1、Reference number IWA 8:2009(E) ISO 2009All rights reservedInternational Workshop Agreement IWA 8 Tableware, giftware, jewellery, luminaries Glass clarity Classification and test method * * * * Verrerie, objets de dcoration, bijouterie, luminaires Clart du verre Classification et mthode dessai Copyri
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7、 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights reservedCopyright International Organization for Standardization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license
8、 from IHS-,-,-Tableware, giftware, jewellery, luminaries Glass clarity Classification and test method IWA 8:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Specifications 1 2.1 General .1 2.2 Specifications for ultra-clear glass1 2.3 Specifications for cle
9、ar glass.2 3 Test methods .2 3.1 General .2 3.2 Apparatus.2 3.3 Sampling 3 3.4 Sample preparation.3 Annex A (normative) Determination of the lightness L* and chroma C*.5 Annex B (normative) Determination of the iron oxide content 8 Bibliography9 Copyright International Organization for Standardizati
10、on Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-IWA 8:2009(E) Tableware, giftware, jewellery, luminaries Glassclarity Classification and test methodiv ISO 2009 All rights reservedForeword ISO (the International Organization
11、 for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). ISOs technical work is normally carried out through ISO technical committees in which each ISO member body has the right to be represented. International organizations, governmental and nongovernmental,
12、 in liaison with ISO, also take part in the work. In order to respond to urgent market requirements, ISO has also introduced the possibility of preparing documents through a workshop mechanism, external to its normal committee processes. These documents are published by ISO as International Workshop
13、 Agreements. Proposals to hold such workshops may come from any source and are subject to approval by the ISO Technical Management Board which also designates an ISO member body to assist the proposer in the organization of the workshop. International Workshop Agreements are approved by consensus am
14、ongst the individual participants in such workshops. Although it is permissible that competing International Workshop Agreements exist on the same subject, an International Workshop Agreement shall not conflict with an existing ISO or IEC standard. An International Workshop Agreement is reviewed aft
15、er three years, under the responsibility of the member body designated by the Technical Management Board, in order to decide whether it will be confirmed for a further three years, transferred to an ISO technical body for revision, or withdrawn. If the International Workshop Agreement is confirmed,
16、it is reviewed again after a further three years, at which time it must be either revised by the relevant ISO technical body or withdrawn. 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 ident
17、ifying any or all such patent rights. International Workshop Agreement IWA 8 was drafted at a workshop held in Paris, France, in October 2009. The workshop, which was proposed by the Institut du Verre and mandated by the International Crystal Federation (ICF) and its European arm European Domestic G
18、lass (EDG), was organized jointly by the Institut du Verre and the Association Franaise de Normalisation (AFNOR). Copyright International Organization for Standardization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Tablewa
19、re, giftware, jewellery, luminaries Glass clarity Classification and test method IWA 8:2009(E) ISO 2009 All rights reserved vIntroduction This International Workshop Agreement is intended to provide a generic definition and classification of glass clarity to permit a global understanding of consumer
20、 quality requirements, with a corresponding method to measure glass clarity. For glass clarity, spectrophotometric measurement is performed in accordance with CIE 15:2004 with a predefined choice of illuminate and observer. Measurement on the sample at two different thicknesses permits calculation o
21、f internal transmission for a defined intermediate thickness and indicates glass clarity irrespective of the refractive index value. The same methodology applies for all mineral glasses. This method has been verified in accordance with visual inspection with a light cabinet. In addition, preliminary
22、 collaborative studies have confirmed the results of these measurements as being coherent with both consumer perception and quality recognition. As it is well known that iron is by far the main contaminant of glass raw materials affecting the transparency and colorimetric purity of the glass, the ir
23、on content has been considered as an additional criterion. Copyright International Organization for Standardization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright International Organization for Standardization Provi
24、ded by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Tableware, giftware, jewellery, luminaries Glass clarity Classification and test method IWA 8:2009(E) ISO 2009 All rights reserved 1Tableware, giftware, jewellery, luminaries Glass cl
25、arity Classification and test method 1 Scope This International Workshop Agreement establishes requirements for the use of the glass designations “clear glass” and “ultra-clear glass” for non-coloured glass items according to their clarity and iron content. This International Workshop Agreement spec
26、ifies a procedure for measuring the clarity of glass items by means of a spectrophotometer. This International Workshop Agreement is applicable to mineral glasses, and glass items where a part is not covered by coating or decoration, and is therefore available for sampling. This International Worksh
27、op Agreement is applicable to the use of glass as tableware, giftware, jewellery and luminaries. This International Workshop Agreement is not applicable to the use of glass in the context of building, containers, medicine and laboratories, and to other technical uses of glass. 2 Specifications 2.1 G
28、eneral The classification of the samples of glass in terms of clarity is based on three criteria: lightness, L*; chroma, C*; iron content of the material. The iron content is a main contaminant influencing the transparency and colour of the glass; the value is expressed in iron oxide (Fe2O3) in mg/k
29、g. NOTE The best classification of clarity is obtained for the maximum value of lightness L* at 100 and the minimum value of chroma C* at zero. 2.2 Specifications for ultra-clear glass Ultra-clear glass shall have: lightness L* W 98,8; chroma C* u 0,5; Copyright International Organization for Standa
30、rdization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-IWA 8:2009(E) Tableware, giftware, jewellery, luminaries Glass clarity Classification and test method2 ISO 2009 All rights reserved iron oxide content u 140 mg/kg. If o
31、ne or more of these criteria are not reached, the glass cannot be classified as ultra-clear glass. 2.3 Specifications for clear glass Clear glass shall have: lightness L* W 98,0; chroma C* u 0,5; iron oxide content u 200 mg/kg. If one or more of these criteria are not reached, the glass cannot be cl
32、assified as clear glass. 3 Test methods 3.1 General The sample shall be prepared in accordance with 3.3 and 3.4. The same sample shall be used to characterize the three criteria, in accordance with the following two determination methods: Annex A shall apply for the determination of lightness L* and
33、 chroma C*; Annex B shall apply for the determination of the iron oxide content. 3.2 Apparatus 3.2.1 Double-beam spectrophotometer, preferably with integrating sphere. 3.2.2 X-ray fluorescence spectrometer, with wavelength dispersion. 3.2.3 Non-metallic hammer. 3.2.4 Non-metallic plate. 3.2.5 Platin
34、um crucible, compatible with the final dimensions of the sample(s). 3.2.6 Electric oven, capable of maintaining a temperature of 1 300 C for a duration of 16 h. 3.2.7 Polishing device. 3.2.8 Manual grinding device, with silicium carbide (SiC) abrasive. 3.2.9 Automatic grinding machine. 3.2.10 Automa
35、tic polishing device. Copyright International Organization for Standardization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Tableware, giftware, jewellery, luminaries Glass clarity Classification and test method IWA 8:2009(
36、E) ISO 2009 All rights reserved 33.3 Sampling 3.3.1 General The sampling is carried out to prepare two pieces of glass: the first with a minimum dimension of 30 mm for one face; the second with a minimum dimension of 10 mm for one face. The two other dimensions shall be greater than the slide dimens
37、ions of the spectrophotometer (3.2.1) for the two pieces. 3.3.2 Cutting Cut a glass block from the glass item (e.g. tumblers with a thick bottom). For glass items covered with coating or decoration, or for glass items of which the minimum dimensions of the sample cannot be reached, melt a sufficient
38、 quantity of glass not covered with coating or decoration, approximately 200 g; crush with a non-metallic hammer (3.2.3) on a non-metallic plate (3.2.4); melt in a platinum crucible (3.2.5) in an electric oven (3.2.6) for a duration of at least 8 h at 1 300 C, in order to obtain a good quality of gl
39、ass; check for the absence of seeds or bubbles; after solidification of the glass, put the crucible outside the furnace in a cold water stream to separate the glass from the crucible. The resulting sample is annealed to avoid residual stresses. 3.4 Sample preparation 3.4.1 General For the internal t
40、ransmission measurements, prepare one sample with at least one face providing 10 mm thickness for measurement and the other sample with at least one face providing 30 mm thickness for measurement (see 3.3.1). The sample thicknesses where the light travels are (10 0,05) mm and (30 0,05) mm respective
41、ly. The dimensions of the samples (cubes) should fit the sample holder of the spectrophotometer that is used. The preparation of the cubes of glass samples are carried out in accordance with the usual procedures of the laboratories, applying a polishing device (3.2.7) on the two faces in the optical
42、 way of transmission (light path). Copyright International Organization for Standardization Provided by IHS under license with ISO Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-IWA 8:2009(E) Tableware, giftware, jewellery, luminaries Glass clarity Classification
43、and test method4 ISO 2009 All rights reserved3.4.2 Cutting Each sample is cut from the part of a glass block that is homogenous and free of bubbles, cords and any other defects, by means of a diamond saw, to dimensions that are approximately 0,5 mm greater than the required final dimensions before m
44、anual grinding with silicon carbide abrasive (see 3.2.8), or approximately 5 mm greater than the required final dimensions before grinding with an automatic machine as used in the glass industry (see 3.2.9). 3.4.3 Grinding In the manual grinding procedure, a sample cube is ground under flowing water
45、 to obtain parallel surfaces at each measured face by means of turning grinding disks (see 3.2.8), using coarse grain size of silicon carbide granules. The final step of grinding is carried out on a flat glass surface, using fine grain size of silicon carbide (less than 25 m) polishing slurry to obt
46、ain the exact final dimensions of the samples and the right surface appearance. With a grinding machine (see 3.2.9), the cube is grinded automatically by 1,5 mm steps (or less). The cube is machined on one side and then on the other side to obtain parallel sides. The thickness is then reduced to 10
47、mm or 30 mm. In both procedures (manual and automatic), the parallelism of the surfaces and the dimensions are continuously checked between the grinding steps. 3.4.4 Polishing Only the two surfaces of the glass sample cube from where the light travels in the spectrophotometer need to be polished. In
48、 the manual procedure, the sample cubes are polished on a turning polishing wheel (see 3.2.7) using cerium oxide powder solution, obtained by diluting approximately 100 g of powder with 500 ml of water. Polishing can also be achieved automatically by a polishing machine using cerium oxide (as used in the glass industry) (see 3.2.10). Lastly, a verification is made that the thickness is within the tolerance of 0,05 mm, as is the parallelism of the ground and polished sample deviation range of the re
