Timber structures - Strength graded structural timber with rectangular cross section - Part 3: Machine grading; additional requirements for factory production control

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.

Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, zusätzliche Anforderungen an die werkseigene Produktionskontrolle

Dieses Dokument legt Anforderungen an die werkseigene Produktionskontrolle für maschinell sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt und mit sägerauer, gehobelter oder anders bearbeiteter Oberfläche fest und das die zulässigen Maßabweichungen nach EN 336 einhält. Die Anforderungen gelten neben den in EN 14081-1 angegebenen.

Structures en bois - Bois de structure à section rectangulaire classé pour sa résistance - Partie 3 : Classement mécanique ; exigences complémentaires relatives au contrôle de la production en usine

Le présent document fixe des exigences qui viennent s'ajouter à celles de l’EN 14081-1 sur le contrôle de production en usine des bois de structure de section rectangulaire classés par machine et profilé par sciage, rabotage ou d’autres méthodes, et dont les écarts admissibles de dimensions respectent les tolérances indiquées dans l'EN 336.

Lesene konstrukcije - Razvrščanje konstrukcijskega lesa pravokotnega prečnega prereza po trdnosti - 3. del: Strojno razvrščanje - Dodatne zahteve za kontrolo proizvodnje v obratu

General Information

Status
Not Published
Current Stage
4599 - Dispatch of FV draft to CMC - Finalization for Vote
Due Date
22-Sep-2021
Completion Date
22-Sep-2021

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SLOVENSKI STANDARD
oSIST prEN 14081-3:2020
01-januar-2020
Lesene konstrukcije - Razvrščanje konstrukcijskega lesa pravokotnega prečnega
prereza po trdnosti - 3. del: Strojno razvrščanje - Dodatne zahteve za kontrolo
proizvodnje v obratu

Timber structures - Strength graded structural timber with rectangular cross section -

Part 3: Machine grading; additional requirements for factory production control
Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit

rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, zusätzliche Anforderungen an

die werkseigene Produktionskontrolle

Structures en bois - Bois de structure à section rectangulaire classé pour sa résistance -

Partie 3 : Classement mécanique ; exigences complémentaires relatives au contrôle de

la production en usine
Ta slovenski standard je istoveten z: prEN 14081-3
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
91.080.20 Lesene konstrukcije Timber structures
oSIST prEN 14081-3:2020 en,fr,de

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

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oSIST prEN 14081-3:2020
---------------------- Page: 2 ----------------------
oSIST prEN 14081-3:2020
DRAFT
EUROPEAN STANDARD
prEN 14081-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2019
ICS 79.040 Will supersede EN 14081-3:2012+A1:2018
English Version
Timber structures - Strength graded structural timber
with rectangular cross section - Part 3: Machine grading;
additional requirements for factory production control

Structures en bois - Bois de structure à section Holzbauwerke - Nach Festigkeit sortiertes Bauholz für

rectangulaire classé pour sa résistance - Partie 3 : tragende Zwecke mit rechteckigem Querschnitt - Teil

Classement mécanique ; exigences complémentaires 3: Maschinelle Sortierung, zusätzliche Anforderungen

relatives au contrôle de la production en usine an die werkseigene Produktionskontrolle

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 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.

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
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. prEN 14081-3:2019 E

worldwide for CEN national Members.
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oSIST prEN 14081-3:2020
prEN 14081-3:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Requirements for the operation, calibration and maintenance of a grading machine ......... 5

5 Additional requirements for factory production control for machine controlled

systems ............................................................................................................................................................... 6

5.1 General ................................................................................................................................................................ 6

5.2 Requirements for bending strength classes with a characteristic bending strength

level above 30 N/mm and for tension strength classes with a characteristic tension

strength level above 21 N/mm ................................................................................................................. 6

6 Additional factory production control requirements for output controlled systems ........... 6

6.1 General ................................................................................................................................................................ 6

6.2 Grading ................................................................................................................................................................ 6

6.3 Sampling ............................................................................................................................................................. 6

6.4 Destructive testing and calculation of characteristic values........................................................... 7

6.5 Batch verification ............................................................................................................................................ 7

6.6 Recording ........................................................................................................................................................... 8

Annex A (normative) Requirements for using control planks....................................................................... 9

A.1 General ................................................................................................................................................................ 9

A.2 Requirements for selecting the control planks .................................................................................... 9

A.3 Requirements for the use of control planks for internal factory production control ............ 9

A.4 Requirements for the use of control planks for third party factory production

control .............................................................................................................................................................. 10

Bibliography ................................................................................................................................................................. 11

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oSIST prEN 14081-3:2020
prEN 14081-3:2019 (E)
European foreword

This document (prEN 14081-3:2019) has been prepared by Technical Committee CEN/TC 124 “Timber

structures”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14081-3:2012+A1:2018.
The other parts of the EN 14081 series are:

— EN 14081-1, 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 type testing.
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oSIST prEN 14081-3:2020
prEN 14081-3:2019 (E)
Introduction

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

nonidentical 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 document gives appropriate

statistical procedures.

The requirements in this document are based on machines in current use and on future types of machines

as far as these can be foreseen. It is recognized that additional clauses or standards may be required if

unforeseen developments take place.
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oSIST prEN 14081-3:2020
prEN 14081-3:2019 (E)
1 Scope

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.

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 384, Structural timber — Determination of characteristic values of mechanical properties and density

EN 408, Timber structures — Structural timber and glued laminated timber — Determination of some

physical and mechanical properties

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

1: General requirements

EN 14081-2:2018, Timber structures — Strength graded structural timber with rectangular cross section

— Part 2: Machine grading; additional requirements for type testing
3 Terms and definitions

For the purpose of this document, the terms and definitions given in EN 14081-1 and the following 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
production batch
one production run where the timber of one source, grade or gr
...

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