ISO 4858-1982 Wood Determination of volumetric shrinkage《木材 体积收缩率的测定》.pdf

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

20、t piece in the longitudinal direction, as a percentage, by the formula (4 max x Ir max la max) - (4 4 x la) Vn = x 100 I t max x 4 max la max lt, r and Ia are the dimensions of the test piece, in millimetres, at a moisture content in equilibrium with the normal environment, measured in the tangentia

21、l, radial and longitudinal directions, respectively; z 1 t maxf r max and za max have the same meaning as in 4.4.1. Express the result to the nearest 0,l %. 5 Mercury volumenometer method 5.1 Apparatus 5.1.1 Mercury volumenometer, capable of measuring the volume of a test piece, from the volume of m

22、ercury it displaces, to an accuracy of 0,Ol cm? NOTE - lt is necessary to observe appropriate when using a mercury volumenometer. safety precautions 51.2 Oven, for drying wood at a temperature of 103 + 2 OC. 5.1.3 Vessel, containing distilled water. 51.4 Air-tight vessel, containing a desiccant. 5.2

23、 Preparation of test pieces 5.2.1 Test pieces may volume of 4 to 16 cm? in any shape, but shall have a 5.2.2 The number of test pieces shall be in accordance with ISO 3129. 5.3 Procedurel) 5.3.1 The moisture content of test pieces shall be con- siderably greater than the Saturation Point of the cell

24、ular Walls of wood. If the moisture content is less than the Saturation Point, soak the test pieces in distilled water in the vessel (5.1.3) at a temperature of 20 + 5 OC, until no further Change in volume occurs. Check the Change in volume every 3 days by repeated measurement of two or three contro

25、l test pieces. Stop the soaking when the differente between two successive measurements does not exceed 0,02 cm3. In this case, it should be reported that the results of the determination of shrinkage are obtained on test pieces which have been previously soaked. 5.3.2 Measure the volume, Vmax, of e

26、very test piece to an ac- curacy of 0,Ol cm3. 5.3.3 Condition the test pieces to a moisture content in equilibrium with the normal environment (relative humidity 65 + 5 %; temperature 20 AI 2 OC) so that no Checks distor- - ting their dimensions and shape occur. Check the changes in volume of two or

27、 three control test pieces by repeated measurements, as specified in 5.3.2, every 6 h after stabiliza- tion of the conditioning environment, Stop the conditioning when the differente between two successive measurements does not exceed 0,02 cm? The conditioning of test pieces may be stopped by using

28、the method of successive weighing in ac- cordante with ISO 3130. 5.3.4 Measure the volume, V, of every test piece, as specified in 5.3.2. 5.3.5 Dry the test pieces to constant volume at a temperature of 103 $r 2 OC in the oven (5.1.2) so that no Checks distorting their dimensions and shape occur. Ch

29、eck the changes in volume of two or three control test pieces by repeated measurements, as specified in 5.3.2, every 2 h after 6 h from the beginning of drying. Stop the drying when the differente between two successive measurements does not exceed 0,02 cm3. The drying of test pieces may be stopped

30、by using the method of successive weighing in accordance with ISO 3130. 5.3.6 Test pieces in which period shall be disregarded. Checks occurred during the test 5.3.7 Cool the test pieces to room temperature in the air-tight vessel containing the desiccant (5.1.4). 5.3.8 Measure the volume, Amin, of

31、every test piece, as specified in 5.3.2. lf necessary, shrinkage may also be determined at relative humidities between 30 and 90 (35. 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license

32、 from IHS-,-,-ISO 48584982 (EI 5.4 Expression of results 5.4.1 Calculate the total volu percentage, by the formula metric shrinkage, vmax, as a t V max - Vmin Vmax = - x 100 V max where Vmax and Vmin are the volumes of the test piece, in cubic centimetres, at a moisture content greater than the Satu

33、ration Point of the cellular Walls of wood, and after drying respect- ivel y . Express the result to the nearest 0,l %. 5.4.2 Calculate the volumetric shrinkage, /IV, when the moisture content changes to equilibrium with the normal en- vironment (relative humidity 65 I!I 5 %; temperature 20 + 2 OC),

34、 as a percentage, by the formula - V max -V V” = x 100 V max V is the volume of the test piece, in cubic centimetres, at a moisture content in equilibrium with the normal environ- ment; V max has the same meaning as in 5.4.1. Express the result to the nearest 0,l %. 6 Test report The test report sha

35、ll include the following particulars: a) reference to this International Standard; b) information required by ISO 3129 (subclause 6.4); Cl method of determining shrinkage; d) type and volume of material tested (stand and number of selected trees; lot of sawn timber and number of selected boards, etc

36、 1; e) shape and of the grains; f) dimensions of the test pieces; the directions number of test pieces tested; g) moisture content in equilibrium with the normal en- vironment (relative humidity 65 + 5 %; temperature 20 z!I 2 OC); h) the test results, calculated as specified in 4.4 or 5.4, and thei

37、r statistical values (together with the relative humidity and temperature if shrinkage was determined under condi- tlons different from those specified in 4.3 and 5.3.3); i) k) date of testing; place of testing. Copyright International Organization for Standardization Provided by IHS under license w

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