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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6920 : Section 2.3 : 1
2、996 ICS 13.060.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water Part 2. Methods of test Section 2.3 Appearance of water L
3、icensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into effect on 15 D
4、ecember 1996 BSI 1996 First published May 1988 Second edition June 1990 Third edition December 1996 The following BSI references relate to the work on this standard: Committee reference EH/3/7 Draft for comment 95/521400 DC ISBN 0 580 26288 X BS 6920 : Section 2.3 : 1996 Amendments issued since publ
5、ication Amd. No.DateText affected Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EH/3, Water quality, to Subcommittee EH/3/7, Effects of materials on water quality, upon which the following bodies were represented: Assoc
6、iation of Manufacturers of Domestic Electrical Appliances Automatic Vending Association of Britain British Adhesives and Sealants Association British Bathroom Council British Cement Association British Iron and Steel Producers Association British Malleable Tube Fittings Association British Non-ferro
7、us Metals Federation British Plastics Federation British Plumbing Fittings Manufacturers Association British Rubber Manufacturers Association Limited British Valve and Actuator Manufacturers Association British Water Cadmium Association Department of the Environment (Drinking Water Inspectorate) Dep
8、artment of the Environment for Northern Ireland Department of Trade and Industry (Laboratory of the Government Chemist) Ductile Iron Producers Association Galvanizers Association Institute of Plumbing Lead Development Association Pipeline Industries Guild Pipeline Protection Association Scottish Ass
9、ociation of Directors of Water and Sewerage Services UK Water Byelaws Scheme Water Research Centre Water Services Association of England and Wales Zinc Development Association Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6920 : Section
10、 2.3 : 1996 BSI 1996i Contents Page Committees responsibleInside front cover Forewordii Method 1Scope1 2References1 3Definitions1 4Principle1 5Reagents1 6Apparatus1 7Samples2 8Test procedure2 9Expression of results2 10Test report3 List of referencesInside back cover Licensed Copy: sheffieldun sheffi
11、eldun, na, Tue Dec 05 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 1996 BS 6920 : Section 2.3 : 1996 Foreword This Section of BS 6920 has been prepared by Subcommittee EH/3/7 under the direction of the Health and Environment Sector Board. This Section of BS 6920 supersedes BS 6920 : Se
12、ction 2.3 : 1990, which is withdrawn. This edition introduces technical changes but it does not reflect a full review or revision of the standard, which will be undertaken in due course. Slight modifications have been introduced to the extraction temperature and sequences to assist laboratories unde
13、rtaking the test, together with an updating of the cross-references. BS 6920 is published in several Parts, namely Part 1 Specification, Part 2 Methods of test and Part 3 High temperature tests. Part 2 is further subdivided into a number of Sections and Subsections as follows: Section 2.1Samples for
14、 testing Section 2.2Taste of water Subsection 2.2.1General method of test Subsection 2.2.2Method of testing tastes imparted to water by hoses Subsection 2.2.3Method of testing tastes imparted to water by hoses for conveying water for food and drink preparation Section 2.3Appearance of water Section
15、2.4Growth of aquatic micro-organisms Section 2.5The extraction of substances that may be of concern to public health Section 2.6The extraction of metals Compliance with a British Standard does not of itself confer immunity from legal obligations. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 0
16、5 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19961 BS 6920 : Section 2.3 : 1996 Method 1 Scope This Section of BS 6920 describes a method designed to assess the ability of a product to impart any noticeable colour or turbidity to water intended for human consumption. The method is appli
17、cable to all types of non-metallic product used in contact with potable water. 2 References 2.1 Normative references This Section of BS 6920 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and
18、the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this Section of BS 6920 only when incorporated in the reference by amendment or revision. For undated referenc
19、es, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This Section of BS 6920 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the
20、inside back cover, but reference should be made to the latest editions. 3 Definitions For the purposes of this Section of BS 6920, the following definitions apply. 3.1 standard unit (of colour) (in mg/l Pt) The colour produced by a solution containing 1 mg of platinum per litre (in the form of hydro
21、gen hexachloroplatinate(IV), in the presence of 2 mg of cobalt(II) chloride hexahydrate per litre. NOTE. The scale derived from this standard unit is sometimes called the Hazen scale or the Pt/Co scale. 3.2 turbidity Reduction of transparency of a liquid caused by the presence of undissolved matter.
22、 NOTE. This definition is taken from BS EN 27027 : 1994. 4 Principle The sample of the product is immersed in water for 24 h and the colour and turbidity of the water are then measured. If any noticeable colour or turbidity is observed in the water, the same sample is immersed in test water for a fu
23、rther six sequential extraction periods, including one 72 h period and concluding with a 24 h period, using fresh test water for each period. The water from the final immersion period is measured and if any noticeable colour or turbidity is observed in the water then a further two samples are subjec
24、ted to the same procedure. 5 Reagents 5.1 Test water, distilled or deionized water conforming to grade 3 of BS EN ISO 3696. The following shall also apply. a) The colour of the water shall be less than 5 standard units (of colour) mg/l Pt when determined in accordance with section 4 of BS EN ISO 788
25、7 : 1995. b) The turbidity of the water shall be less than 1 formazine nephelometric unit (FNU) when determined in accordance with 3.3 of BS EN 27027 : 1994. 5.2 Colour matching solutions, prepared following the instructions given in 4.3 of BS EN ISO 7887 : 1995. 5.3 Formazine solutions, prepared fo
26、llowing the instructions given in 3.2.2 and 3.2.3 of BS EN 27027 : 1994. 6 Apparatus 6.1 Laboratory ware, cleaned thoroughly using an aqueous solution of a biodegradable laboratory detergent followed by thorough rinsing with test water (5.1). 6.2 Test containers, consisting of borosilicate glass bea
27、kers calibrated for a capacity as given in 5.1.2 of BS 6920 : Section 2.1 : 1996. 6.3 Colour measurement apparatus, as specified in 4.4 of BS EN ISO 7887 : 1995. 6.4 Incubator, capable of maintaining a temperature of (251) C. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:49 GMT+00:00
28、2006, Uncontrolled Copy, (c) BSI 2 BSI 1996 BS 6920 : Section 2.3 : 1996 6.5 Turbidity measurement apparatus, consisting of a nephelometer with measuring cells of glass and with a tungsten lamp, operated at between 85 % and 100 % of its rated voltage, as the light source. The total distance travelle
29、d by the incident plus scattered light within the water sample shall not exceed 100 mm. The angle of light acceptance by the detector of the nephelometer shall not exceed 30 and it shall be centred at right angles to the incident light path. 7 Samples 7.1 General Except as given in 7.2 and 7.3, samp
30、les shall conform to all the pertinent requirements given in BS 6920 : Section 2.1. 7.2 Reference materials These are not required. 7.3 Cementitious materials Since the test water used in this method has an aggressivity index of less than 12, precondition all samples made from cementitious materials
31、 in accordance with 5.2.8 of BS 6920 : Section 2.1 : 1996. 8 Test procedure 8.1 Extraction procedure 8.1.1 Sample preparation On the same day as testing is to start, rinse the sample in the test water (5.1) for 10 min. 8.1.2 First extract Place each sample in a separate clean container (6.2). In add
32、ition, with each batch of test samples, include one empty container as a blank test. Add to the container sufficient test water (5.1) to reach the calibration mark given in 5.1.2 of BS 6920 : Section 2.1 : 1996. Seal each container with a fresh piece of aluminium foil. If the density of the sample i
33、s less than that of water, ensure the sample is kept totally submerged in the test water for the duration of the test by using glass-encapsulated weights. Store the containers at (232) C for (241) h in an incubator (6.4). Then remove portions of water from each container and measure their colour and
34、 turbidity in accordance with 8.2. 8.1.3 Further extracts If the first extract (8.1.2) shows either an increase in colour of greater than 5 standard units (of colour) mg/l Pt or an increase in its turbidity of greater than 0.5 FNU, drain the test water from each test container, including the blank,
35、and refill to the same calibration mark with fresh test water and repeat the extraction for a further 24 h immersion period. Repeat the extraction for a further six sequential periods, including one 72 h period and concluding with a 24 h period, using fresh test water for each period. Measure the co
36、lour and turbidity of portions of water withdrawn from the final extracts. If the final extract shows either an increase in colour of greater than 5 standard units (of colour) mg/l Pt or an increase in its turbidity of greater than 0.5 FNU, repeat the procedure described in 8.1.1, 8.1.2 and 8.1.3 us
37、ing two further samples. 8.2 Measurement of colour and turbidity Measure the colour of each extract using the method described in section 4 of BS EN ISO 7887 : 1995. Measure the turbidity of each extract using the method described in 3.3 of BS EN 27027 : 1994. Report the results in accordance with c
38、lause 9. NOTE 1. For the measurement of colour, the method described in section 4 of BS EN ISO 7887 : 1995 is used in preference to that specified in section 3, since some materials impart to water colours which show absorption at wavelengths other than 436 nm. If an increase in turbidity occurs bet
39、ween the first extract (8.1.2) and the final extracts (8.1.3), then this is possibly due to microbial growth. Confirm this effect by carrying out a microscopic examination for organisms on the surfaces of the samples. However, if the product has been examined by the method described in BS 6920 : Sec
40、tion 2.4 and the result did not conform to clause 6 of BS 6920 : Part 1 : 1996, then this suffices for confirmation that the increase in turbidity is due to microbial growth. NOTE 2. Do not report these turbidity results as they are due to microbial growth. Repeat the test using fresh samples, steri
41、le containers and sterile test water. Prewash the samples in sterile test water before starting the test. 9 Expression of results Subtract the value obtained for the blank from each value obtained from a test container. If three samples of the same product have been tested, calculate the arithmetic
42、mean of the values obtained from each of these three test containers. Subtract the value obtained for the blank from the arithmetic mean. Express the resultant values for colour as described in 4.7 of BS EN ISO 7887 : 1995, and for turbidity as described in 3.3 of BS EN 27027 : 1994. Licensed Copy:
43、sheffieldun sheffieldun, na, Tue Dec 05 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19963 BS 6920 : Section 2.3 : 1996 10 Test report The test report shall include the following particulars: a) a reference to this British Standard, i.e. BS 6920 : Section 2.3; b) the name and address of t
44、he laboratory undertaking the testing, the date of the report and a unique laboratory report number; c) the trade name and reference of the product; d) the general composition of the product; e) the names of the product manufacturer, the submitting organization and the organization responsible for p
45、reparing the samples; f) where the samples are articles, e.g. components of water fittings, the trade name(s) and/or reference number(s) of the component(s) and the water fitting(s) together with the name(s) of the relevant manufacturer(s); g) a full description of the samples including: 1) the natu
46、re, appearance and colour of the product; 2) the surface area of each example of the product (in mm2); 3) the number of examples constituting the sample; 4) the calibration mark of the test container used. h) the proposed use of the product and, if applicable, the minimum temperature for application
47、; i) for site-applied products, in addition to the information in a) to h), the report shall contain: 1) the names of primers and undercoats used, together with the wet film thickness of each coating applied if this is specified by the manufacturer or supplier; 2) a full description of the preparati
48、on and application of the product(s) including method of application to the test plates, nature of the test plates and full curing conditions. j) for cementitious products, in addition to the information in a) to i), the report shall contain: 1) the name of the additive or coating under test; 2) the
49、 composition or trade name of the mortar/cement materials; 3) the aggressivity index of the preconditioning water; 4) the number of preconditioning 24 h soaks required to reach a pH of less than 9.00.1. k) the results, expressed in accordance with clause 9, from the first extract and, if undertaken, from the final extracts, together with a statement giving the number of samples tested for the product. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4blank Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 0