ASTM C423-02ae1

Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method

SCOPE
1.1 This test method covers the measurement of sound absorption in a reverberation room by measuring decay rate. Procedures for measuring the absorption of a room, the absorption of an object, such as an office screen, and the sound absorption coefficients of a specimen of sound absorptive material, such as acoustical ceiling tile, are described.
1.2Field Measurements—Although this test method primarily covers laboratory measurements, the test method described in 4.1 can be used for making field measurements of the absorption of rooms (see also 5.5). A non-standard method to measure the absorption of rooms in the field is described in Appendix X2.
1.3 This test method includes information on laboratory accreditation (see Annex A1), asymmetrical screens (see Annex A2), and reverberation room qualification (see Annex A3).
1.4  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.

General Information

• Status: Historical
• Publication Date: 09-Dec-2002
• ICS: 91.120.20 - Acoustics in building. Sound insulation
• Technical Committee: E33 - Building and Environmental Acoustics
• Drafting Committee: E33.01 - Sound Absorption

Relations

• Replaces: ASTM C423-02a - Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
• Effective Date: 10-Dec-2002
• Replaced By: ASTM C423-06 - Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
• Effective Date: 01-Dec-2006
• Referred By: ASTM D5456-21e1 - Standard Specification for Evaluation of Structural Composite Lumber Products
• Effective Date: 10-Dec-2002
• Referred By: ASTM C1014-17 - Standard Specification for Spray-Applied Mineral Fiber Thermal and Sound Absorbing Insulation
• Effective Date: 10-Dec-2002
• Referred By: ASTM C842-05(2021) - Standard Specification for Application of Interior Gypsum Plaster
• Effective Date: 10-Dec-2002
• Referred By: ASTM C384-04(2022) - Standard Test Method for Impedance and Absorption of Acoustical Materials by Impedance Tube Method
• Effective Date: 10-Dec-2002
• Referred By: ASTM C1410-17(2023) - Standard Specification for Cellular Melamine Thermal and Sound-Absorbing Insulation
• Effective Date: 10-Dec-2002
• Referred By: ASTM C1482-23 - Standard Specification for Polyimide Flexible Cellular Thermal and Sound Absorbing Insulation
• Effective Date: 10-Dec-2002
• Referred By: ASTM C1685-15(2021) - Standard Specification for Pneumatically Applied High-Temperature Fiber Thermal Insulation for Industrial Applications
• Effective Date: 10-Dec-2002
• Referred By: ASTM C1071-19 - Standard Specification for Fibrous Glass Duct Lining Insulation (Thermal and Sound Absorbing Material)
• Effective Date: 10-Dec-2002
• Referred By: ASTM E2813-18 - Standard Practice for Building Enclosure Commissioning
• Effective Date: 10-Dec-2002
• Referred By: ASTM E1264-23 - Standard Classification for Acoustical Ceiling Products
• Effective Date: 10-Dec-2002
• Referred By: ASTM E2235-04(2020) - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods
• Effective Date: 10-Dec-2002
• Referred By: ASTM E1222-22 - Standard Test Method for Laboratory Measurement of the Insertion Loss of Pipe Lagging Systems
• Effective Date: 10-Dec-2002
• Referred By: ASTM C844-15(2021) - Standard Specification for Application of Gypsum Base to Receive<brk/> Gypsum Veneer Plaster
• Effective Date: 10-Dec-2002

Standards Content (Sample)

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
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Designation:C423–02a
Standard Test Method for
Sound Absorption and Sound Absorption Coefficients by
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the Reverberation Room Method
This standard is issued under the fixed designation C 423; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
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e NOTE—Adjunct references were corrected editorially in April 2006.
1. Scope S1.6 Preferred Frequencies, Frequency Levels, and Band
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Numbers for Acoustical Measurements
1.1 This test method covers the measurement of sound
S1.11 Specification for Octave-Band and Fractional-
absorption in a reverberation room by measuring decay rate.
4
Octave-Band Analog and Digital Filters
Procedures for measuring the absorption of a room, the
S1.26 Method for the Calculation of the Absorption of
absorption of an object, such as an office screen, and the sound
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Sound by the Atmosphere
absorption coefficients of a specimen of sound absorptive
2.3 ASTM Adjuncts:
material, such as acoustical ceiling tile, are described.
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Historical Applications Note on Sound Absorber
1.2 Field Measurements—Although this test method prima-
rily covers laboratory measurements, the test method described
3. Terminology
in 4.1 can be used for making field measurements of the
3.1 Except as noted in 3.3, the terms and symbols used in
absorption of rooms (see also 5.5). A non-standard method to
this test method are defined in Terminology C 634. The
measure the absorption of rooms in the field is described in
following definition is not currently included in Terminology
Appendix X2.
C 634:
1.3 This test method includes information on laboratory
3.1.1 sound absorption average, SAA—a single number
accreditation (see Annex A1), asymmetrical screens (see An-
rating, the average, rounded off to the nearest 0.01, of the
nexA2), and reverberation room qualification (seeAnnexA3).
sound absorption coefficients of a material for the twelve
1.4 This standard does not purport to address all of the
one-third octave bands from 200 through 2500 Hz, inclusive,
safety concerns, if any, associated with its use. It is the
measured according to this test method.
responsibility of the user of this standard to establish appro-
3.1.1.1 Discussion—The sound absorption coefficients shall
priate safety and health practices and determine the applica-
be rounded off to the nearest 0.01 before averaging. If the
bility of regulatory limitations prior to use.
unrounded average is an exact midpoint, round to the next
2. Referenced Documents higher multiple of 0.01. For example, report 0.625 as 0.63.
2 3.2 In previous versions of this test method a single number
2.1 ASTM Standards:
rating, called the noise reduction coefficient (NRC), was
C 634 Terminology Relating to Environmental Acoustics
defined as follows:
E 548 Guide for General Criteria Used for Evaluating
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9Round the average of the sound absorption coefficients
Laboratory Competence
for 250, 500, 1000, and 2000 Hz to the nearest multiple
E 795 Practices for Mounting Test Specimens During
of 0.05. If the unrounded average is an exact midpoint,
Sound Absorption Tests round to the next higher multiple of 0.05. For example,
0.625 and 0.675 would be reported as 0.65 and 0.70, respectively.9
2.2 ANSI Standards:
The noise reduction coefficient shall be reported in order to
provide comparison with values reported in the past see
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This test method is under the jurisdiction of ASTM Committee E33 on 12.1.3).
EnvironmentalAcousticsandisthedirectresponsibilityofSubcommitteeE33.01on
3.3 Definition of Term Specific to This Standard—The
Sound Absorption.
followingtermhasthemeaningnotedforthistestmethodonly:
Current edition approved Dec. 10, 2002. Published April 2003. Originally
approved in 1958. Last previous edition approved 2002 as C 423 – 02.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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C423–02a
TABLE 1 Requirements for the Temperature and the Relative
3.3.1 outputinterval, Dt,[T],s—ofareal-timea
...