DIN EN 14081-3-2012 Timber structures - Strength graded structural timber with rectangular cross section - Part 3 Machine grading additional requirements for factory production con.pdf

1、April 2012 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS

2、79.040!$R7“1884720www.din.deDDIN EN 14081-3Timber structures Strength graded structural timber with rectangular cross section Part 3: Machine grading; additional requirements for factory productioncontrolEnglish translation of DIN EN 14081-3:2012-04Holzbauwerke Nach Festigkeit sortiertes Bauholz fr

3、tragende Zwecke mit rechteckigem Querschnitt Teil 3: Maschinelle Sortierung, zustzliche Anforderungen an die werkseigeneProduktionskontrolleEnglische bersetzung von DIN EN 14081-3:2012-04Structures en bois Bois de structure section rectangulaire class pour sa rsistance Partie 3: Classement mcanique

4、Exigences complmentaires relatives au contrle de laproduction en usineTraduction anglaise de DIN EN 14081-3:2012-04SupersedesDIN EN 14081-3:2006-03www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 19 pages03.12 DIN EN 14081-3:2012-04 2 A

5、comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee CEN/TC 124 “Timber structures” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was the Normenausschuss Bauwesen (Building and Civil Engineering Standard

6、s Committee), Working Committee NA 005-04-01 AA Holzbau (SpA CEN/TC 124, CEN/TC 250/SC 5). Amendments This standard differs from DIN EN 14081-3:2006-03 as follows: a) the term “indicating property” has been defined; b) Clause 7 has been revised as informative Annex B; c) requirements for using contr

7、ol planks and a decision diagram for internal verification procedure in connec-tion with control planks have been included in Annex A Previous editions DIN EN 518: 1996-07 DIN EN 519: 1996-07 DIN EN 14081-3: 2006-03 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14081-3 January 2012 ICS 79.040

8、 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 section rectangulaire class pour sa rsistance - Par

9、tie 3: Classement mcanique - Exigences complmentaires relatives au contrle de la production en usine Holzbauwerke - Nach Festigkeit sortiertes Bauholz fr tragende Zwecke mit rechteckigem Querschnitt - Teil 3: Maschinelle Sortierung, zustzliche Anforderungen an die werkseigene Produktionskontrolle Th

10、is 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 refe

11、rences 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 CE

12、N 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, Ic

13、eland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any mean

14、s reserved worldwide for CEN national Members. Ref. No. EN 14081-3:2012: EEUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG EN 14081-3:2012 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Terms and definitions .54 Sym

15、bols 55 Requirements for the operation, calibration and maintenance of a grading machine .66 Additional requirements for factory production control for machine controlled systems 66.1 General 66.2 Requirements for strength grades with a characteristic strength level above C30 .67 Additional factory

16、production control requirements for output controlled systems .7Annex A (normative) Requirements for using control planks 8A.1 General 8A.2 Requirements for selecting the control planks 8A.3 Requirements for the use of control planks for internal factory production control .8A.4 Requirements for the

17、 use of control planks for third party factory production control 9Annex B (informative) Additional factory production control requirements for output controlled systems 10B.1 General . 10B.2 Production control 10Annex C (informative) Example of cusum control charts 13Bibliography . 17DIN EN 14081-3

18、:2012-04 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 t

19、ext 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

20、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

21、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 grade

22、d 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 transfe

23、rred 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, Cyp

24、rus, 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. DIN EN 14081-3:2012-04 EN 14

25、081-3:2012 (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 automat

26、ically 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 spe

27、cimens 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 m

28、achines 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 therefo

29、re 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

30、 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 addition

31、al clauses or standards may be required if unforeseen developments take place. DIN EN 14081-3:2012-04 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 rectangula

32、r 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 ap

33、plies. 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 ti

34、mber 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 term

35、s 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 achiev

36、ed 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 det

37、ermining 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 represent

38、ative of one species population 4 Symbols A cusum control parameter B cusum control parameter Bacusum parameter associated with acceptable quality level DIN EN 14081-3:2012-04 EN 14081-3:2012 (E) 6 Brcusum parameter associated with rejectable quality level Epactual modulus of elasticity measured in

39、a proof load test (in N/mm2) E0,meancharacteristic mean modulus of elasticity parallel to grain (in N/mm2) Fpproof load (in N) K cusum control parameter Larun length in acceptable region for cusum control Lrrun length in rejectable region for cusum control N cusum control parameter Y cusum control p

40、arameter 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 manufacturers specification shall be made to the machine. 5.2 Access to all machine adjustments shall be limited to personn

41、el authorised to operate or set up the machine. 5.3 The strength grading machine shall be regularly calibrated in accordance with the manufacturers 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

42、 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

43、 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 syste

44、m, grading accuracy shall be monitored, A grading machines 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 f

45、rom 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 DIN EN 14081-3:2012-04 EN 14081-3:2

46、012 (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, p

47、rovided the relation between the two properties is verified from test data. If the timber is graded to tensile strength classes then this test shall be carried out in tension or bending in accordance with EN 408. 7 Additional factory production control requirements for output controlled systems A pr

48、ocedure is given in Annex B and Annex C. DIN EN 14081-3:2012-04 EN 14081-3:2012 (E) 8 Annex A (normative) Requirements for using control planks A.1 General When grading structural timber in a machine controlled system, grading accuracy shall be monitored by controlling the grading machine whilst it is running at production speed. The installation and calibration shall be checked by the use of control planks, using