1、 ANSI/ASA S12.56-2011 / ISO 3746:2010 (a revision of ANSI S12.56-1999 / ISO 3746:1995) AMERICAN NATIONAL STANDARD Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane
2、(a Nationally Adopted International Standard) Accredited Standards Committee S12, Noise Standards Secretariat Acoustical Society of America 35 Pinelawn Road, Suite 114 E Melville, NY 11747-3177ANSI/ASA S12.56-2011/ISO3746:2010The American National Standards Institute, Inc. (ANSI) is the national coo
3、rdinator 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 organization of scientists and engineers formed in 1929 to increase and diffuse the knowledge of acoustics and to pro
4、mote its practical applications. ANSI/ASA S12.56-2011 / ISO 3746:2010 AMERICAN NATIONAL STANDARD Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane (a nationally ado
5、pted international standard) Secretariat: Acoustical Society of America Approved on June 28, 2011 by: American National Standards Institute, Inc. Abstract This American National Standard specifies methods for determining the sound power level or sound energy level of a noise source from sound pressu
6、re levels measured on a surface enveloping a noise source (machinery or equipment) in a test environment for which requirements are given. The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level) produced by the noise source with frequency A-weighti
7、ng applied is calculated using those measurements. AMERICAN NATIONAL STANDARDS ON ACOUSTICS The Acoustical Society of America (ASA) provides the Secretariat for Accredited Standards Committees S1 on Acoustics, S2 on Mechanical Vibration and Shock, S3 on Bioacoustics, S3/SC 1 on Animal Bioacoustics,
8、and S12 on Noise. These committees have wide representation from the technical community (manufacturers, consumers, trade associations, organizations with a general interest, and government representatives). The standards are published by the Acoustical Society of America as American National Standa
9、rds after approval by their respective Standards Committees and the American National Standards Institute (ANSI). These standards are developed and published as a public service to provide standards useful to the public, industry, and consumers, and to Federal, State, and local governments. Each of
10、the Accredited Standards Committees (operating in accordance with procedures approved by ANSI) is responsible for developing, voting upon, and maintaining or revising its own Standards. The ASA Standards Secretariat administers Committee organization and activity and provides liaison between the Acc
11、redited Standards Committees and ANSI. After the Standards have been produced and adopted by the Accredited Standards Committees, and approved as American National Standards by ANSI, the ASA Standards Secretariat arranges for their publication and distribution. An American National Standard implies
12、a consensus of those substantially concerned with its scope and provisions. Consensus is established when, in the judgment 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
13、majority, but not necessarily unanimity. Consensus requires that all views and objections be considered and that a concerted effort be made towards their resolution. The use of an American National Standard is completely voluntary. Their existence does not in any respect preclude anyone, whether he
14、or she has approved the Standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures 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 Institu
15、te require that action be taken periodically to reaffirm, revise, or withdraw this Standard. Acoustical Society of America ASA Secretariat 35 Pinelawn Road, Suite 114E Melville, New York 11747-3177 Telephone: 1 (631) 390-0215 Fax: 1 (631) 390-0217 E-mail: asastdsaip.org 2011 by Acoustical Society of
16、 America. This standard may not be reproduced in whole or in part in any form for sale, promotion, or any commercial purpose, or any purpose not falling within the provisions of the U.S. Copyright Act of 1976, without prior written permission of the publisher. For permission, address a request to th
17、e Standards Secretariat of the Acoustical Society of America. 2011 Acoustical Society of AmericaAll rights reserved iContents 1 Scope . 1 1.1 General . 1 1.2 Types of noise and noise sources 1 1.3 Test environment 1 1.4 Measurement uncertainty . 1 2 Normative references . 2 3 Terms and definitions .
18、 2 4 Test environment . 7 4.1 General . 7 4.2 Criterion for background noise . 7 4.3 Criterion for acoustic adequacy of test environment 7 5 Instrumentation 7 5.1 General . 7 5.2 Calibration . 8 6 Definition, location, installation and operation of noise source under test . 8 6.1 General . 8 6.2 Aux
19、iliary equipment 8 6.3 Noise source location . 9 6.4 Mounting of the noise source . 9 6.5 Operation of source during test 10 7 Reference box and measurement surface . 10 7.1 Reference box 10 7.2 Measurement surface . 11 8 Determination of sound power levels and sound energy levels 14 8.1 Determinati
20、on of environmental correction . 14 8.2 Microphone positions on the measurement surface . 14 8.3 Determination of sound power levels . 15 8.4 Determination of sound energy levels 18 9 Measurement uncertainty 20 9.1 Methodology . 20 9.2 Determination of omc. 21 9.3 Determination of R021 9.4 Typical u
21、pper bound values of R023 9.5 Total standard deviation totand expanded measurement uncertainty U . 23 10 Information to be recorded . 24 10.1 General . 24 10.2 Noise source under test 24 10.3 Test environment 24 10.4 Instrumentation . 24 10.5 Acoustical data . 25 ii 2011 Acoustical Society of Americ
22、aAll rights reserved11 Test report 25 Annex A (normative) Determination of the environmental correction . 26 Annex B (normative) Microphone arrays on a hemispherical measurement surface . 27 B.1 Key microphone positions and additional microphone positions 27 B.2 Microphone positions for sources adja
23、cent to two reflecting planes 27 B.3 Microphone positions for sources adjacent to three reflecting planes . 27 Annex C (normative) Microphone arrays on a parallelepiped measurement surface . 32 C.1 Microphone positions for sources mounted on one reflecting plane 32 C.2 Microphone positions for sourc
24、es adjacent to two or three reflecting planes 32 Annex D (informative) Guidelines on the development of information on measurement uncertainty . 40 D.1 General . 40 D.2 Considerations on the total standard deviation tot40 D.3 Considerations on omc40 D.4 Considerations on R0. 42 D.5 Combined standard
25、 uncertainty 48 D.6 Measurement uncertainty based on reproducibility data 49 Tables Table 1 Typical upper bound values of the standard deviation of reproducibility of the method, R0, for A-weighted sound power levels and sound energy levels determined in accordance with this American National Standa
26、rd 23 Table A.1 Approximate values of the mean sound absorption coefficient, . 26 Table B.1 Microphone positions for a noise source over a reflecting plane (key microphone positions: 4,5,6,10; additional microphone positions: 14,15,16,20; r is the radius of the measurement hemisphere) . 27 Table B.2
27、 Microphone positions for a source adjacent to two or three reflecting planes . 28 Table D.1 Examples of calculated total standard deviations totfor three different cases . 42 Table D.2 Uncertainty budget for determinations of R0for sound power level and sound energy level, valid for A-weighted meas
28、urements of a source with a relatively flat frequency spectrum . 44 2011 Acoustical Society of AmericaAll rights reserved iiiForeword This Foreword is for information only, and is not a part of the American National Standard ANSI/ASA S12.56-2011 / ISO 3746:2010 American National Standard Acoustics D
29、etermination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane. This standard comprises a part of a group of definitions, standards, and specifications for use in noise. It was developed a
30、nd approved by Accredited Standards Committee S12, Noise, under its approved operating procedures. Those procedures have been accredited by the American National Standards Institute (ANSI). The Scope of Accredited Standards Committee S12 is as follows: Standards, specifications, and terminology in t
31、he field of acoustical noise pertaining to methods of measurement, evaluation, and control, including biological safety, tolerance, and comfort, and physical acoustics as related to environmental and occupational noise. This standard is a revision of ANSI S12.56-1999 (R 2004) / ISO 3746:1995, which
32、has been technically revised. This Standard is identical to International Standard ISO 3746, Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane, which was prepared b
33、y Technical Committee ISO/TC 43 Subcommittee SC 1, Noise. However, in conformance with ANSI and ISO rules, the words “American National Standard“ replace the words “International Standard“ where they appear in the ISO document, decimal points were substituted in place of the decimal commas used in I
34、SO documents, and American English spelling is used in place of British English spelling. The ANSI or ANSI/ASA equivalents for the ISO standards in the ISO 3740 series and other referenced nationally adopted standards are given below: ANSI S12.5 / ISO 6926 is an identical national adoption of ISO 69
35、26; 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 3743-1; ANSI/ASA S12.53/Part 2/ISO 3743-2 is an identical national adoption o
36、f 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/ASA S12.56/ISO 3746 is an identical national adoption of ISO 3746; and ANSI/ASA S12.57/ISO 3747 is an identical national adoption of ISO 3747
37、. 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: 631-390-0217; E-mail: asastdsaip.org. 2011 Acoustical Society of America
38、All rights reserved viiIntroduction This American National Standard is a national adoption of one of the series ISO 37412to ISO 37476, which specify methods for determining the sound power levels and sound energy levels of noise sources including machinery, equipment and their sub-assemblies. Guidel
39、ines to select one of those methods are provided in ISO 37401. The selection depends on the environment of the available test facility and on the precision of the sound power level or sound energy level values required. It may be necessary to establish a test code for the individual noise source in
40、order to select the appropriate sound measurement surface and microphone array from among those allowed in each of the ISO 37401to ISO 37476series, and to give requirements for test unit mounting, loading, and operating conditions under which the sound power levels or sound energy levels are to be o
41、btained. The sound power emitted by a given source into the test environment is calculated from the mean square sound pressure that is measured over a hypothetical measurement surface enclosing the source, and the area of that surface. The sound energy for a single machine event is calculated from t
42、his sound power and the time over which it existed. This American National Standard specifies methods giving results of ISO 12001:1996, accuracy grade 3 (survey grade) when measurements are performed within industrial buildings or outdoors. Ideally, the test source should be mounted on a sound-refle
43、cting plane located in a large open space. For sources normally installed on the floor of machine rooms, corrections are defined to account for undesired reflections from nearby objects, walls, and the ceiling, and for the residual background noises that occur there. The methods specified in this Am
44、erican National Standard permit the determination of the sound power level and the sound energy level with frequency A-weighting applied. For applications where greater accuracy is required, reference can be made to ISO 3744, ISO 37455or an appropriate part of ISO 961414-16. If the relevant criteria
45、 for the measurement environment specified in this American National Standard are not met, it might be possible to refer to another of the ISO 37412to ISO 37476series, or to an appropriate part of ISO 961414-16. AMERICAN NATIONAL STANDARD ANSI/ASA S12.56-2011 / ISO 3746:2010 2011 Acoustical Society
46、of AmericaAll rights reserved 1Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane 1 Scope 1.1 General This American National Standard specifies methods for determini
47、ng the sound power level or sound energy level of a noise source from sound pressure levels measured on a surface enveloping a noise source (machinery or equipment) in a test environment for which requirements are given. The sound power level (or, in the case of noise bursts or transient noise emiss
48、ion, the sound energy level) produced by the noise source with frequency A-weighting applied is calculated using those measurements. NOTE Differently shaped measurement surfaces can yield differing estimates of the sound power level of a given noise source and an appropriately drafted test code (see
49、 ISO 12001) gives detailed information on the selection of the surface. 1.2 Types of noise and noise sources The methods specified in this American National Standard are suitable for all types of noise (steady, non-steady, fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001. This American National Standard is applicable to all types and sizes of noise source (e.g. stationary or slowly moving plant, installation, machine, component or sub-assembly), provided the co
