BS-EN-ISO-6926-2001.pdf

BRITISH STANDARD BS EN ISO 6926:2001 Incorporating Amendment No. 1 to BS ISO 6926:1999 (renumbers the BS ISO as BS EN ISO 6926:2001) Acoustics Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels The European Standard EN ISO 6926:2001 has the status of a British Standard ICS 17.140.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 6926:2001 This British Standard, having been prepared under the direction of the Health and Environment Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 February 2000 © BSI 25 June 2002 ISBN 0 580 34043 0 National foreword This British Standard is the official English language version of EN ISO 6926:2001. It is identical with ISO 6926:1999. The UK participation in its preparation was entrusted by Technical Committee EH/1, Acoustics, to Subcommittee EH/1/4, Machinery noise, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Textual error The textual error set out below was discovered when the English language version of EN ISO 6926:2001 was adopted as the national standard. It has been reported to CEN in a proposal to amend the text of the European standard. In all three language versions of the title on the EN ISO title page, read ISO 6926:2000 as ISO 6926:1999. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. 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. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii to v, a blank page, pages 1 to 11 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments 1340425 June 2002Implementation of the European Standard Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN ISO 6926 July 2001 ICS 17.140.01 English version Acoustics - Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels (ISO 6926:2000) Acoustique - Exigences relatives aux performances et à l'étalonnage des sources sonores de référence utilisées dans la détermination des niveaux de puissance sonore (ISO 6926:2000) Akustik - Anforderungen an die Eigenschaften und die Kalibrierung von Vergleichsschallquellen für die Bestimmung von Schallleistungspegeln (ISO 6926:2000) This European Standard was approved by CEN on 9 June 2001. 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 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 Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels © 2001 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6926:2001 E Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI I NESO 96:6202( 10E) 2 Foreword The text of the International Standard from Technical Committee ISO/TC 43 “Acoustics“ of the International Organization for Standardization (ISO) has been taken over as an European Standard by Technical Committee CEN/TC 211 “Acoustics“, the secretariat of which is held by DS. 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 January 2002, and conflicting national standards shall be withdrawn at the latest by January 2002. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. NOTE FROM CMC The foreword is susceptible to be amended on reception of the German language version. The confirmed or amended foreword, and when appropriate, the normative annex ZA for the references to international publications with their relevant European publications will be circulated with the German version. Endorsement notice The text of the International Standard ISO 6926:1999 has been approved by CEN as a European Standard without any modification. NOTE Normative references to International Standards are listed in annex ZA (normative). EN ISO 6926:2001 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 6926:1999(E) INTERNATIONAL STANDARD ISO 6926 Second edition 1999-12-01 Acoustics Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels Acoustique Exigences relatives aux performances et à l'étalonnage des sources sonores de référence utilisées dans la détermination des niveaux de puissance sonore EN ISO 6926:2001 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2966:(9991)E ?iii Contents?Page Foreword.iv Introduction.v 1?Scope 1 2?Normative references1 3?Terms and definitions .2 4?Measurement uncertainty.4 5?Performance requirements.5 5.1?General5 5.2?Temporal steadiness and repeatability of sound power output.5 5.3?Total broad-band sound power level.5 5.4?Spectral characteristics 5 5.5?Directivity index.6 5.6?Recalibration6 6?Installation and operation of the reference sound source during calibration 6 6.1?General6 6.2?Position of the reference source7 7?Calibration procedure in hemi-anechoic rooms.7 7.1?Test environment.7 7.2?Microphone.7 7.3?Microphone positions .7 7.4?Measurements8 7.5?Air absorption 8 7.6?Calculations8 8?Calibration procedure in reverberation rooms.9 8.1?Test environment.9 8.2?Microphone.9 8.3?Microphone positions .9 8.4?Measurements9 8.5?Calculations9 9?Information to be recorded.10 10?Information to be reported10 Bibliography11 EN ISO 6926:2001 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2966:(9991)E iv? Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 6926 was prepared by Technical Committee ISO/TC 43,Acoustics, Subcommittee SC 1,Noise. This second edition cancels and replaces the first edition (ISO 6926:1990), which has been technically revised. EN ISO 6926:2001 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 2966:(9991)E ?v Introduction Reference sound sources are used extensively in “comparison methods“ for determining the noise emissions of physically stationary sound sources. A reference sound source, of known sound power output, is used to establish the numerical relationship between the sound power level of a source, in a given location in a given acoustical environment and the space- and time-averaged sound pressure level at a set of microphone positions. Once that relationship is established, it is straightforward to measure the average sound pressure level produced by an “unknown source“ and to determine the sound power level produced by that source. This International Standard defines the important physical and performance characteristics of reference sound sources and specifies procedures for their calibration, primarily to determine the sound power level of other sound sources. This International Standard supplements a series of International Standards, the ISO 3740 series, that describes various methods for determining the sound power levels of machines and equipment. This series specifies the acoustical requirements for measurements that are appropriate for different test environments. Five International Standards in the ISO 3740 series include procedures in which a reference sound source is used: ISO 3741, ISO 3743, ISO 3744, ISO 3746 and ISO 3747. ISO 3740 gives guidelines for the use of all the International Standards in the series. It should be noted that the sound power output of reference sound sources will vary, in particular at low frequencies, with the distance from the source to nearby reflecting planes. Sound power data of reference sound sources are thus valid only for the position used during the calibration. In addition to being useful for determining sound power levels by the comparison method, reference sound sources may be used for qualification tests on an acoustic environment and to estimate the influence of an acoustic environment on the sound pressure levels produced by one or more sound sources located in that environment. Examples of International Standards referring to reference sound sources with these applications are ISO 11690-3 and ISO 14257. Requirements other than those of this International Standard may be applicable in these cases. EN ISO 6926:2001 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank 1002:6296 OSI NE Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 07:01:57 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDADR?ISO 6296:(9991)E ?1 Acoustics Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels 1?Scope This International Standard specifies the acoustical performance requirements for reference sound sources: ?temporal steadiness and repeatability of the sound power output, ?spectral characteristics, ?directivity index. The stability of the sound power output and the directivity index, for those sources where directivity is needed, are normally only determined in connection with pattern evaluation of the reference sound source. Because of the directivity measurements (for an exception see 5.5), pattern evaluations can only be performed in a hemi-anechoic environment. For regular verification measurements, only the frequency band sound power levels are normally determined. In this case measurements may be made in either hemi-anechoic or reverberant conditions. This International Standard also specifies procedures for calibrating a sound source intended for use as a reference sound source in terms of its sound power level under the reference condition that the characteristic impedance of air (?c) is equal to 400 Ns/m3in octave and in one-third-octave bands, and with frequency weighting A. Different procedures are specified for pattern evaluation and verification. NOTE?Reference sound sources may also be used for measurements in one-half-octave bands, e.g. for ISO 9295. However, under these circumstances the stability and reproducibility limits stated in this International Standard will not apply. This International Standard specifies methods to calibrate reference sound sources not only in a free field over a reflecting plane but also in reverberation rooms at different distances from the boundary surfaces. For the position of the reference sound source on one reflecting plane, the two different test environments mentioned above are considered equivalent for frequency bands above or equal to 100 Hz. Below 100 Hz the measurement uncertainties are significantly different (see Table 1). This International Standard is applicable to a sound source which is intended for use as a reference sound source. The sound source may either be placed directly on the floor or mounted on a stand to be used at a certain elevation above the floor. For floor-mounted sources, this International Standard is valid only for sources whose maximum vertical dimension is less than 0,5 m and whose maximum horizontal dimension is less than 0,8 m. According to this International Standard on