SIST EN 14081-1:2016+A1:2019

SLOVENSKI STANDARD
SIST EN 14081-1:2016+A1:2019
01-november-2019
Nadomešča:
SIST EN 14081-1:2016
Lesene konstrukcije - Po trdnosti razvrščen konstrukcijski les pravokotnega
prečnega prereza - 1. del: Splošne zahteve
Timber structures - Strength graded structural timber with rectangular cross section -
Part 1: General requirements
Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende zwecke mit
rechteckigem Querschnitt - Teil 1: Allgemeine Anforderungen
Structures en bois - Bois de structure à section rectangulaire classé pour sa résistance -
Partie 1 : Exigences générales
Ta slovenski standard je istoveten z: EN 14081-1:2016+A1:2019
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
91.080.20 Lesene konstrukcije Timber structures
SIST EN 14081-1:2016+A1:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14081-1:2016+A1:2019

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SIST EN 14081-1:2016+A1:2019


EN 14081-1:2016+A1
EUROPEAN STANDARD

NORME EUROPÉENNE

August 2019
EUROPÄISCHE NORM
ICS 79.040 Supersedes EN 14081-1:2016
English Version

Timber structures - Strength graded structural timber
with rectangular cross section - Part 1: General
requirements
Structures en bois - Bois de structure à section Holzbauwerke - Nach Festigkeit sortiertes Bauholz für
rectangulaire classé pour sa résistance - Partie 1 : tragende zwecke mit rechteckigem Querschnitt - Teil 1:
Exigences générales Allgemeine Anforderungen
This European Standard was approved by CEN on 9 February 2016 and includes Amendment 1 approved by CEN on 14 May
2019.

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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14081-1:2016+A1:2019 E
worldwide for CEN national Members.

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SIST EN 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Symbols . 8
5 Requirements for structural timber . 9
5.1 Mechanical resistance . 9
5.1.1 General . 9
5.1.2 Visual strength grading . 9
5.1.3 Machine strength grading . 9
5.2 Fire resistance (charring rate) .11
5.3 Reaction to fire .11
5.4 Release of dangerous substances .12
5.5 Biological durability .12
5.5.1 Structural timber without preservative treatment .12
5.5.2 Structural timber with preservative treatment .12
5.6 Geometrical data .12
6 Assessment and verification of constancy of performance –AVCP .13
6.1 General .13
6.2 Type testing .13
6.2.1 General .13
6.2.2 Test samples, testing and compliance criteria .13
6.2.3 Test reports .14
6.2.4 Shared other party results .15
6.3 Factory production control (FPC) .15
6.3.1 General .15
6.3.2 Requirements .15
6.3.3 Product specific requirements .19
6.3.4 Initial inspection of factory and of FPC .20
6.3.5 Continuous surveillance of FPC .20
6.3.6 Procedure for modifications .20
7 Marking .21
7.1 Marking methods .21
7.2 Information on the timber (method A) or on the package (method B) .21
7.3 Information in the documents accompanying strength graded structural timber .22
8 Environmental issues .23
Annex A (normative) Requirements for strength reducing characteristics for visual grading
standards .24
A.1 Limitations for strength-reducing characteristics .24
A.1.1 Knots .24
A.1.2 Slope of grain .24
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SIST EN 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
A.1.3 Density and rate of growth . 24
A.1.4 Fissures . 25
A.2 Limitations for geometrical characteristics . 25
A.2.1 Wane . 25
A.2.2 Warp . 25
A.3 Limitations for biological characteristics . 26
A.4 Other characteristics . 26
A.4.1 Reaction wood . 26
A.4.2 Other criteria . 26
Annex B (normative) Marking codes for species . 27
B.1 Marking codes for single species . 27
B.2 Marking codes for species combination . 28
Annex C (normative) Measurement of moisture content . 30
C.1 General . 30
C.2 Measurement of moisture content of timber during production. 30
Annex ZA (informative) Relationship of this European Standard with Regulation (EU)
No.305/2011 . 31
ZA.1 Scope and relevant characteristics . 31
ZA.2 System of Assessment and Verification of Constancy of Performance (AVCP) . 33
ZA.3 Assignment of AVCP tasks . 33
Bibliography . 36

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SIST EN 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
European foreword
This document (EN 14081-1:2016) 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 February 2020, and conflicting national standards
shall be withdrawn at the latest by May 2021.
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 2019-05-14.
This document supersedes !EN 14081-1:2016".
The start and finish of text introduced or altered by amendment is indicated in the text by tags !".
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 Regulation n°305/2011.
For relationship with EU Regulation, see informative Annex ZA, which is an integral part of this
document.
EN 14081-4:2009 will be withdrawn and replaced by 5.1.3, paragraph 2 of this document.
Compared to EN 14081-1:2005+A1:2011, the following modifications have been made:
— new Clause 6 for Assessment and Verification of Constancy of Performance linked to the CPR;
— Annex ZA has been adapted to the CPR;
— new clauses on Fire Resistance, release of dangerous substances, geometrical data and
environmental issues have been added;
— marking codes for species combinations have been moved to Annex B;
— improvement of several definitions.
Other parts of the series of EN 14081 are:
— 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.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
Introduction
There are basically two methods of strength grading: visual grading and machine grading.
Machine grading is in common use in a number of countries. The countries use two basic systems,
referred to as 'output control' and 'machine control'. Both systems require a visual override inspection
to cater for strength-reducing characteristics that are not automatically sensed by the machine.
Output control is suitable for use where the grading machines are situated in manufacturing units
grading limited sizes, species and grades in repeated production runs. 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.
Machine control 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.
Machine control 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.
Visual grading is also in common use in a number of countries. There are many different visual strength
grading standards for timber in use in Europe. These have come into existence to allow for:
— different species or groups of species;
— geographic origin;
— different dimensional requirements;
— varying requirements for different uses;
— quality of material available;
— historic influences or traditions.
Because of the diversity of existing visual grading standards in use in different countries, it is currently
impossible to lay down a single standard for all Member States.
The requirements given in this European Standard on visual strength grading are therefore basic
principles, which should be followed when drawing up requirements for limits for some of the
characteristics.
The assignments to strength classes are based on grading reports.
When these grading reports are evaluated and approved by CEN/TC 124/WG2/TG1, they become
Approved Grading Reports (AGR) which are required for assigning visual grades to EN 1912 and for
machine control.
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SIST EN 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
1 Scope
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.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 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 density
EN 844-7, Round and sawn timber — Terminology — Part 7: Terms relating to anatomical structure of
timber
EN 844-9, Round and sawn timber — Terminology — Part 9: Terms relating to features of sawn timber
EN 844-10, Round and sawn timber — Terminology — Part 10: Terms relating to stain and fungal attack
EN 1310:1997, Round and sawn timber — Method of measurement of features
EN 1912, Structural Timber — Strength classes — Assignment of visual grades and species
EN 1995-1-2, Eurocode 5: Design of timber structures — Part 1-2: General — Structural fire design
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SIST EN 14081-1:2016+A1:2019
EN 14081-1:2016+A1:2019 (E)
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 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 test 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 13556, Round and sawn timber — Nomenclature of timbers used in Europe
EN 13823, Reaction to fire tests for building products — Building products excluding floorings exposed to
the thermal attack by a single burning item
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 15804, Sustainability of construction works — Environmental product declarations — Core rules for
the product category of construction products
EN 15228:2009, Structural timber — Structural timber preservative treated against biological attack
EN 16485, Round and sawn timber — Environmental Product Declarations — Product category rules for
wood and wood-based products for use in construction
EN ISO 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1:
Country codes (ISO 3166-1)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dry-graded structural timber
timber for which grading has been completed after it has been dried
3.2
grading standard
a set of grading rules contained in a National Standard or a proprietary document that is publically
available
3.3
machine strength grading
process by which structural timber is sorted by a machine sensing, non-destructively, one or more
properties of the timber, with any necessary visual overriding inspection, into grades or strength
classes to which characteristic values of strength, stiffness and density may be allocated
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EN 14081-1:2016+A1:2019 (E)
3.4
package
structural timber of one grade, of one species or species combination, to be delivered to one customer
3.5
settings
values associated with the variable controls of a grading machine which determine the acceptance to
each grade or strength class of structural timber graded by the machine
3.6
strength class
result of the classification of structural timber based on particular values of its mechanical properties
and density
3.7
structural timber
timber with rectangular cross section strength graded either by visual means or by machine
3.8
strength-reducing characteristic
property or feature of a piece of structural timber that reduces its load bearing capacity
Note 1 to entry: Can result from natural growth of the tree (e.g. knots, slope of grain), changes in moisture
content (e.g. fissures), conversion of the log (e.g. the inclusion of wane), attack from fungi, insects or mechanical
damage.
3.9
timber source
identifiable geographical origin of a species or species combination from which timber is, or is intended
to be, strength graded
3.10
visual strength grading
process by which structural timber is sorted, by visual inspection and assessment, into grades to which
characteristic values of strength, stiffness and density can be allocated
Note 1 to entry: Electronic or mechanical instruments can be used to assist the visual grader in this process.
3.11
thickness
smaller dimension perpendicular to the longitudinal axis of a piece of timber
3.12
width
greater dimension perpendicular to the longitudinal axis of a piece of timber
4 Symbols
M machine graded structural timber
DG dry-graded structural timber
PT preservative treated structural timber
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EN 14081-1:2016+A1:2019 (E)
5 Requirements for structural timber
5.1 Mechanical resistance
5.1.1 General
Mechanical resistance covers modulus of elasticity, bending strength, compressive strength, tension
strength, shear strength and density.
Structural timber shall be either visually graded according to 5.1.2, or machine graded according to
5.1.3, and have characteristic values for the bending strength, tension strength, compression strength,
shear strength, modulus of elasticity and density according to 5.1.2 or 5.1.3. Characteristic values shall
be determined in accordance with EN 384.
If the structural timber is assigned to a strength class from EN 338, the characteristic values for the
properties shall be those given for the strength class in EN 338.
If the grading has been carried out before processing, provided that the processing reduction is not
greater than 5 mm for dimensions greater than or equal to 22 mm but less than or equal to 100 mm, or
not greater than 10 mm for dimensions greater than 100 mm, the grade shall be considered not to have
changed. If the reduction is greater, the structural timber shall be re-graded.
Structural timber that has previously been graded shall not be re-graded to the same or different grades
unless the method of determining characteristic values has made allowances for changes to the timber
population caused by the previous grading.
Since some geometrical characteristics (fissures, distortion) depend on the moisture content and affect
the strength properties, marking shall consider the moisture content at the time of grading.
Moisture content shall be determined in accordance with EN 13183-2 or EN 13183-3 with an accuracy
of ± 3 % moisture content (see Annex C).
Dry graded structural timber shall have at the time it is graded for fissures and distortion, a mean
moisture content of 20 % or less with no individual measurement exceeding 24 %.
If the grading method restricts the structural timber to a special use, e.g. flatwise bending or
compression, this shall be reflected in the marking.
5.1.2 Visual strength grading
Structural timber shall be graded visually in accordance with a grading standard which meets the
requirements given in Annex A. This grading standard shall be publically available.
If the grade and species or species combination have been assigned to a strength class by EN 1912, the
characteristic values for the properties shall be those given for the assigned strength class in EN 338.
Assignments according to EN 384 to be included in EN 1912 should be reported and evaluated by
CEN/TC 124. Accepted reports shall be documented in Approved Grading Reports (AGR).
NOTE Approved Grading Reports are intended to give basic documentation for the certification by a Notified
Body of a manufacturer's factory production control (FPC) needed for the CE marking. A current list of AGRs may
be obtained through CEN/TC 124 secretariat.
If there are any restrictions or additional criteria related to the strength or use of structural timber,
resulting from the method of grading or species or species combination, they shall be stated in the
grading standard.
5.1.3 Machine strength grading
For a grade and species (or species combination) graded by a machine control system, the settings shall
be derived for the total growth area from which the structural timber will be sourced.
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EN 14081-1:2016+A1:2019 (E)
Grading machines shall use settings determined in accordance with EN 14081-2. Grading machines and
settings used in machine control system should be evaluated by CEN/TC 124. Settings which have been
accepted by CEN/TC 124 shall be documented in Approved Grading Reports (AGR).
NOTE Approved Grading Reports are intended to give basic documentation for the certification by a Notified
Body of a manufacturer's factory production control (FPC) needed for the CE marking. A current list of AGRs may
be obtained through CEN/TC 124 secretariat.
The visual characteristics of each piece of machine graded structural timber shall meet the
requirements given in Table 1.
Table 1 — Visual override inspection requirements for machine strength graded structural
timber
Strength class according to C18, D18, T11 and below Above C18, D18, T11
a
EN 338

f
Max. length Fissures not
Fissures less than half the thickness may be ignored
b
going through
of fissures
Not greater than 1,5 m or 1/2 the length Not greater than 1 m or 1/4 the
the thickness
of the piece, whichever is the lesser length of the piece, whichever is
the lesser
Fissures going Not greater than 1 m or 1/4 the length of Only permitted at the ends with
through the the piece, whichever is the lesser. If at a length not greater than the
thickness the ends, a length not greater than two width
...