EN 14298-2004 en Sawn timber - Assessment of drying quality《锯材 烘干质量评定》.pdf

1、BRITISH STANDARDBS EN 14298:2004Sawn timber Assessment of drying qualityThe European Standard EN 14298:2004 has the status of a British StandardICS 79.040g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55

2、g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14298:2004This British Standard was published under the authority of the Standards Policy and Strategy Committee on 16 January 2006 BSI 16 January 2006ISBN 0 580 47655 3National forewordThis British Standard is the official English language

3、 version of EN 14298:2004.The UK participation in its preparation was entrusted to Technical Committee B/543, Round and sawn timber, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standard

4、s which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This pub

5、lication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible internati

6、onal/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page,

7、 pages 2 to 8, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14298November 2004ICS 79.040English versionS

8、awn timber - Assessment of drying qualityBois sci - Estimation de la qualit du schage Schnittholz - Ermittlung der TrocknungsqualittThis European Standard was approved by CEN on 2 September 2004.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions

9、for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official

10、versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium,

11、 Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EURO

12、PEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2004 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14298:2004: EEN 14298:2004 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normat

13、ive references 4 3 Terms and definitions .4 4 Symbols and abbreviations 5 5 Drying quality specification5 5.1 General5 5.2 Standard drying .5 5.3 Specific end-use drying 6 6 Assessment of drying quality of a lot of sawn timber .7 6.1 Range of moisture content .7 6.2 Sampling.7 6.3 Testing and evalua

14、tion7 6.3.1 Moisture content7 6.3.2 Case-hardening7 Annex A (informative) Drying quality specification .8 EN 14298:2004 (E) 3 Foreword This document (EN 14298:2004) has been prepared by Technical Committee CEN/TC 175 “Round and sawn timber”, the secretariat of which is held by AFNOR. This European S

15、tandard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2005, and conflicting national standards shall be withdrawn at the latest by May 2005. According to the CEN/CENELEC Internal Regulations, the national standard

16、s organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slova

17、kia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14298:2004 (E) 4 1 Scope This document defines a method of assessment of drying quality. It applies to a lot of dried sawn timber, a lot of dried planed timber and a lot of dried sawn timber surfaced by other means. It applies to both

18、softwood and hardwood with a thickness not greater than 100 mm. The quality of drying is expressed in terms of target and average moisture content of the lot as well as defining the moisture content variation between individual pieces expressed as allowable upper and lower limits. An option for spec

19、ifying the degree of case-hardening is included. NOTE 1 Other features related to drying, e.g. checking, distortions, stain, etc., are specified in documents for visual grading of sawn timber or in product specifications and are not covered by this document. NOTE 2 In the following the term “sawn ti

20、mber“ is used for all dried timber covered by this the scope. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document

21、(including any amendments) applies. EN 844-3:1995, Round and sawn timber - Terminology Part 3: General terms relating to sawn timber EN 844-4:1997, Round and sawn timber - Terminology Part 4: Terms relating to structure content EN 844-12:2000, Round and sawn timber - Terminology Part 12: Additional

22、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: Determination by oven dry method EN 13183-2, Moisture content of a piece of sawn timber Part 2: Estimation by electrical resistance method ENV 14464, Sawn timber

23、 Method for assessment of case-hardening ENV 12169, Criteria for the assessment of conformity of a lot of sawn timber 3 Terms and definitions 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 mois

24、ture content (targ) desired moisture content of a lot expressed as a single percentage. 3.2 average moisture content(m) arithmetic mean of the moisture content of the pieces in a lot 3.3 lot number of sawn timber pieces of the same thickness for all species and width for softwoods dried to the same

25、specification EN 14298:2004 (E) 5 4 Symbols and abbreviations In conformity to EN 1438, the following symbols are used: - moisture content in percent - targ target moisture content in percent - m average moisture content in percent 5 Drying quality specification 5.1 General A drying specification sh

26、all give the target moisture content, the permitted range of the actual average moisture content relative to the target moisture content and the permitted moisture content variation between individual pieces expressed as allowable upper and lower limits. The permitted degree of case-hardening may be

27、 included in the specification. 5.2 Standard drying Standard drying is to a target moisture content of 7 % to 18 %. For standard drying the allowable range of average moisture content of a lot is given in Table 1. 93.5 % of the pieces shall have an individual moisture content between the upper and l

28、ower limits. These limits are 1,3 x tarand 0,7 x tarrespectively. Sampling to determine average and individual moisture contents shall be in accordance with ENV 12169 single sampling, AQL 6,5. For determination of average and individual moisture contents see Clause 6. EN 14298:2004 (E) 6 Table 1 Sta

29、ndard drying - Allowable range for the average moisture content of a lot relative the target moisture content Target moisture content % Allowable range of average 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/+

30、1,5 15 - 2,0/+1,5 16 - 2,5/+2,0 17 - 2,5/+2,0 18 - 2,5/+2,0 5.3 Specific end-use drying For specific end uses drying quality features different from the standard drying quality may be required. In this case, a drying quality specification shall contain the following information: a) Target moisture c

31、ontent, b) Allowable range of average moisture content in relation totarg, c) Allowable upper and lower limits of moisture content (individual pieces) d) Applicable AQL (see ENV 12169) EN 14298:2004 (E) 7 6 Assessment of drying quality of a lot of sawn timber 6.1 Range of moisture content To comply

32、with a drying specification, the average moisture content of a lot, established by measuring the moisture content of the pieces in a sample drawn from the lot, shall be within a given range relative to the target moisture content and the individual moisture contents of a pre-defined proportion of th

33、e sampled pieces shall be within the upper and lower limits. 6.2 Sampling Sampling shall be carried out in accordance with ENV 12169 with the exception that pieces from the outer layers (top, bottom, sides) shall not be included. 6.3 Testing and evaluation 6.3.1 Moisture content For each of the samp

34、led pieces the moisture content shall be estimated according to EN 131832 (Electrical resistance method). In the case of a dispute, EN 131831 (Oven-dry method) shall be used. To assess the conformity of the lot, the arithmetic mean shall be calculated and the number of non conforming pieces in the s

35、ample 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 ENV 12169 respectively. 6.3.2 Case-hardening If specified, the degree of case-hardening, expressed as mm gap opening, shall be determin

36、ed on every second sampled piece according to the procedure described in ENV 14464. The lot conforms to the requirements of standard drying with respect to case-hardening if the degree of case-hardening in 80 % of the sampled pieces is below the required value. EN 14298:2004 (E) 8 Annex A (informati

37、ve) Drying quality specification For the specification of drying quality of sawn timber the following information should be given: 1. In case of standard drying - standard drying quality according to EN 14298 - target moisture content, - degree of case-hardening (optional). Example: Target moisture

38、content 14% (standard drying quality according to EN 14298) 2. In case of specific end use drying - target moisture content - allowable range of average moisture content - upper and lower moisture content limits for pieces - applicable AQL - degree of case-hardening (optional). Example: Specific end

39、 use drying with target moisture content 10 %; average moisture content between 9 % and 10,5 %; Individual pieces: upper limit 12 %, lower limit 8%, single sampling AQL 4, case-hardening 2 mm. blankBS EN BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent nat

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