SIST EN 14081-3:2012
(Main)Timber structures - Strength graded structural timber with rectangular cross section - Part 3: Machine grading; additional requirements for factory production control
Timber structures - Strength graded structural timber with rectangular cross section - Part 3: Machine grading; additional requirements for factory production control
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.
Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, Zusätzliche Anforderungen an die werkseigene Produktionskontrolle
Diese Europäische Norm legt Anforderungen an die werkseigene Produktionskontrolle für maschinell sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt fest, welches durch Sägen, Hobeln oder andere Produktionsverfahren hergestellt wurde und 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
La présente Norme européenne 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 dimensions s'écartent des dimensions cibles correspondant à l'EN 336.
Lesene konstrukcije - Razvrščanje konstrukcijskega lesa pravokotnega prečnega prereza po trdnosti - 3. del: Strojno razvrščanje - Dodatne zahteve za kontrolo proizvodnje v obratu
Ta evropski standard določa dodatne zahteve poleg zahtev iz standarda EN 14081-1 za kontrolo proizvodnje v obratu strojno razvrščenega konstrukcijskega lesa s pravokotnim prečnim prerezom, oblikovanim z žaganjem, struženjem ali z drugimi metodami, in z odstopanji od ciljnih velikosti v skladu s standardom EN 336. Strojno razvrščanje se splošno uporablja v številnih državah. Države uporabljajo dva osnovna sistema, in sicer sistem na podlagi nadzora proizvodnje in sistem na podlagi strojnega nadzora. Oba sistema zahtevata tudi hkratni vizualni pregled zaradi ugotavljanja lastnosti, ki zmanjšujejo trdnost in ki jih stroj ne more avtomatično zaznati. Sistem na podlagi nadzora proizvodnje je primeren za uporabo, kadar se stroji za razvrščanje nahajajo v žagah, kjer razvrščajo omejene velikosti, vrste in stopnje v zaporednih proizvodnih serijah približno ene delovne izmene ali več izmen. To omogoča nadzor sistema na podlagi preskušanja lesenih vzorcev dnevne proizvodnje. Ti preskusi se skupaj s statističnimi postopki uporabljajo za nadzor in prilagajanje nastavitev stroja, da se za vsak razred trdnosti ohranijo zahtevane lastnosti trdnosti. Pri tem sistemu so lahko zahteve za odobritev stroja manj stroge, za stroje iste vrste pa ni nujna enaka zmogljivost. Sistem na podlagi strojnega nadzora se je razvil v Evropi. Zaradi velikega števila uporabljenih velikosti, vrst in razredov ni bilo mogoče izvajati preskusov nadzora kakovosti na lesenih vzorcih iz proizvodnje. Sistem zato temelji na strogem ocenjevanju in nadzoru strojev ter na znatnem raziskovalnem prizadevanju za določitev nastavitev strojev, ki so pri vseh strojih iste vrste enake. Sprejemljivost strojev za razvrščanje in določitev nastavitev temeljita na statističnih postopkih, zato bodo rezultati odvisni od uporabljene metode. Zato ta evropski standard navaja ustrezne statistične postopke. Zahteve v tem evropskem standardu temeljijo na strojih, ki se trenutno uporabljajo, in na prihodnjih vrstah strojev, kot jih je mogoče predvideti. Ugotovljeno je, da bodo v primeru nepredvidenega razvoja dogodkov morda potrebne dodatne točke in standardi.
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, Zusätzliche Anforderungen an die werkseigene ProduktionskontrolleStructures 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 usineTimber structures - Strength graded structural timber with rectangular cross section - Part 3: Machine grading; additional requirements for factory production control91.080.20Lesene konstrukcijeTimber structures79.040Les, hlodovina in žagan lesWood, sawlogs and sawn timberICS:Ta slovenski standard je istoveten z:EN 14081-3:2012SIST EN 14081-3:2012en,fr,de01-oktober-2012SIST EN 14081-3:2012SLOVENSKI
STANDARDSIST EN 14081-3:20061DGRPHãþD
SIST EN 14081-3:2012
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14081-3
January 2012 ICS 79.040 Supersedes EN 14081-3:2005English 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 rectangulaire classé pour sa résistance - Partie 3: Classement mécanique - Exigences complémentaires relatives au contrôle de la production en usine
Holzbauwerke - Nach Festigkeit sortiertes Bauholz für tragende Zwecke mit rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, zusätzliche Anforderungen an die werkseigene Produktionskontrolle This European Standard was approved by CEN on 16 December 2011.
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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14081-3:2012: ESIST EN 14081-3:2012
EN 14081-3:2012 (E) 2 Contents Page Foreword .3Introduction .41Scope .52Normative references .53Terms and definitions .54Symbols .55Requirements for the operation, calibration and maintenance of a grading machine .66Additional requirements for factory production control for machine controlled systems .66.1General .66.2Requirements for strength grades with a characteristic strength level above C30 .67Additional factory production control requirements for output controlled systems .7Annex A (normative)
Requirements for using control planks .8A.1General .8A.2Requirements for selecting the control planks .8A.3Requirements for the use of control planks for internal factory production control .8A.4Requirements for the use of control planks for third party factory production control .9Annex B (informative)
Additional factory production control requirements for output controlled systems . 10B.1General . 10B.2Production control . 10Annex C (informative)
Example of cusum control charts . 13Bibliography . 17 SIST EN 14081-3:2012
EN 14081-3:2012 (E) 3 Foreword This document (EN 14081-3:2012) has been prepared by Technical Committee CEN/TC124 “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 July 2012, and conflicting national standards shall be withdrawn at the latest by July 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 14081-3:2005. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. Other parts of the series of EN 14081 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 initial type testing; EN 14081-4, Timber structures
Strength graded structural timber with rectangular cross section
Part 4: Machine grading
Grading machine settings for machine controlled systems. Compared to EN 14081-3:2005 the following modifications have been made: the additional factory production control requirements for output controlled systems are transferred in Annex B (informative);
in Annex A, the requirements for using control planks are updated.
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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
SIST EN 14081-3:2012
EN 14081-3:2012 (E) 4 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 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. SIST EN 14081-3:2012
EN 14081-3:2012 (E) 5 1 Scope 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. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. 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, Timber structures — Strength graded structural timber with rectangular cross section — Part 2: Machine grading; additional requirements for initial 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. 3.1 depth dimension perpendicular to the longitudinal axis of a timber beam, in the plane of the bending forces 3.2 grade determining property mechanical or physical property for which a particular value of that property has to be achieved for the material to be assigned to that grade, e.g. bending strength, mean modulus of elasticity and density for the strength classes of EN 338 3.3 indicating property measurement or combination of measurements made by the grading machine, which are closely related to one or more of the grade determining properties. For grading machines which compute and predict values of the grade determining properties directly from numerous measuring devices, the indicating property may be a predicted value of a grade determining property 3.4 sample number of specimens of timber of one size and representative of one species population 4 Symbols A
cusum control parameter
B
cusum control parameter
Ba
cusum parameter associated with acceptable quality level
SIST EN 14081-3:2012
EN 14081-3:2012 (E) 6 Br
cusum parameter associated with rejectable quality level Ep
actual modulus of elasticity measured in a proof load test (in N/mm2)
E0,mean
characteristic mean modulus of elasticity parallel to grain (in N/mm2)
Fp
proof load (in N)
K
cusum control parameter
La
run length in acceptable region for cusum control
Lr
run length in rejectable region for cusum control
N
cusum control parameter
Y
cusum control parameter
Z
cusum control parameter 5 Requirements for the operation, calibration and maintenance of a grading machine 5.1 No modifications that are in conflict with the machine manufacturer’s specification shall be made to the machine. 5.2 Access to all machine adjustments shall be limited to personnel authorised to operate or set up the machine. 5.3 The strength grading machine shall be regularly calibrated in accordance with the manufacturer's specification. 5.4 A strength grading machine shall only be fitted with spare parts equivalent to, or improving upon, the performance of those fitted at the time the machine was assessed by initial type testing. If spare parts are fitted that are not identical to those fitted at the time the machine was assessed by initial type testing, the machine shall be reassessed to establish their effect on grading accuracy. 5.5 The results of routine service and maintenance to the strength-grading machine and ancillary equipment shall be recorded together with the results of calibration checks. 6 Additional requirements for factory production control for machine controlled systems 6.1 General When grading structural timber in a machine controlled system, grading accuracy shall be monitored, A grading machine’s dynamic performance shall be controlled by the use of control planks using the procedures given in Annex A. 6.2 Requirements for strength grades with a characteristic strength level above C30 During each working shift, two pieces of timber from each grade produced shall be randomly selected and tested for edgewise bending strength as given in EN 408 with the tension edge selected at random and the estimated weakest cross section positioned where possible within the centre third of the span. The fifth SIST EN 14081-3:2012
EN 14081-3:2012 (E) 7 percentile value, determined by ranking, of the 100 bending strength values from 50 consecutive shifts shall meet the required bending strength (as given in EN 14081-2). A strength property other than edgewise bending strength may be used for factory production control as an alternative, provided the relation between the two properties is verified from test data. If the timber is graded to tensile strength classes then this t
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