ANSI S12.53 2-1999 Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for small movable sources in reverberant fields - Par.pdf

1、ANSI S12.5312-I999 IS0 3743-2: 1994 AMERICAN NATIONAL STANDARD Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for small, movable sources in reverberant fields = Part 2: Methods for special reverberation test rooms (A Nationally Adopted Int

2、ernational Standard) Accredited Standards Committee SI 2, Noise Standards Secretariat Acoustical Society of America 35 Pinelawn Road, Suite 114 E Melville, NY 1 1747-31 77 Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permit

3、ted without license from IHS-,-,-The American National Standards Institute, Inc. (ANSI) is the national coordinator of voluntary standards development and the clearinghouse in the U.S.A. for information on national and international standards. The Acoustical Society of America (ASA) is an organizati

4、on of scientists and engineers formed in 1929 to increase and diffuse the knowledge of acoustics and to promote its practical applications. Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,

5、-ANSI S12.53/2-1999 IS0 3?43-2:1994 AMERICAN NATIONAL STANDARD Acoustics-Determination of sound power levels of noise sources using sound pressure-Engineering methods for small, movable sources in reverberant fields- Part 2: Methods for special reverberation test rooms (A Nationally Adopted Internat

6、ional Standard) Secretariat Acoustical Society of America (ASA) Approved 18 October 1999 American National Standards Institute, Inc. (ANSI) Abstract IS0 3743 is one of the IS0 3740 series, which specifies various methods for determining the sound power levels of machines, equipment and sub-assemblie

7、s. These basic standards specify the acoustical requirements for measurements appropriate for different test environments as shown in table 0.1. When selecting one of the methods of the IS0 3740 series, it is necessary to select the most appropriate for the conditions and purposes of the noise test.

8、 General guidelines to assist in the selection are provided in IS0 3740. The IS0 3740 series gives only general principles regarding the operating and mounting conditions of the machine or equipment under test. Reference should be made to the noise test code for a specific type of machine or equipme

9、nt, if available, for specifications on mounting and operating conditions. Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AMERICAN NATIONAL STANDARDS ON ACOUSTICS The Acoustical Society

10、of America (ASA) provides the Secretariat for Accredited Standards Committees S1 on Acoustics, S2 on Mechanical Vibration and Shock, S3 on Bioacoustics, and S12 on Noise. These committees have wide represen- tation from the technical community (manufacturers, consumers, and general- interest represe

11、ntatives). The standards are published by the Acoustical Society of America through the American Institute of Physics as American National Stan- dards after approval by their respective standards committees and the American National Standards Institute. These standards are developed and published as

12、 a public service to provide standards useful to the public, industry, and consumers, and to Federal, State, and local governments. Each of the Accredited Standards Committees operating in accordance with pro- cedures approved by American National Standards Institute (ANSI) is responsible for develo

13、ping, voting upon, and maintaining or revising its own standards. The ASA Standards Secretariat administers committee organization and activity and provides liaison between the Accredited Standards Committees and ANSI. After the standards have been produced and adopted by the Accredited Standards Co

14、mmittees, and approved as American National Standards by ANSI, the ASA Standards Secretariat arranges for their publication and distribution. An American National Standard implies a consensus of those substantially con- cerned with its scope and provisions. Cnsensus is established when, in the judgm

15、ent of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consen- sus requires that all views and objections be considered and that a co

16、ncerted effort be made towards their resolution. The use of American National Standards is completely voluntary. Their existence does not in any respect preclude anyone, whether he or she has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or p

17、rocedures not conforming to the standards. NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this Standard. Standards Secretariat Acou

18、stical Society of America 120 Wall Street, 32nd Floor New York, New York 10005-3993 USA Telephone: + 1 21 2 248 0373 Telefax: +1 212 248 0146 E-mail: asastds aip.org Q 1999 by the Acoustical Society of America. This Standard may not be reproduced in whole or in pari in any form for sale, promotion,

19、or any commercial purpose, or any purpose not falling within the provisions of the Copyright Act of 1976, without prior written pemission of the publisher. For permission, address a request to the Standards Secretariat of the Acoustical Society of America. These materials are subject to copyright cl

20、aims of ISO, IEC, ANSI, and ASA. No part of this publication may be reproduced in any form, including an electronic retrieval system, without the prior written perm,ission of the Acoustical Society of America (ASA). All requests per- taining to this standard should be submitted to the Acoustical Soc

21、iety of America (ASA). Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Contents Page Foreword ii Introduction . V 1 Scope 1 2 Normative references 3 3 Definitions 3 4 Requirements for spe

22、cial reverberation test room . 3 5 Instrumentation . 5 6 Installation and operation of source under test 6 7 Measurements in test room . 8 Calculation of sound power levels . 10 9 Information to be recorded . 11 1 O Information to be reported 11 Annexes A Characteristics and calibration of reference

23、 sound source . 12 8 Guidelines for the design of special reverberation test rooms 13 C Examples of suitable instrumentation systems . 18 D Bibliography . 20 7 Fig u res 1 V=70 m3 4 8.1 Hardboard membrane absorber 14 8.2 Sound absorption coefficient (Y for the membrane absorber measured in a 200 m3

24、reverberation room . 14 8.3 Limiting curves for the ratio of the reverberation time T to the nominal reverberation time Trim for a 70 m3 room 16 8.4 Plot of an experimentally determined reverberation time (normalized to T, ooo) as a function of one-third-octave-band centre frequency . 17 Tables 0.1

25、International Standards specifying various methods for determining the sound power levels of machines and equipment vii 1 Estimated values of the standard deviation of reproducibility of sound power levels determined according to this part of IS0 3743 3 Maximum permitted differences between octave-b

26、and power levels of broad-band noise sources measured in accordance Values of R at the one-third-octave-band centre frequencies for 2 with 4.7 a) . 5 3 Relative tolerances for the instrumentation system . 6 4 Minimum number of source locations, N, , for given numbers of microphone positions, Nm , va

27、lues of estimated standard deviations, Sm , and octave-band centre frequencies 8 5 Corrections for background sound pressure levels 1 O A.l Calibration accuracy for reference sound source . 12 8.1 Recommended room dimension ratios for rectangular rooms 13 i Copyright Acoustical Society of America Pr

28、ovided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword This Foreword is not part of the Nationally Adopted Intemational Standard (NAIS), Acoustics -Determination of sound power levels of noise sources using sound pressure - Eng

29、ineering methods for small, movable soutces in reverberant fields - Part 2: Methods for special reverberation test rooms, ANSI C12.53/2-1999, IC0 3743-23 994.1 This Nationally Adopted Intemational Standard (NAIS) comprises a part of a group of definitions, standards, and specifications for use in ac

30、oustical work. It has been adopted by the American National Standards Institute utilizing the Accredited Standards Committee Procedure, under the Secretariat of the Acoustical Society of America. Accredited Standards Cornmittee S12, Noise, under whose jurisdiction this NAIS Standard was adopted, has

31、 the following scope: Standards, specifications, and terminology in the field of acoustical noise pertaining to methods of measurement, evaluation, and control; including biological safey, tolerance and comfort, and physical acoustics as related to environmental and occupational noise. This standard

32、 is in harmony with Intemational Standard IS0 3743-2:1994, Acoustics-Determination of sound power levels of noise sources using sound pressure-Engineering methods for small, movable sources in reverberant fieids-Part 2: Methods for special reverberation test rooms, which was developed by Working Gro

33、up 28 of Technical Committee 43ISubcommittee 1 of the Intema- tional Organization for Standardization (ISOflC 43/SC 1MIG 28). At the time this NAIS Standard was submitted to Accredited Standards Committee S12, Noise, for final approval, the membership was as follows: P. D. Schomer, Chair R. D. Hellw

34、eg, Vice Chair A. Brenig, Secretary Abbott Laboratories., . D. Walton B. Muto (Alt.) Acoustical Society of America . B. M. Brooks W. J. Galloway (Alt.) Acoustical Systems, Inc. R. Goodwin R. Seitz (Alt.) Air Conditioning FAX: + 1 21 2 248 0146. iv Copyright Acoustical Society of America Provided by

35、IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0 IS0 IS0 3743-21994(E) Introduction 0.1 IS0 3743 is one of the IS0 3740 series, which specifies various methods for determining the sound power levels of machines, equipment and sub-ascembli

36、ec. These basic standards specify the acoustical re- quirements for measurements appropriate for different test environments as shown in tableO.l. When selecting one of the methods of the IS0 3740 series, it is necessary to select the most appropriate for the conditions and purposes of the noise tes

37、t. General guidelines to assist in the selection are provided in IS0 3740. The IS0 3740 series gives only general prin- ciples regarding the operating and mounting conditions of the machine or equipment under test. Reference should be made to the noise test code for a specific type of machine or equ

38、ipment, if available, for spe they are not intended for larger pieces of stationary equipment which, due to their manner of operation or installation, cannot readily be moved into the test room and operated as in normal usage. The procedures are intended to be used when an engineering grade of accu-

39、 racy is desired without requiring the use of laboratory facilities. 0.4 In IS0 3743-1, a comparison method is used to determine the octave-band sound power levels of the source. The spatial average (octave-band) sound pressure levels produced by the source under test are compared to the spatial ave

40、rage (octave-band) sound pressure levels produced by a reference sound source of known sound power output. The difference in sound pressure levels is equal to the difference in sound power levels if conditions are the same for both sets of measurements. The A-weighted sound power level is then calcu

41、lated from the octave- band sound power levels. V Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The requirements to be fulfilled by the special reverberation test room for measurements

42、in accordance with this part of IS0 3743 are significantly more restrictive than those placed on the hard-walled test room by the comparison method of IS0 3743-1, vi Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted wi

43、thout license from IHS-,-,-o IS0 IS0 3743-21994E) Table 0.1 - International Standards specifying various methods for determining the sound power levels of machines and equipment I I BI I h E a .- E g $0 c- .- 0- .- ma a, LE u) d IC m O z vii Copyright Acoustical Society of America Provided by IHS un

44、der license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright Acoustical Society of America Provided by IHS under license with ASANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD 0 IS0 IS0 374

45、3-2:1994(E) Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for small, movable sources in reverberant fields - Part 2: Methods for special reverberation test rooms 1 Scope 1.1 General This part of IS0 3743 specifies a relatively simple en-

46、gineering method for determining the sound power levels of small, movable noise sources. The measurements are carried out when the source is in- stalled in a specially designed room having a specified reverberation time over the frequency range of interest. The A-weighted sound power level of the so

47、urce under test is determined from a single A- weighted sound pressure level measurement at each microphone position, rather than from a summation of octave-band levels. This direct method eliminates the need for a reference sound source, but requires the use of a special reverberation test room. Th

48、e di- rect method is based on the premise that the sound pressure level, averaged in space and time in the test room, can be used to determine the sound power level emitted by the source. The properties of the special reverberation test room are chosen so that the rooms influence on the sound power

49、output of the equipment under test is small. The number of micro- phone positions and source locations required in the test room are specified. Guidelines for the design of special reverberation rooms are given in annex B. In addition to the direct method, a comparison method is also described (see 8.3). However, since the requirements on the test room for the compariso