ASA S12 53 PART 1-2011 Acoustics C Determination of sound power levels and sound energy levels of noise sources using sound pressure C Engineering methods for small movable sources.pdf

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1、ANSI/ASA S12.53-2011/Part 1 / ISO 3743-1:2010 DUHYLVLRQRI$16,63DUW,62 $0(5, ANSI/ASA S12.50/ISO 3740 is an identical national adoption of ISO 3740; ANSI/ASA S12.51/ISO 3741 is an identical national adoption of ISO 3741; ANSI/ASA S12.53/Part 1/ISO 3743-1 is an identical national adoption of ISO 3743-

2、1; ANSI/ASA S12.53/Part 2/ISO 3743-2 is an identical national adoption of ISO 3743-2; ANSI/ASA S12.54/ISO 3744 is an identical national adoption of ISO 3744; ANSI S12.55/ISO 3745 is an identical national adoption of ISO 3745; ANSI S12.56/ISO 3746 is an identical national adoption of ISO 3746; and AN

3、SI/ASA S12.57/ISO 3747 is an identical national adoption of ISO 3747. At the time this Standard was submitted to Accredited Standards Committee S12, Noise for approval, the membership was as follows: W.J. Murphy, Chair R.D. Hellweg, Vice-Chair S.B. Blaeser, Secretary 3M Occupational Health FAX: 631-

4、390-0217; E-mail: asastdsaip.org. 2011 Acoustical Society of AmericaAll rights reserved. vii Introduction This American National Standard is a national adoption of one of the series ISO 37401to ISO 37477, which specify various methods for determining the sound power levels and sound energy levels of

5、 noise sources including machinery, equipment and their sub-assemblies. The selection of one of the methods from the series for use in a particular application depends on the purpose of the test to determine the sound power level or sound energy level and on the facilities available. General guideli

6、nes to assist in the selection are provided in ISO 37401. ISO 37401to ISO 37477give only general principles regarding the operating and mounting conditions of the machinery or equipment for the purposes of the test. It is important that test codes be established for individual kinds of noise source,

7、 in order to give detailed requirements for mounting, loading, and operating conditions under which the sound power levels or sound energy levels are to be obtained. The method given in this part of ISO 3743 is based on a comparison of the sound pressure levels in octave frequency bands of a noise s

8、ource under test with those of a calibrated reference sound source; A-weighted sound power levels or sound energy levels may be calculated from the octave-band levels. The method is applied in a hard-walled test room with prescribed acoustical characteristics, where it can be used for small items of

9、 portable equipment. Such a room allows either the sound power levels or the sound energy levels of the noise source under test to be determined, depending on the character of the noise emitted by the source. However, this kind of test room is not suitable for larger pieces of stationary equipment w

10、hich, due to their manner of operation or installation, cannot readily be moved. The application of the method for use where the equipment or machinery is found in situ is described in ISO 37477. The methods specified in this part of ISO 3743 permit the determination of the sound power level and the

11、 sound energy level in frequency bands and/or with frequency A-weighting applied. This part of ISO 3743 describes a method of accuracy grade 2 (engineering grade) as defined in ISO 12001. For applications where greater accuracy is required, reference can be made to ISO 37412or an appropriate part of

12、 ISO 96141517. If the relevant criteria for the measurement environment specified in this part of ISO 3743 are not met, it might be possible to refer to another standard from this series, or to an appropriate part of ISO 96141517. AMERICAN NATIONAL STANDARD ANSI/ASA S12.53-2011/Part 1 / ISO 3743-1:2

13、010 2011 Acoustical Society of AmericaAll rights reserved. 1 American National Standard Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Engineering methods for small movable sources in reverberant fields, Part 1: Comparison method for a har

14、d-walled test room 1 Scope 1.1 General This part of ISO 3743 specifies methods for determining the sound power level or sound energy level of a noise source by comparing measured sound pressure levels emitted by this source (machinery or equipment) mounted in a hard-walled test room, the characteris

15、tics of which are specified, with those from a calibrated reference sound source. The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level) produced by the noise source, in frequency bands of width one octave, is calculated using those measurements.

16、The sound power level or sound energy level with A-weighting applied is calculated using the octave-band levels. 1.2 Types of noise and noise sources The method specified in this part of ISO 3743 is suitable for all types of noise (steady, non-steady, fluctuating, isolated bursts of sound energy, et

17、c.) defined in ISO 12001. The noise source under test may be a device, machine, component or sub-assembly. The maximum size of the source depends upon the size of the room used for the acoustical measurements (see 4.2). 1.3 Test environment The test environment that is applicable for measurements ma

18、de in accordance with this part of ISO 3743 is a hard-walled test room with prescribed acoustical characteristics. 1.4 Measurement uncertainty Information is given on the uncertainty of the sound power levels and sound energy levels determined in accordance with this part of ISO 3743, for measuremen

19、ts made in frequency octave bands and for A-weighted frequency calculations performed on them. The uncertainty conforms to ISO 12001:1996, accuracy grade 2 (engineering grade). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated

20、 references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ANSI/ASA S12.53-2011/Part 1 / ISO 3743-1 2 2011 Acoustical Society of AmericaAll rights reserved. ISO 5725 (all parts), Accuracy (trueness and precis

21、ion) of measurement methods and results ISO 6926, Acoustics Requirements for the performance and calibration of reference sound sources for the determination of sound power levels ISO 12001:1996, Acoustics Noise emitted by machinery and equipment Rules for the drafting and presentation of a noise te

22、st code ISO/IEC Guide 98-3, Uncertainty in measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) IEC 60942:2003, Electroacoustics Sound calibrators IEC 61260:1995, Electroacoustics Octave-band and fractional-octave-band filters IEC 61672-1:2002, Electroacoustics Sound

23、level meters Part 1: Specifications 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 sound pressure p difference between instantaneous pressure and static pressure NOTE 1 Adapted from ISO 80000-8:200719, 8-9.2. NOTE 2 Sound pressure is express

24、ed in pascals. 3.2 sound pressure level Lpten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of a reference value, p0, expressed in decibels 22010lg dBppLp (1) where the reference value, p0, is 20 Pa ISO/TR 25417:200718, 2.2 NOTE 1 If specific f

25、requency and time weightings as specified in IEC 61672-1 and/or specific frequency bands are applied, this is indicated by appropriate subscripts; e.g. LpAdenotes the A-weighted sound pressure level. NOTE 2 This definition is technically in accordance with ISO 80000-8:200719, 8-22. ANSI/ASA S12.53-2

26、011/Part 1 / ISO 3743-1 2011 Acoustical Society of AmericaAll rights reserved. 3 3.3 time-averaged sound pressure level Lp,Tten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p, during a stated time interval of duration, T (starting at t1and

27、ending at t2), to the square of a reference value, p0, expressed in decibels 212,201()d10 lg dBttpTpttTLp(2) where the reference value, p0, is 20 Pa NOTE 1 In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily determined over a certain measurement time in

28、terval. NOTE 2 Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by LpA,T, which is usually abbreviated to LpA. NOTE 3 Adapted from ISO/TR 25417:200718, 2.3. 3.4 single event time-integrated sound pressure level LEten times the logarithm to the base 10 of the r

29、atio of the integral of the square of the sound pressure, p, of an isolated single sound event (burst of sound or transient sound) over a stated time interval T (starting at t1and ending at t2) to a reference value, E0, expressed in decibels 2120()d10 lg dBttEpt tLE(3) where the reference value, E0,

30、 is (20 Pa)2s = 4 1010Pa2s NOTE 1 This quantity can be obtained by ,010lg dBpTTLT , where T0= 1 s NOTE 2 When used to measure sound immission, this quantity is usually called “sound exposure level” (see ISO/TR 25417:200718). 3.5 measurement time interval T portion or a multiple of an operational per

31、iod or operational cycle of the noise source under test for which the time-averaged sound pressure level is determined ANSI/ASA S12.53-2011/Part 1 / ISO 3743-1 4 2011 Acoustical Society of AmericaAll rights reserved. NOTE Measurement time interval is expressed in seconds. 3.6 comparison method metho

32、d by which the sound power level or sound energy level of a noise source under test is determined from a comparison of the sound pressure levels produced by the source under test with those of a reference sound source of known sound power output, when both sources are operated in the same environmen

33、t 3.7 hard-walled test room room in which the acoustical reflectivity of all room surfaces (including the floor and ceiling) is high over the frequency range of interest 3.8 reverberant sound field that portion of the sound field in the test room over which the influence of sound received directly f

34、rom the source is negligible 3.9 sound absorption coefficient at a given frequency and for specified conditions, the relative fraction of sound power incident upon a surface which is not reflected 3.10 reference sound source sound source meeting specified requirements NOTE For the purposes of this A

35、merican National Standard, the requirements are those specified in ISO 6926:1999, Clause 5. 3.11 frequency range of interest for general purposes, the frequency range of octave bands with nominal mid-band frequencies from 125 Hz to 8,000 Hz NOTE For special purposes, the frequency range can be reduc

36、ed, provided that the test environment, reference sound source, and instrument specifications are satisfactory for use over the modified frequency range. The frequency range can be extended downwards as far as the 63 Hz octave band, but cannot be extended upwards beyond the 8,000 Hz band. Any reduce

37、d or extended frequency range is clearly indicated as such in the report. 3.12 reference box hypothetical right parallelepiped terminating on the floor of the test room on which the noise source under test is located, that just encloses the source including all the significant sound radiating compon

38、ents and any test table on which the source is mounted NOTE If required, the smallest possible test table can be used for compatibility with emission sound pressure measurements at bystander positions in accordance with the ISO 11200 to ISO 11204 series. 3.13 background noise noise from all sources

39、other than the noise source under test ANSI/ASA S12.53-2011/Part 1 / ISO 3743-1 2011 Acoustical Society of AmericaAll rights reserved. 5 NOTE Background noise includes contributions from airborne sound, noise from structure-borne vibration, and electrical noise in the instrumentation. 3.14 backgroun

40、d noise correction K1correction applied to the measured sound pressure levels to account for the influence of background noise NOTE 1 Background noise correction is expressed in decibels. NOTE 2 The background noise correction is frequency dependent; the correction in the case of a frequency band is

41、 denoted K1f, where f denotes the relevant mid-band frequency, and that in the case of A-weighting is denoted K1A. 3.15 sound power P through a surface, product of the sound pressure, p, and the component of the particle velocity, un, at a point on the surface in the direction normal to the surface,

42、 integrated over that surface ISO 80000-8:200719, 8-16 NOTE 1 Sound power is expressed in watts. NOTE 2 The quantity relates to the rate per time at which airborne sound energy is radiated by a source. 3.16 sound power level LWten times the logarithm to the base 10 of the ratio of the sound power of

43、 a source, P, to a reference value, P0, expressed in decibels 010lg dBWPLP (4)where the reference value, P0, is 1 pW NOTE 1 If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands are applied, this should be indicated by appropriate subscripts; e.g. LWAdenotes t

44、he A-weighted sound power level. NOTE 2 This definition is technically in accordance with ISO 80000-8:200719, 8-23. ISO/TR 25417:200718, 2.9 3.17 sound energy J integral of the sound power, P, over a stated time interval of duration T (starting at t1and ending at t2) 21()dttJ Pt t(5) ANSI/ASA S12.53

45、-2011/Part 1 / ISO 3743-1 6 2011 Acoustical Society of AmericaAll rights reserved. NOTE 1 Sound energy is expressed in joules. NOTE 2 The quantity is particularly relevant for non-stationary, intermittent sound events. ISO/TR 25417:200718, 2.10 3.18 sound energy level LJten times the logarithm to th

46、e base 10 of the ratio of the sound energy, J, to a reference value, J0, expressed in decibels 010 lg dBJJLJ (6) where the reference value, J0, is 1 pJ NOTE If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands are applied, this should be indicated by appropri

47、ate subscripts; e.g., LJAdenotes the A-weighted sound energy level. ISO/TR 25417:200718, 2.11 4 Test room and size of noise source under test 4.1 Reference box In order to assist in specification of the size of the test room, the reference box shall first be delineated. The reference box is a hypoth

48、etical surface defined by the smallest right parallelepiped that just encloses the noise source under test. The noise source under test shall be taken to include all significant sources of sound emission, including auxiliary equipment which cannot either be removed or adequately quieted, and the ref

49、erence box shall be extended appropriately. When defining the dimensions of the reference box, elements protruding from the source which are not significant radiators of sound may be disregarded. 4.2 Volume of test room and size of noise source under test The volume of the test room shall be at least 40 m3, and at least 40 tim