KON.005 - Timber structures

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.

This document specifies a method based on density, for the selection of pieces of wood used in
determining the strength and stiffness properties of joints between members of structural timber
made with mechanical fasteners. It is intended to be used in conjunction with a test standard specifying
a test method.
It is assumed that the wood pieces are conditioned to the relevant conditions, that the wood density is
normally distributed and that any deviations are reported.
This document is applicable only to specimens of structural timber.
NOTE It is emphasized that the wood density is only one of the properties that can influence the strength of
a joint. Other relevant properties are, for example, growth-ring size and orientation, toughness and hardness.

This European Standard specifies requirements for strength graded structural timber with rectangular cross-sections either visual or machine graded, shaped by sawing, planning or other methods and with cross-sectional dimensions complying with EN 336 (referred to as structural timber in the following clauses).
This European Standard includes provisions for test methods, Assessment and Verification of Constancy of Performance and marking of structural timber.
NOTE 1   For machine strength graded timber additional provisions for type testing (TT) are given in EN 14081-2 and for factory production control (FPC) in EN 14081-3.
NOTE 2   An acceptance procedure for verification of a lot is given in EN 14358 which may be used for a delivery of structural timber.
This European Standard identifies characteristics for which limits have to be given in visual grading standards.
This European Standard covers structural timber, untreated or treated against biological attack.
This European Standard does not cover:
-   timber treated by fire retardant products to improve its fire performance;
-   thermally and/or chemically modified timber;
-   structural finger jointed timber.

This Europen Standard specifies test methods for the determination of the fundamental frequency, damping, unit point load deflection and acceleration of timber or wood based composite beams and flooring systems.

This European Standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual grades and/or strength classes of machine graded structural timber. Additionally it covers the stages of sampling, testing, analysis and presentation of the data.
The standard provides methods to derive strength, stiffness and density properties for structural timber from tests with defect-free specimen.
The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.
NOTE 1   For assigning grades and species to the strength classes in EN 338 only three properties, i.e. bending or tension strength, modulus of elasticity parallel to grain in bending or tension and density need to be determined from test data, other properties can be calculated according to Table 2.
NOTE 2   EN 1912 gives examples of established visual grades assigned to strength classes.

This European Standard specifies requirements additional to those given in EN 14081-1 for factory production control of machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336.

This European Standard specifies requirements, additional to those in EN 14081-1, for type testing of machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336. This includes requirements for strength grading machines.

This document specifies methods for the determination of characteristic 5-percentile strength and density values as well as mean values for stiffness from test results for solid wood, fasteners, and wood-based products in the frame of initial type testing.
This document also gives methods for checking strength, density or stiffness properties in the frame of factory production control by variables. Sampling is not covered by this document, but reference is made to the relevant product standards.
In addition to this standard, specific requirements related to the product are given in separate standards.
NOTE   For example, in the case of solid timber, specific correction factors for calculation of characteristic values are given in EN 384.

This European Standard specifies the test methods for determining the long term behaviour of coated and uncoated dowel-type fasteners in load bearing timber structures (nails, staples, screws, dowels and bolts with nuts).

This document specifies a method of strength grading tropical harwood visually for structural use. This method is only suitable for pieces of timber with rectangular cross'section that is constant along their length.

This European Standard establishes a system of strength classes for general use in design codes.
It gives characteristic strength and stiffness properties and density values for each class to which EN 14081-1 refers.
This standard is applicable to all softwood and hardwood timber for structural use.

This standard specifies test methods for determining the strength and deformation characteristics of stapled joints in load-bearing timber structures.
The methods assess joints with members of timber (solid timber and glued laminated timber) or wood-based products in the combination proposed for use in service and using all types of staples up to 3 mm diameter for circular cross-section staples or 4 mm x 2 mm for rectangular or oval cross-section staples.
The methods determine load-slip characteristics and maximum load of joints with laterally loaded staples where various angles between the applied force and the timber grain direction or the main direction of the wood-based products, respectively, are possible.

This standard specifies the test method for determining the withdrawal capacity of fasteners which have been inserted into timber (solid timber, LVL and glued laminated timber).
The test method applies to all types of nails, screws and staples.

This standard specifies the test method for determining the resistance of timber to the head pull through of timber fasteners.
In this standard 'timber' includes solid timber, glued laminated timber and wood-based products.
The test method applies to all types of nails, screws and staples.

This European Standard specifies the test methods for determining the strength capacity and stiffness of joints made with punched metal plate fasteners in load bearing timber structures, being used to join two or more pieces of timber of the same thickness in the same plane. The properties measured are:
-   load-slip characteristics and maximum load resulting from the lateral resistance of the embedded projections, at various angles between the direction of the applied force and;
-   the axis of the fastener (load-fastener angle );
-   the direction of the grain of the timber (load-grain angle β);
-   the tension capacity of the fastener at various angles ;
-   the compression capacity of the fastener at various angles ;
-   the shear capacity of the fastener at various angles ..
A nail root test method is shown in Annex A.

EN 15497 sets out provisions regarding the performance characteristics for structural finger jointed timber with rectangular cross section for use in buildings and bridges. The use of structural finger jointed timber may be limited to certain service classes in some member states. It also lays down minimum production provisions and procedures for Assessment and Verification of Constancy of Performance for structural finger jointed timber. This European Standard is applicable to structural finger jointed timber made of coniferous timber species listed in this standard or poplar. Although it may be possible to produce structural finger jointed timber made from specific broadleaf species based on some provisions of this European Standard, this standard is not applicable to these products. This European Standard is only applicable to finger joints between timber sections of the same species. This European Standard does not cover impressed (die-formed) finger joints. This European Standard covers structural finger jointed timber untreated or treated against biological attack. Structural finger jointed timber treated with fire retardants is not covered.

This European Standard specifies two classes of permitted deviations from target sizes for structural timber of softwood and hardwood species. It also specifies the moisture content to be used as a reference point for the measurement of sizes, and gives average values for changes in size due to changes in moisture content. It is applicable to sawn and prepared square-edged structural timber with parallel edges having sawn thicknesses or widths greater than 6 mm.

This European Standard lists the visual strength grades, species and sources of timber, and specifies the strength classes to which they are assigned, as documented in EN 338.

This European Standard sets the performance requirements of the following glued laminated products: - Glued laminated timber (glulam); - Glued solid timber; - Glulam with large finger joints; - Block glued glulam for use in buildings and bridges. It also lays down minimum production requirements, provisions for evaluation and attestation of conformity and marking of glued laminated products. This European Standard is applicable for glued laminated timber made of coniferous species listed in this standard or poplar consisting of two or more laminations having a thickness from 6 mm up to 45 mm (inclusive). It may be possible to produce glulam made from specific hardwood species based on some provisions of this European Standard. In this case, Annex ZA does not apply. This European Standard is applicable for glued solid timber made of coniferous species listed in this standard or poplar consisting of two to five laminations having a thickness greater than 45 mm and less than or equal to 85 mm. This European Standard is applicable for large finger joints in glued laminated timber with a finger length of at least 45 mm. This European Standard is applicable for block glued glulam having solid rectangular cross sections. This European Standard also gives the requirements for glued laminated products treated against biological attack. Glued laminated products treated with fire retardants are not covered.

This European Standard specifies test methods for determining the following properties of structural timber and glued laminated timber: modulus of elasticity in bending; shear modulus; bending strength; modulus of elasticity in tension parallel to the grain; tension strength parallel to the grain; modulus of elasticity in compression parallel to the grain; compression strength parallel to the grain; modulus of elasticity in tension perpendicular to the grain; tension strength perpendicular to the grain; modulus of elasticity in compression perpendicular to the grain; compression strength perpendicular to the grain and shear strength.
In addition, the determination of dimensions, moisture content, and density of test pieces are specified.
The methods apply to rectangular and circular shapes (of substantially constant cross section) of solid unjointed timber or finger-jointed timber and glued laminated timber unless stated otherwise.

This European Standard specifies the requirements and test methods for materials, geometry, strength, stiffness and durability ascpects (i.e. corrosion protection) of dowel-type fasteners for use in load bearing timber structures. Only dowel-type fasteners manufactured from steel are covered by this European Standard. For the purpose of this standard, dowel-type fasteners for timber structures are taken to be nails, staples, screws, dowels, and bolts with nuts. Definitions of these items are given in Clause 3. This European Standard specifies also the evaluation of conformity procedures and includes requirements for marking of these products. This European Standard does not cover fasteners treated with fire retardants to improve their fire performance. This European Standard covers fasteners that may be coated for the following purposes: 1. Corrosion protection (e.g. hot dip galvanization, epoxy coating); 2. Lubricants (to facilitate insertion); 3. Withdrawal enhancement and/or collation (adhesive coating).

This European Standard lists the visual strength grades, species and sources of timber, and specifies the strength classes to which they are assigned, as documented in EN 338.

This European Standard specifies the dimensions and the materials of certain well-established connectors for use in joints between members in load-bearing timber structures.
For data on strength and deformation properties of joints made with the connectors, reference is given to EN 13271.

This standard specifies the test method to be used in determining the racking strength and stiffness of timber frame wall panels. The test method is intended, primarily for panels as described, to provide: comparative performance values for the materials used in the manufacture of the panels; and datum information for use in structural design. The principle of the test method is suited to other sizes or shapes of panels and to panels which are partially sheathed and to combinations of panels. The requirements for such panels and their testing are given in Annex A.

This European Standard specifies a method for determining the yield moment of dowel type fasteners.

This European Standard specifies test methods for determining the strength and deformation characteristics of laterally loaded connections with nail, screws, dowels and bolts in load-bearing timber structures.
The methods assess connections with members of timber (solid timber or glued laminated timber) or wood-based products or metal plates (but not punched metal plate fasteners) in the combination proposed for use in service.
The methods are used to determine load-slip characteristics and maximum load of connections where various angles between the applied force and the timber grain direction, or the main direction of the wood-based products, respectively, are possible.

This European Standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual grades and/or strength classes of machine graded structural timber. Additionally it covers the stages of sampling, testing, analysis and presentation of the data.
The standard provides methods to derive strength, stiffness and density properties for structural timber from tests with defect-free specimen.
The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.
NOTE 1   For assigning grades and species to the strength classes in EN 338 only three properties, i.e. bending or tension strength, modulus of elasticity parallel to grain in bending or tension and density need to be determined from test data, other properties can be calculated according to Table 2.
NOTE 2   EN 1912 gives examples of established visual grades assigned to strength classes.

This document specifies requirements, additional to those of EN 14081-1, for type testing of machine graded structural timber with rectangular cross-sections shaped by sawing, planning or other methods, and having deviations from the target sizes corresponding to EN 336. This includes requirements for strength grading machines.

This document specifies requirements additional to those given in EN 14081-1 for factory production control of machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336.

This standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual grades and/or mechanical strength classes of sawn timber. Additionally it covers the stages of sampling, testing, analysis and presentation of the data.
A method is also given for checking the strength of a timber population against its designated value.
The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.
NOTE 1   For assigning grades and species to the strength classes in EN 338 only three characteristic values, i.e. bending or tension strength, mean modulus of elasticity parallel to grain in bending or tension and density need to be determined, other properties can be calculated according to Tab. 6.2.
NOTE 2   EN 1912 gives examples of established visual grades assigned to strength classes.

This draft European Standard specifies the requirements for the following types of dowel-type fasteners: nails, staples, screws, dowels, and bolts with nuts.
Only dowel-type fasteners for structural use in load bearing timber structures, and manufactured from steel, are covered by this European Standard. In addition, this draft European Standard covers also the use of screws:
-   to fix roof or cladding elements to the timber structure, with or without insulation layers;
and
-   as reinforcement inserted in timber or in a glue laminated timber element to improve its resistance to compression perpendicular to the grain.
This draft European Standard specifies also the assessment and verification of constancy of performance (AVCP) procedures and includes requirements for marking of these products.
This draft European Standard covers dowel-type fasteners that may be coated for the following purposes:
-   corrosion protection;
-   lubrication (to facilitate insertion);
-   withdrawal enhancement and/or collation for staples (adhesive and/or resin coatings).
This draft European Standard does not cover fasteners treated with fire retardants to improve their fire performance, nor does it cover glued-in rods.

This European Standard specifies requirements additional to those given in EN 14081-1 for factory production control of machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336.

This European Standard sets out provisions regarding the performance characteristics of structural laminated veneer lumber (LVL) for use in buildings and bridges and non-structural laminated veneer lumber for internal and external applications in construction.
It also lays down procedures for Assessment and Verification of Constancy of Performance of laminated veneer lumber.
This European Standard covers laminated veneer lumber
—   made of at least five veneers having a maximum veneer thickness of 6 mm;
—   which may comprise crossband veneers;
—   which may comprise veneers made from different species;
—   being preservative treated or untreated against biological attack or treated to improve the reaction to fire.
This European Standard defines provisions for bonding strength and durability of bonding strength in dry, humid and exterior conditions. It covers structural LVL to be used in all conditions and non-structural LVL to be used in the respective conditions for which bonding strength tests have been performed.
This European Standard defines strength classes for structural laminated veneer lumber.

This European Standard sets out provisions regarding the performance characteristics for prefabricated structural (load-bearing) wall, floor and roof elements consisting of framing members of timber, glued solid timber, glued laminated timber, laminated veneer lumber (LVL), structural prefabricated wooden beams/columns and sheeting made of wood-based boards/panels or gypsum boards/panels on one or both sides, for use in service class 1 or 2 in accordance with EN 1995-1-1.
This European Standard also specifies additional requirements for the components and for the production of the elements.
It sets down requirements for the provision of performance details of prefabricated elements at point of delivery.
The panels and/or boards are connected to the framing members by suitable structural adhesive bonding or by mechanical fixing. The elements may be insulated or uninsulated. The exterior faces of the elements may also be covered with insulation material.
This European Standard covers glued and mechanically fixed wall elements with length of maximal 16,5 m, height of maximal 3,2 m and of unrestricted thickness.
This European Standard covers mechanically fixed floor and roof elements with length of maximal 16,5 m and a thickness of maximal 1,0 m and a width of maximal 3,5 m. The mechanically fixed floor element may include additional bond lines to increase stiffness to enlarge resistance versus vibrations.
This European Standard covers glued floor and roof elements with length of maximal 12,5 m and a load bearing cross-sectional thickness of maximal 0,35 m and a width of maximal 3,5 m.
This European Standard identifies structural (3.1.4) and non-structural (3.1.3) components to be used in the elements.
This European Standard also lays down provisions and Procedures for Assessment and Verification of Constancy of Performance of these elements.
This European Standard applies to elements that may have openings, e.g. for windows, doors etc. It does not apply to the properties of incorporated doors or windows.
This European Standard does not cover components and elements treated to enhance their fire performance.
Examples of different build-ups are given in Clause 3.

This European Standard specifies the requirements for visual and machine graded structural timber with rectangular cross-sections shaped by sawing, planning or other methods, and having deviations from the target sizes corresponding to EN336.
This European Standard consists of provisions for tests methods, evaluation of conformity ( ITTand FPC) and marking of both grading types of structural timber.

This European Standard specifies requirements , additional to those in EN 14081-1, for initial type testing of machine graded structural timber with rectangular cross sections shaped by sawing, planing or other methods, and having deviations from the target sires corresponding to EN336.This includes requiremnts for strength grading machines and test equipment for proof loading graded material.

This European Standard specifies the requirements and test methods for materials, geometry, strength, stiffness and durability aspects ( i.e corrosion protection ) of dowel-type fasteners for use in load bearing timber structures. Only dowel-type fasteners manufactured from steel are covered by this European Standard. The aim of this amendment is to correct references for the declared raw materials and to cover resin coated dowel-type fasteners.

This European Standard specifies test methods for determining the following properties of structural timber and glued laminated timber: modulus of elasticity in bending; shear modulus; bending strength, modulus of elasticity in tension and tension strength parallel to the grain; modulus of elasticity in compression and compression strength parallel to the grain; modulus of elasticity in tension and tension strength perpendicular to the grain; modulus of elasticity in compression and compression strength perpendicular to the grain; and shear strength.

This European Standard specifies performance requirements at delivery for prefabricated structural (load-bearing) wall, floor and roof elements (diaphragm assemblies) consisting of framing members of timber and/or wood-based panels or boards on one or both sides, for use in service class 1 or 2 in accordance with EN 1995-1-1:2004. The panels and/or boards are connected to the joists by suitable adhesive bonding or by mechanical fixing. The cavities of the elements may be filled entirely or partially with insulating materials. The exterior faces of the elements may also be covered with insulation material.
This European Standard applies to elements with lengths and cross-sectional depths of up to 10 m and 0,30 m, respectively.
This European Standard specifies requirements for structural (3.3) and non-structural (3.4) components and lays down minimum requirements for the production of prefabricated elements.
The European Standard also covers methods to carry out the evaluation of conformity and marking of these elements.
This European Standard applies to elements that may have openings, e. g. for windows, doors etc. It does not apply to the properties of incorporated doors or windows.
Furthermore, it does not cover elements treated to enhance their fire performance.

This European Standard specifies the requirements for visual and machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336.
This European Standard covers structural rectangular timber, untreated or treated against biological attack.
This European Standard does not cover timber treated by fire retardant products.
This European Standard identifies as a minimum the characteristics for which limits shall be given in visual grading rules.
Finger jointed timber is not covered in this European Standard.

This European Standard specifies the requirements for glued laminated timber for use in load bearing structures. It also specifies the requirements for large finger joints in the glued laminated timber. This European Standard specifies the requirements for glued laminated timber produced from untreated timber or from timber treated against biological attack.

To add new visual strength grades/species.

This document specifies the requirements for cross laminated timber with rectangular cross-sections shaped by sawing, planning or other methods.
This document covers cross laminated timber, untreated or treated against biological attack.
This document does not cover timber treated by fire retardant products.

This International Standard specifies a method, based on density, for the selection of pieces of wood used in determining the strength and stiffness properties of connections made with mechanical fasteners. It is assumed the wood density is normally distributed and that any deviations are reported. This International Standard is applicable only to specimens of wood.

This European Standard specifies requirements for visual and machine strength graded structural timber of rectangular cross-section shaped by sawing, planing or other methods and of minimum cross sectional dimensions complying with EN 336.
This European Standard includes provisions for test methods, Assessment and Verification of Constancy of Performance and marking of structural strength graded timber.
NOTE   For machine strength graded timber additional provisions for type testing (TT) are given in EN 14081-2 and for factory production control (FPC) in EN 14081-3.
This European Standard identifies characteristics for which limits have to be given in visual grading standards.
This European Standard covers structural rectangular timber, untreated or treated against biological attack.
This European Standard does not cover:
-   timber treated by fire retardant products to improve its fire performance;
-   finger jointed timber.

This standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual grades and/or mechanical strength classes of sawn timber. Additionally it covers the stages of sampling, testing, analysis and presentation of the data.
A method is also given for checking the strength of a timber population against its designated value.
The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.
NOTE 1   For assigning grades and species to the strength classes in EN 338 only three characteristic values, i.e. bending or tension strength, mean modulus of elasticity parallel to grain in bending or tension and density need to be determined, other properties can be calculated according to Tab. 6.2.
NOTE 2   EN 1912 gives examples of established visual grades assigned to strength classes.

This European Standard specifies requirements, additional to those in EN 14081-1, for initial type testing of machine graded structural timber with rectangular cross sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336. This includes requirements for strength grading machines and test equipment for proof loading graded material.

This European Standard specifies requirements additional to those given in EN 14081-1 for factory production control of machine graded structural timber with rectangular cross-sections shaped by sawing, planing or other methods, and having deviations from the target sizes corresponding to EN 336. Machine grading is in common use in a number of countries. The countries use two basic systems, referred to as ‘output controlled’ and ‘machine controlled’. Both systems require a visual override inspection to cater for strength-reducing characteristics that are not automatically sensed by the machine. The output-controlled system is suitable for use where the grading machines are situated in sawmills grading limited sizes, species and grades in repeated production runs of around one working shift or more. This enables the system to be controlled by testing timber specimens from the daily output. These tests together with statistical procedures are used to monitor and adjust the machine settings to maintain the required strength properties for each strength class. With this system it is permissible for machine approval requirements to be less demanding and for machines of the same type to have non-identical performance. The machine controlled system was developed in Europe. Because of the large number of sizes, species and grades used it was not possible to carry out quality-control tests on timber specimens drawn from production. The system relies therefore on the machines being strictly assessed and controlled, and on considerable research effort to derive the machines settings, which remain constant for all machines of the same type. The acceptability of grading machines and the derivation of settings rely on statistical procedures and the results will therefore depend on the method used. For this reason, this European Standard gives appropriate statistical procedures. The requirements in this European Standard are based on machines in current use and on future types of machines as far as these can be foreseen. It is recognised that additional clauses or standards may be required if unforeseen developments take place.

This European Standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of visual and/or mechanical strength grades of sawn timber. A method is also given for checking the strength of a timber sample against its designated value. The values determined in accordance with this standard for mechanical properties and density are suitable for assigning grades and species to the strength classes of EN 338.