ASTM E2249-02(2016)
(Test Method)Standard Test Method for Laboratory Measurement of Airborne Transmission Loss of Building Partitions and Elements Using Sound Intensity
Standard Test Method for Laboratory Measurement of Airborne Transmission Loss of Building Partitions and Elements Using Sound Intensity
SIGNIFICANCE AND USE
5.1 This test method can be used to obtain an estimate the transmission loss of building elements in a laboratory setting where the source room and the specimen mounting conditions satisfy the requirements of Test Method E90. The acceptability of the receiving room will be determined by a set of field indicators that define the quality and accuracy of the intensity estimate.
5.2 By appropriately constructing the surface over which the intensity is measured it is possible to selectively exclude the influence of sound energy paths including the effects from joints, gaps as well as flanking sound paths. This method may be particularly useful when accurate measurements of a partition can not be made in an Test Method E90 facility because the partition sound insulation is limited by flanking transmission involving facility source and receiver room surfaces, (for example, the path from the source room floor to the receiver room floor via the isolators and the slab supporting the two). Annex A3 discusses this in detail.
5.3 The discrete point method allows the mapping of the radiated sound intensity which can be used to identify defects or unique features (2) of the partition.
5.4 Current research reported in the literature indicate that there exists a bias between measures of transmission loss obtained using the intensity technique and those obtained using the conventional two room reverberation technique (for example, Test Method E90, (3) and (4)). Appendix E provides estimates of the bias that might be expected. Despite the presence of a bias, no corrections are to be applied to the measured data obtained by this test method.
SCOPE
1.1 This test method covers the measurement of airborne sound transmission loss of building partitions such as walls of all kinds, operable partitions, floor-ceiling assemblies, doors, windows, roofs, panels and other space-dividing building elements. It may also be have applications in sectors other than the building industry, although these are beyond the scope.
1.2 The primary quantity reported by this standard is Intensity Transmission Loss (ITL) and shall not be given another name. Similarly, the single-number rating Intensity Sound Transmission Class (ISTC) derived from the measured ITL shall not be given any other name.
1.3 This test method may be used to reveal the sound radiation characteristics of a partition or portion thereof.
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 and health practices and determine the applicability of regulatory limitations prior to use.
Note 1: The method for measuring the sound intensity radiated by the building element under test defined by this ASTM standard meets or exceeds those of ISO 15186-1. Special consideration will have to be given to requirements for the source room and specimen mounting if compliance with ISO 15186-1 is also desired as they differ from those of this standard.
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Designation: E2249 − 02 (Reapproved 2016)
Standard Test Method for
Laboratory Measurement of Airborne Transmission Loss of
Building Partitions and Elements Using Sound Intensity
This standard is issued under the fixed designation E2249; 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.
INTRODUCTION
Thistestmethodispartofasetforevaluatingthesoundtransmissionlossofapartitionorpartition
elementunderlaboratoryconditions.ItdiffersfromTestMethodE90inthatthesoundpowerradiated
by the element under test is measured directly using an intensity probe rather than indirectly from the
space averaged receiver room sound pressure and the room reverberation time. This test method is
especially useful when the receiver room requirements of Test Method E90 can not be achieved, or
flanking sound involving the receiver room surfaces is present but its influence is to be circumvented
(1) , as discussed in Annex A3.
Others test methods to evaluate sound insulation of building elements include: Test Method E90,
airbornetransmissionlossofanisolatedpartitionelementinacontrolledlaboratoryenvironment,Test
Method E492, laboratory measurement of impact sound transmission through floors, Test Method
E336, measurement of sound isolation in buildings, Test Method E1007, measurement of impact
sound transmission in buildings, Guide E966, measurement of sound transmission through building
facades and facade elements.
1. Scope 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the measurement of airborne
responsibility of the user of this standard to establish appro-
sound transmission loss of building partitions such as walls of
priate safety and health practices and determine the applica-
all kinds, operable partitions, floor-ceiling assemblies, doors,
bility of regulatory limitations prior to use.
windows, roofs, panels and other space-dividing building
elements.Itmayalsobehaveapplicationsinsectorsotherthan
NOTE 1—The method for measuring the sound intensity radiated by the
the building industry, although these are beyond the scope. building element under test defined by this ASTM standard meets or
exceedsthoseofISO15186-1.Specialconsiderationwillhavetobegiven
1.2 The primary quantity reported by this standard is Inten-
torequirementsforthesourceroomandspecimenmountingifcompliance
sity Transmission Loss (ITL) and shall not be given another
withISO15186-1isalsodesiredastheydifferfromthoseofthisstandard.
name. Similarly, the single-number rating Intensity Sound
Transmission Class (ISTC) derived from the measured ITL
2. Referenced Documents
shall not be given any other name.
2.1 ASTM Standards:
1.3 This test method may be used to reveal the sound
C634Terminology Relating to Building and Environmental
radiation characteristics of a partition or portion thereof.
Acoustics
E90Test Method for Laboratory Measurement of Airborne
1.4 The values stated in SI units are to be regarded as
Sound Transmission Loss of Building Partitions and
standard. No other units of measurement are included in this
Elements
standard.
E336Test Method for Measurement of Airborne Sound
Attenuation between Rooms in Buildings
E413Classification for Rating Sound Insulation
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
and Environmental Acoustics and is the direct responsibility of Subcommittee
E33.03 on Sound Transmission.
Current edition approved April 1, 2016. Published April 2016. Originally
approved in 2002. Last previous edition approved in 2008 as E2249–02 (2008). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/E2249-02R16. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2249 − 02 (2016)
2.2 ANSI Standards: I
? n?
L 5 10log dB (3)
In
? ?
S1.9Instruments for the Measurement of Sound Intensity I
o
S1.11Specification for Octave-Band and Fractional Octave-
where:
Band Analogue and Digital Filters
W
2.3 ISO Standards:
I 5 10 (4)
o
m
ISO 140-3Acoustics—Measurement of Sound Insulation in
Buildings and of Building Elements—Part 3: Laboratory
3.1.4 normal signed sound intensity level, L —tentimesthe
In
Measurements of Sound Insulation of Building Elements common logarithm of the ratio of the signed value of the
ISO 9614-1Acoustics—Determination of Sound Power
normalsoundintensitytothereferenceintensity I asgivenby:
o
Levels of Noise Sources Using Sound Intensity—Part 1:
I
? n?
Measurement at Discrete Points L 5 sgn~I ! 10 log dB (5)
In n
I
o
ISO 9614-2Acoustics—Determination of Sound Power
where:
Levels of Noise Sources Using Sound Intensity—Part 2:
Measurement by Scanning sgn(I ) = takes the value of negative unity if the sound
n
ISO 15186-1Acoustics—Measurement of Sound Insulation
intensity is directed into the measurement volume,
in Buildings and of Building Elements Using Sound
otherwise it is unity.
Intensity—Part 1: Laboratory Conditions
3.1.5 pressure-residual intensity index, δ —the difference
pI
o
ISO 15186-2Acoustics—Measurement of Sound Insulation
between the sound pressure level, L , and the unsigned normal
p
in Buildings and of Building Elements Using Sound
sound intensity level when the intensity probe is placed and
Intensity—Part 2: In-Situ Conditions
oriented in a sound field where the sound intensity is zero,
2.4 IEC Standard:
expressed in decibels,
IEC 1043Instruments for the Measurement of Sound Inten-
δ 5 L 2 L (6)
pI p In
sity o ? ?
Additional details can be found in IEC 61043.
3. Terminology
3.1.6 measurement surface—surface totally enclosing the
3.1 Definitions:The acoustical terminology used in this
building element under test on the receiving side, scanned or
method is intended to be consistent with the definitions in
sampled by the probe during the measurements. This surface
TerminologyC634andTestMethodE90.Uniquedefinitionsof
has an area S expressed in m .
m
relevance to this test method are presented here:
3.1.7 measurementdistance,d —distancebetweenthemea-
3.1.1 sound intensity, I—timeaveragedrateofflowofsound m
surement surface and the building element under test in a
energy per unit area in the direction of the local particle
direction normal to the element.
velocity. This is a vector quantity which is equal to:
3.1.8 measurement subarea—part of the measurement sur-
1 T W
W
I 5 p t ·Wu t ·dt (1)
* ~ ! ~ !
face being measured with the intensity probe using one
T 0 m
continuous scan or a series of discrete positions. The kth
where: 2
measurement subarea has an area S expressed in m .
mk
p(t) = instantaneous sound pressure at a point, Pascals,
3.1.9 measurement volume—the volume that is bounded by
uW(t) = instantaneous particle velocity at the same point, m/s,
the measurement surface(s), the building element under test,
and
and any connecting non-radiating surfaces.
T = averaging time, s.
3.1.10 measurement array—a series of fixed intensity probe
3.1.2 normal sound intensity, I —component of the sound
n
positions where each position represents a small subarea of the
intensity in the direction normal to a measurement surface
sub-divided area of a measurement surface.
defined by the unit normal vector nW:
3.1.11 discrete point method—a method of integrating the
W
W
sound intensity over the entire measurement surface where a
I 5 I·nW (2)
n 2
m
series of stationary microphone positions are chosen to ad-
equately sample the test partition.
where:
nW = unit normal vector directed out of the volume enclosed 3.1.12 scanning method—a method of integrating the sound
by the measurement surface. intensity over the entire measurement surface whereby a series
of subareas are scanned by moving the intensity probe in a
3.1.3 normal unsigned sound intensity level, L —ten
|In|
methodical fashion to adequately sample the test partition.
times the common logarithm of the ratio of the unsigned value
of the normal sound intensity to the reference intensity I as 3.1.13 field indicators—a series of indicators used to assess
o
given by: the quality of the measurement conditions, and ultimately the
accuracy, of the intensity measurement.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
3.1.13.1 dynamic capability index, L —a measure of the
d
4th Floor, New York, NY 10036, http://www.ansi.org.
usabledynamicrangeofanintensitymeasuringsystem(which
Available from International Electrotechnical Commission (IEC), 3 rue de
is a function of the phase mismatch of the system and the bias
Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
error factor, K), expressed in decibels.
E2249 − 02 (2016)
3.1.13.2 surface pressure-intensity indicator—thedifference of Test Method E90 while the other, the receiver room, has no
between the sound pressure level, and the normal sound specificphysicalrequirementsforsizeorabsorptioncondition.
intensity level on the measurement surface, both being time It is assumed that the sound field in the source room is
and surface averaged. F is used for the discrete point method approximately diffuse since the incident sound power is
and F and for the scanning method. estimated from the space averaged sound pressure level. The
pI
sound power transmitted into the receiver space is estimated
3.1.13.3 negative partial power indicator, F —the differ-
from direct measurement of the radiated sound intensity over a
ence between the average sound pressure level integrated over
measurement surface that completely encloses the portion of
a measurement surface and signed (accounting for direction)
the building element in the receiver room. The transmission
average normal intensity level.
lossofthebuildingelementisthenestimatedusingtheincident
3.1.13.4 field non-uniformity indicator, F — this measure is
and transmitted sound powers. Because transmission loss is a
only applicable to the discrete point method and assess the
function of frequency, measurements are made in a series of
suitability of the selected measurement array.
frequency bands.
NOTE 2—The field indicators and criteria used by this standard are
based on those of ISO 9614 and are a more stringent superset of those
5. Significance and Use
required by ISO 15186-1. Functional definitions are given in Annex A1
5.1 This test method can be used to obtain an estimate the
and Annex A2.
transmission loss of building elements in a laboratory setting
3.1.14 flanking transmission—transmission of sound from a
where the source room and the specimen mounting conditions
source to a receiving location other than directly through the
satisfy the requirements ofTest Method E90.The acceptability
element under consideration.
of the receiving room will be determined by a set of field
3.1.15 sound transmission loss, TL—In a specified fre-
indicators that define the quality and accuracy of the intensity
quency band, ten times the common logarithm of the ratio of
estimate.
the incident sound power, W, to the sound power transmitted
i
5.2 By appropriately constructing the surface over which
though the specimen under test, W, expressed in decibels.
t
the intensity is measured it is possible to selectively exclude
W
i
the influence of sound energy paths including the effects from
TL 5 10log (7)
F G
W
t
joints, gaps as well as flanking sound paths. This method may
NOTE 3—For this standard, TL is operationally defined by Eq 13 and
be particularly useful when accurate measurements of a parti-
differs from the definitions given inTest Method E90 only in the way that
tion can not be made in an Test Method E90 facility because
the transmitted sound power is estimated.
NOTE 4—Transmission loss is a property of the specimen and to a first the partition sound insulation is limited by flanking transmis-
approximation, is independent of the specimen area and dimension.
sion involving facility source and receiver room surfaces, (for
Nevertheless, results of specimens that have significantly different dimen-
example, the path from the source room floor to the receiver
sions and aspect ratios can vary significantly, especially at low
room floor via the isolators and the slab supporting the two).
frequencies, as this will hinder comparison. It is for this reason that this
Annex A3 discusses this in detail.
standard requires a minimum area for the test specimen.
5.3 The discrete point method allows the mapping of the
4. Summary of Test Method
radiated sound intensity which can be used to identify defects
4.1 Thebuildingelementundertestisinstalledbetweentwo
or unique features (2) of the partition.
spaces creating two spaces as conceptually shown in Fig. 1.
5.4 Current research reported in the literature indicate that
The source space is a well-defined room satisfying the criteria
there exists a bias between measures of transmission loss
obtainedusingtheintensitytechniqueandthoseobtainedusing
the conventional two room reverberation technique (for
example, Test Method E90, (3) and (4)).Appendix E provides
estimates of the bias that might be expected. Despite the
presence of a bias, no corrections are to be applied to the
measured data obtained by this test method.
6. Test Rooms
6.1 Source Room—The source room shall possess the fol-
lowing properties:
6.1.1 It shall comply with the relevant sections of Test
MethodE90.Inparticular,itshallpossesstheappropriateroom
size, shape, volume, diffusion, absorption characteristics.
6.1.2 Flankingpathsinvolvingsourceroomsurfacesandthe
specimen shall be insignificant relative to direct transmission
through the specimen under test. The procedure and criterion
of Annex A3 shall be followed and satisfied.
6.2 Receiving Room or Space—The receiving room may be
FIG. 1 Conceptualized Testing Arrangement Showing the Source
and Receiving Rooms any space meeting the requirements for background noise and
E2249 − 02 (2016)
the field indicators and associated field criteria (AnnexA1 for
the discrete point method, and Annex A2 for the scanning
method).
7. Test Partitions
7.1 Size, Mounting and Ageing—Specimens shall be in-
stalledinfullcompliancewithallrelevantrequirementsofTest
Method E90.
8. Test Signal Sound Sources
8.1 Signal Spectrum—Th
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2249 − 02 (Reapproved 2008) E2249 − 02 (Reapproved 2016)
Standard Test Method for
Laboratory Measurement of Airborne Transmission Loss of
Building Partitions and Elements Using Sound Intensity
This standard is issued under the fixed designation E2249; 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 standard test method is part of a set for evaluating the sound transmission loss of a partition
or partition element under laboratory conditions. It differs from Test Method E90 in that the sound
power radiated by the element under test is measured directly using an intensity probe rather than
indirectly from the space averaged receiver room sound pressure and the room reverberation time.
This test method is especially useful when the receiver room requirements of Test Method E90 can not
be achieved, or flanking sound involving the receiver room surfaces is present but its influence is to
be circumvented (1) , as discussed in Annex A3.
Others test methods to evaluate sound insulation of building elements include: Test Method E90,
airborne transmission loss of an isolated partition element in a controlled laboratory environment, Test
Method E492, laboratory measurement of impact sound transmission through floors, Test Method
E336, measurement of sound isolation in buildings, Test Method E1007, measurement of impact
sound transmission in buildings, Guide E966, measurement of sound transmission through building
facades and facade elements.
1. Scope
1.1 This test method covers the measurement of airborne sound transmission loss of building partitions such as walls of all
kinds, operable partitions, floor-ceiling assemblies, doors, windows, roofs, panels and other space-dividing building elements. It
may also be have applications in sectors other than the building industry, although these are beyond the scope.
1.2 The primary quantity reported by this standard is Intensity Transmission Loss (ITL) and shall not be given another name.
Similarly, the single-number rating Intensity Sound Transmission Class (ISTC) derived from the measured ITL shall not be given
any other name.
1.3 This test method may be used to reveal the sound radiation characteristics of a partition or portion thereof.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—The method for measuring the sound intensity radiated by the building element under test defined by this ASTM standard meets or exceeds
those of ISO 15186-1. Special consideration will have to be given to requirements for the source room and specimen mounting if compliance with ISO
15186-1 is also desired as they differ from those of this standard.
2. Referenced Documents
2.1 ASTM Standards:
C634 Terminology Relating to Building and Environmental Acoustics
This test method is under the jurisdiction of ASTM Committee E33 on Building and Environmental Acoustics and is the direct responsibility of Subcommittee E33.03
on Sound Transmission.
Current edition approved Oct. 1, 2008April 1, 2016. Published February 2009April 2016. Originally approved in 2002. Last previous edition approved in 20022008 as
E2249E2249 – 02 (2008).–02. DOI: 10.1520/E2249-02R08.10.1520/E2249-02R16.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2249 − 02 (2016)
E90 Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
E336 Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
E413 Classification for Rating Sound Insulation
2.2 ANSI Standards:
S1.9 Instruments for the Measurement of Sound Intensity
S1.11 Specification for Octave-Band and Fractional Octave-Band Analogue and Digital Filters
2.3 ISO Standards:
ISO 140-3 Acoustics—Measurement of Sound Insulation in Buildings and of Building Elements—Part 3: Laboratory
Measurements of Sound Insulation of Building Elements
ISO 9614-1 Acoustics—Determination of Sound Power Levels of Noise Sources Using Sound Intensity—Part 1: Measurement
at Discrete Points
ISO 9614-2 Acoustics—Determination of Sound Power Levels of Noise Sources Using Sound Intensity—Part 2: Measurement
by Scanning
ISO 15186-1 Acoustics—Measurement of Sound Insulation in Buildings and of Building Elements Using Sound Intensity—Part
1: Laboratory Conditions
ISO 15186-2 Acoustics—Measurement of Sound Insulation in Buildings and of Building Elements Using Sound Intensity—Part
2: In-Situ Conditions
2.4 IEC Standard:
IEC 1043 Instruments for the Measurement of Sound Intensity
3. Terminology
3.1 Definitions:The acoustical terminology used in this method is intended to be consistent with the definitions in Terminology
C634 and Test Method E90. Unique definitions of relevance to this test method are presented here:
3.1.1 sound intensity, I—time averaged rate of flow of sound energy per unit area in the direction of the local particle velocity.
This is a vector quantity which is equal to:
1 T W
W
I 5 p~t!·uW~t!·dt (1)
*
T m
where:
p(t) = instantaneous sound pressure at a point, Pascals,
Wu(t) = instantaneous particle velocity at the same point, m/s, and
T = averaging time, s.
3.1.2 normal sound intensity, I —component of the sound intensity in the direction normal to a measurement surface defined
n
by the unit normal vector Wn:
W
W
I 5 I·nW (2)
n 2
m
where:
Wn = unit normal vector directed out of the volume enclosed by the measurement surface.
3.1.3 normal unsigned sound intensity level, L —ten times the common logarithm of the ratio of the unsigned value of the
|In|
normal sound intensity to the reference intensity I as given by:
o
I
? n?
L 5 10log dB (3)
In
? ?
I
o
where:
W
I 5 10 (4)
o 2
m
3.1.4 normal signed sound intensity level, L —ten times the common logarithm of the ratio of the signed value of the normal
In
sound intensity to the reference intensity I as given by:
o
I
? n?
L 5 sgn I 10 log dB (5)
~ !
In n
I
o
where:
sgn(I ) = takes the value of negative unity if the sound intensity is directed into the measurement volume, otherwise it is unity.
n
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from International Electrotechnical Commission (IEC), 3 rue de Varembé, Case postale 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
E2249 − 02 (2016)
3.1.5 pressure-residual intensity index, δ —the difference between the sound pressure level, L , and the unsigned normal sound
pI p
o
intensity level when the intensity probe is placed and oriented in a sound field where the sound intensity is zero, expressed in
decibels,
δ 5 L 2 L (6)
pI p In
o ? ?
Additional details can be found in IEC 61043.
3.1.6 measurement surface—surface totally enclosing the building element under test on the receiving side, scanned or sampled
by the probe during the measurements. This surface has an area S expressed in m .
m
3.1.7 measurement distance, d —distance between the measurement surface and the building element under test in a direction
m
normal to the element.
3.1.8 measurement subarea—part of the measurement surface being measured with the intensity probe using one continuous
scan or a series of discrete positions. The kth measurement subarea has an area S expressed in m .
mk
3.1.9 measurement volume—the volume that is bounded by the measurement surface(s), the building element under test, and any
connecting non-radiating surfaces.
3.1.10 measurement array—a series of fixed intensity probe positions where each position represents a small subarea of the
sub-divided area of a measurement surface.
3.1.11 discrete point method—a method of integrating the sound intensity over the entire measurement surface where a series
of stationary microphone positions are chosen to adequately sample the test partition.
3.1.12 scanning method—a method of integrating the sound intensity over the entire measurement surface whereby a series of
subareas are scanned by moving the intensity probe in a methodical fashion to adequately sample the test partition.
3.1.13 field indicators—a series of indicators used to assess the quality of the measurement conditions, and ultimately the
accuracy, of the intensity measurement.
3.1.13.1 dynamic capability index, L —a measure of the usable dynamic range of an intensity measuring system (which is a
d
function of the phase mismatch of the system and the bias error factor, K), expressed in decibels.
3.1.13.2 surface pressure-intensity indicator—the difference between the sound pressure level, and the normal sound intensity
level on the measurement surface, both being time and surface averaged. F is used for the discrete point method and F and for
2 pI
the scanning method.
3.1.13.3 negative partial power indicator, F —the difference between the average sound pressure level integrated over a
measurement surface and signed (accounting for direction) average normal intensity level.
3.1.13.4 field non-uniformity indicator, F — this measure is only applicable to the discrete point method and assess the
suitability of the selected measurement array.
NOTE 2—The field indicators and criteria used by this standard are based on those of ISO 9614 and are a more stringent superset of those required
by ISO 15186-1. Functional definitions are given in Annex A1 and Annex A2.
3.1.14 flanking transmission—transmission of sound from a source to a receiving location other than directly through the
element under consideration.
3.1.15 sound transmission loss, TL—In a specified frequency band, ten times the common logarithm of the ratio of the incident
sound power, W , to the sound power transmitted though the specimen under test, W , expressed in decibels.
i t
W
i
TL 5 10 log (7)
F G
W
t
NOTE 3—For this standard, TL is operationally defined by Eq 13 and differs from the definitions given in Test Method E90 only in the way that the
transmitted sound power is estimated.
NOTE 4—Transmission loss is a property of the specimen and to a first approximation, is independent of the specimen area and dimension. Nevertheless,
results of specimens that have significantly different dimensions and aspect ratios can vary significantly, especially at low frequencies, as this will hinder
comparison. It is for this reason that this standard requires a minimum area for the test specimen.
4. Summary of Test Method
4.1 The building element under test is installed between two spaces creating two spaces as conceptually shown in Fig. 1. The
source space is a well-defined room satisfying the criteria of Test Method E90 while the other, the receiver room, has no specific
physical requirements for size or absorption condition. It is assumed that the sound field in the source room is approximately
diffuse since the incident sound power is estimated from the space averaged sound pressure level. The sound power transmitted
into the receiver space is estimated from direct measurement of the radiated sound intensity over a measurement surface that
completely encloses the portion of the building element in the receiver room. The transmission loss of the building element is then
estimated using the incident and transmitted sound powers. Because transmission loss is a function of frequency, measurements
are made in a series of frequency bands.
E2249 − 02 (2016)
FIG. 1 Conceptualized Testing Arrangement Showing the Source and Receiving Rooms
5. Significance and Use
5.1 This test method can be used to obtain an estimate the transmission loss of building elements in a laboratory setting where
the source room and the specimen mounting conditions satisfy the requirements of Test Method E90. The acceptability of the
receiving room will be determined by a set of field indicators that define the quality and accuracy of the intensity estimate.
5.2 By appropriately constructing the surface over which the intensity is measured it is possible to selectively exclude the
influence of sound energy paths including the effects from joints, gaps as well as flanking sound paths. This method may be
particularly useful when accurate measurements of a partition can not be made in an Test Method E90 facility because the partition
sound insulation is limited by flanking transmission involving facility source and receiver room surfaces, (for example, the path
from the source room floor to the receiver room floor via the isolators and the slab supporting the two). Annex A3 discusses this
in detail.
5.3 The discrete point method allows the mapping of the radiated sound intensity which can be used to identify defects or unique
features (2) of the partition.
5.4 Current research reported in the literature indicate that there exists a bias between measures of transmission loss obtained
using the intensity technique and those obtained using the conventional two room reverberation technique (for example, Test
Method E90, (3) and (4)). Appendix E provides estimates of the bias that might be expected. Despite the presence of a bias, no
corrections are to be applied to the measured data obtained by this test method.
6. Test Rooms
6.1 Source Room—The source room shall possess the following properties:
6.1.1 It shall comply with the relevant sections of Test Method E90. In particular, it shall possess the appropriate room size,
shape, volume, diffusion, absorption characteristics.
6.1.2 Flanking paths involving source room surfaces and the specimen shall be insignificant r
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