1、 STD-BSI BS EN IS0 9bL4-2-ENGL 1997 1b2qbbS ObOSbOL 3T3 BS EN IS0 96142 : 1997 BRITISH STANDARD Acoustics - Determination of sound power levels of noise sources using sound intensity Part 2. Measurement by scanning The European Standard EN IS0 96142 : 1996 has the status of a British Standard ICs 17
2、.140.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD-BSI BS EN IS0 SbLq-Z-ENGL 2997 = lb24bb9 Ob05b0Z 23T = issue BS EN IS0 9614-2 : 1997 ; This British Standard, having been prepared under the direction of the Health and Enwonment Sector Board, was published under the
3、authority of the Standards Board and comes into effect on 15 April 1997 O BSI 1997 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EW1, Acoustics, upon which the following bodies were represented Association of Consuiting
4、 Engineers British Broadcasting Corporation British Occupational Hygiene Society British Telecommunications plc Department of the Environment (Building Research Establishment) Department of Heaith Health and Safety Executive institute of Acoustics institute of occupational Hygienists institute of So
5、und and Vibration Research institution of Electrical Engineem National Physical Laboratory Royal institute of British Architects Society of Environmental Engineers The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Advanced Manufacturing Tec
6、hnology Research Institute Agricuitural Engineers Association British Cement Association British Compressed Air Society British Industrial Truck Association British iron and Steel Producers Association Construction industry Research and Information Association Engineering Industries Association Fan
7、Manufacturers Association Federation of the Electronics Industry Federation of Manufacturers of Construction Equipment and Cranes Federation of Piling Specialists Hevac Association institution of Engineering Designers Institution of Mechanical Engineers National Engineering Laboratory National Speci
8、alist Contractors Council Rotating Electrical Machines Association University of Liverpool University of Manchester Amendments issued since publication Amd No. 1 DGg Text affected The foliowing BSI references relate to the work on this I I standard: Committee reference: EW1 Draft for comment W502144
9、 DC ISBN O 580 26658 3 STD.BSI BS EN IS0 SbLq-Z-ENGL 1797 Lb24bb7 Ob05b03 L7b = BS EN IS0 9614-2 : 1997 National foreword This British Standard has been prepared by Technical Committee EW1 and is the English iangUage version of EN IS0 96142 : 1996 Acoust+Detmnin.ut.ion of sound power levels of noise
10、 sources using sound intensitpPart 2 : Measurement by scanning, published by the European Committee for Standardization (CEN), which is identical with IS0 96142 : 1996 published by the International Organization for Stzm-on (ISO). Cross-reference IEC 942 : 1988 Publieution referred to Corresponding
11、British Standard BS 7189 : 1989 Speckation for sound calibmtors Compliance with a British Standard does not of itself confer immunity from legal obligations. * u) * Summary of pages This document comprises a fiont cover, an inside front cover, pages i and ii, the EN IS0 titie page, the EN IS0 forewo
12、rd, the IS0 title page, pages ii to iv, pages 1 to 20, an inside back cover and a back cover. O BSI 1997 i EUROPEAN STANDARD NORME EUROPEENNE EUROPISCHE NORM EN IS0 9614-2 August 1996 ICs 17.160.00 Descriptors: See IS0 document English version Acoustics - Determination of sound power levels of noise
13、 sources using sound intensity - Part 2: Measurement by scanning (IS0 961 4-2: 1 996) Acoustique - DCtermination par ntensidtrie des niveaux de puissance acoustique mis par les sources de bruit - Partie 2: Hesurage par balayage (IS0 9614-2:1996) Akustik - Bestinnung der Schalleistungspegel von Gerus
14、chquellen durch Schallintensittsmessung - Teil 2: Hessig mit kontinuierlicher Abtastung (IS0 9614-2:1996) This European Standard was approved by CEN on 1996-05-19. CEN members are bound to canply with the CENKENELEC Internal Regulations uhich stipulate the conditions for giving this European Standar
15、d 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 CEN menber. lhe European Standards exist in three official versions (English, French, Ger
16、man). A version in any other language made by translation under the responsibility of a CEN mmiber into its own language and notified to the Central Secretariat has the senr status 8s the official versions. CEN members are the national standards bodies of Austria, Belgiun, Dermark, Finland, France,
17、Germany, Greece, Iceland, Ireland, Italy, Luxnibourg, Netherlands, Norway, Portugal, Spain, Sweden. Switzerland and United Kingdom. CEN European Cmittee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: ne de Stassart.36 B-1050 Brussels 0 1996 Cop
18、yright reserved to CEN mmikrs Ref. NO. EN IS0 9614-2:1996 E EN IS0 9614-2 : 1996 Foreword The text of the International Standard IS0 961 4-2: 1996 has been prepared by Technical Committee ISO/TC 43 “Acoustics“ in collaboration with Technical Committee CEN/TC 2 1 1 “Acoustics“, the secretariat of whi
19、ch 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 February 1997, and conflicting national standards shall be withdrawn at the latest by February 1997. According to the CENKENELEC I
20、nternal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the Unit
21、ed Kingdom. Endorsement notice The text of the International Standard IS0 961 4-2:1996 was approved by CEN as a European Standard without any modification. EN IS0 9614-2 : 1996 I NTERNATI O NAL STANDARD IS0 961 412 First edition 1996-08-01 Acoustics - Determination of sound power levels of noise sou
22、rces using sound intensity - Part 2: Measurement by scanning Acoustique - Dtermination par intensimtrie des niveaux de puissance acoustique mis par les sources de bruit - Partie 2: Mesurage par balayage Reference number IS0 9614-211 996(E) STDmBSI BS EN IS0 SbLq-Z-ENGL 1777 m LbZ4bbS Ob05b07 ALL m E
23、N IS0 9614-2 : 1996 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a s
24、ubject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and nongovernmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (
25、IEC) on all matters of electrotechnical standardization. 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. International St
26、andard IS0 961 4-2 was prepared by Technical Committee iSO/TC 43, Acoustics, Subcommittee SC 1, Noise. IS0 9614 consists of the following parts, under the general title Acoustics - Determination of sound power levels of noise sources using sound intensity - Part 1 : Measurement at discre te points -
27、 Part 2: Measurement by scanning - Part 3: Precision method for measurement by scanning Annexes A and B form an integral part of this part of IS0 9614. Annexes C, D, E and F are for information only. D.rcriptot.: aroustics, sound sources, noise (sound), tests, acoustic tests, determination, sound po
28、wer, acoustic measurements. II STD-ES1 BS EN IS0 SbLi-Z-ENGL 1777 Lb2LlbbS Ob05b08 758 EN IS0 9614-2 : 1996 Introduction 0.1 The sound power radiated by a source is equal in value to the inte gral of the scalar product of the sound intensity vector and the associated elemental area vector over any s
29、urface totally enclosing the source. Pre- vious International Standards which describe methods of determination of sound power levels of noise sources, principally IS0 3740 to IS0 3747, without exception specify sound pressure level as the primary acoustic quantity to be measured. The relationship b
30、etween sound intensity level and sound pressure level at any point depends on the characteristics of the source, the characteristics of the measurement environment, and the disposition of the measurement positions with respect to the source. Therefore IS0 3740 to IS0 3747 necessarily specify the sou
31、rce charac- teristics, the test environment characteristics and qualification procedures, together with measurement methods which are expected to restrict the uncertainty of the sound power level determination to within acceptable limits. The procedures specified IS0 3740 to IS0 3747 are not always
32、appropri- ate, for the following reasons. a) Costly facilities are necessary if high precision is required. It is fre- quently not possible to install and operate large pieces of equipment in such facilities. b) They cannot be used in the presence of high levels of extraneous noise generated by sour
33、ces other than that under investigation. 0.2 This part of IS0 9614 specifies methods of determining the sound power levels of sources, within specific ranges of uncertainty, under test conditions which are less restricted than those required by IS0 3740 to IS0 3747. The sound power level is the in s
34、itu sound power level as de- termined by the procedure of this part of IS0 9614; it is physically a function of the environment, and may in some cases differ from the sound power level of the same source determined under other conditions. It is recommended that personnel performing sound intensity m
35、eas- urements according to this part of IS0 9614 are appropriately trained and experienced. 0.3 This part of IS0 9614 complements IS0 9614-1 and the series IS0 3740 to IS0 3747 which specify various methods for the determi- nation of sound power levels of machines and equipment. It differs from the
36、IS0 3740 to IS0 3747 series principally in three aspects: . 111 STD.BS1 BS EN IS0 SbL4-2-ENGL 1977 m Lb24bb Ob05b09 b94 H EN IS0 9614-2 : 1996 measurements are made of sound intensity as well as of sound pressure; the uncertainty of the sound power level determined by the method specified in this pa
37、rt of IS0 9614 is classified according to the results of specified ancillary tests and calculations performed in association with the test measurements; current limitations of intensity measurement equipment which con- forms to IEC 1043 restricts measurements to the one-third-octave range 50 Hz to 6
38、,3 kHz; band-limited A-weighted values are deter- mined from the constituent one-octave or one-third-octave band values and not by direct A-weighted measurement. 0.4 The integral over any surface totally enclosing the source of the scalar product of the sound intensity vector and the associated elem
39、ental area vector provides a measure of the sound power radiated directly into the air by all sources located within the enclosing surface and excludes sound radiated by sources located outside this surface. In practice, this exclusion is effective only if the source under test and other sources of
40、extraneous intensity on the measurement surface are stationary in time. In the presence of sound sources operating outside the measurement surface, any system lying within the surface may absorb a proportion of energy incident upon it. The total sound power absorbed within the measurement surface wi
41、ll appear as a negative contribution to source power, and may produce an error in the sound power determination. In order to minimize the associated error, it is therefore necessary to remove any soundabsorbing material lying within the measurement surface which is not normally present during the op
42、eration of the source under test. This method is based on sampling of the intensity field normal to the measurement surface by moving an intensity probe continuously along one or more specified paths. The resulting sampling error is a function of the spatial variation of the normal intensity compone
43、nt over the meas- urement surface, which depends upon the directivity of the source, the chosen sampling surface, the pattern and speed of the probe scan- ning, and the proximity of extraneous sources outside the measurement s urface. The accuracy of measurement of the normal component of sound inte
44、n- sity at a position is sensitive to the difference between the local sound pressure level and the local normal sound intensity level. A large difference may occur when the intensity vector at a measurement position is directed at a large angle (approaching 90“) to the local normal to the measureme
45、nt surface. Alternatively, the local sound pressure level may contain strong contributions from sources outside the measurement surface, but may be associated with little net sound energy flow, as in a reverberant field in an enclosure; or the field may be strongly reactive because of the pres- ence
46、 of the near field and/or standing waves, The accuracy of determination of sound power level is adversely affected by a flow of sound energy into the volume enclosed by the measurement surface through a portion of that surface, even though it is, in principle, compensated by increased flow out of th
47、e volume through the remaining portion of the surface. This condition is caused by the presence of a strong extraneous source close to, but outside, the measurement surface. iv EN IS0 9614-2 : 1996 Acoustics - Determination of sound power levels of noise sources using sound intensity - Part 2: Measu
48、rement by scanning 1 Scope dicated quality of the determination does not meet the requirements of this part of IS0 9614, the test procedure is to be modified in the manner indicated. 1.1 This part of IS0 9614 specifies a method for - .I e e - measuring the Component Of sound intensin/ nOrf-11 to a s
49、o as to enclose the noise source(s) of which the sound power level is to be determined. This part of IS0 9614 does not apply in any frequency band in which the sound power of the source is found to be negative on measurement. which is 7 _. - * * Surface integration of the intensity component normal to the measurement surface is approximated by sub- 10 dividing the measurement surface into contiguous segments, and scanning the intensity probe over each segment along a continuous path which covers the extent of the segment. The measurement instrument determines the
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