ISO 20392-2007 Thermal-insulating materials - Determination of compressive creep《隔热材料 压缩蠕变测定》.pdf

1、 Reference number ISO 20392:2007(E) ISO 2007INTERNATIONAL STANDARD ISO 20392 First edition 2007-06-15 Thermal-insulating materials Determination of compressive creep Matriaux disolation thermique Dtermination du fluage en compression ISO 20392:2007(E) PDF disclaimer This PDF file may contain embedde

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4、e optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2007 All rights reser

5、ved. 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 the country of the request

6、er. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reservedISO 20392:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative

7、 references . 1 3 Terms and definitions. 1 4 Principle. 3 5 Apparatus 3 6 Test specimens . 4 7 Procedure 5 8 Calculation and expression of results 8 9 Precision 9 10 Test report . 9 Annex A (normative) Calculation of long-term compressive creep 10 Annex B (informative) Example of a linear regression

8、 analysis . 13 Bibliography . 17 ISO 20392:2007(E) iv ISO 2007 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out throug

9、h 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 committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborat

10、es closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standard

11、s. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of thi

12、s document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 20392 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular plastics. INTERNATIONAL STANDARD ISO 20392:2007(E) ISO 2007 All rights rese

13、rved 1 Thermal-insulating materials Determination of compressive creep 1 Scope This International Standard specifies equipment and procedures for determining the compressive creep of test specimens under various conditions of stress. It is applicable to thermal-insulation products. 2 Normative refer

14、ences 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 document (including any amendments) applies. ISO 844, Rigid cellular plastics Determinat

15、ion of compression properties ISO 1923, Cellular plastics and rubbers Determination of linear dimensions 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 thickness linear dimension measured perpendicular to the length and width plane 3.1.1 thi

16、ckness d original product thickness 3.1.2 thickness d sinitial thickness of the test specimen 3.1.3 thickness d Lthickness of the test specimen under the basic compressive stress of the loading device (“dead weight”) 3.1.4 thickness d 0thickness of the test specimen 60 s after the beginning of loadi

17、ng 3.1.5 thickness d tthickness of the test specimen at a given time t ISO 20392:2007(E) 2 ISO 2007 All rights reserved3.2 compressive stress cratio of the compressive force to the initial cross-sectional area of the test specimen 3.3 deformation X reduction in thickness of the test specimen 3.4 rel

18、ative deformation ratio of the deformation X of the test specimen and its thickness d s , measured in the direction of the load 3.5 compressive creep X ctincrease, with time, in the deformation of the test specimen under a constant stress under specified conditions of temperature and humidity NOTE X

19、 ct= X t X 0where X tis the deformation at time t; X 0is the initial deformation (60 s after the beginning of loading). An illustration of the different thicknesses and deformations is given in Figure 1. ISO 20392:2007(E) ISO 2007 All rights reserved 3Key X time, t Y thickness 1 thickness under the

20、“dead weight” of the loading device ( 10 % of the smallest chosen stress for the creep test) 2 point when load is applied for the compressive-creep test 3 deformation curve aIn the illustration, d Lis used as the reference value for the measurements of deformation. If d sis used as the reference val

21、ue, the illustration can be used with the omission of the column for d L(see 7.3). Figure 1 Illustration of the various thicknesses and deformations 4 Principle The compressive creep is determined by measuring the increase in deformation of a test specimen under a constant compressive stress and spe

22、cified conditions of temperature, humidity and time. 5 Apparatus 5.1 Loading device, consisting of two flat plates, one of which shall be movable, so arranged that they compress the test specimen in the vertical direction. The movable plate shall be mounted in such a manner as to be self-aligning. T

23、he plates shall be capable of being loaded smoothly and without distortion so that, during the test, the static stress does not change by more than 5 %. 5.2 Measuring device (e.g. dial gauge), capable of determining the distance between the two plates, i.e. the deformation of the test specimen, to a

24、n accuracy of 0,01 mm. 5.3 Suitable damping facilities, to minimize the effects of external vibration, e.g. a substantial base supporting the apparatus. ISO 20392:2007(E) 4 ISO 2007 All rights reservedExamples of test apparatus are given in Figure 2. Key 1 displacement transducer or dial gauge 2 loa

25、ding bridge 3 load-distribution plate (movable, self-aligning) 4 test specimen 5 base supporting apparatus 6 weights providing the load Figure 2 Examples of test apparatus 6 Test specimens 6.1 Preparation The test specimens for determining the compressive creep shall be taken from the same test samp

26、le, with the same preparation, as the test specimens used for the determination of compression properties in accordance with ISO 844. NOTE Special methods of preparation, when needed, may be given in the relevant product standard. 6.2 Dimensions The test specimens shall be right prisms with a square

27、 base. The thickness of the specimens shall be the original product thickness. The length and width of the specimen base shall not be less than their thickness. Products with facings or integrally moulded skins which are retained in use shall be tested with these faces or skins intact. Test specimen

28、s shall not be layered to produce a greater thickness for testing. ISO 20392:2007(E) ISO 2007 All rights reserved 5 The length and width of the test specimen base are normally specified in the relevant product standard. If not, they shall be agreed between the interested parties, in which case the r

29、ecommended dimensions are: 50 mm 50 mm or 100 mm 100 mm or 150 mm 150 mm or 200 mm 200 mm or 300 mm 300 mm. The length and width of the test specimen base shall be measured in accordance with ISO 1923 to an accuracy of 0,5 %. The tolerance on parallelism between the upper and lower faces of the test

30、 specimens and the tolerance on the flatness of the upper and lower faces shall not be greater than 0,5 % of the test specimen length or width, with a maximum of 0,5 mm. If a test specimen is not flat, it shall be ground flat or a suitable coating applied to prepare the surface for the test. If it i

31、s coated, no significant creep shall occur in the coating or, if creep does occur in the coating, this shall be taken into account by deducting it from the measurements. 6.3 Number The number of test specimens shall be as specified in the relevant product standard. If the number is not specified, th

32、en at least three test specimens shall be used for each of the compressive stresses selected in 7.2. In the absence of a product standard, the number of test specimens may be agreed between the interested parties. 6.4 Conditioning The test specimens shall be conditioned for at least 24 h under the t

33、est conditions. In cases of dispute, the time for conditioning (equilibration of moisture content) shall be as specified in the relevant product standard. 7 Procedure 7.1 Test conditions The test shall be carried out at (23 2) C and (50 10) % relative humidity or (23 5) C and 20 10 50 + % relative h

34、umidity or (27 5) C and 20 10 65 + % relative humidity unless other conditions are given in the relevant product standard. ISO 20392:2007(E) 6 ISO 2007 All rights reserved7.2 Stress selection The test shall be carried out at three or more different stresses. The alternative stresses, c , for the cre

35、ep investigation shall be based on either the compressive strength, m , or the compressive stress, 10 , at 10 % deformation measured in accordance with ISO 844, and shall be calculated as follows: cm 0,15 = or c1 0 0,15 = cm 0, 20 = or c1 0 0, 20 = cm 0, 25 = or c1 0 0, 25 = cm 0, 30 = or c1 0 0, 30

36、 = cm 0, 35 = or c1 0 0, 35 = If appropriate, other values of cmay be chosen. 7.3 Test procedure If the thickness of a test specimen, d s , is determined without using the loading device, it shall be measured to the nearest 0,1 mm in accordance with ISO 1923. Place the test specimen carefully in the

37、 loading device under the “dead weight” of the loading device. The thickness under this load, d L , is considered as the reference value for the measurements of deformation. Determine d Lto the nearest 0,01 mm. The stress imposed by the “dead weight” shall be less than 10 % of the lowest stress sele

38、cted for the test. If the thickness of the test specimen, d s , is determined using the loading device, the specimen shall be preloaded with a pressure of (250 10) Pa and the thickness measured to the nearest 0,01 mm. This value shall then be used as the reference value for measurements of deformati

39、on. If significant deformation occurs under the pressure of 250 Pa, then a load corresponding to 50 Pa may be used assuming it is specified in the relevant product standard. In this case, the thickness d sshall be determined under the same load. Apply the first of the selected stresses uniformly to

40、the test specimen within (10 5) s. Determine the initial deformation, X 0 , to the nearest 0,01 mm (60 5) s after the beginning of loading. Determine the deformation, X t , to the nearest 0,01 mm at the following times after loading: 0,1 h, 1 h, 5 h and then at 1 day, 2 days, 4 days, 7 days, 9 days,

41、 11 days, 14 days, 18 days, 24 days, 32 days, 42 days, 53 days, 65 days, 80 days and at at least one additional time between 90 days and 100 days. NOTE These times, when expressed in hours, give equal time increments on a logarithmic time scale. If the test is continued after 90 days, readings shall

42、 be made at equal time increments (on a logarithmic scale). An example of a suitable test schedule is given in Table 3 and shown in Figure 3. If a coating has been added for test purposes, the compressive creep may be measured by the relative movement of the flat plates of the loading device. Altern

43、atively, it may be measured from the relative movement of reference points on the edges of the specimen. Tabulate the measured deformation values, X t , for each test specimen separately. ISO 20392:2007(E) ISO 2007 All rights reserved 7 Table 1 Example of schedule for taking deformation readings Day

44、 Time Test duration h Day of week 0 10:00 a.m. 0 (loading) Mon 0 10:01 a.m. 0,017 Mon 0 11:00 a.m. 1,0 Mon 0 3:00 p.m. 5,0 Mon 1 10:00 a.m. 24 Tues 2 10:00 a.m. 48 Wed 4 2:00 p.m. 100 Fri 7 10:00 a.m. 168 Mon 9 10:00 a.m. 216 Wed 11 10:00 a.m. 254 Fri 14 10:00 a.m. 336 Mon 18 10:00 a.m. 432 Fri 24 1

45、0:00 a.m. 576 Thurs 32 10:00 a.m. 768 Fri 42 10:00 a.m. 1 008 Mon 53 10:00 a.m. 1 272 Fri 65 10:00 a.m. 1 560 Wed 80 10:00 a.m. 1 920 Thurs 100 10:00 a.m. 2 400 Wed 123 10:00 a.m. 2 952 Fri 156 10:00 a.m. 3 744 Wed 190 10:00 a.m. 4 560 Tues 231 10:00 a.m. 5 544 Mon 295 10:00 a.m. 7 080 Tues 365 10:0

46、0 a.m. 8 760 Tues ISO 20392:2007(E) 8 ISO 2007 All rights reservedKey readings for the required test duration of 90 days (see 7.3) x readings for a test duration longer than 90 days (see 7.4) t time (h) Figure 3 Equal time increments (on logarithmic scale) up to 10 000 h 7.4 Duration of test The com

47、pressive creep shall be measured at time intervals (see 7.3) over a period of at least 90 days. The total test time depends on the time to which the measurements will have to be extrapolated (the long-term deformation time), which shall be determined in accordance with Annex A. 8 Calculation and exp

48、ression of results Calculate the relative deformation, t , as a percentage, for each test specimen using the equation s 100 t t X d = where X tis the deformation, in millimetres, at time t; d sis the initial thickness, in millimetres, of the test specimen. The relative deformation for each test spec

49、imen and the mean value of the three relative deformations for each stress level shall be plotted in a linear/logarithmic (time) or a logarithmic/logarithmic diagram. The calculation of the creep deformation and the equation for its extrapolation is given in Annex A. ISO 20392:2007(E) ISO 2007 All rights reserved 9 9 Precision It has not been possible to include a statement on the precision of the measurements in thi