1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-20818-9 SANS 5797:2008Edition 3 SOUTH AFRICAN NATIONAL STANDARD Metal release from glazed crockery (plain or decorated), and acid resistan
4、ce of decoration Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 5797:2008 Edition 3 Table of changes Change No. Date Scope Foreword This South
5、African standard was approved by National Committee StanSA TC 5140.05, Crockery, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in February 2008. This document supersedes SABS SM 797:1982 (first revision). SAN
6、S 5797:2008 Edition 3 1 Metal release from glazed crockery (plain or decorated), and acid resistance of decoration 1 Scope This standard specifies a method for the determination of the metal release from glazed crocery (plain or decorated) and acid resistance of decoration. 2 Reagents Use only analy
7、tical grade reagents, and distilled or demineralized water. a) Household detergent. b) Acetic acid solution, having a volume fraction of 4 % glacial acetic acid in water. c) Distilled or demineralized water. 3 Apparatus 3.1 Glass rod, of sufficient length to stir the acid solution (see 2(b) and 5.1.
8、5). 3.2 Atomic absorption spectrophometer, with the capacity to measure metals at the concentration range of mg/L. 4 Sampling Take a laboratory sample as specified in the relevant product standard. Where no standard exists, take the laboratory sample as agreed upon between the test laboratory and th
9、e manufacturer to ensure a reasonable and acceptable reliability at a reasonable and acceptable confidence level. 5 Procedure 5.1 Metal release from glazed crockery (plain or decorated) 5.1.1 Wash the test specimen throughly with a household detergent (see 2(a), rinse throughly with water, and allow
10、 to dry. 5.1.2 Place the test specimen on a flat and level surface in a room having a temperature of 25 C 2 C, and fill the test specimen to within 5 mm of the rim with the acetic acid solution (see 2(b). SANS 5797:2008 Edition 3 2 5.1.3 In the case of flat ware (a test specimen that has an internal
11、 depth not exceeding 25 mm when measured from the lowest point to the horizontal plain passing through the upper rim), record its filling volume, (V) in litres. 5.1.4 Cover the test specimen so that the surface under test is not exposed to light and allow to stand for 24 h. 5.1.5 Remove the cover an
12、d ensure homogeneity of the solution by strirring the acid solution thoroughly with a glass rod (see 3.1). 5.1.6 Take a suitable volume of the solution and, by means of the atomic absorption spectrophometer (see 3.2), determine the lead and cadmium contents in milligrams per litre. NOTE If necessary
13、, dilute the solution with the acetic acid solution before making the determination. 5.1.7 Record the lead and cadmium content (C) in the extraction, in milligrams per litre. 5.2 Acid resistance of decoration 5.2.1 Examine the decoration for visible attack, using an untreated test specimen for compa
14、rison. 5.2.2 Classify the acid resistance in accordance with table 1. Table 1 Classification of the acid resistance of decoration 1 2 Rating Description 0 No visual reduction of gloss. 1 Just noticeable reduction of gloss, stratch resistant. 2 Significant reduction of gloss, not scratch resistant. 3
15、 Decorations removed or easily removable by wiping with a damp cloth. 6 Calculation In the case of flat ware calculate the metal release as follows: 6.1 Invert the test specimen on graph paper marked in millimetre squared and draw the contour round the rim. 6.2 Calculate the area enclosed by the con
16、tour (A), and record this as the reference surface area in square decimetres. 6.3 The metal released per area, expressed in milligram per square decimetres as follows: Mr = AVC SANS 5797:2008 Edition 3 3 Where Mr is the metal released per area, expressed in milligrams per square decimetres; C is the
17、 lead and cadmium content of the extraction solution, in milligrams per litre (see 5.17); V is the filling volume of the test specimen, in litres (see 5.1.3); A is the reference surface area, in square decimetres (see 6.2). 7 Test report Report the following information: a) all the data needed to id
18、entify the laboratory sample tested; b) confirmation that the test was carried out in accordance with this standard; c) any deviation from this standard; d) the metal released per area, expressed in milligrams per square decimetres; and e) the acid resistance of the decoration, classified in accordance with table 1. Standards South Africa
