ASTM E90-99
(Test Method)Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
SCOPE
1.1 This test method covers the laboratory 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 elements.
1.2 Laboratory Accreditation -A procedure for accrediting a laboratory for performing this test method is given in Annex A3.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
Designation: E 90 – 99
Standard Test Method for
Laboratory Measurement of Airborne Sound Transmission
Loss of Building Partitions and Elements
ThisstandardisissuedunderthefixeddesignationE90;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method is part of a set for evaluating the sound-insulating properties of building elements.
It is designed to measure the transmission of sound through a partition or partition element in a
laboratory. Others in the set cover the measurement of sound isolation in buildings (Test Method
E336),thelaboratorymeasurementofimpactsoundtransmissionthroughfloors(TestMethodE492),
the measurement of impact sound transmission in buildings (Test Method E1007), the measurement
of sound transmission through building facades and facade elements (Guide E966), the measurement
of sound transmission through a common plenum between two rooms (Test Method E1414), a quick
method for the determination of airborne sound isolation in multiunit buildings (Practice E597), and
the measurement of sound transmission through door panels and systems (Test Method E1408).
1. Scope E597 Practice for Determining a Single-Number Rating of
Airborne Sound Isolation for Use in Multiunit Building
1.1 This test method covers the laboratory measurement of
Specifications
airborne sound transmission loss of building partitions such as
E966 Guide for Field Measurement of Airborne Sound
walls of all kinds, operable partitions, floor-ceiling assemblies,
Insulation of Building Facades and Facade Elements
doors, windows, roofs, panels, and other space-dividing ele-
E1007 Test Method for Field Measurement of Tapping
ments.
Machine Impact Sound Transmission through Floor-
1.2 Laboratory Accreditation—A procedure for accrediting
Ceiling Assemblies and Associated Support Structures
a laboratory for performing this test method is given inAnnex
E1289 Specification for Reference Specimen for Sound
A3.
Transmission Loss
1.3 This standard does not purport to address all of the
E1332 Classification for Determination of Outdoor-Indoor
safety concerns, if any, associated with its use. It is the
Transmission Class
responsibility of the user of this standard to establish appro-
E1375 Test Method for Measuring the Interzone Attenua-
priate safety and health practices and determine the applica-
tion of Furniture Panels Used as Acoustical Barriers
bility of regulatory limitations prior to use.
E1408 Test Method for Laboratory Measurement of the
2. Referenced Documents Sound Transmission Loss of Door Panels and Door Sys-
tems
2.1 ASTM Standards:
E1414 Test Method for Airborne Sound Attenuation Be-
C634 Terminology Relating to Environmental Acoustics
tween Rooms Sharing a Common Ceiling Plenum
E336 Test Method for Measurement of Airborne Sound
2.2 ANSI Standards:
Insulation in Buildings
S1.4 Specification for Sound-Level Meters
E413 Classification for Rating Sound Insulation
S1.6 Standard Preferred Frequencies, Frequency Levels,
E492 Test Method for Laboratory Measurement of Impact
and Band Numbers for Acoustical Measurements
Sound Transmission Through Floor-Ceiling Assemblies
S1.10 Pressure Calibration of Laboratory Standard Pressure
Using the Tapping Method
Microphones
S1.11 Specification for Octave-Band and Fractional-
Octave-Band Analog and Digital Filters
This test method is under the jurisdiction of ASTM Committee E-33 on
S12.31 Precision Methods for the Determination of Sound
EnvironmentalAcousticsandisthedirectresponsibilityofSubcommitteeE33.03on
Sound Transmission.
Current edition approved June 10, 1999. Published September 1999. Originally
published as E90–55. Last previous edition E90–97. AvailablefromtheAmericanNationalStandardsInstitute,11W.42ndSt.,13th
Annual Book of ASTM Standards, Vol 04.06. Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E90–99
PowerLevelsofBroad-BandNoiseSourcesinReverbera- surface without diffraction effects which, if it were the only
tion Rooms absorbing element in the room, would give the same sound
2.3 ISO Standards: decay rate as the room under consideration.
ISO717 Rating of Sound Insulation for Dwellings
NOTE 2—Sound absorption is operationally defined by the Sabine
ISO 3741 Acoustics—Determination of Sound Power
decay rate equation (see Eq 9).
Level of Noise Sources—Precision Methods for Broad-
4. Summary of Test Method
Band Sources in Reverberation Rooms
4.1 Two adjacent reverberation rooms are arranged with an
3. Terminology opening between them in which the test partition is installed.
Care is taken that the only significant sound transmission path
3.1 Definitions of the acoustical terms used in this test
between rooms is by way of the test partition. An approxi-
method are given in Terminology C634. A few definitions of
mately diffuse sound field is produced in one room, the source
special relevance are repeated here for convenience only.
room. Sound incident on the test partition causes it to vibrate
3.1.1 diffuse sound field—the sound in a region where the
and create a sound field in the second room, the receiving
sound intensity is the same in all directions and at every point.
room. The space- and time-averaged sound pressure levels in
3.1.2 direct sound field—the sound that arrives directly
thetworoomsaredetermined(seeFig.1).Inaddition,withthe
from a source without reflection.
test specimen in place, the sound absorption in the receiving
3.1.3 flanking transmission—transmission of sound from
room is determined. The sound pressure levels in the two
the source to a receiving location by a path other than that
rooms,thesoundabsorptioninthereceivingroomandthearea
under consideration—in this case other than through the test
of the specimen are used to calculate transmission loss as
partition.
showninSection12.Becausetransmissionlossisafunctionof
3.1.4 reverberation room—a room so designed that the
frequency, measurements are made in a series of frequency
reverberant sound field closely approximates a diffuse sound
bands.
field, both in the steady state when the sound source is on, and
4.2 Additional procedures that may be followed when
during decay after the source of sound has stopped.
testing doors are given in Test Method E1408.
3.1.5 reverberant sound field—the sound in an enclosed or
partially enclosed space that has been reflected repeatedly or
5. Significance and Use
continuously from the boundaries.
5.1 Soundtransmissionlossasdefinedin3.1.7,referstothe
3.1.6 sound transmission coeffıcient, t (dimensionless)—of
response of specimens exposed to a diffuse incident sound
a partition, in a specified frequency band, the fraction of the
field, and this is the test condition approached by this labora-
airborne sound power incident on the partition that is transmit-
tory test method. The test results are therefore most directly
ted by the partition and radiated on the other side. (Note that,
relevant to the performance of similar specimens exposed to
unless qualified, this term denotes the sound transmission
coefficient obtained when the specimen is exposed to a diffuse similar sound fields. They provide, however, a useful general
sound field as approximated, for example, in reverberation
rooms meeting the requirements of this test method.)
3.1.7 sound transmission loss, TL—of a partition, in a
specified frequency band, ten times the common logarithm of
the reciprocal of the sound transmission coefficient. The
quantity so obtained is expressed in decibels.
3.1.7.1 For the purposes of this test method, transmission
loss is operationally defined as the difference in decibels
between the average sound pressure levels in the reverberant
source and receiving rooms, plus ten times the common
logarithmoftheratiooftheareaofthecommonpartitiontothe
sound absorption in the receiving room (see Eq 12).
NOTE 1—Sound transmission coefficient and sound transmission loss
are related by either of the two equations:
TL 510log~1/t! (1)
–TL/10
t510 (2) FIG. 1 Illustration showing conceptual arrangement of a wall
sound transmission loss suite. This figure is not meant to be a
3.2 noise reduction, NR—in sound transmission measure-
design guide but is for illustrative purposes only. As an example,
ments, in a specified frequency band, the difference between
the room on the right has fixed microphones to measure average
the average sound pressure levels measured in two enclosed sound pressure level; the room on the left has a continuously
moving microphone to measure average sound pressure level.
spaces or rooms due to one or more sound sources in one of
Usually both rooms will have the same microphone system. The
them.
sound sources (loudspeakers) in the rooms generate the
3.3 Definitions of Terms Specific to This Standard:
incident sound fields for the measurement of level differences or
3.3.1 sound absorption, A, [L ]—of a room, in a specified
of sound decay rates. As shown, either room could serve as
frequency band, the hypothetical area of a totally absorbing source or receiving room.
E90–99
measureofperformanceforthevarietyofsoundfieldstowhich if spatial variances of sound pressure level or decay rate are
a partition or element may typically be exposed. reduced. Lateral panel dimensions should be about ⁄2 to 1
5.2 This test method is not intended for field tests. Field wave-length of the sound at the lowest test band, for example,
tests should be performed according to Test Method E336. about 1.2 to 2.5 m.The recommended minimum mass per unit
2 2
area of the panels is 5 kg/m (1 lb/ft ) for operation down to
6. Test Rooms
100 Hz. (Panels of plywood or particleboard measuring 1.2
6.1 Room Size and Shape—To produce an acceptable ap-
32.4 m are often used.) To be effective at lower frequencies,
proximation to the assumed diffuse sound fields, especially in
the size and mass of diffusing panels should be increased in
the lowest test frequency band, the sound fields in the rooms
proportion to the wavelength. It is likely to be impractical to
must satisfy the requirements in Annex A2. They must also
use very large diffusing panels at very low frequencies; they
satisfy any of the following requirements that are mandatory.
might make the room behave like a number of coupled spaces
6.1.1 Minimum Volume—The volume of the source and
rather than a single room, and it might be difficult to position
3 3
receiving rooms must each be 50 m (1765 ft ) or more.
microphones.
6.2 Room Absorption—The sound absorption in each of the
6.3.2 Rotating or Moving Diffusers—One or more rotating
rooms should be made as low as possible to achieve the best
or moving panels set at oblique angles to the room surfaces
possible simulation of the ideal diffuse field condition and to
maybeinstalledineitherorbothrooms.Therecommendations
keep the region dominated by the direct field (of the source or
for weight and size of the panels given in 6.3.1 for fixed
of the test specimen) as small as possible (see 8.5). At each
diffusingpanelsapplyalsotorotatingormovingdiffusers.The
frequency, the sound absorption for each room (as furnished
panelsshouldbelargeenoughthatduringmotiontheyproduce
with diffusers) should be no greater than:
a significant variation in the sound field, yet small enough that
2/3 they do not effectively partition the room at any point in their
A 5 V /3 (3)
movement.
where:
NOTE 3—Moving diffusers can generate mechanical noise or wind and
V = room volume, and
wind noise in microphones. This increased background noise may make
A = sound absorption of the room.
measurements difficult in some cases.
When V is expressed in cubic metres, A is in square metres.
6.4 Flanking Transmission—The test rooms shall be con-
When V is expressed in cubic feet, A is in sabin (square feet).
structed and arranged to minimize the possibility of transmis-
At low frequencies somewhat higher room absorption may be
sion by paths other than that through the test partition. Sound
desirable to accommodate other test requirements (for ex-
pressure levels produced by such flanking transmission should
ample,ANSIS12.31,ISO3741).Soundabsorptionintheroom
1/3
be at least 10 dB lower than the sound radiated into the
is usually increased at frequencies below f=k /V (k is an
2 2
receiving room by the test partition. Supporting one or both
empiricalconstantequalto2000m/swhenVisincubicmetres,
roomsonvibrationisolators(resilientmaterialsorsprings)isa
andequalto6562ft/swhen Visincubicfeet).Inanycase,the
common method of reducing flanking transmission. Structural
sound absorption should be no greater than three times the
discontinuitiesarerecommendedbetweenthesource-roomand
value given by Eq 3. For frequencies above 2000 Hz, atmo-
the test specimen and between the receiving room and the test
spheric absorption may make it impossible to avoid a slightly
specimen to minimize flanking transmission between them.
higher value than that given in Eq 3.
6.2.1 To minimize errors related to atmospheric absorption,
NOTE 4—If the specimen is rigidly connected to the source-room
the temperature and humidity in the receiving room should be structure, there is some risk that, in addition to the incident airborne
sound, sound power may enter the specimen at the edges because of
kept the same during the noise reduction and absorption
vibrationofthesource-roomstructure.Similarly,ifthespecimenisrigidly
measurements. For monitoring purposes, temperature and hu-
connectedtothereceivingroomstructure,soundpowermayflowfromthe
midity shall be measured and recorded at least once during
specimen to the walls of the receiving room and be radiated from them.
each test.
6.3 Methods to Reduce the Variability of the Sound Fields— 6.4.1 The limit on specimen transmission loss measurement
due to flanking transmission must be investigated as follows:
Meeting the requirements of 6.1 and 6.2 can be difficult in the
lowertestbandswhereresultsarelikelytodependcriticallyon 6.4.1.1 Inthetestopening,buildapartitionexpectedtohave
arbitrary features of the test geometry such as positioning of high transmission loss.
the sound sources and individual microphones. Spatial varia- 6.4.1.2 Measure the transmission losses following this test
tionsinsoundpressurelevelanddecayratemaybereducedby method.
one or both of the following types of diffusing panels. The 6.4.1.3 Increasetheexpectedtransmissionlossesbymaking
recommendations that follow are only included as guidelines. asubstantialimprovementtothetestpartition,forexample,by
Satisfaction of the requirements of Annex A2 for confidence adding a heavy shielding structure in front of the test partition.
intervals is the primary criterion,
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