1、Designation: E1704 95 (Reapproved 2010)Standard Guide forSpecifying Acoustical Performance of Sound-IsolatingEnclosures1This standard is issued under the fixed designation E1704; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The guide covers the development of criteria for theacoustical performance of a broad variety of acoustical en
3、clo-sures by identifying information necessary to unambiguouslydescribe acoustical performance. This guide is not a standardASTM specification for a sound-isolating enclosure.1.2 Excluded from the scope of this guide are technicalconsiderations for enclosure design that do not pertain directlyto aco
4、ustical performance.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
5、 use.2. Referenced Documents2.1 ASTM Standards:2C423 Test Method for Sound Absorption and Sound Ab-sorption Coefficients by the Reverberation Room MethodC634 Terminology Relating to Building and EnvironmentalAcousticsE336 Test Method for Measurement of Airborne SoundAttenuation between Rooms in Buil
6、dingsE413 Classification for Rating Sound InsulationE596 Test Method for Laboratory Measurement of NoiseReduction of Sound-Isolating Enclosures2.2 ANSI Standards:ANSI S1.4 Specification for Sound Level Meters3ANSI S3.1 Maximum Permissible Ambient Noise Levelsfor Audiometric Test Rooms3ANSI S3.6 Spec
7、ification for Audiometers3ANSI S12.31S12.35 Methods for Determining the SoundPower Levels of Machines and Equipment32.3 ISO Standard:ISO 37413745 AcousticsMethods for Determining theSound Power Levels of Machines and Equipment42.4 Government Standard:29 CFR 1910.95 Occupational Noise Exposure Occupa
8、-tional Safety and Health Administration52.5 Other Standard:VDI 2711 Schallschutz durch Kapeslung Verein DeutscherIngeireure, Beuth Verlag GmbH, Berlin German NoiseControl by the Use of Enclosures63. Terminology3.1 Definitions:3.1.1 Standard definitions of acoustical terms may be foundin Terminology
9、 C634.3.2 Definitions of Terms Specific to This Standard:3.2.1 A-weighted sound pressure levelsound pressurelevel measurements made with the A-weighting filter appliedas defined in ANSI S1.4, denoted LPAin this guide.3.2.2 C-weighted sound pressure levelsound pressurelevel measurements made with the
10、 C-weighting filter appliedas defined in ANSI S1.4, denoted LPCin this guide.3.2.3 enclosurea structure, usually free-standing, whichsubstantially or completely encloses a given space or object.This does not include barrier walls, partitions within a building,or other partial structures.3.2.4 enclos
11、ure-generated noisesound created by the op-eration of the enclosure systems, such as lighting and ventila-tion.3.2.5 level reductionfor the purposes of this guide, thearithmetic difference between sound pressure levels at aspecific location before and after the installation of the enclo-sure, expres
12、sed in decibels.1This guide is under the jurisdiction of ASTM Committee E33 on Building andEnvironmentalAcoustics and is the direct responsibility of Subcommittee E33.03 onSound Transmission.Current edition approved May 1, 2010. Published August 2010. DOI: 10.1520/E1704-95R10.2For referenced ASTM st
13、andards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Flo
14、or, New York, NY 10036, http:/www.ansi.org.4Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.5Available from the Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC
15、 20402.6Available from Beuth Verlag GmbH, Burggrafenstrasse 4-7, 1000 Berlin 30.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 level reduction specificationspecification of theacoustical performance of an enclosure by stating
16、the reductionin sound pressure level caused by the enclosure.3.2.7 personnel enclosurean enclosure designed to keepsound energy from personnel or equipment therein. Examplesof personnel enclosures include but are not limited to audio-metric booths, in-plant offices, broadcast booths, and acousticalt
17、est chambers.3.2.8 pre-installation sound pressure levelsthe soundpressure levels, as a function of frequency, that are presentprior to the installation of the enclosure. In most cases this isdetermined by measuring the ambient sound pressure levels inthe host area but in some cases, such as new con
18、struction, thesound pressure levels must be predicted.3.2.9 sound pressure level specificationspecification ofthe acoustical performance of an enclosure by stating themaximum sound pressure levels that shall exist after installa-tion.3.2.10 source enclosurean enclosure designed to keepsound energy f
19、rom personnel or equipment on the outside.Such applications include, but are not limited to, equipmentsilencing, secure communications, music practice, and acous-tical testing.4. Summary of Guide4.1 An explanation of the determination and subsequentspecification of acoustical performance of sound-is
20、olatingenclosures is presented.4.2 Two types of specifications are described in this guide.The recommended method (sound pressure level specification)is to specify the maximum permissible sound pressure levelsthat may be present after installation of the enclosure. Thealternate method (level reducti
21、on specification) is to specify theenclosures level reduction.4.3 The type of specification selected depends largely on theenclosure application and the data available. A sound pressurelevel specification usually applies to a specific site, while thelevel reduction specification may have broader app
22、lication.Also, the sound pressure level specification is more appropriatewhere specific sound pressure levels are required, while thelevel reduction specification reflects a more general interest inamounts of noise level reduction.4.4 Some guidance is provided inAppendix X1 on selectinga specificati
23、on type based on the enclosure application and theinformation available.4.5 Substantial guidance is given on the essential acousticaldata that must be compiled.4.6 A non-mandatory model specification Appendix X2 isincluded that embraces both specification types. It also servesas a guide for identify
24、ing and gathering information necessaryto the manufacturer for designing the enclosure.5. Significance and Use5.1 This guide can be used to produce a specification for theacoustical performance of an enclosure.5.2 This guide is intended for those familiar with basicconcepts of acoustics.5.3 Although
25、 this guide provides detailed guidance in mat-ters relating to specification of acoustical enclosures, it is not asubstitute for the experience and judgment of an acoustical ornoise control professional.5.3.1 This guide calls for measurements common withinacoustical practice.5.3.2 The more critical
26、the performance requirements of theenclosure, the more the user should consider seeking theservices of an acoustics or noise control professional.5.4 The specifying of a sound-isolating enclosure has threesequential steps:5.4.1 Determine the sound pressure levels that exist atspecific locations prio
27、r to the introduction of the enclosure,NOTE 1In the case of new construction, the sound pressure level isoften estimated from the sound power levels of noise-emitting equipmentand a general description of the acoustical properties of the environment.5.4.2 Determine the maximum permissible sound pres
28、surelevels that must exist at the same locations after the introduc-tion of the enclosure, and5.4.3 Determine the required enclosure level reduction. Therequired isolation is related to the difference between the soundpressure levels before and after the introduction of the enclo-sure.5.5 Many speci
29、fications are for multiple enclosures orenclosures with multiple functions, or both. It is beyond thescope of this guide to provide detailed guidance for everypossible combination. Separate specifications for each source-enclosure-receiver combination should be used in such a case.5.6 The type of sp
30、ecification that should be selected de-pends both on the purpose of the enclosure and how crucial itsperformance is. In general:5.6.1 If exceeding a particular maximum permissible soundpressure level spectrum would render the enclosure unsuccess-ful, a sound pressure level specification should be us
31、ed.5.6.1.1 This guide assigns all phases of acoustical design aredelegated to the supplier. Compliance is usually more easilyverified than with the level reduction method.5.6.2 If the criteria for the success of the enclosure are lessstringent or not related to a specific maximum permissiblespectrum
32、, a level reduction specification may be used.6. Recommended Specifications6.1 The sound pressure level specification specifies themaximum permissible sound pressure levels that may existeither inside or outside the enclosure after installation. Pre-installation sound pressure levels must also be pr
33、esented.6.1.1 Maximum sound pressure levels should be specified inone-third-octave bands whenever possible to allow a detailedfit to the requirements. Octave band sound pressure levels areappropriate where the noise spectrum is broad band and free ofprominent tones.6.1.2 The desired post-installatio
34、n sound pressure level mayalso be described by a single number descriptor, such asA-weighted sound pressure level or NC or RC ratings.7In thisevent, the pre-installation one-third-octave band sound pres-sure levels at or around the installation site shall also beprovided.7ASHRAE Handbook, Fundamenta
35、ls, Chapter 7, American Society of Heating,Refrigerating and Air Conditioning Engineers, Atlanta, Georgia.E1704 95 (2010)2NOTE 2Other single number ratings for noise may also be available.For further information see ASHRAE Handbook.76.1.3 Measured sound pressure levels are preferred. Whennot availab
36、le, such as in the case of new construction, thefollowing information is usually considered an acceptablesubstitute to allow estimation of sound pressure levels:6.1.3.1 The rated or measured sound power level (heredenoted LW) of equipment and,6.1.3.2 A description of the host environment, including
37、therelative locations of sources of noise, personnel, and theenclosure. Some loss of accuracy should be expected.6.1.4 Inaccurate measurement of sound pressure levels canresult from unsteady or intermittent sources of noise duringmeasurement, changes in site conditions after measurement(for example,
38、 significant sources of noise arising betweenmeasurement and installation), strong low-frequency content(LPCLPA 15), and general inexperience with acousticalmeasurements.6.1.5 Maximum permissible sound pressure levels are oftenprescribed for particular applications by standards or regula-tory docume
39、nts. A short list includes, but is not limited to,hearing conservation regulations, architectural specifications,human comfort, speech intelligibility, speech privacy, andacoustical test standards. Common specific cases are cited inAppendix X1.6.1.6 The maximum permissible interior or exterior sound
40、pressure levels should not be exceeded with all sources ofenclosure-generated noise in normal operation.6.2 The level reduction specification identifies the minimumpermissible level reduction to be provided by the enclosure.This type specification is often used by a buyer who hasalready determined t
41、he isolation needed to meet his soundpressure level requirements. Using this type of specificationwithout such analysis could result in unacceptable results.6.2.1 Level reduction I(f) can be approximated as follows:If! 5 L12 L21 SFwhere:L1= pre-installation sound pressure level in a given band,L2= p
42、ost-installation sound pressure level in a given band,andSF = safety factor.6.2.1.1 The safety factor helps ensure compliance by ac-counting for unforeseen complications due to changes in siteconditions, or unusual acoustical interactions of the enclosureand the space. The more critical the successf
43、ul performance ofthe enclosure, the larger the selected safety factor should be.Typical values are:Not Critical SF = 0 dBModerate SF = 3 dBConservative SF = 6 dBNOTE 3In practice safety factor size varies with frequency as well aswith importance. The user should consider applying stringent safetyfac
44、tors only in bands where they are most needed in order to avoidover-designing the enclosure.6.2.1.2 The introduction of the enclosure may significantlyalter the sound field near the noise source, increasing both theeffective value of L1and the required level reduction. Thiseffect is important when e
45、ither the physical volume or thesound absorption coefficients of the surfaces around the noisesource are reduced by a factor of two or more. In this case,detailed information on noise source and its pre-installationsurroundings should accompany the specification. In addition,a larger safety factor s
46、hould be considered.6.2.2 The level reduction of enclosures is typically quanti-fied by the manufacturer in laboratory prototype testing. Noisereduction (NR) is measured per Test Method E596, and noiseisolation class (NIC) is calculated per Classification E413. Forthe purposes of this guide, noise r
47、eduction data are anacceptable equivalent for level reduction.6.2.2.1 Custom designs are typically not tested, due to cost.6.2.2.2 The actual enclosure being specified may differ incertain particulars from prototypes tested.6.2.2.3 Because of variations in manufacturing materialsand methods and chan
48、ges in test standards, test results shouldbe no older than five years.6.2.2.4 Laboratory noise reduction data obtained in accor-dance with Test Method E596 in prototype testing are oftenaccepted as performance verification.6.2.3 An enclosure may provide the required level reductionwithout achieving
49、a particular sound pressure level spectrum inthe protected space. As an example, sound pressure levelsinside an enclosure will be considerably higher when theenclosure is located in a high ambient noise area.7. Other Noise Control Properties of Enclosures7.1 Vibration IsolationThe effectiveness of an enclosurecan be compromised by structure-borne noise bypassing theacoustical barrier through adjacent building structures. Enclo-sures should be isolated from adjacent structures by means offlexible connections.7.1.1 Vibrations that can be felt by the hand ar
