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 978-0-626-20820-2 SANS 5794:2008Edition 2 SOUTH AFRICAN NATIONAL STANDARD Water absorption of crockery Published by Standards South Africa 1 dr late
4、gan 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 5794:2008 Edition 2 Table of changes Change No. Date Scope Foreword This South African standard was approved by National Committee StanSA TC
5、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 794:1974 (edition 1). SANS 5794:2008 Edition 2 1 Water absorption of crockery 1 Scope This s
6、tandard specifies a method for the determination of the water absorption of crockery. 2 Apparatus 2.1 File or emery paper, suitably abrasive to remove sharp, thin edges of crockery. 2.2 Air oven, maitained at a temperature of 110 C 2 C. 2.3 Desiccator, that contains self-indicating silica gel. 2.4 A
7、nalytical balance, with a resolution of 0,001 g. 2.5 Heat resistant container, of sufficient capacity to allow for the complete immersion of the test specimen. 2.6 Means of heating the water to boiling point. 3 Sampling and preparation of the test specimens 3.1 Sampling Take a laboratory sample as s
8、pecified in the relevant product standard. Where no standard exists, take the laboratory sample as agreed upon between the test laboratory and the manufacturer to ensure a reasonable and acceptable reliability at a reasonable and acceptable confidence level. 3.2 Preparation of the test specimens 3.2
9、.1 From a test specimen that has not been tested for resistance to crazing or to thermal shock, break off a glazed piece having an area of approximately 1 600 mm2. 3.2.2 Remove any sharp, thin edges (by filing or with emery paper (see 2.1), and wipe the test specimen clean. SANS 5794:2008 Edition 2
10、2 4 Procedure 4.1 Heat the test specimen in the oven (see 2.2) for 3 h and then allow it to cool to ambient temperature in a desiccator (see 2.3). 4.2 Determine the mass (see 2.4) of the test specimen to the nearest 0,01 g and record this as the mass of the oven-dried test specimen before immersion.
11、 4.3 Immerse the test specimen completely in water in a suitable container (see 2.5), and boil (see 2.6) vigorously for 5 h. 4.4 Remove the container from the source of heat and allow the test specimen to cool in the water for 20 h. 4.5 Retrieve the test specimen from the container, remove excess mo
12、isture by wiping with a damp cloth, and immediately determine the mass of the test specimen to the nearest 0,01 g. Record this as the mass of the test specimen after immersion. 5 Calculation Calculate the water absorption of the test specimen as follows: WA = AAB 100)( Where A is the water absorptio
13、n, expressed as a percentage of the oven-dried mass of the test specimen; B is the mass of the test specimen, in grams, after immersion (see 4.5); A is the mass of the oven-dried specimen, in grams, before immersion (see 4.2) . 6 Test report Report the following information: a) all the data needed t
14、o identify 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 results, in grams, of the water absorption of the test specimen, expressed as a percentage of the oven-dried mass of the test specimen. Standards South Africa
