ASTM E2249-02
(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
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 E 90. 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.
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 E 90 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.
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.
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 E 90, (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 This test method may be used to reveal the sound radiation characteristics of a partition or portion thereof.
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
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 (e) 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 MethodE90 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 MethodE90 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 MethodE90,
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.
building element under test defined by this ASTM standard meets or
1. Scope
exceedsthoseofISO15186-1.Specialconsiderationwillhavetobegiven
1.1 This test method covers the measurement of airborne
torequirementsforthesourceroomandspecimenmountingifcompliance
sound transmission loss of building partitions such as walls of
withISO15186-1isalsodesiredastheydifferfromthoseofthisstandard.
all kinds, operable partitions, floor-ceiling assemblies, doors,
2. Referenced Documents
windows, roofs, panels and other space-dividing building
elements.Itmayalsobehaveapplicationsinsectorsotherthan
2.1 ASTM Standards:
the building industry, although these are beyond the scope.
C634 Terminology Relating to Environmental Acoustics
1.2 The primary quantity reported by this standard is Inten-
E90 Test Method for Laboratory Measurement ofAirborne
sity Transmission Loss (ITL) and shall not be given another
Sound Transmission Loss of Building Partitions and Ele-
name. Similarly, the single-number rating Intensity Sound
ments
Transmission Class (ISTC) derived from the measured ITL
E336 Test Method for Measurement of Airborne Sound
shall not be given any other name.
Insulation in Buildings
1.3 This test method may be used to reveal the sound
E413 Classification for Rating Sound Insulation
radiation characteristics of a partition or portion thereof.
2.2 ANSI Standards:
1.4 This standard does not purport to address all of the
S1.9 Instruments for the Measurement of Sound Intensity
safety concerns, if any, associated with its use. It is the
S1.11 SpecificationforOctave-BandandFractionalOctave-
responsibility of the user of this standard to establish appro-
Band Analogue and Digital Filters
priate safety and health practices and determine the applica-
2.3 ISO Standards:
bility of regulatory limitations prior to use.
ISO140-3 Acoustics—MeasurementofSoundInsulationin
Buildings and of Building Elements—Part 3: Laboratory
NOTE 1—Themethodformeasuringthesoundintensityradiatedbythe
Measurements of Sound Insulation of Building Elements
ISO 9614-1 Acoustics—Determination of Sound Power
This test method is under the jurisdiction of ASTM Committee E33 on
EnvironmentalAcousticsandisthedirectresponsibilityofSubcommitteeE33.03on
Sound Transmission.
Current edition approved Nov. 10, 2002. Published June 2003. Annual Book of ASTM Standards, Vol 04.06.
2 4
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
this standard. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2249–02
Levels of Noise Sources Using Sound Intensity—Part 1:
where:
Measurement at Discrete Points
sgn(I ) = takes the value of negative unity if the sound
n
ISO 9614-2 Acoustics—Determination of Sound Power
intensity is directed into the measurement vol-
Levels of Noise Sources Using Sound Intensity—Part 2:
ume, otherwise it is unity.
Measurement by Scanning
3.1.5 pressure-residual intensity index, d —the difference
pI
o
ISO 15186-1 Acoustics—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 1: Laboratory Conditions
oriented in a sound field where the sound intensity is zero,
ISO 15186-2 Acoustics—Measurement of Sound Insulation
expressed in decibels,
in Buildings and of Building Elements Using Sound
d 5 L 2 L (6)
pI p |In|
o
Intensity—Part 2: In-Situ Conditions
Additional details can be found in IEC 61043.
2.4 IEC Standard:
3.1.6 measurement surface—surface totally enclosing the
IEC 1043 Instruments for the Measurement of Sound Inten-
building element under test on the receiving side, scanned or
sity
sampled by the probe during the measurements. This surface
3. Terminology has an area S expressed in m .
m
3.1.7 measurement distance, d —distance between the
3.1 The acoustical terminology used in this method is m
measurement surface and the building element under test in a
intended to be consistent with the definitions in Terminology
direction normal to the element.
C634 and Test MethodE90. Unique definitions of relevance
3.1.8 measurement subarea—part of the measurement sur-
to this test method are presented here:
face being measured with the intensity probe using one
3.1.1 sound intensity, I—time averaged rate of flow of
continuous scan or a series of discrete positions. The kth
sound energy per unit area in the direction of the local particle
measurement subarea has an area S expressed in m .
velocity. This is a vector quantity which is equal to: mk
3.1.9 measurement volume—the volume that is bounded by
1 T W
→
→
I 5 p~t!· u ~t!· dt (1)
the measurement surface(s), the building element under test,
* 2
T
m
and any connecting non-radiating surfaces.
3.1.10 measurement array—aseriesoffixedintensityprobe
where:
p(t) = instantaneous sound pressure at a point, Pascals, positions where each position represents a small subarea of the
→
= instantaneousparticlevelocityatthesamepoint,m/s,
sub-divided area of a measurement surface.
u (t)
and
3.1.11 discrete point method—a method of integrating the
T = averaging time, s.
sound intensity over the entire measurement surface where a
3.1.2 normal sound intensity, I —component of the sound
series of stationary microphone positions are chosen to ad-
n
intensity in the direction normal to a measurement surface
equately sample the test partition.
→
3.1.12 scanning method—amethodofintegratingthesound
defined by the unit normal vector n:
intensity over the entire measurement surface whereby a series
W
→ →
I 5 I · n (2)
of subareas are scanned by moving the intensity probe in a
n 2
m
methodical fashion to adequately sample the test partition.
3.1.13 field indicators—a series of indicators used to assess
where:
→
= unit normal vector directed out of the volume enclosed the quality of the measurement conditions, and ultimately the
n
by the measurement surface. accuracy, of the intensity measurement.
3.1.3 normal unsigned sound intensity level, L —tentimes 3.1.13.1 dynamic capability index, L —a measure of the
|In| d
the common logarithm of the ratio of the unsigned value of the
usable dynamic range of an intensity measuring system (which
normalsoundintensitytothereferenceintensity I asgivenby: is a function of the phase mismatch of the system and the bias
o
error factor, K), expressed in decibels.
|I |
n
L 510log dB (3)
|In|
3.1.13.2 surface pressure-intensity indicator—the differ-
I
o
ence between the sound pressure level, and the normal sound
where:
intensity level on the measurement surface, both being time
W
and surface averaged. F is used for the discrete point method
I 510 (4)
o 2
m
and F and for the scanning method.
pI
3.1.4 normalsignedsoundintensitylevel,L —tentimesthe 3.1.13.3 negative partial power indicator, F —the differ-
In 3
ence between the average sound pressure level integrated over
common logarithm of the ratio of the signed value of the
normalsoundintensitytothereferenceintensity I asgivenby: a measurement surface and signed (accounting for direction)
o
average normal intensity level.
|I |
n
L 5 sgn~I !10log dB (5)
In n 3.1.13.4 field non-uniformity indicator, F —this measure is
I 4
o
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
Available from International Electrotechnical Commission (IEC), 3 Rue de
Varembe, CH 1211, Geneva 20, Switzerland. based on those of ISO 9614 and are a more stringent superset of those
E2249–02
required by ISO15186-1. Functional definitions are given in Annex A1
5. Significance and Use
and Annex A2.
5.1 This test method can be used to obtain an estimate the
3.1.14 flanking transmission—transmissionofsoundfroma
transmission loss of building elements in a laboratory setting
source to a receiving location other than directly through the
where the source room and the specimen mounting conditions
element under consideration.
satisfytherequirementsofTestMethodE90.Theacceptability
3.1.15 sound transmission loss, TL—In a specified fre-
of the receiving room will be determined by a set of field
quency band, ten times the common logarithm of the ratio of
indicators that define the quality and accuracy of the intensity
the incident sound power, W, to the sound power transmitted
estimate.
i
though the specimen under test, W, expressed in decibels.
5.2 By appropriately constructing the surface over which
t
the intensity is measured it is possible to selectively exclude
W
i
TL 510log (7)
F G
the influence of sound energy paths including the effects from
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-
differsfromthedefinitionsgiveninTestMethodE90onlyinthewaythat
tion can not be made in an Test MethodE90 facility because
the transmitted sound power is estimated.
the partition sound insulation is limited by flanking transmis-
NOTE 4—Transmission loss is a property of the specimen and to a first
sion involving facility source and receiver room surfaces, (for
approximation, is independent of the specimen area and dimension.
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 frequen-
room floor via the isolators and the slab supporting the two).
cies, as this will hinder comparison. It is for this reason that this standard
Annex A3 discusses this in detail.
requires a minimum area for the test specimen.
5.3 The discrete point method allows the mapping of the
radiated sound intensity which can be used to identify defects
4. Summary of Test Method
or unique features (2) of the partition.
4.1 Thebuildingelementundertestisinstalledbetweentwo
5.4 Current research reported in the literature indicate that
spaces creating two spaces as conceptually shown in Fig. 1.
there exists a bias between measures of transmission loss
The source space is a well-defined room satisfying the criteria
obtainedusingtheintensitytechniqueandthoseobtainedusing
ofTest MethodE90 while the other, the receiver room, has no
the conventional two room reverberation technique (for ex-
specific physical requirements for size or absorption condition.
ample, Test MethodE90, (3) and (4)). Appendix E provides
It is assumed that the sound field in the source room is
estimates of the bias that might be expected. Despite the
approximately diffuse since the incident sound power is
presence of a bias, no corrections are to be applied to the
estimated from the space averaged sound pressure level. The
measured data obtained by this test method.
sound power transmitted into the receiver space is estimated
from direct measurement of the radiated sound intensity over a 6. Test Rooms
measurement surface that completely encloses the portion of
6.1 Source Room—The source room shall possess the fol-
the building element in the receiver room. The transmission
lowing properties:
lossofthebuildingelementisthenestimatedusingtheincident
6.1.1 It shall comply with the relevant sections of Test
and transmitted sound powers. Because transmission loss is a
Method E90. In particular, it shall possess the appropriate
function of frequency, measurements are made in a series of
roomsize,shape,volume,diffusion,absorptioncharacteristics.
frequency bands.
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
any space meeting the requirements for background noise and
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
MethodE90.
8. Test Signal Sound Sources
8.1 Signal Spectrum—Thesoundsignalsusedforthesetests
shall be in full compliance with the requirements of Test
MethodE90.
8.2 Sound Sources—The number, characteristics, orienta-
tion and location of loudspeakers shall be in full compliance
FIG. 1 Conceptualized Testing Arrangement Showing the Source
and Receiving Rooms with the requirements of Test MethodE90.
E2249–02
8.3 Standard Test Frequencies—As a minimum, measure-
ments should be made at all of the one-third-octave bands
stated in Test MethodE90.
9. Measurement Surface
9.1 The measurement surface shall define a measurement
volume that (1) completely encloses the portion of the speci-
men under test, (2) contains no extraneous or fl
...
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