BS ISO 3129-2012 Wood Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens《木材 洁净木材小样品的物理力学试验取样方法和一般要求》.pdf

《BS ISO 3129-2012 Wood Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens《木材 洁净木材小样品的物理力学试验取样方法和一般要求》.pdf》由会员分享，可在线阅读，更多相关《BS ISO 3129-2012 Wood Sampling methods and general requirements for physical and mechanical testing of small clear wood specimens《木材 洁净木材小样品的物理力学试验取样方法和一般要求》.pdf（18页珍藏版）》请在麦多课文档分享上搜索。

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 3129:2012Wood Sampling methodsand general requirements forphysical and mechanical testingof small clear wood specimensBS ISO 3129:2012 BRITISH STANDARDNational forewordThi

2、s British Standard is the UK implementation of ISO 3129:2012.The UK participation in its preparation was entrusted to TechnicalCommittee B/543, Round and sawn timber.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to

3、include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 67539 3ICS 79.040Compliance with a British Standard cannot confer immunity fromlegal obligations.This Brit

4、ish Standard was published under the authority of theStandards Policy and Strategy Committee on 29 February 2012.Amendments issued since publicationDate Text affectedBS ISO 3129:2012 ISO 2012Wood Sampling methods and general requirements for physical and mechanical testing of small clear wood specim

5、ensBois Mthodes dchantillonnage et conditions gnrales pour les essais physiques et mcaniques de petites prouvettes de bois netINTERNATIONAL STANDARDISO3129Second edition2012-02-01Reference numberISO 3129:2012(E)BS ISO 3129:2012ISO 3129:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUME

6、NT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in

7、 the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 3129:2012ISO 3129:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide

8、federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that c

9、ommittee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accor

10、dance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard require

11、s approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 3129 was prepared by Technical Com

12、mittee ISO/TC 218, Timber.This second edition cancels and replaces the first edition (ISO 3129:1975), which has been technically revised. ISO 2012 All rights reserved iiiBS ISO 3129:2012BS ISO 3129:2012Wood Sampling methods and general requirements for physical and mechanical testing of small clear

13、wood specimens1 ScopeThis International Standard specifies methods for the extensive and limited sampling of wood, conditioning and preparation of test pieces. It also specifies the general requirements for physical and mechanical testing of small clear wood specimens. The sampling guidance provided

14、 in this International Standard can be applied for timber taken from either trees, logs, or pieces of ungraded/graded/presorted sawn timber for non-structural applications, such as furniture, windows, doors, etc., only.2 Normative referencesThe following referenced documents are indispensable for th

15、e application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3130, Wood Determination of moisture content for physical and mechanical testsISO 3131, Wood Determinatio

16、n of density for physical and mechanical testsISO 3132, Wood Testing in compression perpendicular to grainISO 3133, Wood Determination of ultimate strength in static bendingISO 3345, Wood Determination of ultimate tensile stress parallel to grainISO 3346, Wood Determination of ultimate tensile stres

17、s perpendicular to grainISO 3348, Wood Determination of impact bending strengthISO 3349, Wood Determination of modulus of elasticity in static bendingISO 3350, Wood Determination of static hardnessISO 3351, Wood Determination of resistance to impact indentationISO 4469, Wood Determination of radial

18、and tangential shrinkageISO 4858, Wood Determination of volumetric shrinkageISO 4859, Wood Determination of radial and tangential swellingISO 4860, Wood Determination of volumetric swellingISO 8905, Sawn timber Test methods Determination of ultimate strength in shearing parallel to grainISO 24294, R

19、ound and sawn timber VocabularyEN 1534, Wood flooring Determination of resistance to indentation Test method3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 24294 apply.INTERNATIONAL STANDARD ISO 3129:2012(E) ISO 2012 All rights reserved 1BS ISO 3129:2

20、012ISO 3129:2012(E)4 General principlesThis International Standard covers procedures of sampling for obtaining small clear specimens which, when tested in accordance with methods prescribed under relevant International Standards, may provide information on the influence on mechanical properties of s

21、uch factors as moisture content, density, position in cross-section, height in the tree and locality of growth.NOTE These International Standards (ISO 3130, ISO 3131, ISO 3132, ISO 3133, ISO 3345, ISO 3346, ISO 3348, ISO 3349, ISO 3350, ISO 3351, ISO 4469, ISO 4858, ISO 4859 and ISO 4860) are curren

22、tly being revised.5 Sampling5.1 Selection of materialThe material intended for physical and mechanical tests shall be selected taking into account the purpose of the test, as well as the requirements to ensure that the properties obtained from the test pieces represent the sample population.5.2 Samp

23、ling of wood materialThe material selected shall be in the form of either logs or sawn timbers.5.2.1 LogsTrees or logs shall be selected to represent the population. For each species to be tested, at least five trees or logs representative of that species or species group shall be selected.A heart p

24、lank shall be cut from a log of acceptable diameter. For a log having an eccentric structure, the heart plank shall cover the geometrical centre (Figure 1). In the case of a log having a diameter of 180 mm or less, the heart plank shall be cut in the direction of two mutually perpendicular diameters

25、 (Figure 2).In the case of an eccentric structure, the plank shall include the pith and not the geometrical centre.The thickness of the heart plank shall be at least 60 mm, except for logs with a diameter of 180 mm or less, where the thickness shall be 40 mm. In this case, to obtain test pieces with

26、 a cross-sectional dimension greater than 30 mm, a disc that is at least 100 mm thick shall be cut from one end of the log prior to sawing out heart planks. This disc may be used for the hardness test.5.2.2 Matching for test of dry materialIf one purpose of the sampling is to provide comparison of g

27、reen and dry properties, provisions may be made for matching of specimens within the tree. The collection of the material has been arranged to provide for tests of both green and dry specimens that are closely matched by selection from adjacent parts of the same tree.To afford matching, the sticks o

28、f one heart plank shall be interchanged with the other sticks from the next adjacent heart plank from the same tree to form two composite heart planks, each being complete and made of equal portions of the adjacent heart planks. The sticks from one of these composite heart planks shall be tested gre

29、en and those from the other shall be tested after drying. Thus, the sticks of each composite heart plank shall be regarded as if they were from the same heart plank.This procedure provides for end-to-end matching (end matching) of sticks to be tested dry with those to be tested green, which is to be

30、 preferred when practicable. If, because of the nature of the material, end matching is not practicable, side matching may be used.5.2.3 Sawn timberIn sampling of sawn timber, sticks shall be cut parallel to the direction of the grain. A sufficient number of sticks shall be cut to ensure that the sa

31、mple and its statistical properties are representative of the population. The 2 ISO 2012 All rights reservedBS ISO 3129:2012ISO 3129:2012(E)sticks shall be not less than 35 mm thick with sides in radial and tangential directions. Sticks containing pith shall be discarded.6 Conditioning of material6.

32、1 Test pieces with a standardized moisture content (dry specimens)Before conversion into test pieces, the wood shall be thoroughly dried (at a temperature lower than 60 C) to a moisture content close to that of the equilibrium state and shall be conditioned at a temperature of (20 2) C and a relativ

33、e humidity of (65 3) % to bring the moisture content of the wood to that of equilibrium. It is desirable that the ends of the test pieces be covered with a moisture-protective substance to prevent splitting.6.2 Test pieces with moisture content of equal to or above fibre saturation point (green spec

34、imens)Prior to cutting into test pieces, the sticks shall be kept under controlled conditions to prevent further drying of the wood.Dimensions in millimetres 60 Figure 1 General cutting pattern of heart plank from a log of diameter 180 mm ISO 2012 All rights reserved 3BS ISO 3129:2012ISO 3129:2012(E

35、)Dimensions in millimetres4040Figure 2 General cutting pattern of heart planks from a log of diameter 180 mm7 Preparation of test pieces7.1 Form and dimensionsOne test piece for each type of test shall be cut from each stick as specified in 5.2.2. The form and dimensions of the test pieces shall be

36、those specified in the relevant International Standards for methods of testing small clear specimens of wood.7.2 Direction of grainThe wood shall be cut with the grain parallel to the longitudinal axis of the test pieces. Growth rings on the end surfaces of test pieces shall be parallel to one pair

37、of opposite faces and perpendicular to the other pair. Adjacent faces shall be at right angles. In the case of tropical timbers where the growth ring is not clear, the cutting shall follow the direction of the rays on the cross-section which represents the radial surface of the test pieces.7.3 Permi

38、ssible deviationsThe permissible deviations of the gauge length of the test pieces from nominal dimensions shall not exceed 0,1 mm. The dimensions of test pieces not used in calculations (for example, the length of the test piece for the static bending test) shall be kept to an accuracy of 1 mm. The

39、 working surfaces of the test pieces shall be clean finished.7.4 MarkingEach test piece obtained from a heart plank shall be numbered to indicate its original position in the plank. In the case of sawn timber, each test piece shall be numbered to indicate the stick from which they were cut. The piec

40、e marking shall indicate whether each piece was cut from sapwood or heartwood, if they are differentiated.4 ISO 2012 All rights reservedBS ISO 3129:2012ISO 3129:2012(E)7.5 Sample size/number7.5.1 Random samplingThe number of test pieces shall be specified, taking into account the purpose of the test

41、ing, for example, determination of the quality of standwood or of a model tree or of a lot of timber or of an individual board, the type of sampling method used, and the degree of test precision required.The average values of the physical and mechanical properties shall be determined to an accuracy

42、of p 0,05 at a confidence level of 95 %.7.5.2 Selective samplingIn selective sampling, the minimum number of test pieces, nmin, is given by the following formula:nmnCtpnVbjbjmin=222222211+(1)wherem is the quantity of selected material (logs, sawn timber, boards, etc.);n is the mean number of test pi

43、eces cut from each piece of the selected material;CVis the percentage coefficient of variation for the property to be determined (refer to Table 1);t is the index of result authenticity (a half-length of the confidence interval in fractions of the standard deviation;p is the percentage index of test

44、 precision (the relation between the standard deviation of the arithmetic mean and the arithmetic mean);b2is the expected variance of the property between trees;j2is the expected variance of the property within trees.The results shall be rounded to the nearest integer.7.5.3 Mechanical samplingIn mec

45、hanical sampling, the minimum number of test pieces, nmin, is given approximately by the formula:nCtpmin=V222(2)where CV, t and p are as defined in 7.5.2.The results shall be rounded to the nearest integer. ISO 2012 All rights reserved 5BS ISO 3129:2012ISO 3129:2012(E)7.5.4 Minimum number of test pi

46、ecesFor an approximate determination of the minimum number of test pieces, the mean values of the coefficients of variation for wood properties shown in Table 1 may be used, except for resistance to impact indentation.For the purpose of determining the number of test specimens for this property, ref

47、erence shall be made to EN 1534, since there was no reference specifying the coefficient of variation of impact indentation (up to the date of this standard being prepared), and based on the requirement of EN 1534 which stated that the number of test specimens to be sampled shall be according to the

48、 number of indentations carried out on each test specimen with a total number of indentations of at least 50. If three indentations are required on each radial and tangential surfaces for each test specimen, and the number of test pieces is 30, the total number of indentations is 180. Hence n = 30 w

49、ill satisfy the requirement of EN 1534 and thus is recommended for the test for the determination of resistance to impact indentationTable 1 Mean values of the coefficients of variation for wood propertiesWood property Coefficient of variation%Number of growth rings in 1 cm 37Percentage of late wood 28Density 10Equilibrium moisture content 5Coefficient of shrinkage: linearCoefficient of shrinkage: volumetric2816Ultimate compressive strength parallel