1、- STD-BSI BS EN L87b-Z-ENGL 1798 Lb24bh9 Ob88984 075 M BRITISH STANDARD Rubber- or plastics-coated fabrics - Low temperature tests Part 2. Impact test on loop The European Standard EN 187 - present to the responsible European committee any enquiries on the interpretation, or proposais for change, an
2、d keep the UK interests informed; - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or Europe
3、an publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include ail the necessary
4、provisions of a c0ntm.c.t Users of BriW Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to
5、6, an inside back cover and a back cover. O BSI 1998 I I ISBN O 680 29276 4 STD-BSI BS EN 187b-2-ENGL 1798 Lb2qbbS Ob8878b b8 = EUROPEAN SilND NORIME EUR0PEE”E EUROP - an and capable of being attached to the specimen holder and withtanding impact without deformation during the test. The anvil and th
6、e test specimen holder shall be level; - a hammer of mas (200 f 2) g made of a vertical axjs cylinder, its diameter being between 17 mm and 30 nun. The base of the cylinder shail be chamfered to an angle of (45 f i“; the chamfered edge being (1 f O, 1) mm high; - a centering system for the hammer eq
7、uipped with a holding down system to permit a free fall of the hammer i-om a height of (200 f 2) nun. Two examples of suitable impact apparatus are given in annex A. 6.2 Cold chamber, containing the impact apparatus, which shall permit a decrease of temperature by steps of 5 “C. The tmpemm of the ch
8、ambes shall be stabilized to f 1 “C Gacent to the test specimen. 6.3 Lens, with a magnification of X4 to X6. 7 Atmospheres for conditioning The atmospheres for conditioning shall be as specified in EN IS0 2231. NOTE. The samples should be conditioned for at least 24 h in a free state. O BSI 1998 STD
9、*BSI BS EN L87b-Z-ENGL 1778 m Lb29bb7 Ob88787 b77 Page 4 EN 1876-2 : 1997 8 Procedure Bend the ends of test specimen to form a loop and clamp on the test specimen holder. Introduce the test specimen holder into the cold chamber (see 6.2). After (120 15) min, when the test specimens are in eqdibrium
10、with the test temperature, drop the hammer (see 6.1) onto the test specimens. lke the test specimens out of the cold chamber and examine them with the lens (see 6.3). A test specimen is considered broken when it shows a rupture visible with a lens, induced totally or partially over the thickness of
11、the coating (fissures, cracks), and not a surface deformation such as a white line or a chap. The initiai test temperature shall be such that no break occurs. Unless otherwise agreed by the parties, it shall be a multiple of 5 “C. At any test tempeme (t), perform the test as follows: - test 10 test
12、specimens and check them for breaks, - If two or more breaks occur, then the test is ended and the temperature (Q) is noted; - If one test specimen oniy breaks, then retest a new set of 10 specimens. If one or more breaks of this new set occur, then the test is ended and the temperature (tf) is note
13、d, otherwise, lower the temperature of the chamber by 5 “C . Resume the tesi at this new mt); - If no break occurs, then lower the temperature of the chamber by 5 “C. Resume the test at this new - = l. 9 Expression of results The temperature limit of brittleness (tb) is expressed by tb=tf +5 where t
14、f is the temperature noted at the end of the test; tb and tf are expressed in “C. 10 bst report The test report shall include the following particulars: a) reference to this standard; b) date of test, c) identification of sample and sampling procedure, if required; d) the temperature limit of brittl
15、eness specified in clause 9 and the type of damage observed on the sample; e) any deviation from the procedure. NOTE. Coated fabrics are generally anisotropic materials and frequently this test is ended because of breaking of the test specimens in one direction oniy, either longitudinal or transvers
16、e. In this case, it is recommended to indicate this direction in the test report. 1 Basefabric 2 Intermediate layer 3 Upper layer Figure 1. Chap Figure 2. Fissure Figure 3. Crack O BSI 1998 STD.BSI BS EN 187b-Z-ENGL 1998 Lb24bb7 b88990 377 Page 5 EN 1876-2 : 1997 Annex A (informative) Examples of im
17、pact apparatus x * in A 1 Hammer 2 Centering tube 3 Test specimen 4 Grip 5 Specimen holder Figure A.l Impact apparatus, with a series of several centering tubes assembled O BSI 1998 STD-BSI BS EN L7b-2-ENGL 1998 = Lb2LibbS b77L 225 Page 6 EN 1876-2 : 1997 i rini I I 1 Hammer 2 Centeringmeans 3 Suppo
18、rtmeans 4 Grip 5 Test specimen 6 Eight-sided holder Figure A.2 Impact apparatus with eight-sided holder O BSI 1998 STD-BSI BS EN L87b-Z-ENGL I998 m LbZibbS Ob88992 LbL m BS EN 1876-2 : 1998 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national b
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