ISO 738-2015 Coniferous sawn timber - Sizes - Permissible deviations and shrinkage《针叶树锯材 尺寸 允许偏差和收缩率》.pdf

1、 ISO 2015 Coniferous sawn timber Sizes Permissible deviations and shrinkage Bois scis rsineux Dimensions carts admissibles et retrait INTERNATIONAL STANDARD ISO 738 Second edition 2015-08-01 Reference number ISO 738:2015(E) ISO 738:2015(E)ii ISO 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT

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4、reword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Permissible deviations and shrinkage 1 Annex A (informative) Average values for shrinkage for coniferous sawn timber (pine, spruc e , fir and other species) ha ving an a v er age density of 0,35 g t o 0,6 g/ cm 3in the abs

5、olut el y dry c ondition 2 Annex B (informative) Average values for shrinkage for coniferous sawn timber (larch and other species) ha ving an a v er age density of 0,61 g t o 0,75 g/cm 3in the absolut el y dry c ondition 3 ISO 2015 All rights reserved iii Contents Page ISO 738:2015(E) Foreword ISO (

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12、nsible for this document is ISO/TC 218, Timber. This second edition cancels and replaces the first edition (ISO 738:1981), which has been technically revised.iv ISO 2015 All rights reserved INTERNATIONAL ST ANDARD ISO 738:2015(E) Coniferous sawn timber Sizes Permissible deviations and shrinkage 1 Sc

13、ope This International Standard specifies permissible deviations, due to inaccuracies in sawing, from nominal thicknesses, widths and lengths, for coniferous sawn timber. It also gives, for information, average values for shrinkage for some wood species. It is applicable to unplanned square-edged an

14、d unedged coniferous sawn timber having thicknesses or widths in the range10 mm to 310 mm. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies.

15、 For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 24294, Timber Round and sawn timber Vocabulary 3 T erms a nd definiti ons For the purposes of this document, the terms and definitions given in ISO 24294 apply. 4 Permissible deviations and

16、 shrinkage The nominal sizes of coniferous sawn timber are established at an absolute moisture content of 20 %. NOTE The absolute moisture content is the moisture content related to the oven-dry mass of the timber, expressed as a percentage. The actual thickness and width of sawn timber having moist

17、ure contents greater than 20 % may be larger than, and those of sawn timber having moisture contents less than 20 % may be smaller than, the nominal sizes, by the corresponding value for shrinkage. Average values for shrinkage are given, for information, in Annexes A and B. The actual thicknesses of

18、 all kinds of coniferous sawn timber, and the widths of square-edged sawn timber with parallel edges, in any cross-section of each piece of sawn timber, may deviate, due to inaccuracy in sawing, from the nominal sizes corrected for shrinkage by not more than a) for thicknesses and widths in the rang

19、e up to and including 30 mm to 105 mm: 2 mm; b) for thicknesses and widths greater than 105 mm: 3 mm. If 20 pieces of the same size are taken at random from a lot of sawn timber, the average actual thickness (irrespective of the kind of sawn timber) and the average actual width of square edged sawn

20、timber with parallel edges shall not be less than the nominal sizes, corrected for shrinkage. The permissible deviations of actual lengths of sawn timber from the nominal length, due to inaccuracy in sawing, shall be +50 mm, and 25 mm. ISO 2015 All rights reserved 1 ISO 738:2015(E) Annex A (informat

21、ive) Average values for shrinkage for coniferous sawn timber (pine, spruc e , fir and other species) 1)ha ving an a v er age density of 0,35 g t o 0,6 g/ cm 3in the absolut el y dry c ondition Table A.1 T h i c k n e s s a nd / o r w i d t h of sawn timber Absolute moisture content of sawn timber, %

22、 range over 38 34 to 38 31 to 33 26 to 30 23 to 25 18 to 22 15 to 17 mean 36 32 28 24 20 16 mm Average shrinkage, % from 10 to 17 +4,0 +3,2 +2,4 +1,6 +0,8 0 0,8 from 18 to 29 +3,4 +2,7 +2,0 +1,4 +0,7 0 0,7 from 30 to 90 +3,2 +2,6 +1,9 +1, 3 +0,6 0 0,6 from 91 to 140 +2,9 +2,3 +1,7 +1,2 +0,6 0 0,6 fr

23、om 141 to 170 +2,7 +2,2 +1,6 +1,1 +0,5 0 0,5 from 171 to 210 +2,6 +2,1 +1,6 +1,0 +0,5 0 0,5 from 211 to 255 +2,6 +2,1 +1,6 +1,0 +0,5 0 0,5 from 256 to 310 +2,5 +2,0 +1,5 +1,0 +0,5 0 0,5 NOTE The values in the table are given as reference data. 1) The botanical names of the wood species are the follo

24、wing: pine: Pinus; spruce: Picea; fir: Abies.2 ISO 2015 All rights reserved ISO 738:2015(E) Annex B (informative) Average values for shrinkage for coniferous sawn timber (larch 2)and other species) ha ving an a v er age density of 0,61 g t o 0,75 g/ cm 3in the absolut el y dry c ondition Table B.1 T

25、 h i c k n e s s a nd / o r w i d t h of sawn timber Absolute moisture content of sawn timber, % range over 38 34 to 38 31 to 33 26 to 30 23 to 25 18 to 22 15 to 17 mean 36 32 28 24 20 16 mm Average shrinkage, % from 10 to17 +5,2 +4,2 +3,1 +2,1 +1,0 0 1,0 from 18 to29 +4,4 +3,5 +2,6 +1,8 +0,9 0 0,9

26、from 30 to 90 +4,1 +3,3 +2,5 +1,6 +0,8 0 0,8 from91 to 140 +3,8 +3,0 +2,3 +1,5 +0,8 0 0,8 from 141 to 170 +3,5 +2,8 +2,1 +1,4 +0,7 0 0,7 from 171 to 210 +3,4 +2,7 +2,0 +1,4 +0,7 0 0,7 from 211 to 255 +3,3 +2,6 +2,0 +1, 3 +0,7 0 0,7 from 256 to 310 +3,2 +2,6 +1,9 +1, 3 +0,6 0 0,6 NOTE The values in the table are given as reference data. 2) The botanical name of larch is Larix. ISO 2015 All rights reserved 3 ISO 738:2015(E) ISO 2015 All rights reserved IC S 79.040 Price based on 3 pages