1、BRITISH STANDARD Materials and articles in contact with foodstuffs - Test methods for water absorption of ceramic articles The European Standard EN 12171997 has the status of a British Standard ICs 67.250; 81.060.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHI LAW BS EN 1217:19
2、98 - STD-BSI BS EN L2L7-ENGL 1778 lb2Libb7 Ob72418 2b7 AmdNo. BS EN 1217:1998 Date Textafected I This British Standard, having been prepared under the direction of the sedor Board for Consumer Products and Services, was pubiished under the authority of the Standars Board and comes into effect on 16
3、Aprii 1998 O BSI 1998 National foreword This British Standard is the English language version of EN 12171997. The UK participation in its preparation was entrusted to Technicai Committee CWB, pabeware, which has the responsibility to: - aid enquirers to understand the tee - present to the responsibl
4、e European committee any enquiries on the inteqxetation, or proposais for change, and 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 secre
5、m. Cross-references The British Sandards which implement intemational or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “Intrnational Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Elect
6、ronic Catalogue. A British Standard does not purport to include aii the necessary provisions of a contract Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legai obligations. Summary of pages This doc
7、ument comprises a front cover, an inside front cover, the EN titie page, pages 2 to 6, an inside back cover and a back cover. Amendments issued since publication ISBN O 680 29529 X NORMI3 EUR0PEE“E EUROP the lower the water absorption, the higher the degree of vitrifcation. A high degree of vitrific
8、ation is necessary for certain categories of ceramic articles to achieve important performance characteristics. Water absorption is one of the properties used to characterize different types of ceramic articles. Any of the three test methods may be used, as appropriate, but method A is based on Euro
9、pean Community Regulation No 679/72, Customs classification of products to be died to porcelain: Vitreous china“ or Semi-vitreous china“ type, and is for use for such classification purposes. 1 scope This European Standard specifies test methods for the determination of the water absorption of ceram
10、ic articles. Three test methods are described - test method A, based on the increase in mass of test specimens after immersion in boiling water under defined conditions, which requires test specimens with not more than one glazed surface; - test method B, based on the same principle and general proc
11、edure as method A but with a longer period of immersion in boiling water; - test method C, based on the increase in mass of test specimens after a combination of evacuation of the test specimens to assist water penetration, followed by immersion in water and boiling; the test specimens may be glazed
12、 on both surfaces and are taken from different parts of a ceramic article to include possible inhomogeneities of the article. NOTE Values of very low water absorption should preferably be determined by test method C. 2 Definitions For the purposes of this standard, the following definitions apply 2.
13、1 water absorption quantity of water that can be absorbed by the body of a ceramic ware 2.2 body ceramic material shaped to constitute the ware, more or less vitrified, which is generally coated with glaze Page 3 EN 12171997 3 Principle The increase in mass is determined as a result of immersion in
14、water under controlled conditions and is expressed as a percentage of the mass of the dry test specimen. 4 Water 4.1 Disliued or de-ionize warn, for test methods A and B. 4.2 De-gassed distilled or b) for hollow-ware, take one test specimen from the top section and the second test specimen from the
15、base area of the sample. NOTE The test specimens obtained in this way may be unglazed, glazed on one major surface, or glazed on both major surfaces. 7 Procedures 7.1 Test methodA Dry the test specimens to constant mass in the oven (5.1.1) at 110 “C * 5 “C. NOTE As a guide, a 3 h period will suffice
16、 for test specimens obtained by breaking an article of tableware. If the test specimens are obtained by cutting an article of tableware using a saw (5.1.8) and are wet, then a longer drying time may he necessary. Place the test specimens in the desiccator (5.1.3) and allow them to cool to ambient te
17、mperature. Weigh each test specimen and record the final mass, ml, to the nearest 0,05 g. Immediately after weighing immerse the test specimens in distilled or deionized water (4.1). To avoid bumping during subsequent boiling ensure that the test specimens are not in contact with the bottom of the v
18、essel (5.1.4). Boil for 2 h f 5 min and then leave the test specimens to soak in the cooling water for a furilter period of not less thCui 24 h. Remove the test specimens from the water and wipe with a clean and slightly moist smooth cotton cloth (5.1.6) to remove surface water. Completely dry the g
19、lazed surface and dry any cavities or holes using a slim, slightly damp brush (5.1.7). Weigh each test specimen and record the masses after immersion, m2, to the nearest 0,05 g. 7.2 Test method B Cany out the test procedure as described for method A in 7.1, except that the period of immersion in boi
20、ling water is extended to 4 h f 10 min. Page 5 EN 1217:1997 7.3 Test method C Dry the test specimens to constant mass in the oven (6.2.1) at 110 “C 5 OC. Place the test specimens in the desiccator (5.2.2) and allow them to cool to ambient temperature. Weigh each test specimen and record the mass, mi
21、, to the nearest 0,Ol g. Place the dry test specimens on setter pins into a suitable vessel (6.2.4), reduce the pressure therein to 2,5 kPa * 1,5 kPa and maintain at this pressure for 60 min 5 min. Without admitting air, admit degassed distilled or degassed de-ionized water (4.2) at ambient temperat
22、ure to the vessel, una the test specimens are fully covered. Then admit air to the vessel, returning it to atmospheric pressure, and boil the water and test specimens for 60 min f 5 min. To avoid bumping during the boiling ensure that the test specimens remain fuily submerged but do not touch the bo
23、ttom of the vessel. Mow the test specimens to cool for not less than 24 h whilst remaining submerged in the boiled water. Remove the test specimens from the water and wipe them with a moistened smooth cotton cloth (5.2.8) such that glazed surfaces are completely dry and broken surfaces retain a thin
24、 film of moisture appearing as a sheen. Weigh each test specimen and record the masses after immersion, m2, to the nearest 0,Ol g. 8 Expression of results For each test specimen, calculate the water absorption as a percentage of the dry mass of the test specimen using the following equation: x 100%
25、rn2 - ml ml water absorption = where: ml m2 is the mass of the test specimen after drying to constant mass, in grams; is the mass of the test specimen after immersion, in grams. Calculate the arithmetic mean of the results obtained for all test specimens to the first decimal place. 9 ist report The
26、test report shall include the following details: a) a reference to this European Standard b) an identification of the article tested; c) the test method used, i.e. A, B or C; d) water absorption for each test specimen calculated in accordance with the equation given in clause 8 and the arithmetic me
27、an of the results obtained for the test specimens. O BSI 1998 STD-BSI BS EN LELT-ENGL 1778 W Lb2LibbS Ob72424 5b0 Page 6 EN l217:1997 Annex A (informative) Bibliography European Community Rewon No. 679/72 - Customs classcaCion of products to be died to pomehin: Vitreous chinu” m “Semi-vitreous chinu
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