EN 384:2016+A2:2022

SLOVENSKI STANDARD
01-september-2022
Konstrukcijski les - Ugotavljanje karakterističnih vrednosti mehanskih lastnosti in
gostote (vključno z dopolnilom A2)
Structural timber - Determination of characteristic values of mechanical properties and
density
Bauholz für tragende Zwecke - Bestimmung charakteristischer Werte für mechanische
Eigenschaften und Rohdichte
Bois de structure - Détermination des valeurs caractéristiques des propriétés
mécaniques et de la masse volumique
Ta slovenski standard je istoveten z: EN 384:2016+A2:2022
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
91.080.20 Lesene konstrukcije Timber structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 384:2016+A2
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2022
EUROPÄISCHE NORM
ICS 79.040 Supersedes EN 384:2016+A1:2018
English Version
Structural timber - Determination of characteristic values
of mechanical properties and density
Bois de structure - Détermination des valeurs Bauholz für tragende Zwecke - Bestimmung
caractéristiques des propriétés mécaniques et de la charakteristischer Werte für mechanische
masse volumique Eigenschaften und Rohdichte
This European Standard was approved by CEN on 8 October 2018 and includes Amendment 2 approved by CEN on 13 March
2022.
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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 384:2016+A2:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 7
5 Mechanical properties determined from full-size specimens . 8
5.1 Sampling . 8
5.2 Testing . 8
5.3 Reference conditions . 9
5.3.1 Moisture content . 9
5.3.2 Bending strength . 9
5.3.3 Tension strength . 9
5.3.4 Density . 9
5.4 Adjustment factors . 9
5.4.1 General . 9
5.4.2 Moisture content . 9
5.4.3 Timber size and test length . 10
5.4.4 Modulus of elasticity . 11
5.4.5 Other adjustments . 12
5.5 Analysis of data . 12
5.5.1 Sub-sample analysis . 12
5.5.2 Characteristic values . 12
6 Bending strength and modulus of elasticity determined from small, clear hardwood
specimens . 14
7 Other mechanical properties for hardwoods and softwoods . 14
8 Report . 16
Annex A (normative) Requirements for reports for visual grading assignment . 17
Bibliography . 20

European foreword
This document (EN 384:2016+A2:2022) 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 December 2022, 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 includes Amendment 1 approved by CEN on 8 October 2018 and Amendment 2
approved by CEN on 13 March 2022.
This document supersedes !EN 384:2016+A1:2018".
The start and finish of text introduced or altered by amendment is indicated in the text by tags !"
and #$.
!Deleted text"
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Introduction
Structural design codes can only function effectively if standard methods of determining the mechanical
and physical properties exist. The aim of the procedures given in this standard is to derive
characteristic values that are comparable in terms of the populations they represent. The standard
permits the use of as much existing test data as possible from various sampling and testing techniques.
Where methods are given to permit characteristic values to be determined from a less than ideal
amount of structural size test data, reduction factors to reflect a lower degree of confidence are
employed.
1 Scope
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.
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 338, Structural timber — Strength classes
EN 408, Timber structures — Structural timber and glued laminated timber — Determination of some
physical and mechanical properties
EN 13183-2, Moisture content of a piece of sawn timber — Part 2: Estimation by electrical resistance
method
EN 13183-3, Moisture content of a piece of sawn timber — Part 3: Estimation by capacitance method
EN 14081-1:2016, Timber structures — Strength graded structural timber with rectangular cross section
— Part 1: General requirements
EN 14081-2, Timber structures — Strength graded structural timber with rectangular cross section —
Part 2: Machine grading; additional requirements for initial type testing
EN 14081-3, Timber structures — Strength graded structural timber with rectangular cross section —
Part 3: Machine grading; additional requirements for factory production control
EN 14358:2016, Timber structures — Calculation and verification of characteristic values
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
characteristic value
representative value of a material property used for design, which is based either on 5-percentile values
(e.g. strength properties and density) or mean values (e.g. modulus of elasticity)
3.2
p-percentile
value for which the probability of getting lower values is p %
3.3
population
timber for which the characteristic values are relevant
3.4
timber source
identifiable geographical origin of a species or species combination from which timber is, or is intended
to be, strength graded
3.5
sample
a number of ungraded specimens of one timber species or species combination, one source, with sizes
and quality representative of the timber population (see 5.1)
3.6
sub-sample
part of one or more samples consisting of specimens of one grade
3.7
small clear test
test to determine mechanical properties of small defect-free specimens
3.8
specimen
piece of timber from which the test piece is taken
3.9
thickness
lesser dimension perpendicular to the longitudinal axis of a piece of timber
3.10
width
larger dimension perpendicular to the longitudinal axis of a piece of timber
3.11
depth
in the case of bending, cross-sectional dimension parallel to the direction of loading; in the case of
tension, the width
4 Symbols and abbreviations
a distance between the inner load points of the bending test (in mm)
f
E modulus of elasticity parallel to grain (in N/mm )
E mean characteristic value of modulus of elasticity parallel to grain (in N/mm )
0,mean
E 5-percentile characteristic value of modulus of elasticity parallel to grain (in N/mm )
0,k
E mean characteristic value of modulus of elasticity perpendicular to grain (in N/mm )
90,mean
mean modulus of elasticity for on
...