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ASTM E477-06a

(Test Method)

Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers

Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers

SIGNIFICANCE AND USE
Specimens tested using this standard, for example, duct silencers, are used to control sound propagation through ventilation ducts. The results gathered from testing specimens to this standard can be used to estimate the reduction in fan sound levels in ducted airflow systems caused by including a sound attenuating device in the system. The device can be a component in a source-path-receiver analysis where calculations are performed to determine the resultant sound level in an occupied space. Proper selection of a sound attenuating device can enable a designer to achieve in-space background noise criteria.
The insertion loss of a silencer is a matter of degree, and varies with frequency and with the direction and speed of airflow. Because silencers partially obstruct the air path and provide resistance to airflow, two other effects must be quantified: pressure drop and airflow-generated noise. Both increase with increasing air speeds; thus data are required for several airflows to correctly characterize performance.
The aerodynamic results from testing specimens to the standard can be used as information for the system design engineer to determine the amount of static pressure drop resistance to be overcome by the system fan(s). Guidelines for appropriate maximum allowable pressure drop for a sound attenuating element have been established in the design community and are based on the procedures described herein.
As stated previously in 1.5 of this test method, the actual performance of a sound attenuating device as installed in an air duct system may be significantly different than reported based on the test procedure herein. This standard does not provide guidance to the user on these system effects.
Silencers are often designed to be used under conditions which do not duplicate the test set-ups of this standard. Mock-ups and specialized test set-ups to determine performance of sound attenuating devices in non-standard configurations may be based on this t...
SCOPE
1.1 This test method covers the laboratory testing of some of the acoustical properties of sound attenuating devices including duct liner materials, integral ducts, and in-duct absorptive straight and elbow silencers used in the ventilation systems of buildings. Procedures are described for the measurement of acoustical insertion loss, airflow generated noise, and pressure drop as a function of airflow.
1.2 Excluded from the scope are reactive mufflers and those designed for uses other than in ventilation systems, such as automobile mufflers.
1.3 This test method includes a provision for a simulated semi-reflective plenum to fit around thin-walled duct and silencer test specimens, since the acoustical environments around such thin-walled specimens can affect the measured insertion loss.
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.
1.4 This method tests the performance of the specimen in well-defined and controlled conditions. If the specimen is installed in the field in any different manner, the results may be different. This standard does not provide estimating procedures for determining the actual installed performance of the specimen field conditions.

General Information

Status
Historical
Publication Date
30-Apr-2006
ICS
91.120.20 - Acoustics in building. Sound insulation
Technical Committee
E33 - Building and Environmental Acoustics
Drafting Committee
E33.08 - Mechanical and Electrical System Noise
Current Stage
Ref Project

Relations

Replaces
ASTM E477-06 - Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers
Effective Date
01-May-2006
Replaced By
ASTM E477-13 - Standard Test Method for Laboratory Measurements of Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers
Effective Date
01-Jun-2013
Referred By
ASTM C634-22 - Standard Terminology Relating to Building and Environmental Acoustics
Effective Date
01-May-2006

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ASTM E477-06a - Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated SilencersASTM E477-06a - Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers
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ASTM E477-06a - Standard Test Method for Measuring Acoustical and Airflow Performance of Duct Liner Materials and Prefabricated Silencers
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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:E477 −06a
StandardTest Method for
Measuring Acoustical and Airflow Performance of Duct
1
Liner Materials and Prefabricated Silencers
This standard is issued under the fixed designation E477; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C423TestMethodforSoundAbsorptionandSoundAbsorp-
tion Coefficients by the Reverberation Room Method
1.1 This test method covers the laboratory testing of some
C634Terminology Relating to Building and Environmental
of the acoustical properties of sound attenuating devices
Acoustics
including duct liner materials, integral ducts, and in-duct
E90Test Method for Laboratory Measurement of Airborne
absorptive straight and elbow silencers used in the ventilation
Sound Transmission Loss of Building Partitions and
systems of buildings. Procedures are described for the mea-
Elements
surement of acoustical insertion loss, airflow generated noise,
E795Practices for Mounting Test Specimens During Sound
and pressure drop as a function of airflow.
Absorption Tests
3
1.2 Excluded from the scope are reactive mufflers and those
2.2 ANSI Standards:
designed for uses other than in ventilation systems, such as
S1.1–1994(R2004)Acoustical Terminology
automobile mufflers.
S1.11–2004Specification Octave, Half-Octave and Third-
1.3 This test method includes a provision for a simulated Octave Band Filter Sets
semi-reflective plenum to fit around thin-walled duct and S12.51–2002/ISO 3741:1999 Acoustics-Determination of
silencer test specimens, since the acoustical environments Sound Power Levels of Noise Sources Using Sound
around such thin-walled specimens can affect the measured Pressure-Precision Method for Reverberation Rooms
4
insertion loss. 2.3 AMCA Standards:
AMCA 300–96, Reverberant Room Method for Sound
1.4 This standard does not purport to address all of the
Testing of Fans
safety concerns, if any, associated with its use. It is the
5
2.4 ASHRAE Documents and Standards:
responsibility of the user of this standard to establish appro-
2001ASHRAE Handbook, Fundamentals Volume, Chapter
priate safety and health practices and determine the applica-
14, Chapter on Measurement and Instruments
bility of regulatory limitations prior to use.
ANSI/ASHRAE 41.3Method for Pressure Measurement
1.5 This method tests the performance of the specimen in
6
2.5 NAIMA Documents and Standards:
well-defined and controlled conditions. If the specimen is
Fibrous Glass Duct Liner Standard3rd ed., 2002
installedinthefieldinanydifferentmanner,theresultsmaybe
different.Thisstandarddoesnotprovideestimatingprocedures
3. Terminology
for determining the actual installed performance of the speci-
3.1 Definitions—The acoustical terms used in this method
men field conditions.
are consistent with Terminology C634, and ANSI S1.1.
2. Referenced Documents
3.2 Definitions of Terms Specific to This Standard:
2
3.2.1 acoustical duct liner material—a material that has
2.1 ASTM Standards:
soundabsorptivepropertiesandisattachedtotheinsidewallof
C384Test Method for Impedance andAbsorption ofAcous-
a duct to attenuate the sound that propagates down that section
tical Materials by Impedance Tube Method
of duct.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
3
and Environmental Acoustics and is the direct responsibility of Subcommittee Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
E33.08 on Mechanical and Electrical System Noise. 4th Floor, New York, NY 10036.
4
Current edition approved May 1, 2006. Published May 2006. Originally Available from Air Movement and Control Association, 30 W. University Dr.,
approved in 1973. Last previous edition approved in 2006 as E477–06. DOI: Arlington Heights, IL 60004.
5
10.1520/E0477-06A. Available from American Society of Heating, Refrigerating, and Air-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 30329.
6
Standards volume information, refer to the standard’s Document Summary page on AvailablefromNorthAmericanInsulationManufacturesAssociation(NAIMA)
the ASTM website. 44 Canal Center Plaza, Suite 310 Alexandria, VA 22314.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E477−06a
3.2.2 airflow generated noise—the noise created by aerody- 3.2.18 traverse—a series of readings made with a pitot tube
namic turbulence caused by air flowing through
...

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ASTM C423-23(Test Method)
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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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5.5 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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1.2 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).  
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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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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.  
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1.1 The sound isolation between two spaces in a building is influenced most strongly by a combination of the direct transmission through the nominally separating building element (as normally measured in a laboratory) and any transmission along a number of indirect paths, referred to as flanking paths. Fig. 1 illustrates the direct paths (D) and some possible structural flanking paths (F). Additional non-structural flanking paths include transmission through common air ducts between rooms, or doors to the corridor from adjacent rooms. Sound isolation is also influenced by the size of the separating partition between spaces and absorption in the receiving space, and in the case of small spaces by modal behavior of the space and close proximity to surfaces.
FIG. 1 Direct (D) and Some Indirect or Flanking Paths (F and Dotted) in a Building  
1.2 The main part of this test method defines procedures and metrics to assess the sound isolation between two rooms or portions thereof in a building separated by a common partition or the apparent sound insulation of the separating partition, including both direct and flanking transmission paths in all cases. Appropriate measures and their single number ratings are the noise reduction (NR) and noise isolation class (NIC) which indicate the isolation with the receiving room furnished as it is during the test, the normalized noise reduction (NNR) and normalized noise isolation class (NNIC) which indicate the isolation expected if the receiving room was a normally furnished living or office space that is at least 25 m3 (especially useful when the test must be done with the receiving room unfurnished), and the apparent transmission loss (ATL) and apparent sound transmission class (ASTC) which indicate the apparent sound insulating properties of a separating partition including both the direct transmission and flanking transmission through the support structure. The measurement of ATL ...

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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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5.1 This is an in situ method, that is, the measurements are made at the actual installation. The sound levels measured according to this test method should be representative for that installation and for the quantity of acoustical absorption actually, permanently present.  
5.2 The test method has the following limitations:  
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3.2 Definitions of Terms Specific to Each Standard:  
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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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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).
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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.
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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  
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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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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  • Standard
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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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  • Standard
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