EN 14298-2017 en Sawn timber - Assessment of drying quality.pdf

1、Sawn timber - Assessment of drying qualityBS EN 14298:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14298 October 2017 ICS 79.040 Supersedes EN 14298:2004English Version Sawn timber - Assessment of drying qua

2、lity Bois sci - Estimation de la qualit du schage Schnittholz - Ermittlung der Trocknungsqualitt This European Standard was approved by CEN on 4 September 2017. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard

3、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, Fr

4、ench, 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, Bulgari

5、a, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerlan

6、d, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Mem

7、bers. Ref. No. EN 14298:2017 ENational forewordThis British Standard is the UK implementation of EN 14298:2017. It supersedes BS EN 14298:2004, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee B/543, Round and sawn timber.A list of organizations represe

8、nted on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580

9、93217 5ICS 79.040Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDAR

10、DBS EN 14298:2017EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14298 October 2017 ICS 79.040 Supersedes EN 14298:2004English Version Sawn timber - Assessment of drying quality Bois sci - Estimation de la qualit du schage Schnittholz - Ermittlung der Trocknungsqualitt This European Standard wa

11、s approved by CEN on 4 September 2017. 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

12、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 l

13、anguage 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, Former Yugoslav Republic of Macedonia, France, Germany, Gre

14、ece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR

15、 NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14298:2017 EBS EN 14298:2017EN 14298:2017 (E) 2 Contents Page European foreword . 3 1 Scope 4 2 Normativ

16、e references 4 3 Terms and definitions . 4 4 Symbols and abbreviations . 5 5 Drying quality specification 5 5.1 General 5 5.2 Standard drying quality 5 5.3 Specific end-use drying . 6 6 Assessment by control of drying quality of a lot of sawn timber . 6 6.1 General 6 6.2 Sampling . 7 6.3 Moisture co

17、ntent . 7 6.4 Criteria drying quality . 8 6.4.1 Moisture content . 8 6.4.2 Case-hardening 8 6.5 Test report . 8 Annex A (informative) Example for an assessment of standard drying quality 12 % 9 A.1 General 9 A.2 Sampling . 9 A.3 Measurements 9 A.4 Assessment of drying quality 9 A.5 Conclusion. 10 BS

18、 EN 14298:2017EN 14298:2017 (E) 3 European foreword This document (EN 14298:2017) has been prepared by Technical Committee CEN/TC 175 “Round and sawn timber”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of

19、an identical text or by endorsement, at the latest by April 2018, and conflicting national standards shall be withdrawn at the latest by April 2018. 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

20、 for identifying any or all such patent rights. This document supersedes EN 14298:2004. 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

21、 Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United

22、Kingdom. BS EN 14298:2017EN 14298:2017 (E) 4 1 Scope This European Standard defines a method of assessment of drying quality. It applies to a lot of dried sawn timber (surfaced or not). It applies to both softwood and hardwood with a thickness not greater than 100 mm. The quality of drying is expres

23、sed in terms of moisture content: target, average of the lot and variation between the pieces of the lot. An option for specifying the degree of case-hardening is included. NOTE 1 Other features related to drying, e.g. check, shake, warp, stain, etc., are specified in documents for visual grading of

24、 sawn timber or in product specifications and are not covered by this document. NOTE 2 In the following the term “sawn timber” is used for all dried timber covered by this scope. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are

25、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 844-3:1995, Round and sawn timber Terminology Part 3: General terms relating to sawn timber EN 844-4:1

26、997, Round and sawn timber Terminology Part 4: Terms relating to moisture content EN 844-12:2000, Round and sawn timber Terminology Part 12: Additional terms and general index EN 1438, Symbols for timber and wood-based products EN 13183-1, Moisture content of a piece of sawn timber Part 1: Determina

27、tion by oven dry method EN 13183-2, Moisture content of a piece of sawn timber Part 2: Estimation by electrical resistance method CEN/TS 12169, Criteria for the assessment of conformity of a lot of sawn timber CEN/TS 14464, Sawn timber Method for assessment of case-hardening 3 Terms and definitions

28、For the purposes of this document, the terms and definitions given in EN 844-3:1995, EN 844-4:1997 and EN 844-12:2000 and the following apply. 3.1 target moisture content targdesired moisture content of a lot expressed as a single percentage 3.2 average moisture content marithmetic mean of the moist

29、ure content measurements of the pieces of a control sample taken from the lot for testing BS EN 14298:2017EN 14298:2017 (E) 5 3.3 lot whole of sawn timber pieces of the same species, same thickness and same specification 3.4 control sample number of individual pieces to be tested according to a pre-

30、defined procedure during quality control 3.5 piece single sawn timber taken from a lot for testing 4 Symbols and abbreviations In conformity to EN 1438, the following symbols are used: moisture content in percent; targtarget moisture content in percent; maverage moisture content in percent. 5 Drying

31、 quality specification 5.1 General A drying specification gives: the target moisture content; the permitted difference between the average moisture content of the lot and the target; the permitted variation of moisture content between individual pieces inside lower and upper limits. The permitted de

32、gree of case-hardening may be included in the specification. 5.2 Standard drying quality The specification of standard drying quality according to this standard is possible for target moisture content between 7 % and 20 %. Sampling to determine average and individual moisture contents shall be in ac

33、cordance with CEN/TS 12169 single sampling, AQL 6.5. For determination of average and individual moisture contents see Clause 6. 93,5 % of the pieces shall have an individual moisture content between the upper and lower limits. These limits are 1,3 x tarand 0,7 x tarrespectively. For standard drying

34、 quality the allowable range of average moisture content of a lot is given in Table 1. BS EN 14298:2017EN 14298:2017 (E) 6 Table 1 Standard drying quality - Allowable range for the average moisture content of a lot relative the target moisture content Target moisture content % Allowable range of ave

35、rage moisture content around target moisture content % 7 1/+1 8 1/+1 9 1/+1 10 1,5/+1,5 11 1,5/+1,5 12 1,5/+1,5 13 - 2,0/+1,5 14 - 2,0/+1,5 15 - 2,0/+1,5 16 - 2,5/+2,0 17 - 2,5/+2,0 18 - 2,5/+2,0 19 - 2,5/+2,5 20 - 2,5/+2,5 5.3 Specific end-use drying For specific end uses drying quality features di

36、fferent from the standard drying quality may be required. In this case, a drying quality specification shall contain the following information: a) target moisture content; b) allowable range of average moisture content in relation to targ; c) allowable upper and lower limits of moisture content (ind

37、ividual pieces); d) applicable AQL (see CEN/TS 12169). 6 Assessment by control of drying quality of a lot of sawn timber 6.1 General To assess the conformity of the lot, the arithmetic mean of moisture contents of the pieces of the control sample taken from the lot shall be calculated and the number

38、 of non-conforming pieces in the control piece shall be determined. The lot conforms if both the average moisture content and the number of non-conforming pieces are within the given limits in EN 14298 and CEN/TS 12169 respectively. In the absence of any specification, the principle is based on the

39、following sampling. BS EN 14298:2017EN 14298:2017 (E) 7 6.2 Sampling Sampling shall be carried out in accordance with CEN/TS 12169, with a level II of inspection, a single sampling and an AQL 6.5. The pieces from the outer layers (top, bottom, sides) are avoided as much as possible. NOTE Non-conform

40、ing with sampling = probability of over 90 % for the lot to contain a percentage of non-conforming pieces greater than 6,5 %. Sampling takes two parameters: the number of packages to be inspected, see Table 2; the number of pieces of a lot to be measured, see Table 3. Table 2 Number of packages to b

41、e inspected in a lot Total number of packages in a lot Number of packages to control 1 1 2 to 5 2 6 to 11 3 12 and over 4 If controlled packages are insufficient compared to the number of pieces to be tested, it should increase the number of packages to be inspected as much as necessary. Table 3 Num

42、ber of pieces to be taken and number of non-conforming parts tolerated Total number of pieces in a lot Number of pieces to assess Maximum number of non-conforming pieces in the control sample 2 to 15 2 0 16 to 50 8 1 51 to 90 13 2 91 to 150 20 3 151 to 280 32 5 281 to 500 50 7 501 to 1 200 80 10 1 2

43、01 to 3 200 125 14 3 201 and over 200 21 6.3 Moisture content For each of the sampled pieces the moisture content shall be estimated according to EN 13183-2 (Electrical resistance method). In the case of a dispute, EN 13183-1 (Oven-dry method) shall be used. BS EN 14298:2017EN 14298:2017 (E) 8 6.4 C

44、riteria drying quality 6.4.1 Moisture content To comply with a drying specification, measures shall satisfy 2 criteria: criterion 1: The moisture content of each individual piece shall be between the lower and upper limits. In the case of a standard drying, these limits are respectively equal to 0,7

45、 x tar(lower) and 1,3 x tar(upper). A maximum number of non-conforming pieces to this requirement is allowed according to the number of pieces taken. In the case of a standard drying quality, it is appropriate to refer to the Table 2; criterion 2: The average moisture content mof the controlled piec

46、es taken from the lot shall be within a given range relative to the target moisture content. In the case of a standard drying quality, it is appropriate to refer to Table 1. 6.4.2 Case-hardening If specified, the degree of case-hardening, expressed as mm gap opening, shall be determined according to

47、 the procedure described in CEN/TS 14464. The number of pieces to control for case hardening is half the number of pieces to control for moisture content The lot conforms to the requirements of case-hardening if the degree of case-hardening in at least 80 % of the sampled pieces is below the require

48、d value. NOTE The measure of the degree of case-hardening of the pieces is a destructive operation. 6.5 Test report The result of an assessment of drying quality of a lot of sawn timber shall be reported in form of a test report. This test report shall have the following components: denomination of

49、the lot of sawn timber (species, type of sawn timber, dimensions, producer, etc.); size of the lot (number of packages, approx. number of pieces, m3, etc.); number of tested packages and individual pieces; result of the assessment. BS EN 14298:2017EN 14298:2017 (E) 9 Annex A (informative) Example for an assessment of standard drying quality 12 % A.1 General A consignment consisting of 4 packages containing 30 boards each has been specified as standard drying 12 %. Drying quality shall be assessed