ASTM E1704-95(2018)

Standard Guide for Specifying Acoustical Performance of Sound-Isolating Enclosures

SIGNIFICANCE AND USE
5.1 This guide can be used to produce a specification for the acoustical performance of an enclosure.  
5.2 This guide is intended for those familiar with basic concepts of acoustics.  
5.3 Although this guide provides detailed guidance in matters relating to specification of acoustical enclosures, it is not a substitute for the experience and judgment of an acoustical or noise control professional.  
5.3.1 This guide calls for measurements common within acoustical practice.  
5.3.2 The more critical the performance requirements of the enclosure, the more the user should consider seeking the services of an acoustics or noise control professional.  
5.4 The specifying of a sound-isolating enclosure has three sequential steps:  
5.4.1 Determine the sound pressure levels that exist at specific locations prior to the introduction of the enclosure,
Note 1: In the case of new construction, the sound pressure level is often estimated from the sound power levels of noise-emitting equipment and a general description of the acoustical properties of the environment.  
5.4.2 Determine the maximum permissible sound pressure levels that must exist at the same locations after the introduction of the enclosure, and  
5.4.3 Determine the required enclosure level reduction. The required isolation is related to the difference between the sound pressure levels before and after the introduction of the enclosure.  
5.5 Many specifications are for multiple enclosures or enclosures with multiple functions, or both. It is beyond the scope of this guide to provide detailed guidance for every possible combination. Separate specifications for each source-enclosure-receiver combination should be used in such a case.  
5.6 The type of specification that should be selected depends both on the purpose of the enclosure and how crucial its performance is. In general:  
5.6.1 If exceeding a particular maximum permissible sound pressure level spectrum would render the enclosure unsuccessf...
SCOPE
1.1 The guide covers the development of criteria for the acoustical performance of a broad variety of acoustical enclosures by identifying information necessary to unambiguously describe acoustical performance. This guide is not a standard ASTM specification for a sound-isolating enclosure.  
1.2 Excluded from the scope of this guide are technical considerations for enclosure design that do not pertain directly to acoustical performance.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2018
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: E33 - Building and Environmental Acoustics
• Drafting Committee: E33.03 - Sound Transmission

Relations

• Replaces: ASTM E1704-95(2010) - Standard Guide for Specifying Acoustical Performance of Sound-Isolating Enclosures
• Effective Date: 01-Oct-2018
• Refers: ASTM E336-19a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Oct-2019
• Refers: ASTM E336-19 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jan-2019
• Refers: ASTM E336-17a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 15-Nov-2017
• Refers: ASTM E336-17 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jul-2017
• Refers: ASTM E336-16a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Oct-2016
• Refers: ASTM E336-16 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jan-2016
• Refers: ASTM E336-15 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Sep-2015
• Refers: ASTM E336-14 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 15-Apr-2014
• Refers: ASTM C634-13 - Standard Terminology Relating to Building and Environmental Acoustics
• Effective Date: 01-Sep-2013
• Refers: ASTM C634-11 - Standard Terminology Relating to Building and Environmental Acoustics
• Effective Date: 01-Dec-2011
• Refers: ASTM E336-11 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Nov-2011
• Refers: ASTM E336-10 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Sep-2010
• Refers: ASTM E413-10 - Classification for Rating Sound Insulation
• Effective Date: 01-Sep-2010
• Refers: ASTM C634-10a - Standard Terminology Relating to Building and Environmental Acoustics
• Effective Date: 01-Sep-2010

Overview

ASTM E1704-95(2018), Standard Guide for Specifying Acoustical Performance of Sound-Isolating Enclosures, provides a comprehensive framework for specifying the acoustical performance of sound-isolating enclosures. Developed by ASTM International, this guide equips practitioners with the critical steps and key information required to produce a specification for enclosures designed to control sound transmission and provide effective noise isolation.

This document is especially relevant for professionals working with acoustical or noise control applications in both industrial and building environments. While it offers detailed guidance, it is intended for users familiar with basic acoustical concepts and is not a substitute for specialist judgment in complex or critical scenarios.

Key Topics

• Purpose and Applicability: The guide outlines methods for defining acoustical performance requirements for a wide range of enclosure types, such as audiometric booths, industrial equipment enclosures, broadcast studios, and music practice rooms.

• Specification Process: The guide details a three-step process for sound-isolating enclosure specification:

  • Determining pre-installation sound pressure levels at specific locations, either by measurement or estimation.
  • Establishing maximum permissible sound pressure levels after the enclosure is installed.
  • Calculating the required level of noise reduction (level reduction) by comparing pre- and post-installation levels.

• Types of Specifications:

  • Sound Pressure Level Specification: Sets explicit post-installation maximum sound pressure levels, which are often site-specific and easier to verify.
  • Level Reduction Specification: Specifies the minimum noise reduction (difference between pre- and post-installation sound pressure levels) required from the enclosure.

• Essential Data: Users are advised on compiling necessary acoustical data, including frequency band levels, absorption coefficients, and vibration isolation considerations.

• Performance Verification: The guide stresses the importance of compliance checks via measurements after installation, ensuring that sound pressure levels meet the specified requirements.

Applications

ASTM E1704-95(2018) has wide-ranging practical value for industries and projects where control of sound transmission is crucial, including:

• Audiometric Enclosures: Ensuring compliance with standards for audiometric testing environments, specifying permissible ambient sound levels.
• Industrial Enclosures: Supporting occupational safety by setting exposure limits and reducing noise in compliance with regulations (such as those from OSHA).
• Broadcast and Recording Studios: Achieving target noise criteria (NC) levels for optimal recording conditions.
• Music Practice Rooms: Providing the necessary acoustic separation between practice rooms and adjacent areas to minimize interference.
• Secure Communication Facilities: Ensuring confidential conversations remain isolated from eavesdropping or external environments.

The guide’s structured approach is also beneficial for designing enclosures that require verification of acoustical performance, dealing with complex multi-enclosure scenarios, or integrating both airborne and structure-borne noise isolation.

Related Standards

ASTM E1704-95(2018) references several important related standards and supporting documents, including:

• ASTM C423 – Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
• ASTM E336 – Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• ASTM E413 – Classification for Rating Sound Insulation
• ASTM E596 – Test Method for Laboratory Measurement of Noise Reduction of Sound-Isolating Enclosures
• ANSI S1.4 – Specification for Sound Level Meters
• ANSI S3.1 – Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms
• ANSI S3.6 – Specification for Audiometers
• ISO 3741-3745 – Acoustics - Methods for Determining the Sound Power Levels of Machines and Equipment
• 29 CFR 1910.95 – Occupational Noise Exposure regulations

Professionals looking to maximize sound isolation and comply with relevant regulations will benefit from the robust methodologies outlined in this guide and its referenced standards.

Keywords: sound-isolating enclosures, acoustical performance, noise reduction, level reduction, sound pressure level, building acoustics, ASTM E1704, noise control, performance verification, acoustic specifications

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1704 − 95 (Reapproved 2018)
Standard Guide for
Specifying Acoustical Performance of Sound-Isolating
Enclosures
This standard is issued under the fixed designation E1704; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ANSI Standards:
ANSI S1.4 Specification for Sound Level Meters
1.1 The guide covers the development of criteria for the
ANSIS3.1 MaximumPermissibleAmbientNoiseLevelsfor
acoustical performance of a broad variety of acoustical enclo-
Audiometric Test Rooms
sures by identifying information necessary to unambiguously
ANSI S3.6 Specification for Audiometers
describe acoustical performance. This guide is not a standard
ANSI S12.31–S12.35 Methods for Determining the Sound
ASTM specification for a sound-isolating enclosure.
Power Levels of Machines and Equipment
1.2 Excluded from the scope of this guide are technical
2.3 ISO Standard:
considerations for enclosure design that do not pertain directly
ISO 3741–3745 Acoustics—Methods for Determining the
to acoustical performance.
Sound Power Levels of Machines and Equipment
1.3 This standard does not purport to address all of the
2.4 Government Standard:
safety concerns, if any, associated with its use. It is the
29 CFR 1910.95 Occupational Noise Exposure [Occupa-
responsibility of the user of this standard to establish appro-
tional Safety and Health Administration]
priate safety, health, and environmental practices and deter-
2.5 Other Standard:
mine the applicability of regulatory limitations prior to use.
VDI 2711 Schallschutz durch Kapeslung [Verein Deutscher
1.4 This international standard was developed in accor-
Ingeireure, Beuth Verlag GmbH, Berlin] [German] [Noise
dance with internationally recognized principles on standard-
Control by the Use of Enclosures]
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3. Terminology
mendations issued by the World Trade Organization Technical
3.1 Definitions:
Barriers to Trade (TBT) Committee.
3.1.1 Standard definitions of acoustical terms may be found
2. Referenced Documents
in Terminology C634.
3.2 Definitions of Terms Specific to This Standard:
2.1 ASTM Standards:
3.2.1 A-weighted sound pressure level—sound pressure
C423 Test Method for SoundAbsorption and SoundAbsorp-
level measurements made with the A-weighting filter applied
tion Coefficients by the Reverberation Room Method
as defined in ANSI S1.4, denoted L in this guide.
C634 Terminology Relating to Building and Environmental PA
Acoustics
3.2.2 C-weighted sound pressure level—sound pressure
E336 Test Method for Measurement of Airborne Sound level measurements made with the C-weighting filter applied
Attenuation between Rooms in Buildings
as defined in ANSI S1.4, denoted L in this guide.
PC
E413 Classification for Rating Sound Insulation
3.2.3 enclosure—a structure, usually free-standing, which
E596 Test Method for Laboratory Measurement of Noise
substantially or completely encloses a given space or object.
Reduction of Sound-Isolating Enclosures
Thisdoesnotincludebarrierwalls,partitionswithinabuilding,
or other partial structures.
This guide is under the jurisdiction ofASTM Committee E33 on Building and
EnvironmentalAcousticsandisthedirectresponsibilityofSubcommitteeE33.03on
Sound Transmission. Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved Oct. 1, 2018. Published November 2018. Originally 4th Floor, New York, NY 10036, http://www.ansi.org.
approved in 1995. Last previous edition approved in 2010 as E1704 – 95 (2010). Available from International Organization for Standardization (ISO), 1, ch. de
DOI: 10.1520/E1704-95R18. la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://
For referenced ASTM standards, visit the ASTM website, www.astm.org, or www.iso.ch.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from the Superintendent of Documents, U.S. Government Printing
Standards volume information, refer to the standard’s Document Summary page on Office, Washington, DC 20402.
the ASTM website. Available from Beuth Verlag GmbH, Burggrafenstrasse 4-7, 1000 Berlin 30.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1704 − 95 (2018)
3.2.4 enclosure-generated noise—sound created by the op- 4.6 A non-mandatory model specification Appendix X2 is
eration of the enclosure systems, such as lighting and ventila- included that embraces both specification types. It also serves
tion. as a guide for identifying and gathering information necessary
to the manufacturer for designing the enclosure.
3.2.5 level reduction—for the purposes of this guide, the
arithmetic difference between sound pressure levels at a
5. Significance and Use
specific location before and after the installation of the
5.1 This guide can be used to produce a specification for the
enclosure, expressed in decibels.
acoustical performance of an enclosure.
3.2.6 level reduction specification—specification of the
5.2 This guide is intended for those familiar with basic
acousticalperformanceofanenclosurebystatingthereduction
concepts of acoustics.
in sound pressure level caused by the enclosure.
5.3 Although this guide provides detailed guidance in mat-
3.2.7 personnel enclosure—an enclosure designed to keep
ters relating to specification of acoustical enclosures, it is not a
sound energy from personnel or equipment therein. Examples
substitute for the experience and judgment of an acoustical or
of personnel enclosures include but are not limited to audio-
noise control professional.
metricbooths,in-plantoffices,broadcastbooths,andacoustical
5.3.1 This guide calls for measurements common within
test chambers.
acoustical practice.
3.2.8 pre-installation sound pressure levels—the sound
5.3.2 The more critical the performance requirements of the
pressure levels, as a function of frequency, that are present enclosure, the more the user should consider seeking the
prior to the installation of the enclosure. In most cases this is
services of an acoustics or noise control professional.
determined by measuring the ambient sound pressure levels in
5.4 The specifying of a sound-isolating enclosure has three
the host area but in some cases, such as new construction, the
sequential steps:
sound pressure levels must be predicted.
5.4.1 Determine the sound pressure levels that exist at
specific locations prior to the introduction of the enclosure,
3.2.9 sound pressure level specification—specification of
the acoustical performance of an enclosure by stating the
NOTE 1—In the case of new construction, the sound pressure level is
maximum sound pressure levels that shall exist after installa-
often estimated from the sound power levels of noise-emitting equipment
tion.
and a general description of the acoustical properties of the environment.
5.4.2 Determine the maximum permissible sound pressure
3.2.10 source enclosure—an enclosure designed to keep
levels that must exist at the same locations after the introduc-
sound energy from personnel or equipment on the outside.
tion of the enclosure, and
Such applications include, but are not limited to, equipment
5.4.3 Determine the required enclosure level reduction. The
silencing, secure communications, music practice, and acous-
requiredisolationisrelatedtothedifferencebetweenthesound
tical testing.
pressure levels before and after the introduction of the enclo-
sure.
4. Summary of Guide
5.5 Many specifications are for multiple enclosures or
4.1 An explanation of the determination and subsequent
enclosures with multiple functions, or both. It is beyond the
specification of acoustical performance of sound-isolating
scope of this guide to provide detailed guidance for every
enclosures is presented.
possible combination. Separate specifications for each source-
4.2 Two types of specifications are described in this guide.
enclosure-receiver combination should be used in such a case.
The recommended method (sound pressure level specification)
5.6 The type of specification that should be selected de-
is to specify the maximum permissible sound pressure levels
pends both on the purpose of the enclosure and how crucial its
that may be present after installation of the enclosure. The
performance is. In general:
alternatemethod(levelreductionspecification)istospecifythe
5.6.1 If exceeding a particular maximum permissible sound
enclosure’s level reduction.
pressure level spectrum would render the enclosure
4.3 Thetypeofspecificationselecteddependslargelyonthe
unsuccessful, a sound pressure level specification should be
enclosure application and the data available. A sound pressure
used.
level specification usually applies to a specific site, while the
5.6.1.1 Thisguideassignsallphasesofacousticaldesignare
level reduction specification may have broader application.
delegated to the supplier. Compliance is usually more easily
Also,thesoundpressurelevelspecificationismoreappropriate
verified than with the level reduction method.
where specific sound pressure levels are required, while the
5.6.2 If the criteria for the success of the enclosure are less
level reduction specification reflects a more general interest in
stringent or not related to a specific maximum permissible
amounts of noise level reduction.
spectrum, a level reduction specification may be used.
4.4 SomeguidanceisprovidedinAppendixX1onselecting
6. Recommended Specifications
a specification type based on the enclosure application and the
6.1 The sound pressure level specification specifies the
information available.
maximum permissible sound pressure levels that may exist
4.5 Substantial guidance is given on the essential acoustical either inside or outside the enclosure after installation. Pre-
data that must be compiled. installation sound pressure levels must also be presented.
E1704 − 95 (2018)
6.1.1 Maximumsoundpressurelevelsshouldbespecifiedin 6.2.1.1 The safety factor helps ensure compliance by ac-
one-third-octave bands whenever possible to allow a detailed counting for unforeseen complications due to changes in site
fit to the requirements. Octave band sound pressure levels are conditions, or unusual acoustical interactions of the enclosure
appropriate where the noise spectrum is broad band and free of and the space. The more critical the successful performance of
prominent tones. the enclosure, the larger the selected safety factor should be.
6.1.2 The desired post-installation sound pressure level may Typical values are:
also be described by a single number descriptor, such as
Not Critical. SF = 0 dB
Moderate. SF = 3 dB
A-weighted sound pressure level or NC or RC ratings. In this
Conservative. SF = 6 dB
event, the pre-installation one-third-octave band sound pres-
NOTE 3—In practice safety factor size varies with frequency as well as
sure levels at or around the installation site shall also be
with importance. The user should consider applying stringent safety
provided.
factors only in bands where they are most needed in order to avoid
over-designing the enclosure.
NOTE 2—Other single number ratings for noise may also be available.
For further information see ASHRAE Handbook.
6.2.1.2 The introduction of the enclosure may significantly
6.1.3 Measured sound pressure levels are preferred. When alter the sound field near the noise source, increasing both the
not available, such as in the case of new construction, the effective value of L and the required level reduction. This
following information is usually considered an acceptable effect is important when either the physical volume or the
substitute to allow estimation of sound pressure levels: sound absorption coefficients of the surfaces around the noise
source are reduced by a factor of two or more. In this case,
6.1.3.1 The rated or measured sound power level (here
denoted L ) of equipment and, detailed information on noise source and its pre-installation
W
surroundings should accompany the specification. In addition,
6.1.3.2 Adescription of the host environment, including the
a larger safety factor should be considered.
relative locations of sources of noise, personnel, and the
6.2.2 The level reduction of enclosures is typically quanti-
enclosure. Some loss of accuracy should be expected.
fied by the manufacturer in laboratory prototype testing. Noise
6.1.4 Inaccurate measurement of sound pressure levels can
reduction (NR) is measured per Test Method E596, and noise
result from unsteady or intermittent sources of noise during
isolation class (NIC) is calculated per Classification E413. For
measurement, changes in site conditions after measurement
the purposes of this guide, noise reduction data are an
(for example, significant sources of noise arising between
acceptable equivalent for level reduction.
measurement and installation), strong low-frequency content
6.2.2.1 Custom designs are typically not tested, due to cost.
(L −L > 15), and general inexperience with acoustical
PC PA
6.2.2.2 The actual enclosure being specified may differ in
measurements.
certain particulars from prototypes tested.
6.1.5 Maximum permissible sound pressure levels are often
6.2.2.3 Because of variations in manufacturing materials
prescribed for particular applications by standards or regula-
and methods and changes in test standards, test results should
tory documents. A short list includes, but is not limited to,
be no older than five years.
hearing conservation regulations, architectural specifications,
6.2.2.4 Laboratory noise reduction data obtained in accor-
human comfort, speech intelligibility, speech privacy, and
dance with Test Method E596 in prototype testing are often
acoustical test standards. Common specific cases are cited in
accepted as performance verification.
Appendix X1.
6.2.3 Anenclosuremayprovidetherequiredlevelreduction
6.1.6 The maximum permissible interior or exterior sound
withoutachievingaparticularsoundpressurelevelspectrumin
pressure levels should not be exceeded with all sources of
the protected space. As an example, sound pressure levels
enclosure-generated noise in normal operation.
inside an enclosure will be considerably higher when the
6.2 Thelevelreductionspecificationidentifie
...