BS-6920-2.1-1996.pdf

| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6920 : Section 2.1 : 1996 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 2.1 Samples for testing Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:45 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 December 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 95/521397 DC ISBN 0 580 26284 7 BS 6920 : Section 2.1 : 1996 Amendments issued since publication 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: Association 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-ferrous 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) Department 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 Association 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 01:30:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6920 : Section 2.1 : 1996 BSI 1996i Contents Page Committees responsibleInside front cover Forewordii Method 1Scope1 2References1 3Definitions1 4Apparatus1 5Procedure1 Table 1Test container calibration mark2 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 1996 BS 6920 : Section 2.1 : 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 : Section 2.1 : 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. Minor changes have been introduced in the sample requirements to assist users of the standard. 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 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 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 05 01:30:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19961 BS 6920 : Section 2.1 : 1996 Method 1 Scope This Section of BS 6920 describes the preparation of samples of non-metallic products for testing for their suitability for use in contact with water intended for human consumption. It is applicable 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 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 references, 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 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 product Manufactured item, in its finished form, that comes into contact with water, including a component part of a manufactured item. 3.2 composite product Product whose water-contact surface is made from a material that differs from those comprising the remainder of the product. 3.3 sample Product, or part of a product, submitted for testing for suitability for use in contact with water intended for human consumption. NOTE. In some cases the sample may consist of more than one example of the product. 3.4 anaerobic adhesive Adhesive that cures spontaneously in the absence of oxygen, curing being inhibited by the presence of oxygen and catalysed by metal ions. 4 Apparatus 4.1 Polyethylene bags, of a type suitable for food contact. Before use these bags shall be stored in a closed container. 4.2 Glass plates, of sand-blasted glass and having a total surface area of (15 000±500) mm2. The width of the plate shall not exceed 60 mm. Clean the plates in an aqueous solution of a biodegradable laboratory detergent. Rinse thoroughly in tap water and then once in distilled water conforming to grade 3 of BS EN ISO 3696. Drain and dry in a hot air cabinet and store in polyethylene bags (4.1). 4.3 Brass couplings, female/female, 15 mm diameter compression brass couplings conforming to BS 864 : Part 2 and with a composition meeting the designations CZ 122 or CZ 132 of BS 2874 or BS 7766. Take the coupling apart and discard the compression olives' retain the body of the coupling and the two screw collars. Immerse the couplings in a cleaning agent (see 4.2) for 5 min. Rinse the couplings with distilled water conforming to grade 3 of BS EN ISO 3696, and then immerse in a 1 % by volume solution of nitric acid for 1 min. Rinse in tap water and then in distilled water again. Drain and dry in a hot air cabinet and store in polyethylene bags (4.1). 4.4 Special glass plates, as specified in 4.2 except that only one side shall be sand-blasted. 4.5 Test container, made of glass, as specified in the respective section of BS 6920, and of size as given in 5.1.2. 5 Procedure 5.1 General requirements 5.1.1 Nature of samples The samples used for testing shall be manufactured products or components of water fittings drawn from production batches that have received no other treatment, except for the exclusions given below. In a very few special applications within water undertakings' distribution systems involving products used for joints in service reservoirs or large tanks constructed in accordance with BS 8007, the surface area to volume ratio used for the tests described in BS 6920 : Section 2.2 to 2.6 shall be 1000 mm2/l. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 1996 BS 6920 : Section 2.1 : 1996 5.1.2 Sample and test container size Use wherever possible a sample with a total surface area of (15 000±500) mm2and a test container (4.5) bearing a calibration mark for a capacity of 1000 ml. If in exceptional circumstances this size of sample cannot be obtained, use a test container calibrated for a capacity in accordance with table 1. The sample shall be made up from one or more articles drawn from the same production batch or cut from a single larger product. The maximum length and width of any single sample shall be 150 mm and 70 mm respectively. During testing, the samples shall always be completely submerged in the test water. If the density of the sample is less than that of water, ensure that the sample is kept totally submerged for the duration of the test by using glass-encapsulated weights. Determine the dimensions of all samples using measuring equipment calibrated in accordance with BS EN 30012 : Part 1. The instruments used shall include rules and callipers conforming to the accuracy requirements of 2.5.4 of BS 4372 : 1968 and clause 6 of BS 887 : 1982, respectively. If the sample has a textured finish to the surface or the shape of the sample is such that accurate calculation of the surface area is impracticable, then a sample of estimated surface area shall be used, but in this case the length and width shall be recorded together with a sufficiently detailed description of the product(s) to enable further samples to be prepared that will be within±10 % of the surface area of the original sample. Table 1. Test container calibration mark Sample surface area a mm2 Volume indicated by calibration mark ml 5 500 # a 9 500500 9 500 # a 13 000750 13 000 # a 19 0001000 19 000 # a # 26 0001500 NOTE. The supplier of the samples should be instructed to ensure that the products or test samples represent the product as it is used in contact with potable water. If the product has to be cut to obtain the required sample area, this should be done before the samples receive any post-cure or special surface treatment and in a manner that ensures the area of the cut edges is as small as possible. 5.1.3 Sample storage Ensure that during the period between packaging and receipt by the laboratory the samples are protected from contamination by dirt, oil, grease, excessive heat, sunlight and volatile chemicals. Store in the laboratory in polyethylene bags (4.1) and in the absence of light at (21±4) ÊC except where the individual supplying the samples provides alternative written storage instructions which are those that the products are subject to in practice. Use a fresh bag for each product or set of products made from an identical material. CAUTION. Do not test samples bearing adhesive tape or labels, ink or pencil marks. 5.2 Special requirements 5.2.1 General Products made from certain material types shall be subject to the additional requirements given in 5.2.2 to 5.2.8. 5.2.2 Elastomeric products Elastomeric products shall be stored in accordance with BS 3574 except that storage envelopes or pockets shall not be sealed, dusting powder shall not be used and cleaning shall not be carried out unless any of these procedures form part of the usual production procedures. Instruct suppliers of products to arrange for storage of the products for at least four weeks before dispatch to the laboratory. NOTE. If samples of elastomeric products are tested within four weeks of manufacture, the results obtained with these methods may not be representative of the material as it is used in practice. 5.2.3 Composite products Samples of composite products shall be made of all the component parts or coatings, but with only the water contact material in contact with the test water. (See also 5.2.9.) NOTE 1. A cistern or spiral-wound glass-reinforced plastics pipe is a typical example of a composite product. NOTE 2. Provided that the product is not one that falls within the definition of site-applied products (see 5.2.7), composite products may be tested in the form of specially prepared samples, provided that they contain all the component materials present in the finished article. 5.2.4 Ion-exchange resins Place 2 g of the resin beads in a test container (4.5) calibrated for a capacity of 1000 ml. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:30:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 19963 BS 6920 : Section 2.1 : 1996 5.2.5 Greases Evenly spread 5 g of the sample over the sand-blasted surface of a special glass plate (4.4). Place the plate in a test container (4.5) calibrated for a capacity of 1000 ml. NOTE. Since the grease may be easily washed off the plate, it is essential to ensure that the test water is added so as to cause the least possible disturbance of the grease film on the test plate in the test containers, both at the commencement of each test, and also at each change of test water. Similarly, it is important to ensure that pre-test rinsing with the test waters does not disturb the grease film. 5.2.6 Factory-applied coatings Instruct the manufacturer or supplier to apply samples of these products to panels of a material with similar adherent properties to the material(s) for which the coating is designed. The panels shall be resistant to rusting or corrosion under the conditions of the tests (for example, stainless steel). Ensure that the panels are given the same number of coats (including primers and undercoats) and identical maturing and curing conditions as would be applied to articles being coated in the factory. All surfaces and edges of the panels shall be covered completely with the coating. The final overall dimensions of the test panels shall conform to 5.1.2. Use a test container (4.5) calibrated for a capacity of 1000 ml. 5.2.7 Site-applied material WARNING. Many site-applied material coatings contain hazardous solvents. Observe all the manufacturer's safety warnings during the preparation of these samples. 5.2.7.1 General NOTE 1. These include all coatings, sealing compounds, soldering fluxes, anaerobic adhesives and most cementitious products intended for application on site. The samples shall consist of all specified component parts. Ensure that they are supplied to the test laboratory together with all relevant instructions for site application, including information on the time for complete cure relative to temperature. Prepare test panels as follows using all the specified component parts of