ASTM C423-02

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-Apr-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 C423-01 - Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
• Effective Date: 10-Apr-2002
• Replaced By: ASTM C423-02a - Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
• Effective Date: 10-Dec-2002
• Referred By: ASTM E1414/E1414M-21a - Standard Test Method for Airborne Sound Attenuation Between Rooms Sharing a Common Ceiling Plenum
• Effective Date: 10-Apr-2002
• Referred By: ASTM E1111/E1111M-14(2022) - Standard Test Method for Measuring the Interzone Attenuation of Open Office Components
• Effective Date: 10-Apr-2002
• Referred By: ASTM C842-05(2021) - Standard Specification for Application of Interior Gypsum Plaster
• Effective Date: 10-Apr-2002
• Referred By: ASTM E90-09(2016) - Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
• Effective Date: 10-Apr-2002
• Referred By: ASTM C1534-22 - Standard Specification for Flexible Polymeric Foam Sheet Insulation Used as a Thermal and Sound Absorbing Liner for Duct Systems
• Effective Date: 10-Apr-2002
• Referred By: ASTM D5456-21e1 - Standard Specification for Evaluation of Structural Composite Lumber Products
• Effective Date: 10-Apr-2002
• Referred By: ASTM F2154-13(2019) - Standard Specification for Sound-Absorbing Board, Fibrous Glass, Perforated Fibrous Glass Cloth Faced
• Effective Date: 10-Apr-2002
• Referred By: ASTM C1685-15(2021) - Standard Specification for Pneumatically Applied High-Temperature Fiber Thermal Insulation for Industrial Applications
• Effective Date: 10-Apr-2002
• Referred By: ASTM E492-22 - Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine
• Effective Date: 10-Apr-2002
• Referred By: ASTM E1264-23 - Standard Classification for Acoustical Ceiling Products
• Effective Date: 10-Apr-2002
• Referred By: ASTM E1374-18e1 - Standard Guide for Office Acoustics and Applicable ASTM Standards
• Effective Date: 10-Apr-2002
• Referred By: ASTM E2813-18 - Standard Practice for Building Enclosure Commissioning
• Effective Date: 10-Apr-2002
• Referred By: ASTM C384-04(2022) - Standard Test Method for Impedance and Absorption of Acoustical Materials by Impedance Tube Method
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 423 – 02
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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1. Scope Numbers for Acoustical Measurements
S1.11 Specification for Octave-Band and Fractional-
1.1 This test method covers the measurement of sound
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Octave-Band Analog and Digital Filters
absorption in a reverberation room by measuring decay rate.
S1.26 Method for the Calculation of the Absorption of
Procedures for measuring the absorption of a room, the
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Sound by the Atmosphere
absorption of an object, such as an office screen, and the sound
absorption coefficients of a specimen of sound absorptive
3. Terminology
material, such as acoustical ceiling tile, are described.
3.1 Except as noted in 3.3, the terms and symbols used in
1.2 Field Measurements—Although this test method prima-
this test method are defined in Terminology C 634. The
rily covers laboratory measurements, the test method described
following definition is not currently included in Terminology
in 4.1 can be used for making field measurements of the
C 634:
absorption of rooms (see also 5.5). A non-standard method to
3.1.1 sound absorption average, SAA—a single number
measure the absorption of rooms in the field is described in
rating, the average, rounded off to the nearest 0.01, of the
Appendix X2.
sound absorption coefficients of a material for the twelve
1.3 This test method includes information on laboratory
one-third octave bands from 200 through 2500 Hz, inclusive,
accreditation (see Annex A1), asymmetrical screens (see An-
measured according to this test method.
nex A2), and reverberation room qualification (see Annex A3).
3.1.1.1 Discussion—The sound absorption coefficients shall
1.4 This standard does not purport to address all of the
be rounded off to the nearest 0.01 before averaging. If the
safety concerns, if any, associated with its use. It is the
unrounded average is an exact midpoint, round to the next
responsibility of the user of this standard to establish appro-
higher multiple of 0.01. For example, report 0.625 as 0.63.
priate safety and health practices and determine the applica-
3.2 In previous versions of this test method a single number
bility of regulatory limitations prior to use.
rating, called the noise reduction coefficient (NRC), was
2. Referenced Documents defined as follows:
9Round the average of the sound absorption coefficients
2.1 ASTM Standards:
for 250, 500, 1000, and 2000 Hz to the nearest multiple
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C 634 Terminology Relating to Environmental Acoustics
of 0.05. If the unrounded average is an exact midpoint,
E 548 Practice for Generic Criteria for Use in Evaluation of
round to the next higher multiple of 0.05. For example,
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0.625 and 0.675 would be reported as 0.65 and 0.70, respectively.9
Testing and Inspection Agencies
E 795 Practices for Mounting Test Specimens During
The noise reduction coefficient shall be reported in order to
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Sound Absorption Tests
provide comparison with values reported in the past see
2.2 ANSI Standards:
12.1.3).
S1.6 Preferred Frequencies, Frequency Levels, and Band
3.3 Definition of Term Specific to This Standard—The
following term has the meaning noted for this test method only:
3.3.1 output interval, Dt, [T], s—of a real-time analyzer, the
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This test method is under the jurisdiction of ASTM Committee E33 on
time between successive outputs; this time is not necessarily
Environmental Acoustics and is the direct responsibility of Subcommittee E33.01 on
the same as the integration time.
Sound Absorption.
Current edition approved April 10, 2002. Published June 2002. Originally
published as C 423-58-T. Last previous edition C 423 – 01.
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Annual Book of ASTM Standards, Vol 04.06.
Available from American National Standards Institute, 1430 Broadway, New
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Annual Book of ASTM Standards, Vol 14.02.
York, NY 10018.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C423–02
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4. Summary of Test Method 5.3 Diffraction effects usually cause the apparent area of a
specimen to be greater than its geometrical area, thereby
4.1 Measurement of the Sound Absorption of a Roo
...