1、BRITISH STANDARD BS 7557:1992 Specification for Limits of metal release from painted surfaces of articles, liable to come into contact with foodstuffsBS7557:1992 This British Standard, having been prepared under the directionof the Consumer and Contract Goods Standards Policy Committee, was publishe
2、dunder the authority ofthe Standards Board and comesinto effect on 28 February 1992 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference CCM/47 Draft for comment 90/47889 DC ISBN 0 580 20528 2 Committees responsible for this British Standard The preparati
3、on of this British Standard was entrusted by the Consumer and Contract Goods Standards Policy Committee (CCM/-) to Technical Committee CCM/47, upon which the following bodies were represented: Aluminium Federation Association of Metropolitan Authorities Association of Public Analysts British Adhesiv
4、es and Sealants Association British Ceramic Gift and Tableware Manufacturers Association British Ceramic Research Ltd. British Cookware Manufacturers Association British Cutlery and Silverware Association British Food Manufacturing Industries Research Association British Glass Manufacturers Confeder
5、ation British Importers Confederation British Paper and Board Industry Federation British Plastics Federation British Resin Manufacturers Association British Retailers Association British Rubber Manufacturers Association Ltd. Catering Equipment Manufacturers Association Catering Equipment Users Asso
6、ciation Co-operative Union Cutlery and Allied Trades Research Association Department of Trade and Industry (Consumer Safety Unit, CA Division) Department of Trade and Industry (Laboratory of the Government Chemist) Flexible Packaging Association Fosfa International Institute of Trading Standards Adm
7、inistration International Tin Research Institute METCOM Ministry of Agriculture, Fisheries and Food Packaging and Industrial Films Association Paintmakers Association of Great Britain Ltd. Pira International Royal Society of Chemistry Stainless Steel Fabricators Association of Great Britain Vitreous
8、 Enamel Development Council Amendments issued since publication Amd. No. Date CommentsBS7557:1992 BSI 08-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Lead and cadmium release 1 Appendix A Method for determination of metal release 2 Publicatio
9、n(s) referred to Inside back coverBS7557:1992 ii BSI 08-1999 Foreword This British Standard has been prepared under the direction of the Consumer and Contract Goods Standards Policy Committee, at the request of the Department of Trade and Industry Consumer Safety Unit, to provide requirements for th
10、e maximum permitted release of lead and cadmium from those painted surfaces of an article which are liable to come into contact with foodstuffs in the course of normal use of the article. The limits specified in this standard and the analytical method of test to determine compliance with these are b
11、ased upon the requirements already established for related products in BS 6748. The limits for lead and cadmium release specified in this standard are intended as an interim safeguard with the object of reducing overall exposure to these metals. The surfaces considered fall within the scope of work
12、currently under way in the European Community on materials and articles in contact with foodstuffs which may lead eventually to an EC Directive on permitted levels of lead and cadmium. When the EC work is complete, this British Standard will be revised and re-issued to include the necessary limits a
13、nd method of test to enable the United Kingdom to implement fully the EC Directive. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itse
14、lf confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be ind
15、icated in the amendment table on the inside front cover.BS7557:1992 BSI 08-1999 1 1 Scope This British Standard specifies limits for lead and cadmium, expressed as a concentration of the elements, released from the painted surfaces of articles liable to come into contact with foodstuffs, when the ar
16、ticle is subjected to a specified method of test. The limits specified apply to all painted surfaces liable to come into direct contact with foodstuffs, including painted shelves, but excluding surfaces in contact only with those foodstuffs which subsequently receive some external preparation, such
17、as washing or peeling, before consumption. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 article item intended for use in the storage, display, preparat
18、ion, cooking and/or serving of food and having a painted surface, or surfaces, liable to come into contact with foodstuffs under normal conditions of use of the item NOTEPainted handles and the painted external surfaces of containers, excepting those of lids and covers which are reversible, are not
19、regarded as surfaces liable to come into contact with foodstuffs under normal conditions of use. 2.2 painted surface surface with a protective and/or decorative and/or release coating provided by means of a bound pigmented film, usually applied as a dispersion or solution in a liquid medium or as a
20、coating of powder NOTESilicate surfaces, i.e. those covered by BS 6748, are not regarded as painted surfaces. 2.3 relevant surface area area of the painted surface of an article which is liable to come into contact with foodstuffs in normal use 3 Lead and cadmium release 3.1 Limits When tested in ac
21、cordance with Appendix A, the painted surface(s) of any article shall not release into the extracting solution a quantity of lead (Pb) or cadmium (Cd), calculated as the element, exceeding0.8 mg of Pb or 0.07 mg of Cd, respectively, per dm 2of relevant surface area. 3.2 Sampling provision Where the
22、painted surface of an article releases a quantity of lead and/or cadmium into the extracting solution at a level exceeding that given in 3.1 by not more than 50%, at least three further articles shall be tested and the average quantity of lead and/or cadmium released per dm 2determined. The average
23、quantity so determined shall not exceed that given in 3.1 for a single article and no one sample shall exceed the value by more than50%.BS7557:1992 2 BSI 08-1999 Appendix A Method for determination of metal release A.1 Reagents A.1.1 General. All reagents shall be of recognized analytical quality. A
24、.1.2 Water, complying with grade 2 of BS 3978. A.1.3 Acetic acid (CH 3 COOH), glacial. A.1.4 Acetic acid solution, (4% V/V). To 500 ml of water (A.1.2) add 40 ml of glacial acetic acid(A.1.3) and make up to 1 l. Freshly prepare the solution prior to use in sufficient quantity to enable the whole of
25、any group of tests and analyses to be completed, using proportionately greater quantities if necessary. A.1.5 Standard metal solutions A.1.5.1 Standard lead solution, containing1000 1mg Pb in 1 l of 4% V/V acetic acid solution (A.1.4). A.1.5.2 Standard cadmium solution, containing500 0.5mg Cd in1l o
26、f 4% V/V acetic acid solution (A.1.4). NOTECommercially available standard solutions for atomic absorption spectroscopy may be used provided that the concentrations of such solutions are known to an equivalent accuracy. A.2 Apparatus A.2.1 Atomic absorption spectrophotometer, with a detection limit
27、equal to or better than 0.2 mg/l Pb (in4% V/V acetic acid solution) and 0.02 mg/l Cd (in4% V/V acetic acid solution). NOTEThe detection limit is the concentration of the element which gives a signal equal to three times the standard deviation of the background noise level of the instrument. A.2.2 La
28、boratory glassware. Volumetric glassware of class B accuracy or better, as specified in BS 700, BS 846 or BS 1792, as appropriate. General laboratory glassware of borosilicate glass incapable of releasing detectable levels of lead or cadmium into 4% V/V acetic acid solution during the test procedure
29、. A.2.3 Waterproof silicone carbide abrasive paper, of grammage 74 6 g/m 2coated with 1200 grade abrasive (see BS 871). A.2.4 Metal cutting implement, comprising shears, saw or punch, clean and free of grease on all cutting edges and any surfaces contacting test pieces during their preparation. NOTE
30、The paint on some hacksaw blades is known to contain lead and such blades should be effectively stripped of paint before use. A.3 Preparation of samples Abrade the relevant surface area(s) of the article using abrasive paper (A.2.3) lubricated copiously with a solution containing 1 ml/l of domestic
31、liquid detergent until a uniformly smooth surface is achieved, taking care to avoid abrading through the paint to the underlying base material. Rinse the abraded surface with tap water and dry with a disposable paper towel. Inspect the surface for any unabraded areas of paint and, if areas evidently
32、 have not been abraded, continue the abrasion process. Dry the abraded surface carefully, and by means of the cutting implement (A.2.4) cut or punch a test piece of area 0.36 0.01 dm 2from this, avoiding contamination by any lubricant on the cutting instrument. In cases of difficulty in obtaining a
33、single test piece of the correct size, take smaller and/or multiple test pieces to provide an equivalent area. Wash the test piece in an aqueous solution at40 5 C containing 1ml/l of domestic liquid detergent. Rinse the sample and wipe it carefully with a damp disposable paper towel. Inspect the pap
34、er towel for any pigment debris transferred from the abraded surface; if loose particles are present rewash the test piece and again wipe with a damp disposable paper towel. NOTE 1The use of a paper towel of contrasting colour to that of the painted surface under test will facilitate inspection for
35、pigment debris. If pigment debris is not present rewash the test piece, rinse thoroughly with water (A.1.2) and allow to drain then dry with clean filter paper. Do not use any test piece which shows residual staining. After washing and drying, cover any exposed bare metal surfaces and edges of the t
36、est piece(s) with a protective coating which will withstand the effect of4% V/V acetic acid solution and will not release any detectable levels of Pb or Cd into 4% V/V acetic acid solution during the test procedure. NOTE 2High melting point paraffin wax is a suitable coating. Do not handle the surfa
37、ce to be tested after it has been prepared. A.4 Procedure A.4.1 Determine and record the exposed area of the test piece, a, in dm 2to an accuracy of 0.001 dm 2by any convenient means and transfer the test piece to a suitable glass vessel (A.2.2) with the abraded surface uppermost. Condition the test
38、 piece and vessel to 22 2 C.BS7557:1992 BSI 08-1999 3 NOTEWhere the test piece is taken from an article painted on both sides, only that side liable to come into contact with foodstuffs should be considered and the other side should be effectively masked-off during the test procedure or, if of the s
39、ame paint composition, the test result obtained may be divided by two provided that this side has also been prepared in accordance withA.3 and has been exposed fully to the extracting solution. A.4.2 Immerse the conditioned test piece in a volume of (140 a) 1 ml of 4% V/V acetic acid solution (A.1.4
40、) at 22 2 C, cover and weigh the vessel and its contents to an accuracy of 0.1 g. NOTECling film is a suitable means for covering the vessel. A.4.3 Where tests are for cadmium or for both cadmium and lead, place the covered vessel with the test piece in a dark place and ensure that throughout the ex
41、traction period the surface under test is kept in complete darkness. NOTEIf lead only is to be determined, the test may be conducted in normal lighting. Maintain the immersed test pieces at 22 2 C for24 0.5 h. At the end of the extraction period reweigh the covered vessel and its contents, if the di
42、fference between the mass at the commencement of the extraction period and its completion exceeds1%, apply an appropriate correction factor in the calculation of the result for lead and cadmium release. A.4.4 Homogenize the extract solution, by stirring or other method, without loss of solution or a
43、brasion of the surface being tested and withdraw or otherwise transfer a portion for the determination of lead and/or cadmium. NOTEA suitable method of homogenizing the extract solution is to remove a quantity by pipette and allow it to run back into, or onto, the sample several times, avoiding dilu
44、tion or evaporation losses in the process. A.5 Analysis A.5.1 Set up the atomic absorption spectrophotometer having regard to the manufacturers instructions using wavelengths of217.0 nm for lead determination and 228.8 nm for cadmium determination with appropriate correction for background absorptio
45、n effects. NOTEWhere appropriate, a wavelength of 283 nm may be used for the analytical confirmation of lead. A.5.2 Aspirate water (A.1.2) and adjust the zero. Aspirate a range of dilute standard metal solutions prepared by dilution of the standard metal solutions(A.1.5) with 4% V/V acetic acid solu
46、tion(A.1.4). Aspirate water (A.1.2) after each standard metal solution and record the absorbance values obtained. A.5.3 Aspirate water (A.1.2) and then 4% V/V acetic acid solution (A.1.4) and measure the absorbance value. Aspirate the sample extracts (see A.4.4), accurately diluted where appropriate
47、, interspersed with water (A.1.2). Measure the absorbance values of the sample extracts or accurately diluted sample extracts. A.5.4 To check for instrument drift, aspirate dilute standard metal solutions interspersed with sample extracts and with water (A.1.2). Provided that the absorbance values o
48、f the dilute standard metal solutions and of the 4% V/V acetic acid solution (A.1.4) indicate minimal drift, the results may be calculated by the bracketing technique (see A.6), from a manually prepared calibration curve or by using the calibration facilities of the instrument. A.6 Calculation of re
49、sults by the bracketing technique The lead or cadmium content, C 0 , expressed in mg/dm 2of relevant surface is given by the equation where NOTEThe lower and upper bracketing solutions should be chosen to have absorbance values close to that of the sample extract or diluted sample extract. A.7 Test report The test report shall contain the following information: a) the nature of the article under test; b) the amount of lead and/or cadmium released from the article expressed as milligrams of Pb or Cd per square decimetre of relevant surface area. A 0 is th
