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1、BRITISH STANDARD BS 6920-2.2.3: 2000 Incorporating Amendment No. 1 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 2.2: Odour and flavour of water Subsection 2.2.
2、3: Method of testing odours and flavours imparted to water by hoses for conveying water for food and drink preparation ICS 13.060.20 ? BS 6920-2.2.3:2000 This British Standard, having been prepared under the direction of the Health and Environment Sector Committee, was published under the authority
3、of the Standards Committee and comes into effect on 15 May 2000 BSI 21 January 2004 The following BSI references relate to the work on this British Standard: Committee reference EH/6 Draft for comment 99/560127 DC ISBN 0 580 331075 Committees responsible for this British Standard The preparation of
4、this British Standard was entrusted to Technical Committee EH/6, Effects of materials on water quality, upon which the following bodies were represented: Automatic Vending Association of Britain British Cement Association BCF British Coatings Federation Ltd British Malleable Tube Fittings Associatio
5、n British Plastics Federation British Plumbing Fittings Manufacturers Association British Precast Concrete Federation Ltd British Rubber Manufacturers Association Ltd British Water DEFRA Water and Land Directorate Galvanizers Association Laboratory of the Government Chemist Pipeline Industries Guild
6、 UK Steel Association Water Regulations Advisory Scheme Water Research Centre plc Amendments issued since publication Amd. No.DateComments 1472021 January 2004 Insertion of new Figure A.1 BS 6920-2.2.3:2000 BSI 21 January 2004 i Contents Page Committees responsibleInside front cover Forewordii Intro
7、duction1 1Scope1 2Normative references1 3Terms and definitions1 4Principle1 5Reagents1 6Apparatus2 7Samples2 8Test procedure2 9Expression of results3 10Test report4 Annex A (informative) Test sequence5 Figure A.1 Test sequence5 BS 6920-2.2.3:2000 ii BSI 21 January 2004 Foreword This subsection of BS
8、 6920 has been prepared by Technical Committee EH/6. It supersedes BS 6920-2.2.3:1996, which is withdrawn. This edition introduces technical changes but it does not reflect a full review or revision of the standard. BS 6920 is published in several parts, namely Part 1: Specification, Part 2: Methods
9、 of test, Part 3: High temperature tests and Part 4: Method for the GCMS identification of water leachable organic substances. Part 2 is further subdivided into a number of sections and subsections as follows. Section 2.1: Samples for testing; Section 2.2: Odour and flavour of water; Subsection 2.2.
10、1: General method of test; Subsection 2.2.2: Method of testing odours and flavours imparted to water by hoses and composite pipes and tubes; Subsection 2.2.3: Method of testing odours and flavours imparted to water by hoses for conveying water for food and drink preparation; Section 2.3: Appearance
11、of water; Section 2.4: Growth of aquatic microorganisms test; Section 2.5: The extraction of substances that may be of concern to public health; Section 2.6: The extraction of metals. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for i
12、ts correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 5 and a back cover. The BSI copyright notice displayed in this document indi
13、cates when the document was last issued. BS 6920-2.2.3:2000 BSI 21 January 2004 1 Introduction Flexible hoses are used for conveying water in equipment for food and drink preparation. Overnight, during shut-downs and at various other times, the water may be static in these hoses for varying periods
14、of time. With a high surface area of the material of the hose exposed to a relatively small volume of water, the water may readily pick up substances from the hose capable of producing a discernible odour or flavour. Additionally, the hose may react with any residual chlorine in the water to produce
15、 a disinfectant-type odour and/or flavour. Experience has shown that, even when the water-contact material does not produce any odour or flavour in water, when fabricated into a complete hose, substances from the outer material may interact with the water contact material in such a way as to produce
16、 such effects. For these applications, it is therefore important not only to test the complete hose, including any reinforcements and outer layers, but to use a ratio of surface area of water-contact material to volume of water representative of the worst situation likely to be encountered in practi
17、ce. 1 Scope This subsection of BS 6920 describes a method designed to assess the ability of flexible hoses (including reinforcements) to impart a discernible odour or flavour to water intended for use in the preparation of food and drinks. It is applicable only to the testing of hoses intended for i
18、nstallation in equipment used for food and drink preparation. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of BS 6920. For dated references, subsequent amendments to or revisions of, any of these
19、 publications do not apply. For undated references, the latest edition of the publication referred to applies. BS 6920, 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. BS 6920-2.2.1, Suitabilit
20、y 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 2.2: Odour and flavour of water Subsection 2.2.1: General method of test. 3 Terms and definitions For the purposes of this s
21、ubsection of BS 6920, the definitions given in BS 6920-2.2.1 apply. 4 Principle Lengths of hose are filled with test water for 24 h. This water is assessed for the presence of any discernible odour. If none is detected it is then diluted (once) and assessed for the presence of any discernible flavou
22、r, compared to the test water blank, by test panellists. If any odour or flavour is detected then the same hoses are refilled with fresh test water for one further 24 h period. The water from this final soaking period is assessed by the test panellists. The test procedure is repeated using chlorinat
23、ed test water. NOTE 1A flow diagram showing the sequence of the test procedures is given in Annex A. NOTE 2The procedures for assessing the water samples for odour and flavour are described in full in BS 6920-2.2.1. NOTE 3The procedures do not involve any testing of the outer layers of reinforced ho
24、ses on their own, but only as part of the complete hoses. NOTE 4This procedure involves the preparation of only two sequential extracts from the test samples, compared with the seven extracts prepared from test samples in BS 6920-2.2.1 and BS 6920-2.2.2. 5 Reagents The reagents shall be as given in
25、BS 6920-2.2.1. BS 6920-2.2.3:2000 2 BSI 21 January 2004 6 Apparatus The apparatus shall be as given in BS 6920-2.2.1. 7 Samples Samples of hoses shall conform to BS 6920-2.1:2000, 5.2.9. If samples are taken from a reel of hose, two samples shall be taken from one end of the reel, and two samples fr
26、om the other end. 8 Test procedure 8.1 General WARNING. Conduct this test with due regard to the possible presence of substances in the extracts that may be hazardous to the health of the test panellists. Only products found to conform to the microbial growth test requirement in accordance with BS 6
27、920-1:2000, Clause 6 and deemed suitable for contact with water intended for human consumption in accordance with BS 6920-1:2000, Clause 7 (toxicological test) may be assessed in this test, unless details of the chemical composition and process of manufacture of the sample(s) are known, and any poss
28、ible hazard can be assessed. Instruct the test panellists not to swallow any test extract under any circumstances. 8.2 Extraction procedures 8.2.1 Chlorine-free water 8.2.1.1 Extraction On the same day as testing is to start, rinse the inner surface of four 1 m lengths of the hose (see Clause 7) usi
29、ng a minimum of 10 l of chlorine-free test water for each (see BS 6920-2.2.1:2000, 6.2). Clamp two 1 m lengths of hose, one from each end of the reel, in a “U” bend configuration. Completely fill each length of hose using chlorine-free test water. Cover each end of the hoses with a fresh piece of al
30、uminium foil. In addition, fill an empty 1 l test container conforming to BS 6920-2.2.1:2000, 7.1 with chlorine-free test water; this constitutes the blank test. Seal the containers with fresh pieces of aluminium foil. Store the hose under test and the containers of water at either (23 2) C for (24
31、1) h for cold water testing, or at the selected temperature in the case of high temperature tests in accordance with BS 6920-3. 8.2.1.2 Dilution At the end of the storage period, unclamp the hoses and transfer the contents of the hose to separate appropriately sized clean glass graduated measuring c
32、ylinders conforming to BS 604 and determine and record the volume of the water. To the water samples from the hoses add equal volumes of fresh chlorine-free test water (see BS 6920-2.2.1:2000, 6.2). In the same way prepare a dilution of the blank test water. Instruct the test panellists to assess th
33、ese samples in accordance with 8.3. 8.2.2 Chlorinated water Repeat the procedure described in 8.2.1.1 using the other two lengths of hose (see Clause 7) and chlorinated test water (see BS 6920-2.2.1:2000, 6.3) instead of chlorine-free water. After the extraction period, neutralize any free residual
34、chlorine in the water from the hoses in accordance with BS 6920-2.2.1:2000, 10.4.2, prepare the dilution (see 8.2.1.2) and instruct the test panellists to assess the dilution prepared using chlorine-free water (see 8.3). 8.3 Testing procedure 8.3.1 Temperature of test solution Adjust the temperature
35、 of the dilutions to (25 1) C by placing the beakers containing the dilutions in a temperature-controlled water bath (see BS 6920-2.2.1:2000, Annex B). BS 6920-2.2.3:2000 BSI 21 January 2004 3 8.3.2 Assessment of extract(s) and their dilutions 8.3.2.1 Odour assessment Remove the sample extracts (one
36、 for each length of test hose) and the reference water from the water bath or incubator. Transfer 100 ml of each sample extract and the reference water to clean 250 ml flasks with a neck diameter of at least 45 mm, stopper the flasks and, if necessary, re-adjust the temperature to (25 1) C. Ask the
37、assessor to shake each flask thoroughly, remove the stopper, immediately smell the extract, and record his/her decision compared with the reference water. If there is no perceived difference between the test extracts and the reference water describe the test extract as odourless and proceed with fla
38、vour assessment (8.3.2.2). If an odour is perceived in the extracts from either hose sample, repeat the extraction procedure (8.2.1.1) one more time. Assess these extracts for odour as set out above; if they are free from discernible odour undertake an assessment of flavour on them (8.3.2.2). NOTEA
39、list of odours and flavours commonly encountered is given in BS 6920-2.2.1:2000, Annex B. 8.3.2.2 Flavour assessment Do not undertake this assessment until an odour assessment (8.3.2.1) has been undertaken and the extract is free from discernible odour. Remove the dilution of the blank test from the
40、 water bath and pour off (30 5) ml of the water into a clean tasting glass (see BS 6920-2.2.1:2000, 7.4). Instruct each test panellist to take into the mouth whatever volume of water is comfortable and to hold it in the mouth for several seconds before discharging it without swallowing. Rinse the ta
41、sting glass thoroughly with chlorine-free water (see BS 6920-2.2.1:2000, 6.2) between samples. If a flavour is detected in the dilution of the blank water, then start the complete test again from the beginning of Clause 8 using fresh samples, fresh test water and fresh test containers. Similarly ass
42、ess the dilutions of the test sample extracts. If no flavour is detected in either of the diluted extracts, record this result and discontinue the test. NOTEA list of odours and flavours commonly encountered is given in BS 6920-2.2.1:2000, Annex B. 8.4 Repeat testing If an odour or flavour is detect
43、ed record a description of them and, using the same two hose samples and the same type of test water, repeat once more the procedure in 8.1 and 8.2, as appropriate, ending with the testing of the final extracts. NOTEA list of odours and flavours commonly encountered is given in BS 6920-2.2.1:2000, A
44、nnex B. 9 Expression of results Express the results in accordance with BS 6920-2.2.1:2000, Clause 11. BS 6920-2.2.3:2000 4 BSI 21 January 2004 10 Test report In addition to the requirements for the test report given in BS 6920-2.2.1:2000, Clause 12, the report shall include the following particulars
45、: a description of the hose, including details of reinforcements and outer coverings; a statement saying that extracts were prepared by filling lengths of hose with test water and subsequently diluting this with an equal quantity of test water; the length of the test samples; the internal diameter o
46、f the test samples; the surface area of the material in contact with the test water; the volume of test water contained within the test sample during extraction; whether an odour was detected in either of the first or second extracts from either of the hose samples; whether a flavour was detected in
47、 the dilution of either the first or second extracts from either of the hose samples. BS 6920-2.2.3:2000 BSI 21 January 2004 5 Annex A (informative) Test sequence 1) Test extracts de-chlorinated before testing. Figure A.1 Test sequence Rinse 1 m lengths of hose 10 litres of chlorine-free test water
48、(8.2) Odour and flavour assessment - stabilize at 25 C - make two 1:1 dilutions for flavour assessment - compare odour and flavour with reagent blank (8.3/8.4) Odour and flavour assessment - stabilize at 25 C - measure volume of water in hose - compare odour and flavour with reagent blank (8.3/8.4)
49、If the extracts have an odour and any flavour is detected in the 1st dilution of either extract, continue the test (8.3/8.4) If the extracts have no odour and no flavour is detected in the 1st dilution of either extract, discontinue the test (8.3/8.4) End of test End of test Test water chlorine-free Fill hose & cap ends (8.2.1) Fill hose & cap ends (8.2.2) Leave for 24 h (8.2) Leave for 24 h Leave for 24 h1) (8.2) Test water chlorinated (1mg/l) Leave for 24 h1