oSIST prEN 15497:2006

Finger jointed structural timber - Performance requirements and minimum production requirements

This European standard specifies performance and production requirements for finger jointed structural timber with rectangular cross-section. This standard covers also test and/or calculation methods to carry out the evaluation of conformity and requirements for marking of these finger joints.
This standard is only applicable to finger joints between timber members of the same species or species combination.
The standard covers not only coniferous species but also broad-leaved species where it has been shown that the type of adhesive used and the assembly conditions for finger-jointing timber are suitable for that type of species.
This standard covers finger-jointed structural timber untreated or treated against biological attack after finger-jointing.
This standard does not cover impressed (die formed) finger joints.
Individual finger jointed laminations and large finger joints for glued laminated timber are not covered by the present standard.
Structural timber treated against fire is not covered by this standard.

Keilzinkenverbindungen im Bauholz - Leistungsanforderungen und Mindestanforderungen an die Herstellung

Diese Norm enthält Leistungs- und Herstellungsanforderungen an Bauholz für tragende Zwecke mit recht-eckigem Querschnitt und geklebten Keilzinkenverbindungen.
Diese Norm gilt nur für Keilzinkenverbindungen in Holzbauteilen derselben Holzart oder Holzartenkombination.
Diese Norm umfasst Nadelholzarten sowie Laubholzarten, sofern Angaben vorliegen, die eine zufrieden stellende Klebung dieser Holzarten ergeben.
Bauholz für tragende Zwecke, das zum Schutz gegen den biologischen Befall behandelt wurde, ist ebenfalls Gegenstand dieser Norm.
Verbindungen, die mit Pressverformung („die-formed“) hergestellt werden, sind in dieser Norm nicht berück-sichtigt.
Einzellamellen in Brettschichtholz und Universal-Keilzinkenverbindungen in Brettschichtholz werden in dieser Norm nicht behandelt.
Bauholz für tragende Zwecke, das zum Schutz gegen Feuer behandelt wurde, ist nicht Gegenstand dieser Norm.

Aboutages a entures multiples dans les bois de construction - Exigences de performance et exigences minimales de fabrication

La présente norme prescrit les performances et les exigences de production relatives au bois de structure à section rectangulaire avec aboutages à entures multiples. La présente norme couvre également les méthodes d’essais et/ou de calcul permettant l ‘évaluation de la conformité ansiainsi que les exigences pour le marquage de ces aboutages.
La présente norme s’applique uniquement aux aboutages à entures multiples entre éléments en bois de même type d’essence ou de combinaison d’essences.
La présente norme ne s’applique pas qu’aux essences résineuses mais aussi aux essences feuillues lorsqu’il a été démontré que le type d’adhésif utilisé et les conditions d’assemblage pour le bois abouté conviennent à ce type d’essences.
La présente norme s’applique aux bois de structure avec aboutages à entures multiples non traité ou traité contre les attaques biologiques après l’aboutage.
Cette norme ne traite pas des aboutages emboutis.
Les lamelles individuelles aboutées et les aboutages à entures multiples de grandes dimensions pour du bois lamellé collé ne sont pas couvertes par la présente norme.
Le bois de structure traité contre le feu n’est pas couvert par la présente norme.

Konstrukcijski les z zobatimi stiki - Zahteve za uporabo in minimalne zahteve za proizvodnjo

General Information

• Status: Not Published
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: KON - Structures
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 28-Oct-2013
• Due Date: 02-Nov-2013
• Completion Date: 29-Oct-2013
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Mandate: M/112 - Mandate to CEN/CENELEC concerning the execution of standardization work for harmonized standards on structural timber products
• Ref Project: prEN 15497 - Finger jointed structural timber - Performance requirements and minimum production requirements

Overview

The European standard oSIST prEN 15497:2006 titled Finger jointed structural timber - Performance requirements and minimum production requirements is developed by CEN to regulate the quality and production of finger jointed structural timber. This standard applies to structural timber with a rectangular cross-section, featuring bonded finger joints between timber members of the same species or species combination.

The document specifies:

• Performance requirements for finger jointed timber
• Minimum production requirements for manufacturing these joints
• Test and calculation methods for conformity evaluation
• Marking requirements for finger joints

The scope covers both coniferous and broad-leaved timber species, provided the adhesives and bonding processes are suitable. It does not cover impressed (die-formed) finger joints, individual laminations for glued laminated timber (covered by EN 385), nor structural timber treated against fire.

This standard is essential for manufacturers, suppliers, and engineers involved in the production and use of finger jointed timber, ensuring consistent quality and structural integrity.

Key Topics

1. Timber Specifications

• Timber must meet strength class requirements as per EN 14081-1.
• Only timber species suitable for finger joint bonding are covered.
• Restrictions on knots and fissures near joints ensure joint integrity:
  • Knots >6 mm diameter are not permitted within joints.
  • Minimum distances from knots to joint ends are defined to prevent weak points.
• Wane (edge damage) limits restrict damage to no more than 1% of cross-sectional area near joint.

2. Adhesive Requirements

• Adhesives must ensure durable, high-strength bonds throughout service life.
• Compliant adhesives include those meeting EN 301 type I or type II (for service classes 1 and 2).
• Alternatives must offer equivalent durability and strength, considering temperature, moisture, and fire exposure risks.
• Phenolic and aminoplastic adhesives are common standards in production.

3. Strength and Stiffness

• Characteristic mechanical properties e.g., bending strength, tension, compression, and shear, must conform to EN 384 and EN 408.
• The finger joints themselves must meet minimum strength values to ensure reliable load transfer and stiffness.

4. Production Control

• Factory production control (FPC) systems are required, covering raw materials, equipment, adhesive application, and final product testing.
• Production batches must be homogeneous, using the same species, strength class, adhesive, and joint profile.
• Continuous monitoring and testing guarantees compliance with the standard.

5. Conformity Evaluation and Marking

• Initial and ongoing type testing verifies product compliance.
• CE marking and proper labelling inform consumers about conformity status.
• Documentation and traceability of production processes are mandatory.

Applications

oSIST prEN 15497:2006 is applicable to various structural timber products where the use of finger jointing enhances resource efficiency and structural performance including:

• Load-bearing beams and columns in timber construction
• Engineered wood products with uniform performance
• Structural elements in buildings and civil infrastructure requiring durable joints
• Timber components treated against biological decay after finger jointing (excluding fire retardant treatments)

This standard supports sustainable forestry utilization by enabling the efficient use of smaller or lower-grade timber pieces through finger jointing while maintaining structural safety.

Related Standards

To complement oSIST prEN 15497:2006 in timber construction and material quality, the following standards are relevant:

• EN 14081-1: Strength graded structural timber with rectangular cross section
• EN 385: Individual finger jointed laminations for glued laminated timber
• EN 387: Large finger joints for glued laminated timber members
• EN 301: Adhesives for load-bearing timber structures
• EN 350-1 / EN 350-2: Natural durability and treatability of wood species
• EN 384: Determination of characteristic mechanical properties of structural timber
• EN 408: Physical and mechanical properties testing for timber and glued laminated timber
• EN 13501-1: Fire classification of construction products

These related standards ensure comprehensive regulation of the materials, adhesives, testing methods, and safety classifications for timber structures in Europe.

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Keywords: finger jointed structural timber, performance requirements, production requirements, timber species, adhesive standards, structural timber testing, factory production control, European timber standard, oSIST prEN 15497:2006, finger joint strength, timber manufacturing quality, CE marking timber, timber construction standards.

Standards Content (Sample)

SLOVENSKI oSIST prEN 15497:2006

PREDSTANDARD
may 2006
Konstrukcijski les z zobatimi stiki - Zahteve za uporabo in minimalne zahteve
za proizvodnjo
Finger jointed structural timber - Performance requirements and minimum
production requirements
ICS 79.040 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2006
ICS
English Version
Finger jointed structural timber - Performance requirements and
minimum production requirements
Aboutages à entures multiples dans les bois de
construction - Exigences de performance et exigences
minimales de fabrication
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 124.
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 Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland 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
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15497:2006: E
worldwide for CEN national Members.

Contents
Foreword .5
Introduction.6
1 Scope.6
2 Normative references.6
3 Terms and definitions .7
4 Symbols and abbreviations.8
5 Requirements.8
5.1 General .8
5.2 Timber.9
5.2.1 Strength .9
5.2.2 Species .9
5.2.3 Knots and fissures.9
5.2.4 Wane or edge damage.9
5.3 Adhesives .10
5.4 Strength and stiffness.11
5.4.1 Timber.11
5.4.2 Finger joints .11
5.4.3 Testing of finger joints .11
5.5 Natural durability.11
5.6 Reaction to fire.11
6 Evaluation of conformity .11
6.1 General .11
6.2 Type testing .11
6.2.1 Initial type testing.11
6.2.2 Further type testing.12
6.2.3 Type testing of the timber .12
6.2.4 Type testing of the finger joints.12
6.3 Factory production control (FPC) .13
6.3.1 General .13
6.3.2 Equipment.13
6.3.3 Raw materials and components .13
6.3.4 Product testing and evaluation .13
7 Marking.14
Annex A (normative) Manufacturing requirements.15
A.1 Production conditions.15
A.2 Timber .15
A.3 Adhesive application .15
A.3.1 Adhesive application by machine.15
A.3.2 Manual adhesive application.15
A.4 Assembly and end pressure.15
A.4.1 Assembly.15
A.4.2 Adhesive.16
A.4.2 End pressure.16
ZA.1 Scope and relevant characteristics.17
ZA2 Procedure for attestation of conformity of structural finger jointed timber.18
ZA.2.1 System of attestation of conformity.18
ZA.3 CE marking and labelling.19

Foreword
This document (prEN 15497:2006) has been prepared by Technical Committee CEN/TC 124 "Timber
structures", the secretariat of which is held by SFS.
This document is currently submitted to the CEN Enquiry.
This document will not replace any existing standard.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.

Introduction
1 Scope
This standard specifies requirements for structural timber with rectangular cross-section with bonded finger
joints and minimum requirements for the manufacture of cut, interlocking, bonded finger joints in structural
timber members.
This standard is only applicable to finger joints between timber members of the same species type.

The standard covers coniferous species as well as broad-leaved species where information is available to
enable them to be satisfactorily bonded.

This standard does not cover impressed (die-formed) joints.

Individual laminations for glued laminated timber are covered by EN 385.

Large finger joints in glued laminated timber members are covered by EN 387.

Structural timber treated against biological attack or fire is not covered in this standard.

2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply
to this European Standard only when incorporated in it by amendment or revision. For undated references
the latest edition of the publication referred to applies (including amendments).

EN 301 Adhesives, phenolic and aminoplastic for load-bearing timber
structures - Classification and performance requirements
EN 350-1 Durability of wood and wood-based products – Natural durability of
solid wood – Part 1: Guide to the principles of testing and
classification of the natural durability of wood
EN 350-2 Durability of wood and wood-based products – Natural durability of
solid wood – Part 2: Guide to natural durability and treatability of
selected wood species of importance in Europe
EN 384 Structural timber – Determination of characteristic values of
mechanical properties and densities
EN 408 Timber structures - Structural timber and glued laminated timber -
Determination of some physical and mechanical properties
EN 13501-1 Fire classification of construction products and building elements –
Part 1: Classification using test data from reaction to fire tests
prEN 14081-1 Timber structures – Strength graded structural timber with
rectangular cross section – Part 1: General requirements
EN 14358 Structural timber – Calculation of characteristic 5-percentile values
EN/ISO 9001 Quality management systems - requirements

3 Terms and definitions
For the purposes of this standard, the following definitions apply:

3.1
characteristic strength:
population 5-percentile value obtained from the results of tests with a duration of 300 s using test pieces at an
o
equilibrium moisture content resulting from a temperature of 20 C and a relative humidity of 65 %.
3.2
finger joint:
self-locating end joint formed by machining a number of similar, tapered, symmetrical fingers in the ends of
timber members, which are then bonded together. See figure 1.

Figure 1: Typical profile of finger joint showing finger length l, pitch p, tip width b ,
t
and tip gap l ,    1) grain direction
t
3.2
finger length:
distance between the finger base and the tip of the finger, measured along the centre line of the finger.
3.3
grade:
strength grade or strength class.
3.4
pitch:
distance between fingers, centre to centre.
3.5
producer:
legal entity responsible for finger jointing the timber.
3.6
production batch:
joints, all of which have the same profile, manufactured from the same species of timber, the same strength
class, having the same nominal cross section, bonded with the same adhesive and made during a continuous
run on one production line.
3.7
service class 1:
service class 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 65 % for a few weeks per year.
NOTE: In service class 1 the average equilibrium moisture content in most softwoods will not exceed 12 %.
3.8
service class 2:
service class 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: In service class 2 the average equilibrium moisture content in most softwoods will not
exceed 20 %.
3.9
service class 3:
service class characterized by climatic conditions leading to higher moisture contents than service class 2.
3.10
strength class
classification of timber based on particular values of mechanical properties.
3.11
tip gap:
distance between finger tip and slot base in a bonded finger joint.
3.12
tip width:
distance between finger faces, measured at the tip of the finger.

4 Symbols and abbreviations
A area, in square millimetres;
A area of one wane, in square millimetres;
W
a diagonal length of wane, in millimetres;
W
b width of cross section, in millimetres;
b tip width, in millimetres;
t
d diameter, in millimetres;
f bending strength, in newtons per square millimetre;
m
f characteristic bending strength, in newtons per square millimetre;
m,k
f characteristic bending strength of 15 specimens, see 6.3.4.2, in newtons per square millimetre;
m,15,k
f mean value of bending strength of 15 specimens, see 6.3.4.2, in newtons per square
m,15,mean
millimetre;
f characteristic bending strength, declared by the manufacturer, in newtons per square
m,dc,k
millimetre;
h depth of cross section, in millimetres;
k factor, see 6.2.4.3,
f
k statistical factor, see 6.3.4.2;
l finger length, in millimetres;
l tip gap, in millimetres;
t
p pitch, in millimetres;
s standard deviation (the variable is given in parenthesis).

5 Requirements
5.1 General
The cutting and the bonding operations of finger joints shall result in reliable and durable bonds of required
strength.
These general requirements shall be considered satisfied if both the requirements in this clause and the
minimum production requirements in clause 6 and Annex A are fulfilled.
5.2 Timber
5.2.1 Strength
Timber shall fulfil the requirements of EN 14081-1.
5.2.2 Species
Sufficient information on the timber species shall be available to enable the timber to be satisfactorily bonded.
5.2.3 Knots and fissures
For the following requirements knots with a diameter not greater than 6 mm shall be disregarded.
There shall be no knots, fissures or pronounced grain disturbance within the joint itself. Outside the joint the
distance between a knot and the end of the cross-cut timber shall be not less than l + 3d where d is the
diameter of the knot measured perpendicular to the grain direction (longitudinal direction), see figure 2.

Figure 2 - Minimum distance from the end of the timber to a knot

Where a member is cross-cut to remove a knot, the cut shall be made at a distance from the knot at least
equal to a length of 3d, see figure 3.

Figure 3 - Minimum distance for a cross-cut to remove a knot

5.2.4 Wane or edge damage
There shall be no wane or edge damage affecting more than two corners at the joint within the finger length
and within 75 mm of the root of the fingers. The area, A , of the wane at any corner shall not exceed 1 % of
w
the cross-sectional area, see figure 4.

NOTE: Conformity with this requirement can be verified by measuring the diagonal a of the
w
wane and demonstrating that it is less than the maximum diagonal given in figure 5 as a function
of the cross-sectional area A.
Figure 4 - Cross section of timber with wane

Figure 5 - Maximum diagonal of wane = A /5
aW,max
5.3 Adhesives
The adhesive shall enable joints of such strength and durability to be produced that the integrity of the bond is
maintained throughout the intended lifetime of the structure.

The adhesive shall meet the requirements of

either
EN 301 type I, or for structures in service class 1 or 2 provided the temperature of the member in the structure
will always be below 50 °C, an adhesive of type II,

or
provide a bond with equivalent durability and strength as adhesives covered by EN 301, special
considerations being given to creep failure, the ability to maintain structural integrity during fire and elevated
temperature and moisture conditions in ordinary service.

NOTE 1: The adhesive should be chosen considering the climatic conditions in service, the
timber species, the preservative used (if any) and the production methods.
NOTE 2: Such strength and durability can be achieved by a polycondensation adhesive of the
phenolic or aminoplastic type as defined in EN 301.
5.4 Strength and stiffness
5.4.1 Timber
The characteristic strength in bending, tension, compression and shear, and the modulus of elasticity
estimated in accordance with EN 384 based on tests in accordance with EN 408 shall not be less than the
values declared by the producer for the product.
5.4.2 Finger joints
The characteristic strength in edgewise bending estimated in accordance with EN 14358 based on test in
accordance with clause 5.4.3 and 6.2.4 shall not be less than the
...