ASA S12 42-2010 American National Standard Methods for the Measurement of Insertion Loss of Hearing Protection Devices in Continuous or Impulsive Noise Using Microphone-in-Real-Ear.pdf

1、 ANSI/ASA S12.42-2010 (Revision of ANSI S12.42-1995) AMERICAN NATIONAL STANDARD Methods for the Measurement of Insertion Loss of Hearing Protection Devices in Continuous or Impulsive Noise Using Microphone-in-Real-Ear or Acoustic Test Fixture Procedures Accredited Standards Committee S12, Noise Stan

2、dards Secretariat Acoustical Society of America 35 Pinelawn Road, Suite 114 E Melville, NY 11747-3177ANSI/ASAS12.42-2010 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 nation

3、al 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 promote its practical applications. ANSI/ASA S12.42-2010 (Revision of ANSI S12.42-1995) AMERICAN NATIONAL ST

4、ANDARD Methods for the Measurement of Insertion Loss of Hearing Protection Devices in Continuous or Impulsive Noise Using Microphone-in-Real-Ear or Acoustic Test Fixture Procedures Secretariat: Acoustical Society of America Approved January 11, 2010 by: American National Standards Institute, Inc. Ab

5、stract This standard specifies microphone-in-real-ear (MIRE) methods for the measurement of the insertion loss of active and passive circumaural earmuffs, helmets, and communications headsets, and specifies acoustic test fixture (ATF) methods for the measurement of the insertion loss of active and p

6、assive earplugs, earmuffs, helmets, and communications headsets. The MIRE methods are appropriate for use with continuous noise whereas the ATF methods may be used with both continuous noise and high-level impulsive noise test signals. The standard contains information on instrumentation, calibratio

7、n, and electroacoustic requirements, procedures for determining sound pressure levels in the ear with and without the hearing protection devices in place, and procedures for calculating the corresponding insertion loss values. The standard also describes how to combine the active contribution of ins

8、ertion loss for active devices measured using the MIRE method with the passive real-ear attenuation measured in accordance with ANSI/ASA S12.6 to obtain an attenuation value for use in estimating sound pressure levels for active protectors in accordance with ANSI/ASA S12.68. Requirements for reporti

9、ng of the data are also described. 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, and S12 on Noise

10、 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 Standards after approv

11、al 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 the accredited S

12、tandards 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 Accredited Standard

13、s 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 a consensus of t

14、hose 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 majority, but no

15、t 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 or she has appro

16、ved 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 Institute require that

17、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 2010 by Acoustical Society of America. This s

18、tandard 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 the Standards Secr

19、etariat of the Acoustical Society of America. 2010 Acoustical Society of America All rights reserved iContents 1 Scope . 1 2 Normative references . 1 3 Terms and definitions . 2 4 Applicability of the test methods . 4 5 Requirements for product samples and band force . 5 5.1 Required number of HPD s

20、amples . 5 5.2 Measurement of band force 6 5.3 Devices with adjustable band force 6 6 Acoustic test fixture(s) continuous and impulsive noise methods . 6 6.1 Introduction . 6 6.2 Critical dimensions 7 6.3 Self insertion loss 7 6.4 Microphone and preamplifier requirements 7 6.5 Earcanal couplers . 8

21、6.6 Earcanal extension 8 6.7 Flesh simulation 8 7 Continuous noise methods MIRE test subjects. 8 7.1 Anatomical features 8 7.2 Otoscopic inspection . 8 7.3 Measurement of head dimensions 9 7.4 Gender balance . 9 7.5 Eyeglasses and jewelry. 9 7.6 Number of subjects . 9 7.7 Subjects for MIRE tests of

22、ANR devices . 9 8 Continuous noise methods facilities and instrumentation (MIRE and ATF) 9 8.1 Test signals . 9 8.2 Sound field characteristics 10 8.3 Fitting noise . 11 8.4 Head position reference device 11 8.5 Observation of subjects 11 8.6 Instrumentation . 12 8.7 Microphones MIRE method . 12 9 C

23、ontinuous noise methods test procedures and data reduction (MIRE and ATF) . 13 9.1 Introduction . 13 9.2 Verification of test spectrum and signal level 14 9.3 Fitting of HPDs 15 9.4 Measurement of insertion loss 16 9.5 Number and sequence of measurements . 18 9.6 Data analysis . 22 9.7 Uncertainty f

24、or continuous noise methods 24 9.8 Information to be included in the test report . 24 9.9 Graphical presentation of the data 25 2010 Acoustical Society of America All rights reserved ii 10 Impulsive noise methods facilities and instrumentation (ATF) 25 10.1 Impulse characteristics . 25 10.2 Instrume

25、ntation . 26 10.3 Free-field pressure probe / microphone 26 10.4 Positioning of the ATF and free-field pressure probe . 27 11 Impulsive noise methods test procedures and data reduction (ATF) 28 11.1 Introduction . 28 11.2 Measurement of time waveforms 28 11.3 Computation of the peak insertion loss .

26、 29 11.4 Uncertainty for impulsive noise method 30 11.5 Information to be included in the test report . 31 Annex A (normative) Procedure for measurement of the band force of semi-insert devices . 32 Annex B (informative) Acoustic Test Fixtures (ATF) general information 34 Annex C (normative) Procedu

27、re for measuring head dimensions 36 Annex D (informative) Methods for mounting MIRE microphones in the ear 37 Annex E (normative) Procedure for MIRE AIL measurement of ANR deep-insert custom-molded earplugs . 39 Annex F (informative) Uncertainty for continuous noise methods 40 F.1 MIRE uncertainty 4

28、0 F.2 ATF uncertainty . 41 Annex G (informative) Procedure for generation of impulsive noise . 43 G.1 Introduction . 43 G.2 Shock tube 43 G.3 Explosive discharge 44 Annex H (informative) Example MATLABcode for computing impulsive peak insertion loss 46 Annex I (informative) Uncertainty for impulsive

29、 noise method 50 Bibliography . 52 Tables Table 1 Applicability of test methods to different hearing protection device types . 5 Table 2 Allowable random incidence field response variation for corresponding microphone free-field rejection a,b11 Table 3 Example of estimating TA at 500 and 1000 Hz by

30、combining mean REAT with median AIL 24 Table 4 Bone-conduction limit (BCL) estimate for correcting TA . 24 Table A.1 Pinna dimensions for band force measurements of semi-insert devices, from Table II ANSI S3.36-1985 . 32 2010 Acoustical Society of America All rights reserved iiiTable F.1 Uncertainty

31、 budget for the determination of MIRE PIL and AIL . 41 Table F.2 Uncertainty budget for the determination of ATF PIL and AIL . 42 Table G.1 Suggested distances at which Reynolds RP83 blasting cap igniters will generate impulses of specified peak levels with suitable A-durations 44 Table G.2 Suggeste

32、d mass of explosive and distances at which a C-4 RDX charge will generate impulses of specified peak levels with suitable A-durations . 45 Table I.1 Uncertainty budget for the determination of ATF IPIL . 51 Figures Figure 1 Position of the MIRE microphone in the ear . 14 Figure 2 Free-field pressure

33、 probe . 27 Figure 3 Perspective and plan views of the configuration of the ATF, impulse source, free-field pressure probe and the impulsive noise source 28 Figure A.1 Definitions of semi-insert pinna adapter dimensions: (1) antihelix, (2) crus of helix, (3) concha. 33 Figure A.2 Rigid base plate su

34、itable for pinna adapter . 33 Figure B.1 Examples of acoustic test fixtures ISL head (left) and G.R.A.S. Type 45CA (right) 35 Figure C.1 Bitragion width and head height, with arrows denoting the tragion and the top of the head 36 Figure D.1 Cylindrical microphone mounted on stud inserted into foam e

35、arplug shown before and after insertion into earcanal . 37 Figure D.2 Cylindrical microphone bonded to premolded earplug shown before and after insertion into the earcanal 38 Figure D.3 Cylindrical microphone inserted into a cored foam earplug before and after insertion into the earcanal . 38 2010 A

36、coustical Society of America All rights reserved iv Foreword This Foreword is for information only and is not a part of the American National Standard ANSI/ASA S12.42-2010 American National Standard Methods for the Measurement of Insertion Loss of Hearing Protection Devices in Continuous or Impulsiv

37、e Noise Using Microphone-in-Real-Ear or Acoustic Test Fixture Procedures. This standard comprises a part of a group of definitions, standards, and specifications for use in noise. It was developed and approved by Accredited Standards Committee S12, Noise, under its approved operating procedures. Tho

38、se 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 the field of acoustical noise pertaining to methods of measurement, evaluation, and control, including

39、biological safety, tolerance, and comfort, and physical acoustics as related to environmental and occupational noise. This standard is a revision of ANSI S12.42-1995 (R2004). This revision adds procedures for determining the insertion loss of active earmuffs on real heads and of active earmuffs and

40、earplugs on an acoustic test fixture. This revision also adds methods for determining the insertion loss of earmuffs, earplugs, and helmets in impulsive noise. This standard is in part comparable to ISO Standard 4869-3:2007 Acoustics Hearing protectors Part 3: Measurement of insertion loss of earmuf

41、f type protectors using an acoustic test fixture. The ISO standard only addresses passive hearing protectors and only on a simplified acoustic test fixture, while this standard addresses active and passive hearing protectors on both human subjects and on an acoustic test fixture that includes an occ

42、luded ear simulator, flesh simulation, and pinna. Two other related ISO Standards are ISO 4869-1:1990 Acoustics Hearing protectors Part 1: Subjective method for the measurement of sound attenuation and ISO/TR 4869-4:1998 Acoustics Hearing protectors Part 4: Measurement of effective sound pressure le

43、vels for level-dependent sound-restoration ear-muffs 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-mai

44、l: asastdsaip.org. 2010 Acoustical Society of America All rights reserved viiIntroduction This standard contains two objective procedures, a microphone-in-real-ear (MIRE) method and an acoustic test fixture (ATF) method, for the measurement of the insertion loss of hearing protection devices. Insert

45、ion loss, when measured using microphone-based techniques, is an objective estimate of the attenuation of noise by a hearing protection device. Both methods may be used to measure insertion loss as a function of frequency with specified continuous noise test signals, and the ATF method can also be u

46、sed to measure the peak insertion loss of hearing protection devices when exposed to specified impulsive test signals. The two procedures are similar except for the location of the protector (human head or test fixture) and the sequence in which measurements are made. The MIRE method utilizes human

47、subjects who serve as test fixtures with microphones positioned in their ears; it is the preferred method for continuous noise since it captures the performance and variability of the hearing protection device on human subjects/users. The ATF method utilizes an acoustical test fixture with a measure

48、ment microphone embedded at each ear position. The MIRE method employs miniature microphones in the ear to measure the insertion loss of hearing protection devices such as active and passive earmuffs or helmets. Insertion loss is the difference between sound pressure levels measured with the test mi

49、crophones uncovered and with the microphones covered by the hearing protection device under evaluation. The MIRE procedure is objective rather than psychophysical and is not limited to passive linear attenuation hearing protection devices; it may be used to evaluate amplitude-sensitive and active noise reduction circumaural and supra-aural devices. This standard also specifies how to combine the active contribution to insertion loss with the passive contribution measured using the methods in ANSI