00768968 PDF BRITISH STANDARD BS EN 61094 4 1996 IEC 1094 4 1995 Specification for Measurement microphones — Part 4 Specifications for working standard microphones The European Standard EN 61094 4 199[.]
BRITISH STANDARD Specification for Measurement microphones — Part 4: Specifications for working standard microphones The European Standard EN 61094-4:1995 has the status of a British Standard ICS 17.140.50; 33.160.50 BS EN 61094-4:1996 IEC 1094-4: 1995 BS EN 61094-4:1996 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EPL/29, Electroacoustics, upon which the following bodies were represented: British Association of Otolaryngologists British Hearing Aid Industry Association British Medical Association British Society of Audiology British Telecommunications plc Confederation of British Industry Department of Health Department of Trade and Industry (National Physical Laboratory) Health and Safety Executive Institute of Acoustics Institute of Sound and Vibration Research Institution of Electrical Engineers Medical Research Council Ministry of Defence Royal Aeronautical Society Royal National Institute for Deaf people Society of Environmental Engineers University of Exeter This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 July 1996 © BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference EPL/29 Draft for comment 94/202601 DC ISBN 580 25909 Amendments issued since publication Amd No Date Comments BS EN 61094-4:1996 Contents Committees responsible National foreword Foreword Text of EN 61094-4 List of references © BSI 09-1999 Page Inside front cover ii Inside back cover i BS EN 61094-4:1996 National foreword This British Standard has been prepared by Technical Committee EPL/29 and is the English language version of EN 61094-4:1995, Measurement microphones — Part 4: Specifications for working standard microphones, published by the European Committee for Electrotechnical Standardization (CENELEC) It is identical with IEC 1094-4, first edition 1995 Cross-references Publication referred to Corresponding British Standard HD 556 S1:1991 (IEC 942:1988) BS 7189:1989 Specification for sound calibrators BS EN 61094 Specification for measurement microphones EN 61094-1:1994 (IEC 1094-1:1992) Part 1:1995 Specifications for laboratory standard microphones EN 61094-2:1993 (IEC 1094-2:1992) Part 2:1994 Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique EN 61094-3:1995 (IEC 1094-3:1995) Part 3:1996 Primary method for free-field calibration of laboratory standard microphones by the reciprocity technique 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 12, 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 09-1999 EUROPEAN STANDARD EN 61094-4 NORME EUROPÉENNE December 1995 EUROPÄISCHE NORM ICS 17.140.50; 33.160.50 Descriptors: Electroacoustics, measuring instruments, microphones, definitions, classifications, standard measures, characteristics, specifications English version Measurement microphones Part 4: Specifications for working standard microphones (IEC 1094-4:1995) Microphones de mesure Partie 4: Spécifications des microphones étalons de travail (CEI 1094-4:1995) Meßmikrofone Teil 4: Anforderungen an Gebrauchs-Normalmikrofone (IEC 1094-4:1995) This European Standard was approved by CENELEC on 1995-11-28 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 © 1995 Copyright reserved to CENELEC members Ref No EN 61094-4:1995 E EN 61094-4:1995 Foreword 6.5 The text of document 29/295/DIS, future edition of IEC 1094-4, prepared by IEC TC 29, Electroacoustics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61094-4 on 1995-11-28 The following dates were fixed: — latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1996-09-01 — latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 1996-09-01 Annexes designated “normative” are part of the body of the standard Annexes designated “informative” are given for information only In this standard, Annex ZA is normative and Annex A is informative Annex ZA has been added by CENELEC Contents Foreword Scope and object Normative references Definitions 3.1 Working standards microphone 3.2 Principal axis of a microphone 3.3 Reference plane of a microphone 3.4 Effective front volume of a microphone 3.5 Correction grid Reference environmental conditions Classification of working standard microphones 5.1 General 5.2 Type designation Characteristics of working standard microphones 6.1 Sensitivity 6.2 Effective front volume 6.3 Upper limit of the dynamic range of a microphone 6.4 Linearity range of the microphone sensitivity level Page 3 3 3 3 Static pressure dependence of microphone sensitivity 6.6 Temperature dependence of microphone sensitivity 6.7 Humidity dependence of microphone sensitivity 6.8 Stability of microphone sensitivity 6.9 Pressure equalizing leakage Specifications 7.1 Mechanical dimensions 7.2 Electroacoustical specifications 7.3 Identification markings Annex A (informative) Provisional ground-shield reference configuration for type WS3 microphones 10 Annex ZA (normative) Normative references to international publications with their corresponding European publications 11 Figure — Mechanical configuration of microphones Figure — Tolerance curves for frequency response on a logarithmic frequency scale, where f0, f1 and f2 are specified in Table Figure A.1 — Mechanical attachment to microphone, showing the provisional ground-shield reference configuration for type WS3 microphones 10 Table — Nominal mechanical dimensions and tolerance limits for working standard microphones in Figure Table —Electrocoustical specifications for working standard microphones Table — Tolerance values for the frequency response (in details) 4 4 4 4 © BSI 09-1999 EN 61094-4:1995 Scope and object Definitions This part of IEC 1094 is applicable to working standard microphones It specifies mechanical dimensions and certain electroacoustical characteristics for working standard microphones used in measuring systems for the determination of sound pressure to enable these microphones to be used as transfer standards in the calibration of acoustic measurement instruments It establishes a system for classifying working standard microphones into a number of types according to their dimensions and properties in order to facilitate the specification of measurement systems, the calibration of measuring systems and microphones by sound calibrators, and the interchangeability of microphones in given measuring and calibration systems It does not specify the transduction principle by which working standard microphones operate For the purpose of this part of IEC 1094, the following definitions apply in addition to the definitions given in IEC 1094-1 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC 1094 At the time of publication, the editions indicated were valid All normative documents are subject to revision, and parties to agreements based on this part of IEC 1094 are encouraged to investigate the possibility of applying the most recent editions of the normative documents listed below Members of IEC and ISO maintain registers of currently valid International Standards IEC 942:1988, Sound calibrators IEC 1094-1:1992, Measurement microphones — Part 1: Specifications for laboratory standard microphones IEC 1094-2:1992, Measurement microphones — Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique IEC/DIS 1094-3:199x, Measurement microphones — Part 3: Primary method for free-field calibration of laboratory standard microphones by the reciprocity technique1) (revision of IEC 486) ANSI B1.1:1982, Unified inch screw threads2) ISO: 1993, Guide to the expression of uncertainty in measurement 1) 3.1 working standard microphone microphone capable of being calibrated by at least one of the following: a) a method specified in IEC 1094-2 or IEC 1094-3; b) by comparison with a calibrated laboratory standard microphone; c) by a sound calibrator as specified in IEC 942 a working standard microphone meets certain requirements on mechanical dimensions and electroacoustical characteristics, especially with respect to stability in time and dependence on environmental conditions 3.2 principal axis of a microphone line through the centre of and perpendicular to the diaphragm of the microphone 3.3 reference plane of a microphone plane perpendicular to the principal axis immediately in front of the protection grid of the microphone 3.4 effective front volume of a microphone at reference conditions, the volume of air that has the same acoustic compliance as the cavity bounded by the reference plane, the diaphragm and the outer cylindrical surface of the microphone at the reference plane, including the equivalent volume of the microphone configuration The effective front volume is generally a function of frequency 3.5 correction grid specially shaped grid, substituted for the normal protection grid of a microphone, for the purpose of changing the directivity response of the microphone, thereby changing the acoustical classification of the microphone At present at the stage of draft International Standard (29/294/DIS) is given to ANSI B1.1 in the absence of an equivalent International Standard 2) Reference © BSI 09-1999 EN 61094-4:1995 Reference environmental conditions Characteristics of working standard microphones The reference environmental conditions are: — temperature 23,0 °C 6.1 Sensitivity — static pressure 101,325 kPa — relative humidity 50 % The sensitivity of the microphone is the open-circuit sensitivity as defined in IEC 1094-1 If the insert voltage technique is used to determine this sensitivity for type WS1 and WS2 microphones, the appropriate ground-shield reference configuration given in IEC 1094-1 shall apply For type WS3 the provisional ground-shield reference configuration given in Annex A is recommended NOTE The reference temperature is chosen to be 23,0 °C because practical considerations require that most calibrations be carried out at, or near, this temperature Classification of working standard microphones 5.1 General The sound pressure in a given sound field will generally depend on position and should ideally be measured at a point with a transducer of infinitesimally small dimensions and infinitely high acoustic impedance However, the finite dimensions and acoustic impedance of a real microphone, and the mounting of this microphone cause practical measurements of sound pressure to depart from this ideal The effect of diffraction is accounted for by defining different sensitivities of a microphone each referring to idealized sound fields, for example pressure, free-field, and diffuse-field sensitivities A microphone is usually so constructed that one of the above sensitivities is essentially independent of frequency in the widest possible frequency range 5.2 Type designation Working standard microphones are described by a mnemonic system consisting of the letters WS (for Working Standard) followed by a number representing the mechanical configuration and a third letter representing the electroacoustical characteristic The third letter may be P, F or D representing, respectively, microphones having a pressure, free-field or diffuse field sensitivity, which is approximately independent of frequency in the widest possible frequency range The designation WS2P thus refers to a working standard microphone of mechanical configuration having a nearly constant pressure sensitivity as a function of frequency The type designation does not always prevent the use of these microphones under other conditions, such as pressure, free-field or diffuse field conditions after proper calibration NOTE If the microphone is equipped with a protection grid, this will influence the free-field and diffuse field sensitivities The manufacturer should state whether the sensitivity has been specified with or without grid By definition, the pressure sensitivity of a microphone does not depend on the presence or absence of a protection grid However, the sound pressure that is measured in a small cavity with a microphone is influenced by the microphone grid 6.2 Effective front volume The effective front volume of the microphone is an important quantity when the microphone is calibrated with a sound calibrator [see 4.2 item d) of IEC 942] and when used in small couplers such as ear simulators The effective front volume shall be specified as a function of frequency in the frequency range from 160 Hz to 000 Hz inclusive NOTE Methods for determining the effective front volume are given in clause E.2 of Annex E of IEC 1094-2 6.3 Upper limit of the dynamic range of a microphone The upper limit of the dynamic range shall be stated in terms of the sound pressure level which, throughout the frequency range from 160 Hz to 000 Hz, results in a total harmonic distortion of % NOTE At present no generally accepted measuring method exist for determining this upper limit at frequencies above 000 Hz 6.4 Linearity range of the microphone sensitivity level The sensitivity level of the microphone at reference conditions shall not vary by more than 0,2 dB at any frequency in the range from 160 Hz to 000 Hz when the sound pressure level varies within the range specified in Table 2, item NOTE To determine the sensitivity level at the lowest sound pressure levels of the linearity range, narrow band filtering is usually necessary The bandwidth of the filter should be small enough to ensure that inherent noise in the measurement set-up does not influence the result © BSI 09-1999 EN 61094-4:1995 6.5 Static pressure dependence of microphone sensitivity The sensitivity of the microphone depends on the static pressure which influences the impedance of the air enclosed in the cavity behind the diaphragm The static pressure dependence shall be given as a function of frequency for the static pressure range of from 65 kPa to 115 kPa NOTE At present, it is impractical to determine the dependence of free-field and diffuse-field sensitivities on static pressure, and a comparison technique in a environmental chamber may be used 6.6 Temperature dependence of microphone sensitivity Small and slow temperature variations usually cause reversible changes in sensitivity Large or rapid temperature changes (temperature shock) can lead to a permanent change of microphone sensitivity The temperature dependence shall be given as a function of frequency for the temperature range from – 10 °C to + 50 °C NOTE At present, it is impractical to determine the dependence of free-field and diffuse-field sensitivities on temperature, and a comparison technique in a environmental chamber may be used 6.7 Humidity dependence of microphone sensitivity The sensitivity of the microphone can depend on the relative humidity The relative humidity dependence shall be given as a function of frequency for the range of relative humidity from 10 % to 90 % at reference temperature and reference static pressure NOTE At present, it is impractical to determine the dependence of free-field and diffuse-field sensitivities on relative humidity, and a comparison technique in a environmental chamber may be used 6.9 Pressure equalizing leakage The cavity behind the diaphragm is normally fitted with a narrow pressure equalizing tube to permit the static pressure to be the same on both sides of the diaphragm Consequently, at very low frequencies, this tube also partially equalizes the sound pressure, and the free-field sensitivity and diffuse-field sensitivity will be significantly lower than the pressure sensitivity The pressure equalizing leakage shall be described either in terms of the minimum time constant for the equalizing tube and back cavity system or in terms of the lower limiting frequency This lower limiting frequency is that frequency at which the free-field sensitivity level is dB less than the pressure sensitivity level at 250 Hz It shall be described whether the pressure equalizing tube connects to the outside through the housing or to the back of the microphone into the preamplifier Specifications 7.1 Mechanical dimensions The working standard microphone shall conform to the mechanical configuration given in Figure and to the corresponding nominal dimensions and tolerance limits listed in Table Working standard microphones are generally supplied with a protective grid to prevent accidental damage to the diaphragm For microphones of type WSnP (n = 1, 2, 3) the grid shall be removable For other types the grid may be fixed or removable The maximum force which can be applied to the central electrical contact of the microphone without noticeable change in the actual electroacoustical performance shall be stated by the manufacturer 6.8 Stability of microphone sensitivity The sensitivity of a microphone can change over a period of time even when stored under typical climatic conditions The stability coefficients shall be stated for reference environmental conditions at a frequency within the range from 200 Hz to 000 Hz © BSI 09-1999 EN 61094-4:1995 Figure — Mechanical configuration of microphones Table — Nominal mechanical dimensions and tolerance limits for working standard microphones in Figure Dimensions in milimeters Dimension symbol d1 Type WS1P/F/D ø d2 d3 ø d4 ø d5 l1 length of thread l2 thread ød3 ø ø 23,77 +0,05 – 0,1 23,77 ± 0,1 23,11 4–6 > 12,2 3–4 > 2,7 60 UNS-2B 7.2 Electroacoustical specifications Electroacoustical specifications are given in Table The manufacturer shall provide type specifications for all of the characteristics listed, except for item 12, together with individual data for items and For type WS1 and WS2 microphones, the sensitivity shall be clearly stated as the open-circuit sensitivity If an additional sensitivity, valid under other conditions, is given for these microphones, these conditions shall be stated For type WS3 microphones the provisional ground-shield reference configuration given in Annex A is preferred If a different configuration or other mechanical connection to the preamplifier is used, it shall be stated by the manufacturer Type WS2P/F/D 13,2 +0,05 – 0,1 12,7 ± 0,1 11,70 3–5 > 7,8 3,6 – 4,6 > 2,2 60 UNS-2B Type WS3P/F/D +0,03 – 0,05 7,0 6,35 ± 0,05 5,70 2–3 > 3,5 0,8 – 1,4 > 1,6 60 UNS-2B The sensitivity level shall be given with a resolution of 0,1 dB or better together with a statement of the measurement uncertainty determined according to the ISO Guide given in clause The frequency response shall be given as a curve together with the tolerance curves shown in Figure Tabulated values of the tolerances are given in Table In addition, it is recommended that typical values for the free-field minus pressure sensitivity levels and the diffuse-field minus pressure sensitivity levels are given as a function of frequency © BSI 09-1999 EN 61094-4:1995 The manufacturer shall specify the essential characteristics of the preamplifier or amplifier to which the microphone should be connected for it to meet the electro-acoustical specifications given in Table For example, if applicable, the minimum input impedance of the preamplifier, the value of the polarizing voltage, and the minimum source impedance of the polarizing voltage supply shall be stated 7.3 Identification markings Each working standard microphone shall be inscribed with the manufacturer’s model number and the individual serial number Figure — Tolerance curves for frequency response on a logarithmic frequency scale, where f0, f1 and f2 are specified in Table © BSI 09-1999 EN 61094-4:1995 Table — Electroacoustical specifications for working standard microphones Item Characteristics Remark Type WS1P/F/D – 34 Type WS2P/F/D – 40 Type WS3P/F/D – 60 Unit Minimum sensitivity level at f0 within the range (re V/Pa) 200 Hz to 000 Hz dB Frequency responsea see Figure and Table relative to the sensitivity 10 to 000 10 to 16 000 10 to 31 600 Hz level at f0 and stated as f1 – f2 on the tolerance curve Figure Effective front volume at 160 Hz to 000 Hz e e e mm3 Modulus of equivalent volume (type P only) at 200 Hz to 500 Hz < 200 < 50 135 > 140 > 150 dB Linearity range (re 20 4Pa) for a variation in 10 to 130 sensitivity level of 0,2 dB at 160 Hz to 000 Hz 25 to 135 40 to 145 dB Static pressure coefficient see 6.5 – 0,03 to + 0,03 – 0,03 to + 0,03 – 0,03 to + 0,03 dB/kPa Temperature coefficient see 6.6 – 0,03 to + 0,03 – 0,03 to + 0,03 – 0,03 to + 0,03 dB/K Relative humidity coefficient see 6.7 – 0,001 to – 0,001 to + 0,001 + 0,001 – 0,001 to + 0,001 dB/% > 0,05 > 0,05 > 0,05 s 10 Pressure equalizing time constantbc 11 Long-term stability coefficient at 15 °C to 25 °C at 200 Hz to 000 Hz < 0,03 < 0,03 < 0,03 dB/year 12 Short-term stability coefficientd at 15 °C to 25 °C at 200 Hz to 000 Hz < 0,03 < 0,03 < 0,03 dB a The frequency response refers to the pressure-, diffuse- or free-field sensitivity level according to the type designation required for specific purposes, the time constant should not be larger than s, otherwise the requirements on short-term stability may not be met c For a microphone with a pressure equalizing leakage that cannot be described as a first order system, the order of the system shall be stated, and the dB lower limiting frequency shall be stated instead of the pressure equalizing time constant d The figures shall be derived from at least five measurements taken over a period of 10 days and with an interval of not less than 24 h (see 3.12 of IEC 1094-1) e Nominal values and tolerance limits shall be given by the manufacturer in frequency range stated b Unless © BSI 09-1999 EN 61094-4:1995 Table — Tolerance values for the frequency response (in decibels) Frequency Hz < 10 10 12,5 16 20 — — — f0 — — — 000 500 150 000 000 300 000 10 000 12 500 16 000 Type WS1 + 2,0 Z + 2,0 – 2,0 + 1,5 – 1,5 + 1,0 – 1,0 + 0,5 – 0,5 — — — reference — — — + 0,5 – 0,5 + 0,75 – 0,75 + 1,0 – 1,0 + 1,25 – 1,25 + 1,5 – 1,5 + 1,75 – 1,75 + 2,0 – 2,0 + 2,0 – 6,0 + 2,0 – 10,0 + 2,0 Z Type WS2 + 2,0 Z + 2,0 – 2,0 + 1,5 – 1,5 + 1,0 – 1,0 + 0,5 – 0,5 — — — reference — — — — + 2,0 Z + 2,0 – 2,0 + 1,5 – 1,5 + 1,0 – 1,0 + 0,5 – 0,5 — — — reference — — — — — — — — + 0,5 – 0,5 + 0,75 – 0,75 + 1,0 – 1,0 + 1,25 – 1,25 + 1,5 – 1,5 + 1,75 – 1,75 + 2,0 – 2,0 + 2,0 – 6,0 + 2,0 – 10,0 + 2,0 Z — 20 000 — 25 000 — 31 500 — 40 000 — — 50 000 — — > 50 000 — — © BSI 09-1999 Type WS3 — — + 0,5 – 0,5 + 0,75 – 0,75 + 1,0 – 1,0 + 1,25 – 1,25 + 1,5 – 1,5 + 1,75 – 1,75 + 2,0 – 2,0 + 2,0 – 6,0 + 2,0 – 10,0 + 2,0 Z EN 61094-4:1995 Annex A (informative) Provisional ground-shield reference configuration for type WS3 microphones According to IEC 1094-1 the open-circuit voltage of the microphone is measured by means of a specified ground-shield configuration For type WS1 and WS2 microphones the reference ground-shield configuration specified in IEC 1094-1 for laboratory standard microphones applies If the insert voltage technique is used to determine the sensitivity for a type WS3 microphone, the provisional ground-shield reference configuration shown below in Figure A.1 is recommended Figure A.1 — Mechanical attachment to microphone, showing the provisional ground-shield reference configuration for type WS3 microphones 10 © BSI 09-1999 EN 61094-4:1995 Annex ZA (normative) Normative references to international publications with their corresponding 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 (including amendments) NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies Publication Year Title EN/HD IEC 942 1988 Sound calibrators HD 556 S1 IEC 1094-1 1992 Measurement microphones Part 1: Specifications for laboratory standard microphones EN 61094-1 1994 IEC 1094-2 1992 Part 2: Primary method for pressure calibration of laboratory standard microphones by the reciprocity technique EN 61094-2 1993 IEC 1094-3 1995 Part 3: Primary method for free-field calibration of laboratory standard microphones by the reciprocity technique EN 61094-3 1995 ANSI B1.1 1982 Unified inch screw threads — — ISO 1983 Guide to the expression of uncertainty in measurement — — a EN Year 1991 a 61094-1 includes the corrigendum February 1993 to IEC 1094-1 © BSI 09-1999 11 12 blank BS EN 61094-4:1996 List of references See national foreword © BSI 09-1999 BS EN 61094-4:1996 IEC 1094-4: 1995 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