1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 1183 : 1997 The Eur
2、opean Standard EN 1183 : 1997 has the status of a British Standard ICS 67.250 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Materials and articles in contact with foodstuffs Test methods for thermal shock and thermal shock enduranceBS EN 1183 : 1997 This British Standard, ha
3、ving been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 September 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference CW/29 Draft fo
4、r comment 93/311360 DC ISBN 0 580 27673 2 Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee CW/29, Tableware, upon which the following bodies were represented:
5、 Association of Consulting Scientists Association of Metropolitan Authorities Association of Public Analysts British Ceramic Confederation British Ceramic Gift and Tableware Manufacturers Association British Ceramic Research Ltd. British Glass Manufacturers Confederation British Hardware and Housewa
6、res Manufacturers Association British Importers Association British Retail Consortium CESA The Association of Catering Equipment Manufacturers and Importers Co-operative Union Consumer Policy Committee of BSI Department of Trade and Industry, Consumer Safety Unit Stoneware Potteries Association Vitr
7、eous Enamellers Association BSI 1997 i BS EN 1183 : 1997 National foreword This British Standard has been prepared by Technical Committee CW/29 and is the English language version of EN 1183 : 1997 Materials and articles in contact with foodstuffs Test methods for thermal shock and thermal shock end
8、urance, published by the European Committee for Standardization (CEN). 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, pages i and ii, the EN title page, pages 2 to 6, an insi
9、de back cover and a back cover.ii blankCEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 Copyright reserved to CEN members Ref. No. EN 1183 : 1997 E EUROPEAN STANDARD EN 1183 N
10、ORME EUROPE ENNE EUROPA ISCHE NORM March 1997 ICS 67.250 Descriptors: Kitchen utensils, materials, food-container contact, thermal shock tests, thermal shock resistance English version Materials and articles in contact with foodstuffs Test methods for thermal shock and thermal shock endurance Mate r
11、iaux et objets en contact avec les denre es alimentaires Me thodes dessai pour le choc thermique et la re sistance au choc thermique Werkstoffe und Gegensta nde in Kontakt mit Lebensmitteln Pru fverfahren fu r Temperaturschock und Temperaturwechselbesta ndigkeit This European Standard was approved b
12、y CEN on 1997-02-14. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards
13、 may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the
14、Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN
15、1183 : 1997 BSI 1997 Foreword This European Standard has been prepared by Technical Committee CEN/TC 194, Utensils in contact with food, the secretariat of which is held by BSI. Further European Standards are being prepared with the following titles: EN 1184 Materials and articles in contact with fo
16、odstuffs Test methods for translucency of ceramic articles EN 1217 Materials and articles in contact with foodstuffs Test method for water absorption of ceramic articles A further standard is proposed with the following title Materials and articles in contact with foodstuffs Test method for crazing
17、resistance of ceramic articles This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 1997, and conflicting national standards shall be withdrawn at the latest by September 1997. According to t
18、he CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerl
19、and and the United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Definitions 3 3 Principle 3 4 Apparatus 3 5 Samples 3 6 Procedures 3 7 Expression of results 4 8 Test report 4 Annex A (informative) Bibliography 5 Annex B (informative) Calculation of thermal shock endurance from test results 5Page 3
20、EN 1183 : 1997 BSI 1997 1 Scope This European Standard specifies test methods for thermal shock and for thermal shock endurance for brittle materials, for example glass, glass-ceramics and ceramics intended for use in ovens or as tableware. Two test methods are described: Test method A is used for a
21、rticles known to be sensitive to thermal shock; Test method B is generally applicable. The test method to be applied depends on the intended use of the article and/or its thermal shock resistance. 2 Definitions For the purpose of this European Standard, the following definitions apply: 2.1 thermal s
22、hock Sudden change in temperature. 2.2 thermal shock endurance, Dt 50 Value for the resistance against sudden change in temperature corresponding to the temperature difference at which, for the first time, 50 % of the samples fail. 2.3 temperature variation Difference at any given time between the t
23、emperature at the centre of the working space of the water bath or test oven and at any other point in that working space. 2.4 temperature fluctuation Short term change in temperature at any point in the working space of the water bath or test oven. 3 Principle Samples are heated and then cooled rap
24、idly under controlled conditions to determine their resistance to thermal shock. Thermal shock tests are repeated using increasing temperature differences until 50 % of the samples fail. The temperature differenceDt 50 is given as the thermal shock endurance. 4 Apparatus NOTE. Clauses 4.1, 4.2 and 4
25、.4 apply to method A, clauses 4.1, 4.3, 4.4, 4.5 and 4.6 apply to method B. 4.1 Cold water bath, comprising a bath or tank capable of containing at least five times the apparent volume of the overall dimensions of the samples being tested (including the volume of the basket) at one time; fitted with
26、 a water circulator, a thermometer and thermostatic control capable of maintaining during all the duration of the test the water temperature to within 2 C of a specified lower temperature, t 2 , within the range 10 C to 20 C. 4.2 Hot water bath, comprising a bath or tank capable of containing at lea
27、st five times the apparent volume of the overall dimensions of the samples being tested (including the volume of the basket) at one time; fitted with a water circulator, a thermometer and thermostatically-controlled heater capable of maintaining during all the duration of the test the water temperat
28、ure to within 2 C of the specified upper temperature, t 1 . 4.3 Test oven, preferably electrically heated, capable of achieving a temperature of at least 300 C, fitted with an air circulating device to ensure that the temperature variation does not exceed 5 C and a thermostatic control capable of ma
29、intaining the temperature fluctuation to within 2 C up to 180 C and to within 3 C above 180 C. 4.4 Basket, for testing two or more samples simultaneously, made out of, or coated with, an inert material which will not damage the surface of the samples during the test procedure. The basket is capable
30、of holding the samples in a position which ensures that air escapes and water can immediately enter the inside of holloware. The samples are held separately to allow free passage of water between them. The basket is fitted with clamps to prevent the samples from floating when immersed. NOTE. For the
31、 multiple testing of samples, the basket may be combined with an automatic device for immersing it in the hot water bath (4.2) or oven (4.3) and transferring it to the cold water bath (4.1). 4.5 Tongs, with tips protected by a head resisting material such as glass or mineral wool. 4.6 Gloves, gauntl
32、et-type, made from a heat-resisting material. 4.7 Staining agent NOTE. A suitable staining agent is eosine present at a concentration of (5 1) g/l and a domestic washing up liquid present at a concentration of (5 1) g/l. 5 Samples The test shall be performed on not less than ten samples. Use only un
33、used samples to start the test. 6 Procedures 6.1 Test method A 6.1.1 Remove any dirt or loose debris from the samples and allow the samples to reach ambient temperature. Protect the apparatus from draughts throughout the test. 6.1.2 Fill the cold water bath (4.1) with water, containing a staining ag
34、ent, to a volume equal to not less than five times the apparent volume of the overall dimensions of the samples to be tested including the volume of the basket and to a depth sufficient for complete immersion of the samples plus not less than 50 mm. Adjust and maintain the water temperature to withi
35、n 2 C of the specified lower temperature, t 2 .Page 4 EN 1183 : 1997 BSI 1997 6.1.3 Fill the hot water bath (4.2) with not less than the same volume of water and to the same depth as in 6.1.2, then adjust and maintain the water temperature to within 2 C of the specified upper temperature, t 1 (see 6
36、.3). 6.1.4 Place the empty samples in the basket (4.4)s o that they are held separately and meet the conditions of 4.4, then fasten the samples and immerse the basket in the hot water bath, until the tops of the samples are not less than 50 mm below the water level and, in the case of holloware they
37、 are completely filled with water. If necessary, adjust the heat control to maintain the bath temperature to within 2 C of the specified temperature, t 1 , and keep the samples immersed at this temperature until they have reached equilibrium. 6.1.5 Drain the loaded articles and transfer the loaded b
38、asket, either mechanically or manually, within 5 s or 6 s after removal from the hot water bath to the cold water bath so that the samples are completely immersed in the cold water bath. Keep the samples immersed for 30 s, then remove the basket and its contents from the cold water bath. 6.1.6 Inspe
39、ct immediately each sample for chipping, cracking, crazing or breakage and determine the number of samples which have failed the test. 6.2 Test method B 6.2.1 Remove any dirt or loose debris from the samples and, if necessary, dry the sample. CAUTION: Handle hot samples only with dry tongs or gloves
40、. 6.2.2 Fill the cold water bath (4.1) with water, containing a staining agent (4.7), to a volume equal to not less than five times the apparent volume of the overall dimensions of the samples to be tested (including the volume of the basket) and to a depth sufficient for complete immersion of the s
41、amples plus not less than 50 mm. Locate the cold water bath (4.1) near to the test oven and adjust and maintain the water temperature to within 2 C of the specified lower temperature, t 2 . 6.2.3 Place the samples, either separately or contained in the basket (4.4) in the test oven (4.3) which has b
42、een previously heated to the upper temperature, t 1 (see 6.3). Maintain the samples at this temperature until they have reached equilibrium. 6.2.4 Remove the samples from the test oven either one at a time, holding them with the tongs (4.5)o r ,i f the samples are large or contained in the basket (4
43、.4), with the gloves (4.6). Immerse the samples without impact completely in the cold water bath for a specified period between 8 s and 2 min ensuring that all holloware is filled with water. Complete the process of transferring each sample, or the basket with samples, from opening of the test oven
44、to immersion in (5 1) s. Ensure that the difference in temperature between the test oven (4.3) and the cold water (4.1) is not more than 3 C from the required temperature value at the time of transference. 6.2.5 Remove the samples from the cold water bath. Inspect immediately each sample for chippin
45、g, cracking, crazing or breakage and determine the number of samples which have failed the test. 6.3 Determination of thermal shock resistance Repeat the testing procedure with the remaining test samples according to method A (6.1) or method B( 6.2) as appropriate, with increasing temperature differ
46、ence values, t 1 2 t 2 , until all samples have failed. Commence testing with a temperature difference value, t 1 2 t 2 of not less than 40 C and increase temperature t 1 , by 10 C for t 1 2 t 2 # 100 C and by 20 C for t 1 2 t 2 100 C. 7 Expression of results 7.1 Requirements for failure by thermal
47、shock Samples which do chip, crack, craze or break are recorded as having failed the thermal shock test at the temperature difference t 1 2 t 2 . 7.2 Thermal shock endurance Record the number of failures at each temperature difference and determine theDt 50 - value by listing the cumulative percenta
48、ge of failures versus the temperature difference at which the samples failed (see annex B). Determine the standard deviation s by computing the failure/temperature difference data for the complete set of results. 8 Test report The test report shall include the following details: a) a reference to th
49、is European Standard; b) an identification of the article tested; c) the number of samples taken for the test and the sampling method; d) for the thermal shock test: the test method used, i.e. A or B; the temperature difference t 1 2 t 2 in degrees Celsius; the number of samples which failed the test and the mode of their failure; e) for the thermal shock endurance test: the test method used for thermal shock, i.e. A or B; the temperature differenceDt 50 at which 50 % of the
