ASTM E2249-02(2008)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E2249 − 02(Reapproved 2008)
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
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.
ThistestmethodisespeciallyusefulwhenthereceiverroomrequirementsofTestMethodE90cannot
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 Oct. 1, 2008. Published February 2009. Originally
approved in 2002. Last previous edition approved in 2002 as E2249–02. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E2249-02R08. 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 (2008)
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 (2008)
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 (2008)
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.
...