

3.4
service class 3
climatic conditions leading to higher moisture contents than in service class 2
Note 1 to entry: Exterior conditions typically belong to service class 3.
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oSIST prEN 16254:2022
prEN 16254:2021 (E)
[SOURCE: EN 1995-1-1:2004, 2.3.1.3, modified – Note 1 to entry has been added]
3.5
glue line
adhesive layer between the wood members
3.6
close contact glue line (cc)
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 groves, spacers or similar device.
3.7
thick glue line
glue line of nominal thickness in the range of 0,2 mm to 0,5 mm in the test

Note 1 to entry: Thick glue lines can be achieved by using spacers, grooves or similar devices with a thickness of

0,2 mm to 0,5 mm when two plain members are glued together.
4 Classification

Adhesives for structural purpose shall produce joints of such strength and durability that the integrity of

the bond is maintained in the assigned service class throughout the expected life of the structure.

EPI-adhesives according to prEN 16254 are classified by Type (climate condition in use), Maximum test

temperature and Maximum glue line thickness in use. These three subclasses are subdivided as follows:

Type I: to be used in service class 1 and 2.
Type II: to be used in service class 1 only.
Maximum test temperature: 50 °C, 70 °C or 90 °C.
Maximum glue line thickness in use: 0,1 mm, 0,2 mm and 0,3 mm.

Depending on the maximum glue line thickness in use, the adhesives are assigned to different application

areas as described below and shown in Table 1.

— General purpose adhesives (GP): to be used for bond lines between laminations (maximum glue line

thickness 0,3 mm) and for finger-joints in laminations.

— Small dimension adhesives (SD): to be used in beams with a maximum cross section 45 000 mm

(maximum glue line thickness 0,2 mm) and for finger-joints in laminations. The beam width shall not

exceed 180 mm and the beam height shall not exceed 300 mm.

— Finger-jointing adhesives (FJ): to be used for finger-jointing of laminations and structural timber only

(maximum glue line thickness 0,1 mm).

The application of EPI shall always be in mixed state. These adhesives shall be applied according to the

manufacturer's instructions.

NOTE The definition of "General purpose" and "Type" could be different in other standards.

Each area of application and use shall be given in the designation code of the adhesive.

Adhesives tested for working properties according to Clause 7 are specified by the letter “w” at the end

of the designation code (example: EN 16254 I 90 GP 0,3 w).
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oSIST prEN 16254:2022
prEN 16254:2021 (E)
Table 1 — Adhesive classes
Adhesive type Application area Max. test Max. glue line Service classes
designation temperature thickness
°C mm
Normal use Test Use
EN 16254 I 70 GP 0,3
General purpose 70 0,5 0,3 1, 2
Special use
EN 16254 I 90 GP 0,3 General purpose 90 0,5 0,3 1, 2
EN 16254 I 90 SD 0,2 Small dimension 90 0,3 0,2 1, 2
EN 16254 I 90 FJ 0,1 Finger-jointing 90 0,3 0,1 1, 2
EN 16254 I 70 SD 0,2 Small dimension 70 0,3 0,2 1, 2
EN 16254 I 70 FJ 0,1 Finger-jointing 70 0,3 0,1 1, 2
EN 16254 II 50 GP 0,3 General purpose 50 0,5 0,3 1
EN 16254 II 50 SD 0,2 Small dimension 50 0,3 0,2 1
EN 16254 II 50 JF 0,1 Finger-jointing 50 0,3 0,1 1
Tested according to
...