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BS EN 7232009 ICS 77.150.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Copper and copper alloys Combustion for determination of the carbon content on the inner surface of copper tubes or fittings This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2009 BSI 2009 ISBN 978 0 580 56377 5 Amendments/corrigenda issued since publication DateComments BS EN 7232009 National foreword This British Standard is the UK implementation of EN 7232009. It supersedes BS EN 7231996 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee NFE/34, Copper and copper alloys. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. BS EN 7232009 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 723 April 2009 ICS 77.150.30Supersedes EN 7231996 English Version Copper and copper alloys - Combustion for determination of the carbon content on the inner surface of copper tubes or fittings Cuivre et alliages de cuivre - Mthode de dtermination par combustion de la teneur en carbone la surface interne des tubes ou des raccords en cuivre Kupfer und Kupferlegierungen - Verfahren zur Bestimmung des Kohlenstoffs auf der Innenoberflche von Kupferrohren oder Fittings durch Verbrennen This European Standard was approved by CEN on 19 March 2009. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions English, French, German. A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre Avenue Marnix 17, B-1000 Brussels 2009 CENAll rights of exploitation in any and by any means reserved worldwide for CEN national Members. Ref. No. EN 7232009 E BS EN 7232009 EN 7232009 E 2 Contents Page Foreword ..............................................................................................................................................................3 1 Scope ......................................................................................................................................................4 2 Terms and definitions ...........................................................................................................................4 3 Principle ..................................................................................................................................................4 4 Preparation of samples and test pieces ..............................................................................................4 4.1 Preparatory procedures ........................................................................................................................4 4.1.1 General ....................................................................................................................................................4 4.1.2 Residual carbon content .......................................................................................................................5 4.1.3 Total carbon content .............................................................................................................................5 4.1.4 Potential carbon content .......................................................................................................................5 4.2 Preparation of samples .........................................................................................................................5 4.2.1 Tubes ......................................................................................................................................................5 4.2.2 Fittings ....................................................................................................................................................5 4.3 Cleaning of sample surfaces ................................................................................................................5 4.3.1 Cleaning of inner surface of sample ....................................................................................................5 4.3.2 Cleaning of outer surface of sample....................................................................................................6 4.4 Preparation of test pieces .....................................................................................................................7 4.4.1 Tubes ......................................................................................................................................................7 4.4.2 Fittings ....................................................................................................................................................8 5 for carbon content determination ..........................................................................................9 5.1 General ....................................................................................................................................................9 5.2 Determination of the carbon content ................................................................................................ 10 5.3 Determination of the blank value ...................................................................................................... 10 6 Expression of results ......................................................................................................................... 10 7 Calibration ........................................................................................................................................... 11 8 Test report ........................................................................................................................................... 11 Bibliography ..................................................................................................................................................... 12 BS EN 7232009 EN 7232009 E 3 Foreword This document EN 7232009 has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2009, and conflicting national standards shall be withdrawn at the latest by October 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 7231996. In comparison with the first edition of EN 7231996, the following significant technical changes and one significant editorial change were made improvement of the accuracy of the ; extension of the scope of the standard to fittings of copper alloys; simplification by limitation to only one for carbon content determination, namely that of infrared absorption spectrometry [ using tetrabutylammonium hydroxide HTBA and of determination by measurement of differential electrical conductivity coulometric deleted]; simplification by limitation to only one cutting for tubes with diameters exceeding the furnace diameter by deletion of the “longitudinal cutting “; change of Clause 2 “Normative References“ into “Bibliography“ with renumbering. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 7232009 EN 7232009 E 4 1 Scope This European Standard specifies a combustion for determining the carbon content, if any, on the inner surface of tubes of copper or fittings of copper or copper alloys. This standard applies only to seamless, round copper tubes as specified for example in EN 1057 and EN 13348 or fittings of copper or copper alloys as specified in EN 1254 all parts. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply 2.1 residual carbon CR carbon present in the chemical of elemental carbon 2.2 potential carbon CP carbon present in the chemical of organic compounds EXAMPLE Organic compounds oils, greases, etc. 2.3 total carbon CT sum of residual carbon and potential carbon 3 Principle Combustion of the carbon present on the inner surface of a tube or fitting sample, carried out at a given temperature in an oxygen flow. Determination, by infrared absorption spectrometry, of the residual or total carbon content, or both, by measurement of the carbon dioxide generated. Calculation of potential carbon content is by subtraction of the residual carbon content from the total carbon content. 4 Preparation of samples and test pieces 4.1 Preparatory procedures 4.1.1 General Carry out the procedures in 4.1.2, 4.1.3 or 4.1.4 depending on the carbon to be determined and taking account of the following precautions a metal cutting tool shall be free from protective paint; b clamps shall be flat and consist of copper, aluminium, steel or an alternative material. Alternative materials shall not be detrimental to their cleanliness; BS EN 7232009 EN 7232009 E 5 c all tools and implements used for cutting or clamping samples shall be degreased before sample preparation; d degreasing shall be done by wiping with a lint-free cloth containing absorbed tetrachloroethylene, trichloroethylene or trichloroethane or, because of potential for environmental harm, other solvents of equivalent perance, e.g. acetone. These solvents shall also be used for cleaning/immersion of samples where appropriate; e suitable protective gloves should be used to ensure skin contact with the surface under test is avoided; f between the cleaning operation and the combustion operation, the test pieces shall be kept in a non- contaminating environment, such as a clean laboratory or in a desiccator containing sodium hydroxide pellets. The tests shall be completed within approximately 5 h of cleaning the sample, or if not, the sample shall be re-cleaned. 4.1.2 Residual carbon content a prepare samples see 4.2; b clean inner and outer surface of sample see 4.3.1 and 4.3.2; c prepare test pieces see 4.4. 4.1.3 Total carbon content a prepare samples see 4.2; b clean outer surface of sample see 4.3.2; c prepare test pieces see 4.4. 4.1.4 Potential carbon content Prepare separate samples and test pieces following the procedures in 4.1.2 and 4.1.3. 4.2 Preparation of samples 4.2.1 Tubes Cut a sample approximately 30 cm long from a tube, using a metal-cutting saw or a pipe cutter. Deburr the outer and inner edges of the sample ends, using a smooth file or a trimming blade, take care that any burrs removed do not fall into the bore of the tube. 4.2.2 Fittings Select sufficient fittings from the batch in order to be able to cut test pieces from them having a minimum total internal surface area of 10 cm2. 4.3 Cleaning of sample surfaces 4.3.1 Cleaning of inner surface of sample The following steps shall be pered in a fume cupboard. Immerse the sample, for a minimum of 2 min in an agitated bath of boiling chlorinated solvent, for example, analytical grade trichloroethylene or trichloroethane, that shall be used as reference in case of dispute ensuring that the solvent baths are kept topped up, such that the sample remains totally immersed in the solvent. Immerse the sample in a second, boiling solvent bath for at least 30 s. BS EN 7232009 EN 7232009 E 6 Remove the sample from the bath and place it vertically under a fume hood or on a grease-free plate in an oven operating at a temperature of at least 80 C for a minimum of 60 s, until the solvent has totally evaporated. Refresh both baths periodically, as appropriate, in accordance with written internal procedures. 4.3.2 Cleaning of outer surface of sample 4.3.2.1 General Degrease the outside surface of the sample by wiping with a clean, lint-free, solvent-containing cotton cloth, taking care to ensure that no fibres remain on the sample after wiping. Clean the sample by chemical cleaning , see 4.3.2.2, or for tubes in R250 and R290 material conditions1 only, the alternative mechanical cleaning , see 4.3.2.3, except in cases of dispute or preparation for blank value determination, may be used. 4.3.2.2 Chemical cleaning 4.3.2.2.1 Sealing a For annealed tubes only Squashing/flattening a 20 mm approx. portion of the tube extending from one end, between clamps see 4.1 placed between the jaws of a vice. The squashed end is then folded over and also squashed/flattened against the adjacent, 20 mm approx. length of tube, again using clamps see 4.1 fixed between the jaws of a vice. This shall be used for reference testing. b For tubes or fittings Seal one tube end or all fitting ends by inserting appropriately-sized, silicone or neoprene plugs. NOTE If necessary, the ends of tubes in annealed material condition should firstly be re-rounded using an appropriate, degreased re-rounding tool, in order to obtain a leak-tight seal with the plug. 4.3.2.2.2 Cleaning Place the degreased sample in a clean beaker containing fresh diluted nitric acid for half starting from 50 concentrated nitric acid. The temperature of the acid shall be at least 20 C and for ha
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