1、 Reference number ISO 20394:2007(E) ISO 2007INTERNATIONAL STANDARD ISO 20394 First edition 2007-06-15 Thermal-insulating materials Determination of freeze-thaw resistance Matriaux disolation thermique Dtermination de la rsistance au gel-dgel ISO 20394:2007(E) PDF disclaimer This PDF file may contain
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6、 requester. 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 20394:2007(E) ISO 2007 All rights reserved iii Foreword ISO (the International Organizat
7、ion for Standardization) is a worldwide 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 h
8、as 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 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Int
9、ernational 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 Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Public
10、ation 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 this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent ri
11、ghts. ISO 20394 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular plastics. INTERNATIONAL STANDARD ISO 20394:2007(E) ISO 2007 All rights reserved 1 Thermal-insulating materials Determination of freeze-thaw resistance 1 Scope This International Standard specifies t
12、he equipment and procedures for determining the effect, on the mechanical properties and moisture content of a product, of the successive cycling of the product from dry conditions at 20 C to wet conditions (water) at +20 C. It is applicable to thermal-insulation products. The method is intended to
13、simulate freeze-thaw effects on thermal-insulation products which are frequently exposed to water and low-temperature conditions, e.g. inverted roofs and unprotected ground insulation. This test method is not recommended for all thermal-insulation products. It will normally be clear from the product
14、 standard if this International Standard is applicable to a particular product. 2 Normative references 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 re
15、ferenced document (including any amendments) applies. ISO 2896, Rigid cellular plastics Determination of water absorption ISO 20392, Rigid cellular plastics Determination of long-term compressive creep ISO 20393, Rigid cellular plastics Determination of long-term water absorption by diffusion 3 Term
16、s and definitions For the purposes of this document, the following terms and definitions apply. 3.1 freeze-thaw resistance ability of a product to withstand repeated wetting followed by freezing conditions, this ability being quantified in terms of the water absorption and the change in compression
17、behaviour 4 Principle The freeze-thaw resistance is determined as the change in the amount of water absorbed and the change in compression strength or stress of a test specimen which is subjected to 300 successive cycles from dry conditions at 20 C to wet conditions (water) at +20 C. The freezing ta
18、kes place in air, the thawing in water. The freeze-thaw exposure is carried out in conjunction with one of the following long-term water absorption tests: a) water absorption by diffusion as specified in ISO 20393; b) water absorption by total immersion as specified in ISO 2896. The water absorption
19、 test to be used will be indicated in the relevant product standard. ISO 20394:2007(E) 2 ISO 2007 All rights reserved5 Apparatus 5.1 Cold chamber, at a constant temperature of ( 20 2) C. 5.2 Water tank, with a constant water temperature of (20 2) C, equipped with a device for holding the test specim
20、en in position. NOTE Normally, no accelerated thermal-exchange facilities, e.g. fan assistance in the cold chamber or turbulent water circulation in the water tank, are provided. 5.3 Balance, which permits reading to 0,1 g. 5.4 Compression-testing machine, including measuring devices, as specified i
21、n ISO 20392. 6 Test specimens 6.1 General The test specimens used for this method (set A) shall be the same test specimens which have been used for the determination of long-term water absorption by diffusion in accordance with ISO 20393 or by total immersion in accordance with ISO 2896. 6.2 Dimensi
22、ons The thickness of the test specimens shall be the original product thickness. The test specimens for set A shall be square, with squarely cut edges, having sides of length (500 1) mm or (200 1) mm, depending on the water absorption method chosen. 6.3 Number The number of test specimens in set A w
23、ill depend on the sizes of the two sets of specimens for the compression test (sets B1 and B2) which are prepared from set A. The number of test specimens in each of sets B1 and B2 for the compression test, and their dimensions, shall be as specified in the relevant product standard or another inter
24、national technical specification. In the absence of such a specification, the number of specimens and their dimensions shall be as defined in ISO 20392. 6.4 Preparation If possible, the test specimens shall be cut so that they do not include original product edges. The preparation of the specimens s
25、hall be by methods that do not change the original structure of the product. Any skins, facings and/or coatings shall be retained. 6.5 Conditioning The test specimens shall be conditioned for at least 6 h at (23 5) C. In cases of dispute, they shall be conditioned at (23 2) C and (50 5) % relative h
26、umidity for the time stated in the relevant product standard, but in any case for a minimum of 6 h. ISO 20394:2007(E) ISO 2007 All rights reserved 3 7 Procedure Carry out the freeze-thaw exposure by the procedure described below and illustrated in Figure 1. All test specimens in both set A and the s
27、eparate set for compression testing of the original product shall be taken from the same sample. Determine the compression behaviour ( mor 10 ) of the original product in accordance with ISO 20392. Determine the long-term water absorption of the test specimens using either ISO 2896 or ISO 20393, rec
28、ording the mass of each test specimen at the end of the water absorption test as m 0 . Place the test specimens in the cold chamber and maintain the temperature at ( 20 2) C for 1 h. Remove the test specimens from the cold chamber and immerse them in water maintained at a temperature of (20 2) C for
29、 1 h. Figure 1 Flow chart for the test procedure ISO 20394:2007(E) 4 ISO 2007 All rights reservedContinue the freeze-thaw exposure for a total of 300 cycles (see Figure 2). If there are interruptions of longer than 1 h in the specified freeze-thaw cycle, e.g. during the night or the weekend, the tes
30、t specimens shall be left in the cold chamber during the interruption. On completion of the 300 cycles, determine the mass, m 1 , of each of the test specimens (set A) to the nearest 0,1 g. Key X time Y temperature, C a1 cycle. Figure 2 Test cycle duration Examine the test specimens visually for def
31、ects, e.g. cracks, blisters. Prepare the test specimens for set B1 and set B2. Within 24 h of the last freeze-thaw cycle, determine, in accordance with ISO 20392, the compression behaviour of the test specimens in set B1 (compression behaviour in wet conditions, m,wetor 10,wet ). Dry the test specim
32、ens from set B2 in a ventilated drying chamber for the time and temperature specified in the relevant product standard or any other technical specification agreed between the interested parties. In the absence of such a specification, dry the test specimens to constant mass (considered to have been
33、reached when the change in mass between two consecutive weighings at 24 h intervals is less than 0,5 % of the total mass at a drying temperature of at least 40 C). NOTE Commonly used drying conditions are 105 C for 24 h, 70 C for 4 days and 40 C for 7 days. ISO 20394:2007(E) ISO 2007 All rights rese
34、rved 5 Determine, in accordance with ISO 20392, the compression behaviour of the test specimens in set B2 (compression behaviour in dry conditions, m,dryor 10,dry ). Ideally, the freeze-thaw exposure is carried out immediately after the determination of the long-term water absorption. In the event t
35、hat this is not possible, wrap the wet test specimens in polyethylene film and store them at ambient laboratory conditions. 8 Calculation and expression of results 8.1 Water absorption Calculate the water absorption for each test specimen, W mor W V , in percent by mass or in percent by volume, resp
36、ectively, using Equation (1) or (2): 10 m 0 100 mm W m = (1) 10 V w 100 mm W V = (2) where m 1is the mass of the test specimen after 300 freeze-thaw cycles, in grams; m 0is the mass of the test specimen at the end of the water absorption by diffusion or by total immersion, in grams; V is the volume
37、of the test specimen, in cubic centimetres; wis the density of water, assumed to be 1 g/cm 3 . Express the result of the test as the mean value of the individual values calculated above, rounding the mean value of W mto the nearest 0,1 % by mass and the mean value of W Vto the nearest 0,1 % by volum
38、e. 8.2 Changes in the compression behaviour For each test specimen, calculate the change in compression behaviour determined in wet conditions and in dry conditions, wetand dry , in percent, using Equation (3) or (4) and Equation (5) or (6): m,wet wet m 100 = (3) or 10,wet wet 10 10 = (4) m,dry dry
39、m 100 = (5) or 10,dry dry 10 100 = (6) where m,wetis the compressive strength of the test specimen in wet conditions, in kilopascals; 10,wetis the compressive stress of the test specimen at 10 % relative deformation in wet conditions, in kilopascals; m,dryis the compressive strength of the test spec
40、imen in dry conditions, in kilopascals; 10,dryis the compressive stress of the test specimen at 10 % relative deformation in dry conditions, in kilopascals; ISO 20394:2007(E) 6 ISO 2007 All rights reserved mis the compressive strength of the original product, in kilopascals; 10is the compressive str
41、ess at 10 % relative deformation of the original product, in kilopascals. Express the results of the test as the mean value of the individual values of wetcalculated above and the mean value of the individual values of dry , rounding each of the mean values to two significant figures. 9 Precision It
42、 has not been possible to include a statement on the precision of the measurements in this edition of this International Standard, but it is intended to include such a statement when the standard is next revised. 10 Test report The test report shall include the following information: a) a reference
43、to this International Standard; b) product identification: 1) the name of the product, the factory where it was manufactured and the manufacturer or supplier, 2) the production code number, 3) the type of product, 4) the type of packaging, 5) the form in which the product arrived at the laboratory,
44、6) details of any skins, facings or coatings, 7) any other information as appropriate, e.g. nominal thickness, nominal density; c) test procedure: 1) details of pre-test history and sampling, e.g. who sampled and where, 2) details of conditioning, 3) details of any deviations from the requirements s
45、pecified in Clauses 6 and 7, 4) the dates of testing, 5) the dimensions of the test specimens and the number tested, 6) the long-term water absorption method used (ISO 20393 or ISO 2896), 7) details of any events which may have affected the results; d) results: 1) all individual values and the mean
46、values, 2) any visual observations after the freeze-thaw exposure, e.g. cracks, blisters. Information about the apparatus and the identity of the technician should be available in the laboratory, but need not be recorded in the test report. ISO 20394:2007(E) ICS 83.100 Price based on 6 pages ISO 2007 All rights reserved
