ISO 4858-1982 Wood Determination of volumetric shrinkage《木材 体积收缩率的测定》.pdf
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1、International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONWIEMYHAPOLHAR OPIXHM3AUMR fl0 CTAHAAPTH3AMlMORGANISATION INTERNATIONALE DE NORMALISATION Wood - Determination of volumetric shrinkage Bois - Determination du retrait volumique First edition - 1982-12-01 - UDC 674.03 : 620.193.23 53
2、9.388.8 Descriptors : wood, tests, dimensional stability tests, shrinkage, volume measurement. Ref. No. ISO 4858-1982 (E) Price based on 3 pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted withou
3、t license from IHS-,-,-Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards institutes (ISO member bedies). The work of developing Inter- national Standards is carried out through ISO technical committees. Every member body interested in a
4、 subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmentai, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulate
5、d to the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 4858 was developed by Technical Committee ISO/TC 55, Sawn timber and sawlogs, and was circulated to the member bodies in April 1980. lt has been approved by the membe
6、r bodies of the following countries: Australia France Austria Ghana Belgium Hungary Bulgaria . India Czechoslovakia Italy Egypt, Arab Rep. of Korea, Rep. of Finland Norway Poland Romania South Africa, Rep. of Spain Sweden Turkey USSR The member bodies of on technical grounds : the following cou Cana
7、da I reland Netherlands expressed disapproval of the docu 0 International Organkation for Standardkation, 1982 l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license
8、 from IHS-,-,-INTERNATIONAL STANDARD ISO 48584982 (E) Wood - Determination of volumetric shrinkage 1 Scope and field of application This International Standard specifies two methods for the determination of the volumetric shrinkage of wood: - the stereometric method, used for test pieces made in acc
9、ordance with ISO 4469; - the mercury volumenometer method, used for test pieces of any shape. 2 References ISO 3129, Wood - Sampling methods and general re- quiremen ts for ph ysical and mechanical tests. ISO 3130, Wood - Determination of moisture con ten t for ph ysical and mechanical tests. ISO 44
10、69, Wood - Determination of radial and tangential shrinkage. 3 Principle Determination of the Change in volume of test pieces after dry- ing, at a moisture content in equilibrium with the normal en- vironment, and at a moisture content equal to or greater than the Saturation Point of the cellular Wa
11、lls of wood. 4 Stereometric method 4.1 Apparatus See ISO 4469, clause 4. 4.2 Preparation of test pieces See ISO 4469, clause 5. 4.3 Procedure 1) 4.3.1 Carry out the test in accordance with ISO 4469, clause 6. 4.3.2 For species showing significant shrinkage along the grain, also measure the dimension
12、al changes of the test piece in the longitudinal direction. 4.4 Expression of results 4.4.1 Calculate the volume shrinkage, Pvmax, as a percen- tage, without taking into account the swelling along the grain, by the (approximate) formula 4 max x 4 max) - (4 min x 4 min) Vmax = x 100 1 t max 4 max whe
13、re I t max and 4 max are the dimensions of the test piece, in millimetres, at a moisture content greater than the satura- tion Point of the cellular Walls of wood, measured in the tangential and radial directions, respectively; I t min and lr min are the dimensions of the test piece, in millimetres,
14、 after drying, measured in the tangential and radial directions, respectively. Express the result to the nearest 0,l %. Calculate the total volumetric shrinkage, Vmaxl if dimensional changes have also been measured on the test piece in the longitudinal direction, as a percentage, by the formula Vmax
15、 = U = t max x I, max x la max) - (4 min x h-min x la min) x loo I t max x 4 max la max where I I t maxf r maxl and za max are the dimensions of the test piece, in mi!limetres, at a moisture content greater than the Saturation Point of the cellular Walls of wood, measured in the tangential, radial a
16、nd longitudinal directions, respectively; I t minf 4 min and la min are the dimensions of the test piece, in millimetres, after dtying, measured in the tangential, radial and longitudinal directions, respectively. Express the result to the nearest 0,l %. 1) If necessary, shrinkage may also be determ
17、ined at relative humidities between 30 and 90 %. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 4858-1982 (El 4.4.2 Calculate the volumetric shrinkage, vn, when the
18、moisture content changes to equilibrium with the normal en- vironment (relative humidity 65 rt 5 %; temperature 20 + 2 OC), as a percentage, by the formula - Vn = (4 max I, max) - (4 zr) x 100 # * 4 max 4 max lt and jr are the dimensions of the test piece, in milimetres, c at a moisture content in e
19、quilibrium with the normal en- vironment, measured in the tangential and radial directions, respect ivel y . 1 t max and 4 max have the same meaning as in 4.4.1. Express the result to the nearest 0,l %. Calculate the volumetric shrinkage, vn, if dimensional changes have also been measured on the tes
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