Standard Test Method for Laboratory Measurement of Noise Reduction of Sound-Isolating Enclosures

SIGNIFICANCE AND USE
The noise reduction of an enclosure is a property of the enclosure, the location of the sound source used to measure noise reduction, and the space in which the enclosure is placed. It is not a property of the enclosure alone, and its measurement under different conditions can be expected to give different results. When the noise reduction is measured in accordance with this test method, the sound source is outside the enclosure and the sound field outside the enclosure approximates a diffuse sound field. Measurements made in accordance with this test method can be expected to be reproducible from one laboratory to another.
The noise reduction measured in accordance with this test method may be used for the following purposes:
To rank the order of sound-isolating enclosures according to noise isolation class, NIC.
To estimate the highest one-third octave band sound pressure levels that can occur outside the enclosure without exceeding specified sound pressure levels inside the enclosure.
To estimate the one-third octave band sound pressure levels that will occur inside the enclosure with specified sound pressure levels outside.
The noise reduction measured in accordance with this test method may not estimate accurately the isolation that the enclosure will provide when it is used to isolate a noise source inside it from the space outside. The user should be cautious when using noise reductions measured by this test method to evaluate enclosures used to enclose noise sources.
Sound-isolating enclosures are frequently made from prefabricated modular panels. The noise reduction measured by this test method applies to the complete enclosure and not to individual panels from which it is made and cannot be used to infer the sound transmission loss of the individual panels.
Specifications for sound-isolating enclosures may include reference to noise reduction and noise isolation class measured in accordance with this test method.
SCOPE
1.1 This test method covers the reverberation room measurement of the noise reduction of sound-isolating enclosures.
1.2 The noise isolation class may be determined from the noise reduction measured in accordance with this test method.
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 and health practices and determine the applicability of regulatory limitations prior to use.

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Publication Date
31-Mar-2009
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ASTM E596-96(2009) - Standard Test Method for Laboratory Measurement of Noise Reduction of Sound-Isolating Enclosures
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E596 − 96(Reapproved 2009)
Standard Test Method for
Laboratory Measurement of Noise Reduction of Sound-
1
Isolating Enclosures
This standard is issued under the fixed designation E596; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3.2.1 sound-isolating enclosure—any enclosure that com-
pletely encloses a space, is intended to provide sound isolation
1.1 This test method covers the reverberation room mea-
for the enclosed space, and can be tested in a reverberation
surement of the noise reduction of sound-isolating enclosures.
room.
1.2 The noise isolation class may be determined from the
3.2.2 useful volume of a sound isolating enclosure—the part
noise reduction measured in accordance with this test method.
of the space inside the enclosure in which the noise reduction
1.3 This standard does not purport to address all of the
is of interest. For example, in an audiometric booth, the useful
safety concerns, if any, associated with its use. It is the
volume is the part of the space inside the booth where a test
responsibility of the user of this standard to establish appro-
subject’s head is likely to be during audiometric tests.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Test Method
4.1 The enclosure to be tested is placed in a reverberation
2. Referenced Documents
room and prepared for testing. The background noise levels
2
2.1 ASTM Standards:
inside the enclosure and in the reverberation room are mea-
C423 Test Method for SoundAbsorption and SoundAbsorp-
sured in one-third octave bands. After bands of random noise
tion Coefficients by the Reverberation Room Method
are produced in the reverberation room, one-third octave band
C634 Terminology Relating to Building and Environmental
sound pressure levels are measured at several points in the
Acoustics
reverberation room and at appropriate points inside the enclo-
E413 Classification for Rating Sound Insulation
sure. The noise reduction in each one-third octave band is the
2.2 ANSI Standards:
difference between the space-averaged sound pressure level in
3
S1.4 Specification for Sound Level Meters
the reverberation room and the space-averaged sound pressure
S1.11 Specification for Octave-Band and Fractional-Octave-
level inside the enclosure. The noise isolation class (NIC) may
3
Band Analog and Digital Filters
be determined from the noise reduction data.
3. Terminology
5. Significance and Use
3.1 Definitions and Symbols—Except as noted in 3.2, the
5.1 The noise reduction of an enclosure is a property of the
terms and symbols used in this test method are defined in
enclosure, the location of the sound source used to measure
Terminology C634.
noise reduction, and the space in which the enclosure is placed.
3.2 Definitions of Terms Specific to This Standard:
It is not a property of the enclosure alone, and its measurement
under different conditions can be expected to give different
results. When the noise reduction is measured in accordance
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
with this test method, the sound source is outside the enclosure
and Environmental Acoustics and is the direct responsibility of Subcommittee
and the sound field outside the enclosure approximates a
E33.03 on Sound Transmission.
diffuse sound field. Measurements made in accordance with
Current edition approved April 1, 2009. Published August 2009. Originally
approved in 1977. Last previous edition approved in 2002 as E596 – 96 (2002).
this test method can be expected to be reproducible from one
DOI: 10.1520/E0596-96R09.
laboratory to another.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2 The noise reduction measured in accordance with this
Standards volume information, refer to the standard’s Document Summary page on
test method may be used for the following purposes:
the ASTM website.
3
5.2.1 To rank the order of sound-isolating enclosures ac-
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. cording to noise isolation class, NIC.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E596 − 96 (2009)
5.2.2 To estimate the highest one-third octave band sound 6.2 Background Noise
...

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