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1、BRITISH STANDARD BS EN 13183-3:2005 Moisture content of a piece of sawn timber Part 3: Estimation by capacitance method The European Standard EN 13183-3:2005 has the status of a British Standard ICS 79.040 ? Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled
2、 Copy, (c) BSI BS EN 13183-3:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2005 BSI 31 March 2005 ISBN 0 580 45799 0 National foreword This British Standard is the official English language version of EN 13183-3:2005. The UK p
3、articipation 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-references The British Standards which implement international
4、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 publication does not purport to in
5、clude 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 international/European committee any enq
6、uiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside
7、 back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN
8、 STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13183-3 March 2005 ICS 79.040 English version Moisture content of a piece of sawn timber - Part 3: Estimation by capacitance method Teneur en humidit dune pice de bois sci - Partie 3: Estimation par mthode capacitive Feuchtegehalt eines Stckes Schnittholz
9、 - Teil 3: Schtzung durch kapazitives Messverfahren This European Standard was approved by CEN on 3 February 2005. 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
10、alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by t
11、ranslation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greec
12、e, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre:
13、 rue de Stassart, 36 B-1050 Brussels 2005 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13183-3:2005: E Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13183-3:2005 (E)
14、 2 Contents Page Foreword3 1 Scope 4 2 Normative references4 3 Terms and definitions .4 4 Moisture content estimation with hand-held capacitance moisture meters .4 4.1 Limits of application4 4.2 Apparatus .5 4.3 Initial type testing 5 4.4 Procedure .5 4.5 Expression of results 5 5 Moisture content e
15、stimation with in-line capacitance moisture meters5 5.1 Limits of application5 5.2 Apparatus and measuring set-up.6 5.3 Initial type testing 6 5.4 Calibration6 5.5 Procedure .6 5.6 Expression of results 6 Annex A (normative) Procedure for assessing the accuracy of capacitance moisture meters7 Annex
16、B (informative) Moisture content of a lot 9 Bibliography10 Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13183-3:2005 (E) 3 Foreword This document (EN 13183-3:2005) has been prepared by Technical Committee CEN/TC 175 “Round and sawn tim
17、ber”, 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 September 2005, and conflicting national standards shall be withdrawn at the latest by September 20
18、05. This document is one of a series, dealing with methods of measurement for round timber and sawn timber. Other standards in this series are: 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 - P
19、art 2: Estimation by electrical resistance method EN 1309-1, Round and sawn timber - Method of measurement of dimensions - Part 1: Sawn timber EN 1310, Round and sawn timber - Method of measurement of features EN 1311, Round and sawn timber - Method of measurement of biological degrade This document
20、 includes a Bibliography. According to the CEN/CENELEC Internal Regulations, the national standards 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,
21、Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13183-3:2005 (E) 4 1 Scope Thi
22、s document specifies a non destructive method for estimating the moisture content of a piece of sawn timber. The standard describes the conditions which shall be met by a capacitance measuring system to derive a moisture content estimate for individual pieces of timber. The standard applies to sawn
23、timber and timber which has been planed or surfaced by other means. 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 doc
24、ument (including any amendments) applies. EN 844-1:1995, Round and sawn timber - Terminology - Part 1: General terms common to round timber and sawn timber 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 Terminol
25、ogy - Part 4: Terms relating to moisture content EN 844-6:1997, Round and sawn timber - Terminology - Part 6: Terms relating to dimensions of sawn timber EN 844-7:1997, Round and sawn timber - Terminology - Part 7: Terms relating to anatomical structure of timber EN 844-9:1997, Round and sawn timber
26、 - Terminology - Part 9: Terms relating to features of sawn timber EN 844-12:2000, Round and sawn timber - Terminology - Part 12: Additional terms and general index EN 13183-1, Moisture content of a piece of sawn timber - Part 1: Determination by oven dry method EN ISO/IEC 17025, General requirement
27、s for the competence of testing and calibration laboratories (ISO/IEC 17025:1999) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 844-1:1995, EN 844-3:1995, EN 844-4:1997, EN 844-6:1997, EN 844-7:1997, EN 844-9:1997 and EN 844-12:2000 apply. 4 Moistur
28、e content estimation with hand-held capacitance moisture meters 4.1 Limits of application This method is suitable for estimating the average moisture content of a piece of timber having a moisture content between approximately 7 % and 30 %. NOTE Any type of bipolar preservative, flame retardant, che
29、mical or surface treatment may affect the accuracy of the measurement and requires special calibration of the instrument for each type of treatment. The estimated moisture content can be strongly affected by the type and reach of the moisture sensing system, the moisture content distribution and the
30、 wood density under the sensor, the operating modus, the dimensions of the piece of timber to be measured and the operator skills. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13183-3:2005 (E) 5 Any air gap between the timber surface a
31、nd the sensing unit will strongly influence the reading. Very rough sawn or uneven surfaces can only be measured if the shape of the condensator plate or probe secures good contact. 4.2 Apparatus Hand-held capacitance moisture meter equipped with a flat shaped condensator plate surface, surface spri
32、ng electrodes or special non-invasive measuring probes, graduated up to at least 30 % in units of maximum 1 % moisture content. NOTE Normally capacitance moisture meters are equipped with a setting for correction for density and are applicable or adjustable for different thicknesses. Density correct
33、ion may also be carried out by using special tables or formulas provided by the suppliers of the instrument. 4.3 Initial type testing The accuracy of the measuring system and its operating instructions shall be tested in accordance with Annex A of this document by a laboratory compliant with EN ISO/
34、IEC 17025. The results of these tests shall be made available with the apparatus. 4.4 Procedure Before taking measurements the capacitance moisture meter shall be checked according to the instructions provided by the supplier of the instrument. Set the moisture measuring unit to its basic settings w
35、ith the assistance of a check block. The capacitance moisture meter shall be adjusted for density. If the actual density of the timber to be measured is unknown, an average density for the species to be measured may be selected from the operating manual provided by the supplier of the instrument. En
36、sure that the instrument being used is adjusted or applicable for the thickness of the timber being measured. Air gaps or bad contact between the condensator plates and the wood surface shall be avoided. The measurement area shall be free from features affecting the measurement such as bark, knots,
37、resin pockets, wetted surface or checks. The measurement shall be taken at a point 300 mm from one of the ends of the piece. If this position contains any of the defects detailed above the measurement shall be taken on the nearest defect free point towards the centre of the piece. For pieces less th
38、an 600 mm long, measure at mid-length. 4.5 Expression of results The estimation results shall be expressed at least to the nearest one percentage point. 5 Moisture content estimation with in-line capacitance moisture meters 5.1 Limits of application This method is suitable for estimating the average
39、 moisture content of a piece of timber having a moisture content between approximately 7 % and 30 %. NOTE Any type of bipolar preservative, flame retardant, chemical or surface treatment may affect the accuracy of the measurement and requires special calibration of the instrument for each type of tr
40、eatment. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 05:24:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13183-3:2005 (E) 6 The estimated moisture content can be strongly affected by the type and reach of the moisture sensing system, the moisture content distribution and the wood densi
41、ty in the sensor reach, the operating modus, the geometry of the measuring set up and variations in the dimensions of the piece of timber to be measured. The air gap between the timber surface and the sensing unit will strongly influence the reading. To reduce this influence, caused by twisted and b
42、owed boards, vibration or unstable transport conditions, a press device securing a constant distance to the sensor(s) is recommended. 5.2 Apparatus and measuring set-up A moisture measuring unit consisting of a fixed framework carrying one or several sensing units, through which the timber is passed
43、 lengthwise or transversal to the direction of travel, connected to an evaluation unit. The sensing unit(s) shall be installed at a position in the production line that is easy to access, to keep clean and free of vibrations. The sensing unit(s) and the corresponding cabling shall be shielded to avo
44、id electromagnetic interference. The measuring area shall be kept free of dust or dirt by means of an appropriate system (e.g. pressurised air nozzles). The read-out from the equipment shall be graduated up to at least 30 % in units of maximum 1 % moisture content. 5.3 Initial type testing The accur
45、acy of the measuring system and its operating instructions shall be tested in accordance with Annex A of this document by a laboratory compliant with EN ISO/IEC 17025. The results of these tests shall be made available with the apparatus. 5.4 Calibration Before an in-line measuring system can be use
46、d the system shall be calibrated according to the instructions of the supplier. NOTE 1 Calibration involves the collection of in-line moisture content readings from a number of individual boards with the same dimension and approximately the same moisture gradient. For each of the instrument reading
47、positions on these boards the moisture content is determined by the oven-dry method according to EN 13183-1. Features such as bark, knots etc should be avoided. This data forms the basis for a linear regression, the coefficients of which are stored by the system forming a measuring programme for the
48、 individual dimension and species being measured. NOTE 2 The accuracy of capacitance moisture meters is affected by local density variations. If these density variations within the timber to be measured result in an unacceptable accuracy, a density measuring unit can be connected to the moisture mea
49、suring unit. This density measuring unit should be calibrated separately according to the instructions of the supplier. 5.5 Procedure Set the moisture measuring unit to its basic settings with the help of a check block. Select an appropriate measuring programme before changing to the measurement mode. 5.6 Expression of results The estimation results shall be expressed at least to the nearest one percentage point. NOTE The indicated moisture content of each board passing through the system is
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