00334252 PDF BRITISH STANDARD BS EN 60867 1994 IEC 867 1993 Insulating liquids — Specifications for unused liquids based on synthetic aromatic hydrocarbons The European Standard EN 60867 1994 has the[.]
BRITISH STANDARD Insulating liquids — Specifications for unused liquids based on synthetic aromatic hydrocarbons The European Standard EN 60867:1994 has the status of a British Standard UDC 621.315.615 BS EN 60867:1994 IEC 867:1993 BS EN 60867:1994 Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was prepared, comprises the national committees of the following countries: Austria Belgium Denmark Finland France Germany Greece Iceland Ireland This British Standard, having been prepared under the direction of the Cables and Insulation Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 June 1994 © BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIL/10 Draft for comment 92/03949 DC ISBN 580 23336 Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Amendments issued since publication Amd No Date Comments BS EN 60867:1994 Contents Cooperating organizations National foreword Foreword Text of EN 60867 National annex NA (informative) Committees responsible National annex NB (informative) Cross-references © BSI 12-1999 Page Inside front cover ii Inside back cover Inside back cover i BS EN 60867:1994 National foreword This British Standard has been prepared under the direction of the Cables and Insulation Standards Policy Committee and is the English language version of EN 60867:1994 Insulating liquids — Specifications for unused liquids based on synthetic aromatic hydrocarbons, published by the European Committee for Electrotechnical Standardization (CENELEC) It is identical with IEC 867:1993 published by the International Electrotechnical Commission (IEC) This British Standard supersedes BS 6802:1987 which is withdrawn BS 6802:1987 was identical with IEC 867:1986 WARNING This British Standard calls for the use of substances and procedures that may be injurious to health if adequate precautions are not taken It refers only to technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage 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 itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages to 10, 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 indicated in the amendment table on the inside front cover ii © BSI 12-1999 EUROPEAN STANDARD EN 60867 NORME EUROPÉENNE January 1994 EUROPÄISCHE NORM UDC 621.315.615 Supersedes HD 497 S1:1987 Descriptors: Liquid electrical insulating materials, aromatic hydrocarbons, specifications, characteristics, tests English version Insulating liquids — Specifications for unused liquids based on synthetic aromatic hydrocarbons (IEC 867:1993) Isolants liquides Spécifications pour liquides neufs base d’hydrocarbures aromatiques de synthèse (CEI 867:1993) Isolierflüssigkeiten Bestimmungen für ungebrauchte Isolierflüssigkeiten auf Basis synthetischer aromatischer Kohlenwasserstoffe (IEC 867:1993) This European Standard was approved by CENELEC on 1993-12-08 CENELEC 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 Central Secretariat or to any CENELEC 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 CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels © 1994 Copyright reserved to CENELEC members Ref No EN 60867:1994 E EN 60867:1994 Foreword The text of document 10(CO)269, as prepared by IEC Technical Committee No 10: Fluids for electrotechnical applications, was submitted to the IEC-CENELEC parallel vote in October 1992 The reference document was approved by CENELEC as EN 60867 on December 1993 This European Standard replaces HD 497 S1:1987 The following dates were fixed: — latest date of publication of an identical national standard (dop) 1994-12-01 — latest date of withdrawal of conflicting national standards (dow) 1994-12-01 For products which have complied with HD 497 S1:1987 before 1994-12-01, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 1999-12-01 Annexes designated “normative” are part of the body of the standard In this standard, Annex ZA is normative Contents Foreword Scope Normative references Definitions Identification and general delivery requirements Sampling Test methods Precision and interpretation of test results Specifications for capacitor and cable alkylbenzenes Specifications for capacitor alkyldiphenylethanes 10 Specifications for capacitor alkylnaphthalenes 11 Specifications for capacitor methylpolyarylmethanes Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications Sheet — Specifications for capacitor and cable alkylbenzenes Sheet — Specifications for capacitor alkyldiphenylethanes Sheet — Specifications for capacitor alkylnaphthalenes Sheet — Specifications for capacitor methylpolyarylmethanes Page 3 3 5 6 7 © BSI 12-1999 EN 60867:1994 Scope This International Standard covers specifications and test methods for unused synthetic aromatic hydrocarbons intended for use as insulating liquid in electrical equipment Normative references For the purposes of this International Standard, the following definitions apply 3.1 alkylbenzenes insulating liquids consisting of a benzene ring and an alkylgroup The alkyl group may be a straight chain or a branched-chain type The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard At the time of publication, the editions indicated were valid All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below Members of IEC and ISO maintain registers of currently valid International Standards IEC 156:1963, Method for the determination of the electric strength of insulating oils IEC 247:1978, Measurement of relative permittivity, dielectric dissipation factor and d.c resistivity of insulating liquids IEC 475:1974, Method of sampling liquid dielectrics IEC 628:1985, Gassing of insulating liquids under electrical stress and ionization IEC 814:1985, Determination of water in insulating liquids by automatic coulometric Karl Fischer titration IEC 1039:1990, General classification of insulating liquids ISO 2719:1988, Petroleum products and lubricants — Determination of flash point — Pensky-Martens closed cup method ISO 3016:1974, Petroleum oils — Determination of pour point ISO 3104:1976, Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and calculation of dynamic viscosity ISO 3675:1976, Crude petroleum and liquid petroleum products — Laboratory determination of density or relative density — Hydrometer method ISO 5662:1978, Petroleum products — Electrical insulating oils — Detection of corrosive sulphur NOTE The two types of alkylbenzene can be distinguished by infra-red spectrophotometric analysis The straight-chain type shows a single absorption peak in the region 360 cm–1 to 380 cm–1 and the branched chain type shows a double peak in that region Definitions Sampling shall be carried out in accordance with the procedure described in IEC 475 General remark Gas chromatographic analyses can be useful for composition identification and detection of impurities © BSI 12-1999 3.2 alkyldiphenylethanes insulating liquids consisting of diphenylethanes derivatives; normally the two aryl groups carry short alkyl groups NOTE This type of product is characterized by infrared absorption bands at 070, 606 and 705 cm–1 3.3 alkylnaphthalenes insulating liquids consisting of a naphthalene structure with substituent aklyl groups NOTE This type of product is characterized by infrared absorption bands at 070, 605, 380 and 360 cm–1 3.4 methylpolyarylmethanes insulating liquids consisting of methylpolyarylmethanes derivatives mainly based on a blend of mono/di-benzyl toluene (M/DBT) NOTE This type of product is characterized by infrared absorption bands at 025, 606 and 705 cm–1 Identification and general delivery requirements 4.1 The products are normally delivered in road or rail tank wagons or in drums, which shall be specially cleaned for this purpose 4.2 The drums and sample containers shipped by the supplier shall carry at least the following markings: — number of this standard; — supplier’s designation; — type of product Sampling EN 60867:1994 Test methods 6.1 Appearance Appearance shall be evaluated by examining, in transmitted light, a representative sample of the liquid having a thickness of approximately 10 cm, at ambient temperature 6.2 Density Any recognized test method may be used In case of dispute, the method to be used shall be that given in ISO 3675 Density shall be measured at 20 °C 6.3 Kinematic viscosity Kinematic viscosity shall be measured according to ISO 3104 6.4 Flash-point Flash-point shall be determined according to ISO 2719 6.5 Pour-point Pour-point shall be determined according to ISO 3016 6.6 Neutralization value 6.6.1 Reagents a) Standard alcoholic potassium hydroxide (KOH) solution 0,1 mol/dm3 b) Toluene, sulphur-free c) Azeotropic ethanol (boiling-point 78,2 °C) d) Standard hydrochloric acid solution (HCl) 0,1 mol/dm3 e) Alkali blue indicator solution: g of alkali blue B are dissolved in 100 cm3 of azeotropic ethanol containing cm3 hydrochloric acid 0,1 mol/cm3 After 24 h, carry out an acid value test to check whether the indicator has been sufficiently sensitized The indicator is satisfactory if the colour changes distinctly from blue to a red comparable to that of a 10 % solution of cobalt nitrate [Co(NO3)2.6H2O] Should sensitization be insufficient, repeat the addition of 0,1 mol/dm3 hydrochloric acid and check again after 24 h Continue until sensitization is satisfactory Filter and store in a brown glass bottle in the dark 6.6.2 Procedure Weigh 20 g of the sample to the nearest 0,05 g into a 250 cm3 stoppered conical flask To a mixture of 60 cm3 of toluene and 40 cm3 of ethanol in a second flask add cm3 of indicator solution Neutralize the solution with 0,1 mol/dm3 KOH solution until a red colour comparable to that of a solution of 10 % cobalt nitrate [Co(NO3)2.6H2O] is obtained and persists for at least 15 s Add this solution to the sample, swirl and immediately titrate at a temperature not above 25 °C with 0,1 mol/dm3 KOH solution to the above end-point The neutralization value (NV) is calculated from the expression: ´ N ´ 56,1NV = V -m where V N m is the number of cubic centimeters of 0,1 mol/dm3 KOH used in the titration is the molarity of the KOH solution is the mass of the sample in grams 6.7 Chlorine content The method described in this subclause is suitable for obtaining the total chlorine content in hydrocarbon liquids However, any other chemical or instrumental method known to produce comparable results could be used 6.7.1 Reagents — Standard solution of nitric acid (HNO3), analytical grade Dilute 190 g of concentrated nitric acid to dm3 with distilled water — Isopropyl alcohol, analytical grade — Silver nitrate (AgNO3), analytical grade Standard solution (0,025 mol/dm3) — Weigh accurately 0,4247 g of silver nitrate Transfer it to litre volumetric flask and add distilled water to dissolve Add cm3 of concentrated nitric acid (density 1,42 kg/dm3) and then add distilled water to the dm3 mark of the volumetric flask Standardize this solution against a pure chloride standard Check the solution at least monthly to assure a constant reagent NOTE A sodium chloride crystal as used in infra-red spectrometer cells is a suitable chloride standard NOTE Dry the silver nitrate overnight in a desiccator before making up the solution Both the solid material and the solution must be protected from light by storage in brown glassware in the dark — Sodium diphenyl solution (C6H5C6H4Na) NOTE Organic halogen reagent: 30 cm3 of this reagent are normally required to give excess reagent Preparation of sodium diphenyl solution is described in “McCoy — The Inorganic Analysis of Petroleum, Chemical Publishing Co Inc., 212 Fifth Avenue, New York” 6.7.2 Apparatus — Separatory funnel, 250 cm3 — Potentiometric titration apparatus — Electrodes: silver and glass electrode combination is preferred A silver electrode with a mercurous sulphate reference electrode is an acceptable alternative — Microburette, cm3 with 0,01 cm3 divisions © BSI 12-1999 EN 60867:1994 6.7.3 Procedure 6.8 Water content 6.7.3.1 Dissolve 35,5 g ± 0,1 g of the liquid under test in 25 cm3 toluene in a 150 cm3 beaker by stirring with a small glass rod Transfer the solution to a separatory funnel Rinse the beaker several times with a total of 25 cm3 toluene and add the rinses to the funnel 6.7.3.2 Add an excess (about 30 cm3 is usually sufficient) of sodium diphenyl solution to the contents of the separatory funnel The excess is indicated by a colour change of blue or green Stopper the vessel and gently shake to thoroughly mix the solution, venting occasionally to release the excess pressure build-up 6.7.3.3 Allow the blue-green mixture to stand to ensure complete reaction Remove stopper, add cm3 of isopropyl alcohol, and swirl with stopper removed until excess reagent is destroyed 6.7.3.4 Add slowly 50 cm3 of the nitric acid solution Ensure that the organic and aqueous phases are in intimate and uniform contact by gentle swirling and rocking for Loosen the stopper occasionally to release slight pressure Drain the aqueous phase into a beaker Extract the organic phase twice more with 50 cm3 portions of nitric acid solution Drain the aqueous phases into the beaker containing the first extract 6.7.3.5 Place the beaker containing the aqueous phase on the titration stand and insert the electrode system Start the stirrer and record the initial value of potential or pH Titrate slowly with AgNO3 solution (0,025 mol/dm3), recording readings after the addition of each drop of AgNO3 solution Continue titrating until the point of maximum change in potential or pH scale reading is reached Plot the volume of silver nitrate as abscissa and voltage or pH reading as ordinates The end-point is selected at the point of inflection of the curve 6.7.3.6 Blank Titrate the same volume of solvent without the sample, as a blank Water content shall be determined according to IEC 814 6.7.4 Calculation Calculate the amount of total chlorine as follows: Total chlorine (mg/kg) = [(A – B) N/m] 35,5 × 103 where A B N m 35,5 is the number of cubic centimetres of AgNO3 solution required for titration of the sample is the number of cubic centimetres of AgNO3 solution required for titration of the blank is the molarity of the AgNO3 solution is the mass in grams of sample used is the atomic mass of chlorine © BSI 12-1999 6.9 Corrosive sulphur Corrosive sulphur shall be determined according to ISO 5662 6.10 Breakdown voltage Breakdown voltage shall be determined according to IEC 156 6.11 Dielectric dissipation factor and volume resistivity The properties shall be determined according to IEC 247 6.12 Stability under electrical stress and ionization (gassing) The gassing shall be determined by either Method A or Method B of IEC 628 Precision and interpretation of test results Precision data given in the specified methods are to be used solely as a guide to the expected agreement between duplicate measurements of the property and are not to be regarded as tolerances applicable to the limits specified in Sheet 1, Sheet 2, Sheet and Sheet Specifications for capacitor and cable alkylbenzenes When tested in accordance with the methods specified in clause 6, the properties of alkylbenzene-based products which are intended for use as impregnants in capacitors and hollow-core cables shall meet the requirements given in the specification Sheet According to IEC 1039 they are designated as follows: L-NY-867-1 NOTE Alkylbenzenes are sometimes used in transformers but this application is not wide enough to justify the development of international specifications The preparation of a specification could be undertaken if necessary Specifications for capacitor alkyldiphenylethanes When tested in accordance with the methods specified in clause 6, the properties of alkyldiphenylethane-based products used as impregnant in capacitors shall meet the requirements given in specification Sheet According to IEC 1039 they are designated as follows: L-NC-867-2 EN 60867:1994 10 Specifications for capacitor alkylnaphthalenes 11 Specifications for capacitor methylpolyarylmethanes When tested in accordance with the methods When tested in accordance with the methods specified in clause the properties of specified in clause 6, the properties of alkylnaphthalene-based products used as polyalkylarylmethane based products used as impregnant in capacitors shall meet the impregnant in capacitors shall meet the requirements given in specification Sheet requirements given in specification Sheet According to IEC 1039 they are designated as According to IEC 1039 they are designated as follows: L-NC-867-4 follows: L-NC-867-3 Sheet — Specifications for capacitor and cable alkylbenzenes Property Test method (subclause) Permissible value Class I Class II Class III Physical Clear, no suspended matter of sediments — Appearance 6.1 — Density at 20 °C (kg/dm3) — Kinematic viscosity at 40 °C (mm2/s) 6.2 6.3 — Flash-point (°C) — Pour-point (°C) 6.4 6.5 0,850 to 0,880 0,850 to 0,880 Max Min – Max 11 Min 110 Min 130 Max – 45 Max – 45 Chemical — Neutralization value (mg KOH/g) — Chlorine content (mg/kg) — Water content (mg/kg) — Corrosive sulphur 6.6 6.7 6.8 6.9 Max 0,03 Max 30 Max 75 Non-corrosive 6.10 6.11 6.11 Min 30a Min 0,5a Max 0,002a Electrical — Breakdown voltage (kV) — Volume resistivity at 90 °C (T7.m) — Dielectric dissipation factor, tan $ at 90 °C and 40 Hz to 60 Hz — Stability under electrical stress and ionization (gassing)b (either method A or method B) Absorption (mm3/min) Absorption (cm3) 0,850 to 0,885 Min 10 – Max 50 Min 150 Max – 30 6.12 Method A Method B Min 20 Min 2,5 a The specified limiting values take into account the most unfavourable delivery conditions These values relate to liquids as received b Specification requires that alkylbenzenes meet the gassing limits as measured by either method A or method B It is not intended that the property is measured by both methods © BSI 12-1999 EN 60867:1994 Sheet — Specifications for capacitor alkyldiphenylethanes Property Test method (subclause) Permissible value Physical — Appearance 6.1 — Density at 20 °C (kg/dm3) — Kinematic viscosity at 40 °C (mm2/s) — Flash-point (°C) — Pour-point (°C) 6.2 6.3 6.4 6.5 Clear, no suspended matter or sediments 0,950 to 1,000 Max Min 140 Max – 40 6.6 6.7 6.8 6.9 Max 0,03 Max 30 Max 100 Non-corrosive 6.10 6.11 6.11 Min 30a Min 0,5a Max 0,002a 6.12 Method A Min 100 Chemical — Neutralization value (mg KOH/g) — Chlorine content (mg/kg) — Water content (mg/kg) — Corrosive sulphur Electrical — Breakdown voltage (kV) — Volume resistivity at 90 °C (T7.m) — Dielectric dissipation factor, tan $ at 90 °C and 40 Hz to 60 Hz — Stability under electrical stress and ionization (gassing) Absorption (mm3/min) a The specified limiting values take into account the most unfavourable delivery conditions These values relate to liquids as received Sheet — Specifications for capacitor alkylnaphthalenes Property Test method (subclause) Permissible value Physical — Appearance 6.1 Clear, no suspended matter or sediments — Density at 20 °C (kg/dm3) — Kinematic viscosity at 40 °C (mm2/s) — Flash-point (°C) — Pour-point (°C) 6.2 6.3 6.4 6.5 0,950 to 1,000 Max Min 140 Max – 40 6.6 6.7 6.8 6.9 Max 0,03 Max 30 Max 100 Non-corrosive 6.10 6.11 6.11 Min 30a Min 0,5a Max 0,002a 6.12 Method A Min 100 Chemical — Neutralization value (mg KOH/g) — Chlorine content (mg/kg) — Water content (mg/kg) — Corrosive sulphur Electrical — Breakdown voltage (kV) — Volume resistivity at 90 °C (T7.m) — Dielectric dissipation factor, tan $ at 90 °C and 40 Hz to 60 Hz — Stability under electrical stress and ionization (gassing) Absorption (mm3/min) a The specified limiting values take into account the most unfavourable delivery conditions These values relate to liquids as received © BSI 12-1999 EN 60867:1994 Sheet — Specifications for capacitor methylpolyarylmethanes Property Test method (subclause) Permissible value Physical — Appearance 6.1 — Density at 20 °C (kg/dm3) — Kinematic viscosity at 40 °C (mm2/s) — Flash-point (°C) — Pour-point (°C) 6.2 6.3 6.4 6.5 Clear, no suspended matter or sediments 0,980 to 1,020 Max Min 130 Max – 50 6.6 6.7 6.8 6.9 Max 0,03 Max 30 Max 100 Non-corrosive 6.10 6.11 6.11 Min 30a Min 0,25a Max 0,004a 6.12 Method A Min 130 Chemical — Neutralization value (mg KOH/g) — Chlorine content (mg/kg) — Water content (mg/kg) — Corrosive sulphur Electrical — Breakdown voltage (kV) — Volume resistivity at 90 °C (T7.m) — Dielectric dissipation factor, tan $ at 90 °C and 40 Hz to 60 Hz — Stability under electrical stress and ionization (gassing) Absorption (mm3/min) a The specified limiting values take into account the most unfavourable delivery conditions These values relate to liquids as received © BSI 12-1999 EN 60867:1994 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications This European Standard incorporates by dated or undated reference, provisions from other publications These normative references are cited at the appropriate places in the text and the publications are listed hereafter For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision For undated references the latest edition of the publication referred to applies NOTE When the international publication has been modified by CENELEC common modifications, indicated by (mod), the relevant EN HD applies IEC publication Date Title EN/HD Date 156 1963 — — 247 1978 — — 475 628 1974 1985 814 1985 1039 1990 Method for the determination of the electric strength of insulating oils Measurement of relative permittivity, dielectric dissipation factor and d.c resistivity of insulating liquids Method of sampling liquid dielectrics Gassing of insulating liquids under electrical stress and ionization Determination of water in insulating liquids by automatic coulometric Karl Fischer titration General classification of insulating liquids — — HD 488 S1 1987 HD 487 S1 1987 HD 618 S1 1992 Other publications ISO 2719:1988 ISO 3016:1974 ISO 3104:1976 ISO 3675:1976 ISO 5662:1978 © BSI 12-1999 Petroleum products and lubricants — Determination of flash point — Penskey-Martens closed cup method Petroleum oils — Determination of pour point Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and calculation of dynamic viscosity Crude petroleum and liquid petroleum products — Laboratory determination of density or relative density — Hydrometer method Petroleum products — Electrical insulating oils — Detection of corrosive sulphur 10 blank BS EN 60867:1994 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Cables and Insulation Standards Policy Committee (CIL/-) to Technical Committee CIL/10, upon which the following bodies were represented: Association of Consulting Engineers Chemical Industries Association Electricity Industry in United Kingdom ERA Technology Ltd Health and Safety Executive Institute of Petroleum Transmission and Distribution Association (BEAMA Ltd.) The following bodies were also represented in the preparation of the standard, through subcommittees and panels: British (AC) Capacitor Manufacturers’ Association (BEAMA Ltd.) British Cable Makers’ Confederation British Lubricants Federation Ltd National Association of Waste Disposal Contractors National annex NB (informative) Cross-references Publication referred to Corresponding British Standard IEC 156:1963 IEC 247:1978 BS 5874:1980 Method for determination of the electric strength of insulating oils BS 5737:1979 Method for the measurement of relative permittivity, dielectric dissipation factor and d.c resistivity of insulating liquids BS 5797:1986 Methods for measurement of gassing of insulating liquids under electrical stress and ionization BS 6725:1986 Method for determination of water in liquid dielectrics by automatic coulometric Karl Fischer titration BS 6664 Flashpoint of petroleum and related products Part 5:1990 Method for determination of flashpoint by Pensky-Martens closed tester BS 2000 Methods of test for petroleum and its products Part 15:1993 Determination of pour point BS 4714:1980 Method for laboratory determination of density or relative density of crude petroleum and liquid petroleum products (hydrometer method) BS 5680:1979 Method for detection of corrosive sulphur in petroleum-based electrical insulating oils IEC 628:1985 IEC 814:1985 ISO 2719:1988 ISO 3016:1974 ISO 3675:1976 ISO 5662:1978 © BSI 12-1999 BS EN 60867:1994 IEC 867:1993 BSI — British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter Revisions British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions It is the constant aim of BSI to improve the quality of our products and services We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel: 020 8996 9000 Fax: 020 8996 7400 BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel: 020 8996 9001 Fax: 020 8996 7001 In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service Various BSI electronic information services are also available which give details on all its products and services Contact the Information Centre Tel: 020 8996 7111 Fax: 020 8996 7048 Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards For details of these and other benefits contact Membership Administration Tel: 020 8996 7002 Fax: 020 8996 7001 Copyright Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of the publications of the international standardization bodies Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, photocopying, recording or otherwise – without prior written permission from BSI This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained BSI 389 Chiswick High Road London W4 4AL If permission is granted, the terms may include royalty payments or a licensing agreement Details and advice can be obtained from the Copyright Manager Tel: 020 8996 7070