1、ANSI S3.1-1999(Revision of ANSI S3.1-1991) AMERICAN NATIONAL STANDARD Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms Accredited Standards Committee S3, BioacousticsStandards Secretariat Acoustical Society of America 35 Pinelawn Road, Suite 114 E Melville, NY 11747-3177 ANSI S3.1
2、-1999 Reaffirmed by ANSI October 15, 2003 Reaffirmed by ANSI October 28, 2008 Reaffirmed by ANSI November 26, 2013 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
3、 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. American National StandardMaximum Permissible AmbientNoise Levels for Audiomet
4、ric Test RoomsSecretariatAcoustical Society of AmericaApproved 3 August 1999American National Standards Institute, Inc.AbstractThis Standard specig383es maximum permissible ambient noise levels (MPANLs) allowed in an audiometrictest room that produce negligible masking (H110882 dB) of test signals p
5、resented at reference equivalentthreshold levels specig383ed in ANSI S3.6-1996 American National Standard Specig383cation of Audiometers.The MPANLs are specig383ed from 125 to 8000 Hz in octave and one-third octave band intervals for twoaudiometric testing conditions (ears covered and ears not cover
6、ed) and for three test frequency ranges(125 to 8000 Hz, 250 to 8000 Hz, and 500 to 8000 Hz). The Standard is intended for use by all personstesting hearing and for distributors, installers, designers, and manufacturers of audiometric test rooms. Thisstandard is a revision of ANSI S3.1-1991 American
7、National Standard Maximum Permissible AmbientNoise Levels for Audiometric Test Rooms.ANSI S3.1-1999(Revision ofANSI S3.1-1991)Reaffirmed by ANSI October 15, 2003 Reaffirmed by ANSI October 28, 2008 Reaffirmed by ANSI on June 24, 2007 Reaffirmed by ANSI on June 24, 2007 AMERICAN NATIONAL STANDARDS ON
8、 ACOUSTICSThe Acoustical Society of America (ASA) provides the Secretariat for AccreditedStandards 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,
9、 and general-interest representatives). The standards are published by the Acoustical Society ofAmerica through the American Institute of Physics as American National Stan-dards after approval by their respective standards committees and the AmericanNational Standards Institute.These standards are d
10、eveloped and published as a public service to providestandards 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 ANSI) is responsible for developing, voting upon
11、, and main-taining or revising its own standards. The ASA Standards Secretariat administerscommittee organization and activity, and provides liaison between the AccreditedStandards Committees and ANSI. After the Standards have been produced andadopted by the Accredited Standards Committees, and appr
12、oved as AmericanNational Standards by ANSI, the ASA Standards Secretariat arranges for theirpublication and distribution.An American National Standard implies a consensus of those substantially con-cerned with its scope and provisions. Consensus is established when, in thejudgment of the ANSI Board
13、of Standards Review, substantial agreement hasbeen reached by directly and materially affected interests. Substantial agreementmeans much more than a simple majority, but not necessarily unanimity. Consen-sus requires that all views and objections be considered and that a concertedeffort be made tow
14、ard their resolution.The use of American National Standards is completely voluntary. Their existencedoes not in any respect preclude anyone, whether he or she has approved thestandards or not, from manufacturing, marketing, purchasing, or using products,processes, or procedures not conforming to the
15、 standards.NOTICE: This American National Standard may be revised or withdrawn at anytime. The procedures of the American National Standards Institute require thataction be taken periodically to reaffirm, revise, or withdraw this Standard.Standards SecretariatAcoustical Society of America120 Wall St
16、reet, 32nd FloorNew York, New York 10005-3993USATelephone: 11 212 248 0373Telefax: 11 212 248 0146E-mail: asastdsaip.orgInternet: http:/asa.aip.org 1999 by the Acoustical Society of America. This Standard may not be reproduced inwhole or in part in any form for sale, promotion, or any commercial pur
17、pose, or any purposenot falling within the provisions of the Copyright Act of 1976, without prior written permissionof the publisher. For permission, address a written request to the Standards Secretariat ofthe Acoustical Society of America.ContentsPageForeword ii1 Scope, purpose, and applications 1
18、2 References 23 Definitions of terms . 24 Recommended ambient noise levels and measurements 45 Compliance with Standard . 7AnnexesA Derivation of ambient noise levels 8B Present compared with previous (1991) ambient noise levels 11C Interim low frequency ambient noise levels 12D High frequency ambie
19、nt noise levels 13E Techniques for physical measurement 14F Passive noise-reducing enclosures . 15G General considerations in the planning of an audiometrictest room 15Tables1 Ears Covered: Octave band MPANLs for supra-aural earphonesand for insert earphones for three test frequency ranges; in dBre:
20、 20 mPa to nearest 0.5 dB 42 Ears Covered: One-third octave band MPANLs for supra-auralearphones and for insert earphones for three test frequencyranges; in dB re: 20 mPa to the nearest 0.5 dB 53 Ears Not Covered: Octave and one-third octave band MPANLsfor three test frequency ranges; in dB re: 20 m
21、Pa to the nearest0.5dB 5A.1 Derivation of the MPANLs for ears not covered and ears coveredusing a supra-aural earphone and insert earphone for the testfrequency range 125 to 8000 Hz as reported in tables 13.Values in parentheses are interpolated or extrapolated fromexisting data . 9A.2 Average stand
22、ard deviations of the attenuation provided by asupra-aural and insert earphone. Values in parentheses areinterpolated or extrapolated from existing data . 10B.1 Differences between the present and the 1991 octave bandMPANLs for ears covered and ears not covered for each testfrequency range; in dB re
23、: 20 mPa to the nearest 0.5 dB 11B.2 Differences between the present and the 1991 one-third octaveband MPANLs for ears covered and ears not covered for eachtest frequency range; in dB re: 20 mPa to the nearest 0.5 dB 12C.1 Ears Covered: Interim octave band MPANLs using a supra-aural and insert earph
24、one for each test frequency range; in dBre: 20 mPa to the nearest 0.5 dB . 13C.2 Ears Covered: Interim one-third octave band MPANLs using asupra-aural and insert earphone for each test frequency range;in dB re: 20 mPa to the nearest 0.5 dB 13C.3 Ears Not Covered: Interim octave and one-third octave
25、bandMPANLs for each test frequency range; in dB re: 20 mPa to thenearest 0.5 dB . 13iForewordThis Foreword is for information only and is not an integral part of ANSI S3.1-1999 Ameri-can National Standard Maximum Permissible Ambient Noise Levels for Audiometric TestRooms.This Standard is a revision
26、of ANSI S3.1-1991 American National Standard Maxi-mum Permissible Ambient Noise Levels for Audiometric Test Rooms. The 1991Standard specified maximum permissible ambient noise levels (MPANLs) from125 to 8000 Hz in octave and one-third octave bands allowed in an audiometrictest room that would produc
27、e negligible masking of pure tones presented at ref-erence equivalent threshold sound pressure levels specified in ANSI S3.6-1989for two audiometric conditions (ears covered using a supra-aural earphone andears not covered) and for three test frequency ranges (1258000 Hz, 2508000Hz, and 5008000 Hz).
28、 The MPANLs were derived using reference equivalentthreshold sound pressure levels measured in a NBS 9-A coupler.This revision also specifies MPANLs from 125 to 8000 Hz in octave and one-thirdoctave bands allowed in an audiometric test room that would produce negligiblemasking of pure tones for two
29、audiometric conditions and three test frequencyranges. However, the MPANLs specified in this revision were derived using adifferent computational method based on sound field thresholds, principles ofmasking for a given threshold shift, power-law summation of masking, and ear-phone attenuation values
30、. Since the new computational method does not use NBS9-A coupler based measurements as done in 1991, MPANLs have been specifiedfor an insert as well as for a supra-aural earphone. The present Standard allowsslightly more low frequency and slightly less very high frequency ambient noise inan audiomet
31、ric test room than specified in 1991.The annexes detail the derivation of the MPANLs and provide information forinterim low frequency MPANLs, high frequency ambient noise levels, techniquesfor physical measurement of ambient noise, supra-aural earphones encased inpassive noise-reducing enclosures, a
32、nd general considerations in planning for anaudiometric test room.Further experimental work concerning the influence of masking on hearing thresh-olds is encouraged, especially masking of low frequency noise on higher fre-quency hearing thresholds, very low and high frequency earphone attenuation,an
33、d the attenuation provided by passive noise-reducing earphone enclosures. Asa result of this research, a more precise specification of permissible ambient noiselevels may be developed.This Standard, a revision of ANSI S3.1-1991 American National Standard Maximum Per-missible Ambient Noise Levels for
34、 Audiometric Test Rooms, was developed under thejurisdiction of Accredited Standards Committee S3, Bioacoustics, which has the followingscope:Standards, specifications, methods of measurement and test, and terminology,in the fields of psychological and physiological acoustics, including aspects ofge
35、neral acoustics, shock and vibration which pertain to biological safety, toler-ance, and comfort.iiAt the time this Standard was submitted to Accredited Standards Committee S3,Bioacoustics, for final approval, the membership was as follows:R. F. Burkard, ChairJ. Franks, Vice ChairA. Brenig, Secretar
36、yAcoustical Society of America R.F.BurkardJ. Franks (Alt.)American Academy of Otolaryngology, Head and NeckSurgery, Inc. . G.A.GatesL. A. Michael (Alt.)American Industrial Hygiene Association. L.H.RoysterJ. F. Meagher (Alt.)American College of Occupational Medicine. . P.J.BrownsonJ. Sataloff (Alt.)A
37、merican Otological Society, Inc. R.F.NauntonAmerican Speech-Hearing-Language Association . J.D.RoysterM. E. Thompson(Alt.)AT unit, decibel (dB).NOTES1 Typically, a pure tone audiometer is calibratedso that an output of 0 dB HL, for a specified trans-ducer at a specified frequency, is equal to the re
38、fer-ence threshold level for that transducer (by air orbone conduction). Thus, if a listener had a hearingthreshold equal to the reference equivalent thresholdlevel, the listeners threshold would be 0 dB HL (au-diometer output at the listeners threshold) or the av-erage threshold of otologically nor
39、mal listeners.2 If a listener had a hearing threshold of 40 dBhigher than the reference equivalent threshold level,the listeners threshold would be 40 dB HL (audiom-eter output at the listeners threshold) or 40 dB higher(less sensitive) than the average threshold of otologi-cally normal listeners.3
40、If a listener had a hearing threshold 10 dB lowerthan the reference equivalent threshold level, the lis-teners threshold would be 210 dB HL (audiometeroutput at the listeners threshold) or 10 dB lowerANSI S3.1-19993 1999 Acoustical Society of America(more sensitive) than the average threshold of oto
41、-logically normal listeners.3.10 hearing threshold level. For a given lis-tener and specified signal, the minimum soundpressure level or force level that is capable ofevoking an auditory sensation in a specified frac-tion of trials. Sound reaching the ears from othersources is assumed to be negligib
42、le. Unit, decibel(dB).NOTES1 The characteristics of the test signal, the mannerin which it is presented to the listener, and the placeat which the sound pressure level or force level ismeasured should be specified.2 The pure tone threshold measurement proce-dure described in ANSI S3.21-1978 (R 1992)
43、 recom-mends that the threshold be defined as the lowestinput level at which responses occur in at least 50%of ascending trials in a series.3.11 pure tone. A sound wave, the instanta-neous sound pressure of which is a simple sinu-soidal function of time.3.12 ambient noise. All encompassing noisenorm
44、ally associated with a given environment be-ing usually a composite of sounds from manysources near and far.NOTES1 An example would be a narrowband noise thatcontains a region in the frequency spectrum whoselevel is at least 10 dB greater than the level of theneighboring frequency region and whose e
45、ffectivebandwidth is the same as or less than one criticalband at the frequency of concern.2 Another example would be a wideband noisethat contains no spectral maxima.3 Another example would be any type of unwantednoise that would create a nuisance or perceptualconfusion for the listener undergoing
46、a hearing test.3.13 normally hearing listener. A personwho has air conduction thresholds 0 dB HL from1258000 Hz in each ear when tested in an au-diometric test room having MPANLs less than orequal to those specified in this Standard for thefrequency range to be employed in the test room.4 Recommende
47、d ambient noise levelsand measurements4.1 Maximum permissible ambient noise lev-els MPANLs . The MPANLs allowed in an au-diometric test room are shown in tables 13. Table1 shows octave band and table 2 shows one-thirdoctave band MPANLs for ears covered testing us-ing a supra-aural or insert earphone
48、 for each testfrequency range. Table 3 shows octave and one-third octave band MPANLs for ears not coveredtesting for each test frequency range.NOTES1 See Annex A for information concerning the deri-vation of the MPANLs.2 If the ambient noise levels measured in an au-diometric test room are equal to
49、those in tables 13,an elevation in a hearing threshold level for a puretone no greater than 2 dB may occur when testing isdone at reference equivalent threshold levels speci-fied in ANSI S3.6-1996.Table 1 Ears Covered: Octave band MPANLs for supra-aural earphones and for insert ear-phones for three test frequency ranges; in dB re: 20 mPa to nearest 0.5 dB.Supra-aural EarphoneaInsert EarphonebOct Band 125 to 250 to 500 to 125 to 250 to 500 toIntervalsc8000 Hz 8000 Hz 8000 Hz 8000 Hz 8000 Hz 8000 Hz125 35.0 39.0 49.0 59.0 67.0 78.0250 25.0 25.0 35.0 53.0 53.0 64.0500 21.0 21
