Timber structures - Cross laminated timber - Requirements

This document sets out requirements regarding the performance of characteristics of the following types of cross laminated timber to be used in buildings and bridges:
-   type 1: Straight or curved cross laminated timber comprising only timber layers but no large finger joints;
-   type 2: Straight cross laminated timber comprising only timber layers and large finger joints;
-   type 3: Straight cross laminated timber comprising timber and wood-based panel layers but no large finger joints.
It also lays down procedures for assessment and verification of constancy of performance (AVPC) of characteristics and specifies marking and labelling of cross laminated timber.
This document covers cross laminated timber of all three types of cross laminated timber:
-   manufactured according to this standard, which sets up provisions for:
-   boundary conditions during manufacture of cross laminated timber;
-   moisture content and temperature of timber to be bonded;
-   production of finger joints and bonds between layers;
-   to be used in service class 1 or 2 according to EN 1995 1 1;
-   made of coniferous species and poplar listed in this standard;
-   which may be made of layers made of different species having similar properties;
-   bonded with phenolic or aminoplastic or moisture curing one-component polyurethane or emulsion polymer isocyanate adhesives of adhesive type I according to the respective standard;
-   built up of at least three orthogonally bonded layers (at least two of them timber layers);
-   which may have, depending on the number of layers, adjacent layers bonded parallel to the grain;
-   made of timber layers which are made of strength graded timber according to EN 14081 1;
-   made of timber layers having nominal thicknesses between 6 mm (including) and 60 mm (including) depending on the layup;
-   made of timber layers
-   which may comprise non-structural edge bonds; and
-   have a mean gap width of less than or equal to 0,6 mm and a 90th percentile of the gap width of 2 mm;
-   having nominal overall thicknesses up to 500 mm.
Additional provisions of this document apply for straight cross laminated timber comprising only timber layers and comprising large finger joints (type 2):
-   made from cross laminated timber pieces having the same cross-section and layup;
-   made from cross laminated timber pieces having nominal cross-sectional thicknesses from 51 mm (including) up to 345 mm (including) and nominal minimum thicknesses of the outer layers not less than 17 mm (including).
-   made from cross laminated timber pieces solely comprising timber layers;
-   made from plane cross laminated timber pieces;
-   with parallel x-axes of the jointed components;
-   with finger joints having a finger length of at least 45 mm and fingers which are visible at the two narrow sides of the components;
-   bonded with phenolic or aminoplastic or moisture curing one-component polyurethane adhesives of adhesive type I according to the respective standard.
Additional provisions of this document apply for straight cross laminated timber comprising timber and wood-based panel layers but no large finger joints (type 3):
-   made of structural wood-based panels specified in this European standard;
-   made of one panel per layer and;
-   having thicknesses between 6 mm (including) and 45 mm (including);
This document applies to cross laminated timber untreated or treated against biological attack.
This document  does not cover:
-   cross laminated timber treated with fire retardants;
-   cross laminated timber which is produced from re-used timber or wood-based panels comprising re-used timber.

Holzbauwerke - Brettsperrholz - Anforderungen

In diesem Dokument werden die Anforderungen an die Leistungsmerkmale der folgenden Arten von Brett-sperrholz festgelegt, die in Gebäuden und Brücken verwendet werden:
-   Typ 1 ebenes oder gekrümmtes Brettsperrholz, das nur Brettlagen, aber keine Universal-Keilzinken-verbindungen umfasst;
-   Typ 2: ebenes Brettsperrholz, das nur Brettlagen und Universal-Keilzinkenverbindungen umfasst;
-   Typ 3: ebenes Brettsperrholz, das Bretter und Holzwerkstofflagen, aber keine Universal-Keilzinken-verbindungen umfasst.
Darüber hinaus legt die Norm auch Verfahren zur Bewertung und Überprüfung der Leistungsbeständigkeit (AVCP) von Merkmalen sowie die Kennzeichnung und Etikettierung von Brettsperrholz fest.
Dieses Dokument gilt für alle drei Arten von Brettsperrholz:
-   das nach dieser Norm hergestellt wurde, die folgende Bestimmungen festlegt:
-   Randbedingungen bei der Herstellung von Brettsperrholz;
-   Feuchtegehalt und Temperatur der zu verklebenden Bretter;
-   Herstellung von Keilzinkenverbindungen und Klebverbindungen zwischen Lagen;
-   das in der Nutzungsklasse 1 oder 2 nach EN 1995 1 1 angewendet wird;
-   das aus Pappel oder Nadelholzarten besteht, die in dieser Norm aufgeführt sind;
-   das aus Lagen bestehen darf, die aus verschiedenen Holzarten mit ähnlichen Eigenschaften hergestellt sind;
-   das mit Phenoplast  und Aminoplast-Klebstoffen oder einem feuchtigkeitsvernetzenden Ein-komponenten-Klebstoff auf Polyurethanbasis oder Emulsion-Polymer-Isocyanat-Klebstoffen vom Typ I nach der jeweiligen Norm verklebt ist;
-   das aus mindestens drei rechtwinklig zueinander verklebten Lagen (mindestens zwei Lagen sind Brettlagen) besteht;
-   bei dem je nach Anzahl der Lagen aneinandergrenzende Lagen parallel zur Faser verklebt werden dürfen;
-   das aus Lagen aus Vollholz (Bretter oder Bohlen, im Folgenden als Bretter bezeichnet) besteht, das entsprechend EN 14081 1 nach Festigkeit sortiert ist;
-   das aus Brettlagen mit Nenndicken von 6 mm (einschließlich) bis 60 mm (einschließlich) besteht, je nach Aufbau;
-   das aus Brettlagen besteht;
-   das möglicherweise keine Schmalseitenverklebungen für tragende Zwecke enthält; und
   das eine mittlere Spaltbreite von kleiner oder gleich 0,6 mm und ein 90. Perzentil der Spaltbreite von 2 mm aufweist;
-   das Gesamt-Nenndicken von bis zu 500 mm hat.
Zusätzliche Bestimmungen dieses Dokuments gelten für ebenes Brettsperrholz, das nur Brettlagen und Universal-Keilzinkenverbindungen (Typ 2) enthält:
-   das aus Brettsperrholzstücken mit gleichem Querschnitt und Aufbau besteht;
-   das aus Brettsperrholzstücken mit Querschnitts-Nenndicken von 51 mm (einschließlich) bis 345 mm (einschließlich) besteht, wobei die Mindest-Nenndicken der äußeren Lagen mindestens 17 mm (einschließlich) betragen;
-   das aus Brettsperrholzstücken besteht, die ausschließlich Brettlagen enthalten;
-   das aus ebenen Brettsperrholzstücken besteht;
-   mit parallelen x Achsen der verbundenen Bauteile;
-   das Keilzinkenverbindungen mit einer Keilzinkenlänge von mindestens 45 mm enthält, wobei die Keilzinken an den beiden Schmalseiten der Komponenten sichtbar sind;
-   das mit Phenoplast  und Aminoplast-Klebstoffen oder einem feuchtigkeitsvernetzenden Ein-komponenten-Klebstoff auf Polyurethanbasis vom Typ I nach der jeweiligen Norm verklebt ist.
Zusätzliche Bestimmungen dieses Dokuments gelten für ebenes Brettsperrholz, das Bretter und Holz-werkstofflagen, aber keine Universal Keilzinkenverbindungen (Typ 3) enthält:
-   das aus den in dieser Europäischen Norm festgelegten Holzwerkstoffen für tragende Zwecke besteht;
-   das aus einer Platte je Lage besteht und;
-   mit Dicken zwischen 6 mm (einschließlich) und 45 mm (einschließlich).
Dieses Dokument gilt für Brettsperrholz, das unbehandelt ist oder gegen biologischen Befall behandelt wurde.
...

Structures en bois - Bois lamellé croisé - Exigences

Le présent document établit les exigences relatives aux propriétés pour les types suivants de bois lamellé croisé devant être utilisés dans les bâtiments et les ponts :
-   type 1 : Bois lamellé croisé, droit ou courbe, constitué uniquement de couches de bois et sans aboutage à entures multiples de grandes dimensions ;
-   type 2 : Bois lamellé croisé droit, constitué uniquement de couches de bois et comprenant des aboutages à entures multiples de grandes dimensions ;
-   type 3 : Bois lamellé croisé droit, constitué de couches de bois et de couches en panneaux à base de bois, sans aboutage à entures multiples de grandes dimensions.
Il établit également les procédures d'évaluation et de vérification de la constance des performances (EVCP) pour les caractéristiques et spécifie le marquage et l'étiquetage du bois lamellé croisé.
Le présent document couvre le bois lamellé croisé appartenant à l'ensemble des trois types de bois lamellé croisé :
-   fabriqué conformément à la présente norme, qui établit les dispositions pour :
-   les exigences minimales relatives à la fabrication du bois lamellé croisé ;
-   la teneur en humidité et la température du bois à coller ;
-   la production des aboutages à entures multiples et du collage entre les couches ;
-   destiné à être utilisé en classe de service 1 ou 2 conformément à l'EN 1995 1 1 ;
-   constitué des essences de bois de résineux et de peuplier énumérés dans la présente norme ;
-   qui peut être constitué de couches provenant de différentes essences avec des propriétés similaires ;
-   collé avec des adhésifs de nature phénolique ou aminoplaste, des adhésifs polyuréthane monocomposants durcissant à l'humidité ou des adhésifs à base d'isocyanate et de polymère en émulsion de type I conformément à la norme correspondante ;
-   constitué d'au moins trois couches collées orthogonalement (au moins deux d'entre elles étant des couches de bois) ;
-   pouvant comporter, en fonction du nombre de couches, des couches contigües collées parallèlement au fil ;
-   comportant des couches de bois constituées de bois classé pour sa résistance mécanique conformément à l'EN 14081 1 ;
-   constitué de couches de bois avec une épaisseur nominale comprise entre 6 mm et 60 mm selon la combinaison ;
-   constitué de couches de bois :
-   pouvant comporter des collages sur chant non structuraux ; et
-   possédant une largeur de jeu moyenne inférieure ou égale à 0,6 mm et un 90e percentile pour la largeur de jeu de 2 mm ;
-   ayant des épaisseurs totales nominales inférieures ou égales à 500 mm.
Des dispositions supplémentaires du présent document s'appliquent au bois lamellé croisé droit, constitué uniquement de couches de bois avec aboutages à entures multiples de grandes dimensions (type 2) :
-   constitué de pièces de bois lamellé croisé ayant la même section transversale et la même combinaison ;
-   constitué de pièces de bois lamellé croisé ayant des épaisseurs de section transversale nominales comprises entre 51 mm (inclus) et 345 mm (inclus), ainsi que des épaisseurs minimales nominales des couches extérieures supérieures ou égales à 17 mm ;
-   constitué de pièces de bois lamellé croisé comprenant uniquement des couches de bois ;
-   constitué de pièces de bois lamellé croisé planes ;
-   avec des axes x parallèles pour les composants aboutés ;
-   avec des aboutages à entures multiples ayant une longueur d'au moins 45 mm et des entures qui sont visibles au niveau des deux faces étroites des composants ;
-   collé avec des adhésifs de nature phénolique ou aminoplaste, ou des adhésifs polyuréthane monocomposants durcissant à l'humidité de type I conformément à la norme correspondante.
...

Lesene konstrukcije - Križno lamelirani les - Zahteve

General Information

Status
Published
Public Enquiry End Date
14-Jan-2019
Publication Date
18-May-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
24-Feb-2021
Due Date
01-May-2021
Completion Date
19-May-2021

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SLOVENSKI STANDARD
SIST EN 16351:2021
01-julij-2021
Nadomešča:
SIST EN 16351:2015
Lesene konstrukcije - Križno lamelirani les - Zahteve
Timber structures - Cross laminated timber - Requirements
Holzbauwerke - Brettsperrholz - Anforderungen
Structures en bois - Bois lamellé croisé - Exigences
Ta slovenski standard je istoveten z: EN 16351:2021
ICS:
79.060.10 Vezan les Plywood
91.080.20 Lesene konstrukcije Timber structures
SIST EN 16351:2021 en,fr,de

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

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SIST EN 16351:2021
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SIST EN 16351:2021
EN 16351
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2021
EUROPÄISCHE NORM
ICS 79.060.10 Supersedes EN 16351:2015
English Version
Timber structures - Cross laminated timber -
Requirements

Structures en bois - Bois lamellé croisé - Exigences Holzbauwerke - Brettsperrholz - Anforderungen

This European Standard was approved by CEN on 4 January 2021.

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, Turkey 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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16351:2021 E

worldwide for CEN national Members.
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SIST EN 16351:2021
EN 16351:2021 (E)

Contents Page

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

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

1 Scope .......................................................................................................................................................... 7

2 Normative references .......................................................................................................................... 8

3 Terms, definitions and symbols .....................................................................................................10

3.1 Terms and definitions .......................................................................................................................10

3.2 Symbols ...................................................................................................................................................16

3.2.1 Main symbols ........................................................................................................................................16

3.2.2 Subscripts ...............................................................................................................................................17

4 Characteristics .....................................................................................................................................19

4.1 Modulus of elasticity, bending strength, compressive strength, tensile strength and

shear strength ......................................................................................................................................19

4.1.1 General ....................................................................................................................................................19

4.1.2 Geometrical data of cross laminated timber .............................................................................21

4.1.3 Strength, stiffness and density properties of layers ...............................................................22

4.1.4 Bending strength of large finger joints .......................................................................................24

4.1.5 Rolling shear strength, compression strength perpendicular to grain and density of

cross laminated timber .....................................................................................................................24

4.2 Bonding strength .................................................................................................................................25

4.2.1 General ....................................................................................................................................................25

4.2.2 Bonding strength of glue lines between layers ........................................................................25

4.2.3 Bonding strength of structural edge bonds ...............................................................................26

4.2.4 Bonding strength of large finger joints .......................................................................................26

4.3 Resistance to fire .................................................................................................................................26

4.4 Reaction to fire .....................................................................................................................................27

4.4.1 General ....................................................................................................................................................27

4.4.2 Classification without further testing ..........................................................................................27

4.4.3 Classification based on testing .......................................................................................................29

4.5 Dimensional stability .........................................................................................................................30

4.6 Emission of formaldehyde ...............................................................................................................30

4.7 Durability ...............................................................................................................................................31

4.7.1 Durability of bonding strength .......................................................................................................31

4.7.2 Durability of other characteristics ...............................................................................................32

5 Assessment and Verification of Constancy of Performance (AVCP) .................................33

5.1 General ....................................................................................................................................................33

5.2 Type testing ...........................................................................................................................................33

5.2.1 General ....................................................................................................................................................33

5.2.2 Test samples, testing and compliance criteria .........................................................................34

5.2.3 Test reports ...........................................................................................................................................41

5.3 Factory production control (FPC) .................................................................................................41

5.3.1 General ....................................................................................................................................................41

5.3.2 Provisions ..............................................................................................................................................41

5.3.3 Initial inspection of factory and of FPC .......................................................................................51

5.3.4 Continuous surveillance of FPC ......................................................................................................51

5.3.5 Procedure for modifications ...........................................................................................................51

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SIST EN 16351:2021
EN 16351:2021 (E)

Annex A (normative) Delamination test of glue lines between layers ......................................... 52

Annex B (normative) Tests with laminations with or without finger joints .............................. 56

Annex C (normative) Determination of strength, stiffness and density characteristics of

cross laminated timber .................................................................................................................... 59

Annex D (normative) Measurement of moisture content ................................................................. 76

Annex E (normative) Adhesive application for finger joints in laminations.............................. 77

Annex F (normative) Minimum production provisions ..................................................................... 78

Annex G (normative) Shear tests................................................................................................................ 92

Annex H (normative) Additional test methods and requirements for adhesives of subclass

FJ for use in structural edge bonds ............................................................................................... 95

Bibliography ....................................................................................................................................................... 96

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SIST EN 16351:2021
EN 16351:2021 (E)
European foreword

This document (EN 16351:2021) has been prepared by Technical Committee CEN/TC 124 “Timber

structures”, the secretariat of which is held by AFNOR.

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 September 2021, and conflicting national standards shall

be withdrawn at the latest by December 2022.

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 16351:2015.
The following changes have been made:

— the standard has been adjusted to the latest versions of standards for adhesives;

— the provisions for reaction and resistance to fire have been modified;

— the provisions for gap widths and ratios of lamination width by thickness have been modified;

— missing provisions for factory production control have been added;

— the provisions for determination of strength, stiffness and density characteristics of cross laminated

timber have been modified;
— the standard has been adjusted to the latest templates;
— Annex ZA has been deleted.

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, Turkey and the United

Kingdom.
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SIST EN 16351:2021
EN 16351:2021 (E)
Introduction

Figure 1 shows the relation of some European Standards on structural timber products.

Key
1 boards 6 glued laminated timber (glulam)
2 is a component for 7 glulam with large finger joints
3 structural finger jointed timber 8 block glued glulam
4 glued laminated products 9 cross laminated timber
5 glued solid timber 10 cross laminated timber with large finger joints
Figure 1 — Relation of some European Standards on structural timber products
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SIST EN 16351:2021
EN 16351:2021 (E)

Cross laminated timber in accordance with this document and multilayer solid wood panels in

accordance with EN 13353 may have the same layup, but for cross laminated timber the timber is

strength graded according to EN 14081-1 and the adhesives are tested according to the provisions of this

document.

The following standards mentioned in Clause 2, EN 13986, EN 14080, EN 14081-1, EN 14374 and

EN 15497, are harmonized product standards. The applicable version cited in the Official Journal of the

EU are not necessarily the latest published by CEN.
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SIST EN 16351:2021
EN 16351:2021 (E)
1 Scope

This document sets out provisions regarding the performance of characteristics of the following Types of

cross laminated timber for use in buildings and bridges:

— Type 1: Straight or curved cross laminated timber comprising only timber layers but no large finger

joints;

— Type 2: Straight cross laminated timber comprising only timber layers and large finger joints;

— Type 3: Straight cross laminated timber comprising timber and wood-based panel layers but no large

finger joints.

This document covers cross laminated timber of all three Types of cross laminated timber:

— manufactured according to this document, which sets up provisions for:
— boundary conditions during manufacture of cross laminated timber;
— moisture content and temperature of timber to be bonded;
— production of finger joints and bonds between layers;
— to be used in service class 1 or 2 according to EN 1995-1-1;
— made of coniferous species and poplar listed in this document;
— which may be made of layers made of different species;

— bonded with phenolic or aminoplastic or moisture curing one-component polyurethane or emulsion

polymer isocyanate adhesives of adhesive Type I according to the respective standard;

— made of timber laminations having a nominal width between 40 mm (including) and 300 mm

(including);

— built up of at least three orthogonally bonded layers (at least two of them timber layers);

— which may have, depending on the number of layers, adjacent layers bonded parallel to the grain;

— made of timber layers which are made of strength graded timber according to EN 14081-1;

— made of timber layers having nominal thicknesses between 6 mm (including) and 47 mm (including);

— made of timber layers which may comprise edge bonds;
— having nominal overall thicknesses up to 500 mm.

Additional provisions of this document apply for straight cross laminated timber comprising only timber

layers and comprising large finger joints (Type 2):

— made from cross laminated timber pieces having the same cross-section and layup;

— made from cross laminated timber pieces having nominal cross-sectional thicknesses from 51 mm

(including) up to 345 mm (including) and nominal minimum thicknesses of the outer layers not less

than 17 mm (including);
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SIST EN 16351:2021
EN 16351:2021 (E)
— made from cross laminated timber pieces solely comprising timber layers;
— made from plane cross laminated timber pieces;
— with parallel x-axes of the jointed components;

— with large finger joints having a finger length of at least 45 mm and fingers which are visible at the

two narrow sides of the components;

— having large finger joints bonded with phenolic or aminoplastic or moisture curing one-component

polyurethane adhesives of adhesive Type I according to the respective standard.

Additional provisions of this document apply for straight cross laminated timber comprising timber and

wood-based panel layers but no large finger joints (Type 3):
— made of structural wood-based panels specified in this document;
— made of one panel per layer and;
— having thicknesses between 6 mm (including) and 45 mm (including).

This document applies to cross laminated timber untreated or treated against biological attack.

This document does not cover:
— cross laminated timber treated with fire retardants;

— cross laminated timber which is produced from re-used timber or wood-based panels comprising re-

used timber.

It also lays down procedures for assessment and verification of constancy of performance (AVPC) of cross

laminated timber.
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 301:2017, Adhesives, phenolic and aminoplastic, for load-bearing timber structures - Classification and

performance requirements

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 338, Structural timber - Strength classes

EN 335, Durability of wood and wood-based products - Use classes: definitions, application to solid wood

and wood-based products

EN 350, Durability of wood and wood-based products - Testing and classification of the durability to

biological agents of wood and wood-based materials
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SIST EN 16351:2021
EN 16351:2021 (E)

EN 351-1, Durability of wood and wood-based products - Preservative-treated solid wood - Part 1:

Classification of preservative penetration and retention

EN 408:2010+A1:2012, Timber structures - Structural timber and glued laminated timber - Determination

of some physical and mechanical properties

EN 717-1, Wood-based panels - Determination of formaldehyde release - Part 1: Formaldehyde emission by

the chamber method

EN 789, Timber structures - Test methods - Determination of mechanical properties of wood based panels

EN 1995-1-1, Eurocode 5: Design of timber structures - Part 1-1: General - Common rules and rules for

buildings

EN 1995-1-2, Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire design

EN 12369-2, Wood-based panels - Characteristic values for structural design - Part 2: Plywood

EN 12369-3, Wood-based panels - Characteristic values for structural design - Part 3: Solid-wood panels

EN 13183-1, Moisture content of a piece of sawn timber - Part 1: Determination by oven dry method

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 by capacitance method

EN 13238, Reaction to fire tests for building products - Conditioning procedures and general rules for

selection of substrates

EN 13501-1, Fire classification of construction products and building elements - Part 1: Classification using

data from reaction to fire tests

EN 13501-2, Fire classification of construction products and building elements - Part 2: Classification using

data from fire resistance tests, excluding ventilation services

EN 13823, Reaction to fire tests for building products - Building products excluding floorings exposed to the

thermal attack by a single burning item

EN 13986, Wood-based panels for use in construction - Characteristics, evaluation of conformity and

marking

EN 14081-1, Timber structures - Strength graded structural timber with rectangular cross-section - Part 1:

General requirements

EN 14358, Timber structures - Calculation and verification of characteristic values

EN 14374, Timber structures - Structural laminated veneer lumber - Requirements

EN 15228:2009, Structural timber - Structural timber preservative treated against biological attack

EN 15425:2017, Adhesives - One component polyurethane (PUR) for load-bearing timber structures -

Classification and performance requirements

EN 16254:2013+A1:2016, Adhesives - Emulsion polymerized isocyanate (EPI) for load bearing timber

structures - Classification and performance requirements
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SIST EN 16351:2021
EN 16351:2021 (E)

EN ISO 9239-1, Reaction to fire tests for floorings - Part 1: Determination of the burning behaviour using a

radiant heat source (ISO 9239-1)

EN ISO 11925-2:2020, Reaction to fire tests - Ignitability of products subjected to direct impingement of

flame - Part 2: Single-flame source test (ISO 11925-2)
3 Terms, definitions and symbols

For the purposes of this document, the following terms, definitions and symbols apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1 Terms and definitions
3.1.1
actual size
measured size of a cross laminated timber at a given moisture content
[SOURCE: EN 14080:2013, 3.1 - modified]
3.1.2
bonding strength

structural effectiveness of adhesives between timber pieces when subjected to stresses

[SOURCE: EN 14080:2013, 3.2]
3.1.3
contact-free application
application without contact between timber and application unit
3.1.4
corrected size

size of a cross laminated timber corrected by calculation from its actual size to its size at the reference

moisture content
[SOURCE: EN 14080:2013, 3.6 - modified]
3.1.5
cross laminated timber

structural timber member composed by at least three face-bonded layers which comprise solid timber

laminations and may comprise wood-based panels, at least one layer orthogonally oriented to the two

adjacent layers
Note 1 to entry: See also Figure 2.
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EN 16351:2021 (E)
Key
1 plane of the element 2 wide face 3 narrow faces 4 outer layers
5 inner layers 6 laminations 7 finger joints in lamination 8 large finger joint
9 usually the length 10 usually the width b of a plate or height h of a beam
CL CL
Figure 2 — Cross laminated timber
3.1.6
delamination length

sum of the lengths of delaminations in one glue line measured around the circumference of a test piece

[SOURCE: EN 14080:2013, 3.8 - modified]
3.1.7
edge bond
bond between adjacent laminations within a timber layer
3.1.8
finger angle
inclination α of each side of the fingers of a finger joint
[SOURCE: EN 14080:2013, 3.10]
Note 1 to entry: See Figure 3.
3.1.9
finger joint

interlocking end joint formed by machining a number of similar, tapered, symmetrical fingers in the ends

of timber components using a finger joint cutter and then bonded together
[SOURCE: EN 14080:2013, 3.11]

Note 1 to entry: In this document, the term finger joint is used for finger joints in laminations whereas finger

joints between cross laminated timber are defined as large finger joints (see 3.1.13).

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EN 16351:2021 (E)
Key
b tip width of the cutter b tip width l finger length l slot base p pitch
cut t j t
α finger angle 1 tip base 2 fingertip 3 finger flank
Figure 3 — Typical profile of a finger joint
3.1.10
finger length

distance l between the finger base and the tip of the finger, measured along the centre line of the finger

[SOURCE: EN 14080:2013, 3.12]
Note 1 to entry: See Figure 3.
3.1.11
finished thickness
thickness after machining
[SOURCE: EN 14080:2013, 3.13]
3.1.12
lamination

part of a structural glued timber product consisting of one board or two or more finger-jointed boards

[SOURCE: EN 14080:2013, 3.19 - modified]
3.1.13
large finger joint

finger joint through the full cross-sectional area of two cross laminated timber components

[SOURCE: EN 14080:2013, 3.20 - modified]
Note 1 to entry: See Figure 4.
Figure 4 — Cross laminated timber with large finger joint
3.1.14
layer
courses lying over or under another
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EN 16351:2021 (E)
3.1.15
layup

cross-sectional arrangement of timber layers which may be assigned to different strength classes

according to EN 338 or different sets of individual values of strength, stiffness and density characteristics

or wood-based panel layers which may be assigned to different strength classes according to EN 12369-2

or EN 12369-3 or different sets of individual values of strength, stiffness and density characteristics

[SOURCE: EN 14080:2013, 3.21 - modified]
3.1.16
maximum delamination length
largest delamination length in any single glue line
[SOURCE: EN 14080:2013, 3.24 - modified]
3.1.17
mean moisture content

mean value of the moisture content of cross laminated timber calculated from at least two measurements

[SOURCE: EN 14080:2013, 3.25 - modified]
Note 1 to entry: See D.2.
3.1.18
minimum mean density

required mean density at reference moisture content, estimated as the weighted mean of the mean

densities of the layers, if necessary
[SOURCE: EN 14080:2013, 3.26]

Note 1 to entry: Minimum mean density is used for the classification of the reaction to fire.

3.1.19
nominal size
size specified at the reference moisture content to which deviations are related
3.1.20
pitch
distance between centres of adjacent fingertips
[SOURCE: EN 14080:2013, 3.27]
Note 1 to entry: See Figure 3.
3.1.21
ratio of resin to hardener
proportion of resin to hardener by mass with the resin set at 100 parts
[SOURCE: EN 14080:2013, 3.28]
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EN 16351:2021 (E)
3.1.22
reduction factor
ratio ν between tip width b and pitch p
[SOURCE: EN 14080:2013, 3.29 - modified]
Note 1 to entry: See Figure 3.
3.1.23
reference moisture content
moisture content of 12 % at which nominal sizes are established
[SOURCE: EN 14080:2013, 3.30]
3.1.24
relative tip gap
ratio e between tip gap l and finger length l
t j
[SOURCE: EN 14080:2013, 3.31 - modified]
Note 1 to entry: See Figure 3.
3.1.25
re-used timber
timber product made from timber which has been used before
3.1.26
rolling shear

shear stress for which both complementary stress components are perpendicular to the grain

3.1.27
solid wood failure

wood failure which is invariably more than two cell layers away from the adhesive layer

3.1.28
straight cross laminated timber
cross laminated timber having a precamber of up to 1 % of the respective span
3.1.29
timber layer
layer made of timber laminations with or without edge bonds
3.1.30
tip gap
distance l between fingertip and slot base in a bonded finger joint
[SOURCE: EN 15497:2014, 3.11]
Note 1 to entry: See Figure 3.
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EN 16351:2021 (E)
3.1.31
tip width
distance b between finger flanks, measured at the tip of the finger
[SOURCE: EN 14080:2013, 3.35 - modified]
Note 1 to entry: See Figure 3.
3.1.32
total delamination length
sum of delamination lengths of all glue lines
[SOURCE: EN 14080:2013, 3.36 - modified]
3.1.33
wood-based panels
structural plywood and structural solid wood panels according to EN 13986
and structural LVL according to EN 14374
3.1.34
wood-based panel layer
layer made of one piece of wood-based panel
3.1.35
wood failure percentage

percentage of the solid wood failure area after splitting in relation to the glued area before splitting

[SOURCE: EN 14080:2013, 3.38 - modified]
3.1.36
x-axis

axis parallel to grain of the timber layers or outer layers or veneers of wood-based panel layers

Note 1 to entry: See Figure 2.
3.1.37
z-axis
axis perpendicular to the layers
Note 1 to entry: See Figure 2.
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SIST EN 16351:2021
EN 16351:2021 (E)
3.2 Symbols
3.2.1 Main symbols
A area, in mm ;
A area of wane, in mm (see Figure F.1);
A* net sehar area,
a size or distance between support and load introduction or excess length in mm;
a length of the diagonals of wane, in mm (see Figure F.1);
a maximum length of the diagonal of wane, in mm (see Figure F.2);
w,max
b width, in mm;
b tip width of the cutter (see Figure 3);
cut
b tip width, in mm (see Figure 3);
b gap width, in mm;
gap
d diameter, in mm;
d distance, in mm (see Figure 6);
Delam maximum delamination, in %;
max
Delam total delamination, in %;
tot
e relative tip gap;
E modulus of elasticity, in N/mm ;
E modulus of elasticity related to I , in N/mm ;
local CL,net
(EI) appereant bending stiffnes
...

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