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ASTM E2235-04(2012)

(Test Method)

Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods

Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods

SIGNIFICANCE AND USE
Several ASTM test methods to evaluate the sound-insulating properties of building elements require the measurement of room sound absorption as part of the procedure. The room sound absorption in these standards appears in an equation in the form 10 log (x/A), where x is a quantity with the same units as A, m2. Room sound absorption is calculated from the decay rate using Eq 1.
The requirements of this standard have been chosen so the uncertainty associated with the measurement of room sound absorption will be acceptably small so long as the logarithm of the absorption is being used in calculations.
Other test methods should specify explicitly that they make use of this test method.
Where measurement requirements in the parent standard differ from those given here, the requirements in the parent standard shall be satisfied.
This test method shall not be used when room sound absorption or decay rate is to be used directly to satisfy some criterion, for example in a room that must not be overly reverberant so speech will be intelligible.
Note 1—The uncertainty of the room sound absorption obtained will usually be too high and additional measurements are necessary.
Any companion standard may specify the use of the procedures in this method for determining whether the decay rates in a room are slow enough to satisfy the requirements of the companion standard. The measured decay rates shall still be used only to calculate the logarithm of the room absorption.
SCOPE
1.1 This test method covers the measurement of sound decay rate in rooms and the calculation of the sound absorption of the room and its contents. The sound absorption so calculated may be used in calculations in sound insulation test methods.
1.2 The method shall be used only in conjunction with other test methods where the logarithm of the sound absorption is used in formulas. It is not sufficiently precise for use in situations where room sound absorption is to be used without taking logarithms.
1.3 For laboratory measurements of the sound absorption of materials and objects, Test Method C423 should be used.
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
31-Mar-2012
ICS
91.120.20 - Acoustics in building. Sound insulation
Technical Committee
E33 - Building and Environmental Acoustics
Drafting Committee
E33.01 - Sound Absorption
Current Stage
Ref Project

Relations

Replaces
ASTM E2235-04e1 - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods
Effective Date
01-Apr-2012
Replaced By
ASTM E2235-04(2020) - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods
Effective Date
01-Apr-2020
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
01-Apr-2012
Referred By
ASTM E90-09(2016) - Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
Effective Date
01-Apr-2012
Referred By
ASTM C423-23 - Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
Effective Date
01-Apr-2012
Referred By
ASTM C634-22 - Standard Terminology Relating to Building and Environmental Acoustics
Effective Date
01-Apr-2012
Referred By
ASTM E966-18a - Standard Guide for Field Measurements of Airborne Sound Attenuation of Building Facades and Facade Elements
Effective Date
01-Apr-2012
Referred By
ASTM E1007-21 - Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures
Effective Date
01-Apr-2012
Referred By
ASTM E336-23 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
Effective Date
01-Apr-2012

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ASTM E2235-04(2012) - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test MethodsASTM E2235-04(2012) - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods
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ASTM E2235-04(2012) - Standard Test Method for Determination of Decay Rates for Use in Sound Insulation Test Methods
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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
Designation: E2235 − 04 (Reapproved 2012)
Standard Test Method for
Determination of Decay Rates for Use in Sound Insulation
1
Test Methods
This standard is issued under the fixed designation E2235; 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.
INTRODUCTION
This test method is part of a set of methods used to evaluate the sound-insulating properties of
building elements. It is intended for use in conjunction with methods for measuring the transmission
of sound through a partition or partition element in a laboratory or in a building. These methods
include the laboratory measurement of airborne sound transmission loss of building partitions and
elements(TestMethodE90),themeasurementofsoundisolationinbuildings(TestMethodE336),the
laboratory measurement of impact sound transmission through floors (Test Method E492), the
measurement of impact sound transmission in buildings (Test Method E1007), the measurement of
sound transmission through building facades and facade elements (Guide E966), and the measurement
of sound transmission through a common plenum between two rooms (Test Method E1414).
1. Scope 2. Referenced Documents
2
1.1 This test method covers the measurement of sound 2.1 ASTM Standards:
decay rate in rooms and the calculation of the sound absorption C423 Test Method for SoundAbsorption and SoundAbsorp-
of the room and its contents. The sound absorption so calcu- tion Coefficients by the Reverberation Room Method
lated may be used in calculations in sound insulation test C634 Terminology Relating to Building and Environmental
methods. Acoustics
E90 Test Method for Laboratory Measurement of Airborne
1.2 The method shall be used only in conjunction with other
Sound Transmission Loss of Building Partitions and
test methods where the logarithm of the sound absorption is
Elements
used in formulas. It is not sufficiently precise for use in
E336 Test Method for Measurement of Airborne Sound
situations where room sound absorption is to be used without
Attenuation between Rooms in Buildings
taking logarithms.
E492 Test Method for Laboratory Measurement of Impact
1.3 For laboratory measurements of the sound absorption of
Sound Transmission Through Floor-Ceiling Assemblies
materials and objects, Test Method C423 should be used.
Using the Tapping Machine
1.4 This standard does not purport to address all of the
E966 Guide for Field Measurements of Airborne Sound
safety concerns, if any, associated with its use. It is the Attenuation of Building Facades and Facade Elements
responsibility of the user of this standard to establish appro-
E1007 Test Method for Field Measurement of Tapping
priate safety and health practices and determine the applica-
Machine Impact Sound Transmission Through Floor-
bility of regulatory limitations prior to use. Ceiling Assemblies and Associated Support Structures
E1414 Test Method for Airborne Sound Attenuation Be-
tween Rooms Sharing a Common Ceiling Plenum
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
and Environmental Acoustics and is the direct responsibility of Subcommittee
2
E33.01 on Sound Absorption. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2012. Published August 2012. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ε1
approved in 2003. Last previous edition approved in 2004 as E2235 – 04 . DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2235-04R12. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2235 − 04 (2012)
3
2.2 ANSI Standards: 5.3 Other test methods should specify explicitly that they
S1.4 Specification for Sound-Level Meters make use of this test method.
S1.6 Standard Preferred Frequencies, Frequency Levels, and
5.4 Wheremeasurementrequirementsintheparentstandard
Band Numbers for Acoustical Measurements
differ from those given here, the requirements in the parent
S1.11 Specification for Octave-band and Fractional-Octave-
standard shall be satisfied.
Band Analog and Digital Filters
5.5 This test method shall not be used when room sound
absorption or decay rate is to be used directly to satisfy some
3. Terminology
criterion, for example in a room that must not be overly
3.1 Definitions of the acoustical terms used in this test
reverberant so speech will be intelligible.
method are given in Terminology C634.
NOTE 1—The uncertainty of the room sound absorpt
...

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ASTM C423-23(Test Method)
Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method

SIGNIFICANCE AND USE
5.1 Measurement of the sound absorption of a room is part of the procedure for other acoustical measurements, such as determining the sound power level of a noise source or the sound transmission loss of a partition. It is also used in certain calculations such as predicting the sound pressure level in a room when the sound power level of a noise source in the room is known.  
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5.3 Diffraction effects4 usually cause the apparent area of a specimen to be greater than its geometrical area, thereby increasing the coefficients measured according to this test method. When the test specimen is highly absorptive, these values may exceed unity.  
5.4 The coefficients measured by this test method should be used with caution because not only are the areas encountered in practical usage usually larger than the test specimen, but also the sound field is rarely diffuse. In the laboratory, measurements must be made under reproducible conditions, but in practical usage the conditions that determine the effective absorption are often unpredictable. Regardless of the differences and the necessity for judgment, coefficients measured by this test method have been used successfully by architects and consultants in the acoustical design of architectural spaces.  
5.5 Field Measurements—When sound absorption measurements are made in a building in which the size and shape of the room are not under the operator's control, the approximation to a diffuse sound field is not likely to be very close. This matter should be considered when assessing the accuracy of measurements made under field conditions. (See Te...
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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.  
1.2 Field Measurements—Although this test method 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 method to measure the absorption of rooms in the field is described in Test Method E2235.  
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 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
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ASTM E336-23(Test Method)
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5.1 The main part of this standard uses procedures originally developed for laboratory measurements of the sound transmission loss of partitions. These procedures assume that the rooms in which the measurements are performed have a sound field that reasonably approximates a diffuse field. Sound pressure levels in such rooms are reasonably uniform throughout the room and average levels vary inversely with the logarithm of the room sound absorption. Not all rooms will satisfy these conditions. Experience and controlled studies (1)6 have shown that the test method is applicable to smaller spaces normally used for work or living, such as rooms in multi-family dwellings, hotel guest rooms, meeting rooms, and offices with volumes less than 150 m3. The measures appropriate for such spaces are NR, NNR, and ATL. The corresponding single number ratings are NIC, NNIC and ASTC. The ATL and ASTC are measurable between larger spaces that meet a limitation on absorption in the spaces to provide uniform sound distribution.  
5.2 Annex A1 was developed for use in spaces that are very large (volume of 150 m3 or greater). Sound pressure levels during testing vary markedly across large rooms so that the degree of isolation varies strongly with distance from the common (separating) partition. This procedure evaluates the isolation observed near the partition. The appropriate measure is NR, and the appropriate single number rating is NIC.  
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FIG. 1 Direct (D) and Some Indirect or Flanking Paths (F and Dotted) in a Building  
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4.1 The sound absorption of a material that covers a flat surface depends not only on the physical properties of the material but also on the way in which the material is mounted over the surface. The mountings specified in these practices are intended to simulate in the laboratory conditions that exist in normal use.  
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3.1 Definitions—Terms and related definitions given in Section 4 are intended for use uniformly and consistently in all building and environmental acoustic test standards in which they appear.  
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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.  
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5.1 The spectrum of the noise in the room below the test specimen is determined by the following:  
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5.1.2 The acoustical response of the room below,  
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5.1.4 The nature of the actual impact itself.  
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1.1 This test method covers the laboratory measurement of impact sound transmission of floor-ceiling assemblies using a standardized tapping machine. It is assumed that the test specimen constitutes the primary sound transmission path into a receiving room located directly below and that a good approximation to a diffuse sound field exists in this room.  
1.2 Measurements may be conducted on floor-ceiling assemblies of all kinds, including those with floating-floor or suspended ceiling elements, or both, and floor-ceiling assemblies surfaced with any type of floor-surfacing or floor-covering materials.  
1.3 This test method prescribes a uniform procedure for reporting laboratory test data, that is, the normalized one-third octave band sound pressure levels transmitted by the floor-ceiling assembly due to the tapping machine.  
1.4 Laboratory Accreditation—The requirements for accrediting a laboratory for performing this test method are given in Annex A2.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
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Standard Test Method for Impedance and Absorption of Acoustical Materials by Impedance Tube Method

SIGNIFICANCE AND USE
5.1 The acoustical impedance properties of a sound absorptive material are related to its physical properties, such as airflow resistance, porosity, elasticity, and density. As such, the measurements described in this test method are useful in basic research and product development of sound absorptive materials.  
5.2 Normal incidence sound absorption coefficients are more useful than random incidence coefficients in certain situations. They are used, for example, to predict the effect of placing material in a small enclosed space, such as inside a machine.  
5.3 Estimates of the random incidence or statistical absorption coefficients for materials can be obtained from normal incidence impedance data. For materials that are locally reacting, that is, without sound propagation inside the material parallel to its surface, statistical absorption coefficients can be estimated from specific normal acoustic impedance values using an expression derived by London (1).5 Locally reacting materials include those with high internal losses parallel with the surface such as porous or fibrous materials of high density or materials that are backed by partitioned cavities such as a honeycomb core. Formulas for estimating random incidence sound absorption properties for both locally and bulk-reacting materials, as well as for multilayer systems with and without air spaces have also been developed (2).
SCOPE
1.1 This test method covers the use of an impedance tube, alternatively called a standing wave apparatus, for the measurement of impedance ratios and the normal incidence sound absorption coefficients of acoustical materials.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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.

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ASTM C522-03(2022)(Test Method)
Standard Test Method for Airflow Resistance of Acoustical Materials

SIGNIFICANCE AND USE
5.1 The specific airflow resistance of an acoustical material is one of the properties that determine its sound-absorptive and sound-transmitting properties. Measurement of specific airflow resistance is useful during product development, for quality control during manufacture, and for specification purposes.  
5.2 Valid measurements are made only in the region of laminar airflow where, aside from random measurement errors, the airflow resistance (R = P/U) is constant. When the airflow is turbulent, the apparent airflow resistance increases with an increase of volume velocity and the term “airflow resistance” does not apply.  
5.3 The specific airflow resistance measured by this test method may differ from the specific resistance measured by the impedance tube method in Test Method E384 for two reasons. In the presence of sound, the particle velocity inside a porous material is alternating while in this test method, the velocity is constant and in one direction only. Also, the particle velocity inside a porous material is not the same as the linear velocity measured outside the specimen.
SCOPE
1.1 This test method covers the measurement of airflow resistance and the related measurements of specific airflow resistance and airflow resistivity of porous materials that can be used for the absorption and attenuation of sound. Materials cover a range from thick boards or blankets to thin mats, fabrics, papers, and screens. When the material is anisotropic, provision is made for measurements along different axes of the specimen.  
1.2 This test method is designed for the measurement of values of specific airflow resistance ranging from 100 to 10 000 mks rayls (Pa·s/m) with linear airflow velocities ranging from 0.5 mm/s to 50 mm/s and pressure differences across the specimen ranging from 0.1 Pa to 250 Pa. The upper limit of this range of linear airflow velocities is a point at which the airflow through most porous materials is in partial or complete transition from laminar to turbulent flow.  
1.3 A procedure for accrediting a laboratory for the purposes of this test method is given in Annex A1.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4.1 Table 1 is provided for user to convert into cgs units.    
cgs acoustic ohm  
mks acoustic ohm (Pa·s/m3)  
105  
cgs rayl  
mks rayl (Pa·s/m)  
10    
cgs rayl/cm  
mks rayl/m (Pa·s/m2)  
103  
cgs rayl/in.  
mks rayl/m (Pa·s/m2)  
394  
mks rayl/in.  
mks rayl/m (Pa·s/m2)  
39.4  
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ASTM E1042-22(Classification)
Standard Classification for Acoustically Absorptive Materials Applied by Trowel or Spray

SIGNIFICANCE AND USE
4.1 Acoustically absorptive materials are used for the control of reverberation and echoes in rooms. This standard provides a classification method for acoustically absorptive materials applied directly to surfaces by trowel or by spray.
SCOPE
1.1 This classification covers materials applied by trowel or spray to surfaces for the purpose of increasing their acoustical absorption.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.

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ASTM
ASTM E1573-22(Test Method)
Standard Test Method for Measurement and Reporting of Masking Sound Levels Using A-Weighted and One-Third-Octave-Band Sound Pressure Levels

SIGNIFICANCE AND USE
5.1 Acoustical performance is dependent on many factors (see Guide E1374 for a discussion on general office acoustical considerations). One of these factors is the masking sound. The masking spectrum shape and level must conform within specified tolerances throughout the treated area. The measurement and recording of these parameters are addressed in this test method.  
5.2 The results from this test method are used to determine if the masking sound meets a particular specification.
SCOPE
1.1 This test method specifies the procedure used to measure the masking sound in terms of A-weighted and one-third-octave-band sound pressure levels.  
1.2 The results of this test method can be used to determine if and where the masking sound meets (or does not meet) a particular specification.  
1.3 This test method does not evaluate the overall acoustical environment. It is intended only to measure and report the masking sound levels.  
1.4 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.  
1.5 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.  
1.6 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.

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