ASTM E1414/E1414M-21a

Standard Test Method for Airborne Sound Attenuation Between Rooms Sharing a Common Ceiling Plenum

SIGNIFICANCE AND USE
5.1 Modern offices and other multipurpose buildings commonly have suspended acoustical ceilings installed over room dividing partitions. The test facility prescribed in this test method is useful for providing ceiling attenuation data on the relevant ceiling/partition elements and systems, to ensure that the transmission of sound through the ceiling and plenum space, or through the combination of ceiling, plenum space, and partition systems, provides a suitable degree of acoustical isolation.  
5.2 This test method is useful for rating and specifying, under standardized conditions, the sound attenuation performance of ceiling materials when mounted in a specified suspension system.  
5.3 This test method may be useful for selecting a wall-ceiling system for probable compliance with a performance specification for overall sound isolation between rooms. However, the actual field performance may differ significantly, particularly if the field plenum depth is not within the limits specified in this test method or if the plenum space contains large ducts, beams, etc., or both. (See Test Method E336.)  
5.4 The flexibility inherent in the test facility enables evaluation of the effects of penetrations, induced leakage paths, luminaire, and air diffuser installations and discontinuities in the ceiling suspension system at the partition line, including penetration of the partition into the ceiling plenum. The effect of installing plenum barriers at the partition line may also be investigated.  
5.5 With the concentration of sound absorbent area offered by a suspended sound absorbent ceiling installed in a room, it is not possible to obtain a good approximation to a diffuse sound field in that room. The plenum dimensions prevent the maintenance of a diffuse sound field above the test specimen. These factors affect the values of the measured ceiling sound attenuation and thus the measurements are not a fundamental property of the ceiling. The test method measures the acou...
SCOPE
1.1 This test method utilizes a laboratory space so arranged that it simulates a pair of horizontally adjacent small offices or rooms separated by a partition and sharing a common plenum space. The partition either extends to the underside of a common plenum space or penetrates through it. In the prescribed configuration, special design features of the facility ensure that the only significant sound transmission path is by way of the ceiling and the plenum space.  
1.2 Within the limitations outlined in the significance statement, the primary quantity measured by this test method is the ceiling attenuation of a suspended ceiling installed in a laboratory environment. By accounting for receiving room sound absorption, the normalized ceiling attenuation may be determined.  
1.3 The test method may also be used to evaluate the attenuation of composite ceiling systems comprised of the ceiling material and other components such as luminaires and ventilating systems.  
1.4 The field performance of a ceiling system may differ significantly from the results obtained by this test method (see Section 5, Significance and Use, and Test Method E336).  
1.5 The procedures may also be used to study the additional sound insulation that may be achieved by other attenuation measures. This would include materials used either as plenum barriers or as backing for all or part of the ceiling.  
1.6 The facility may also be used to study the performance of an integrated system comprising plenum, ceiling, and partition, tested as a single assembly.  
1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.8 This standard does not purport to address all of the safety concerns, ...

General Information

• Status: Published
• Publication Date: 30-Apr-2021
• ICS: 91.120.20 - Acoustics in building. Sound insulation
• Technical Committee: E33 - Building and Environmental Acoustics
• Drafting Committee: E33.03 - Sound Transmission

Relations

• Refers: ASTM E90-23 - Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
• Effective Date: 01-Dec-2023
• Refers: ASTM E336-19a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Oct-2019
• Refers: ASTM E336-19 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jan-2019
• Refers: ASTM E336-17a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 15-Nov-2017
• Refers: ASTM E336-17 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jul-2017
• Refers: ASTM E3091-17 - Standard Specification for Systems to Measure Sound Levels
• Effective Date: 01-Jul-2017
• Refers: ASTM E90-09(2016) - Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
• Effective Date: 01-Dec-2016
• Refers: ASTM E336-16a - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Oct-2016
• Refers: ASTM E336-16 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Jan-2016
• Refers: ASTM E336-15 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 01-Sep-2015
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E336-14 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
• Effective Date: 15-Apr-2014
• Refers: ASTM C634-13 - Standard Terminology Relating to Building and Environmental Acoustics
• Effective Date: 01-Sep-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013

Overview

ASTM E1414/E1414M-21a is the internationally recognized standard test method developed by ASTM for measuring airborne sound attenuation between rooms that share a common ceiling plenum, typically found in modern office and multipurpose building designs. This standard outlines laboratory procedures to evaluate the sound reduction provided by suspended ceiling systems over room-dividing partitions. By simulating a pair of adjacent rooms separated by a partition with a shared plenum, the method determines the primary sound transmission path and provides quantifiable data on ceiling attenuation performance.

Key Topics

• Airborne Sound Attenuation: Measures the reduction in sound transmission through suspended ceilings and plenum spaces between adjacent rooms.
• Laboratory Simulation: Utilizes a controlled environment to recreate small rooms separated by a partition with a shared ceiling plenum, ensuring standardized and reproducible results.
• Ceiling Attenuation Class (CAC): Provides a single-figure, normalized rating for ceiling sound attenuation, supporting easy product comparison.
• Evaluation of System Components: Assesses the performance impact of ceiling materials, suspension systems, luminaires, diffusers, penetrations, and plenum barriers.
• Standardized Reporting: Requires detailed documentation on the configuration, materials, installation, and measurement conditions to ensure repeatability and comparability of results.
• Normalization Procedures: Adjusts attenuation measurements for sound absorption in the receiving room, providing normalized ceiling attenuation values.
• Field vs. Laboratory Performance: Highlights that actual field performance may vary due to real-world conditions not replicated in the laboratory (e.g., different plenum depths, additional plenum contents).

Applications

• Office and Commercial Buildings: Designers and acoustic consultants use this standard to select or specify suspended ceiling systems that provide effective privacy and noise control in open-plan or divided workspaces.
• Product Development and Certification: Manufacturers of ceiling systems test products using ASTM E1414/E1414M-21a to obtain certified sound attenuation ratings, facilitating performance-based product marketing.
• Regulatory and Performance Compliance: Building codes, project specifications, and green building programs often reference sound attenuation ratings, making this standard essential for proving compliance.
• Design Optimization: Architects and engineers use data derived from this method to optimize ceiling and partition configurations for improved acoustic isolation.
• Quality Assurance: Testing laboratories apply this method as part of product quality verification during production and R&D cycles.

Related Standards

• ASTM E336: Field measurement of airborne sound attenuation between rooms in building applications.
• ASTM E413: Classification for rating sound insulation, including ceiling attenuation class (CAC) derivation.
• ASTM C423: Laboratory measurement of sound absorption for materials, referenced for plenum lining properties.
• ASTM C636: Installation practice for ceiling suspension systems, ensuring consistent product setup during testing.
• ASTM E90: Laboratory measurement of airborne sound transmission loss for building partitions and elements.
• ANSI S1.11: Specification for octave-band and fractional-octave-band analog and digital filters, used in instrumentation for acoustic testing.
• IEC 61672-1: International standard for sound level meters, relevant to the measurement setup.

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Keywords: airborne sound attenuation, ceiling plenum, suspended ceiling, acoustical isolation, sound attenuation testing, ASTM E1414, Ceiling Attenuation Class (CAC), commercial buildings, office noise control, plenum barriers, laboratory acoustic measurement.

Adherence to ASTM E1414/E1414M-21a ensures that building designs using shared ceiling plenums achieve their intended acoustic performance, supporting occupant comfort and privacy in diverse built environments.

Standards Content (Sample)

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.
Designation: E1414/E1414M − 21a
Standard Test Method for
Airborne Sound Attenuation Between Rooms Sharing a
Common Ceiling Plenum
ThisstandardisissuedunderthefixeddesignationE1414/E1414M;thenumberimmediatelyfollowingthedesignationindicatestheyear
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 test method is designed to measure the sound attenuation provided by a suspended ceiling in
the presence of a continuous plenum space under prescribed laboratory test conditions. The test
methodisanadaptationofAMA1-II-1967MethodofTest.Thismodifiedtestmethodmaygiveresults
differing from the AMA-1-II procedure.
1. Scope 1.6 The facility may also be used to study the performance
of an integrated system comprising plenum, ceiling, and
1.1 This test method utilizes a laboratory space so arranged
partition, tested as a single assembly.
that it simulates a pair of horizontally adjacent small offices or
1.7 The values stated in either SI units or inch-pound units
rooms separated by a partition and sharing a common plenum
are to be regarded separately as standard. The values stated in
space. The partition either extends to the underside of a
each system may not be exact equivalents; therefore, each
common plenum space or penetrates through it. In the pre-
system shall be used independently of the other. Combining
scribed configuration, special design features of the facility
values from the two systems may result in non-conformance
ensure that the only significant sound transmission path is by
with the standard.
way of the ceiling and the plenum space.
1.8 This standard does not purport to address all of the
1.2 Within the limitations outlined in the significance
safety concerns, if any, associated with its use. It is the
statement,theprimaryquantitymeasuredbythistestmethodis
responsibility of the user of this standard to establish appro-
the ceiling attenuation of a suspended ceiling installed in a
priate safety, health, and environmental practices and deter-
laboratory environment. By accounting for receiving room
mine the applicability of regulatory limitations prior to use.
sound absorption, the normalized ceiling attenuation may be
1.9 This international standard was developed in accor-
determined.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
1.3 The test method may also be used to evaluate the
attenuation of composite ceiling systems comprised of the Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
ceiling material and other components such as luminaires and
ventilating systems. Barriers to Trade (TBT) Committee.
1.4 The field performance of a ceiling system may differ
2. Referenced Documents
significantly from the results obtained by this test method (see
2.1 ASTM Standards:
Section 5, Significance and Use, and Test Method E336).
C423 Test Method for SoundAbsorption and SoundAbsorp-
1.5 The procedures may also be used to study the additional
tion Coefficients by the Reverberation Room Method
sound insulation that may be achieved by other attenuation
C634 Terminology Relating to Building and Environmental
measures. This would include materials used either as plenum
Acoustics
barriers or as backing for all or part of the ceiling.
C636 Practice for Installation of Metal Ceiling Suspension
Systems for Acoustical Tile and Lay-In Panels
E90 Test Method for Laboratory Measurement of Airborne
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
and Environmental Acoustics and is the direct responsibility of Subcommittee
E33.03 on Sound Transmission. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2021. Published June 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1991. Last previous edition approved in 2021 as E1414/E1414M – 21. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E1414_E1414M-21A. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1414/E1414M − 21a
Sound Transmission Loss of Building Partitions and 3.2.7 reverberant sound field—the sound in an enclosed or
Elements partiallyenclosedspacethathasbeenreflectedrepeatedlyfrom
E177 Practice for Use of the Terms Precision and Bias in the enclosure boundaries.
ASTM Test Methods
4. Summary of Test Method
E336 Test Method for Measurement of Airborne Sound
Attenuation between Rooms in Buildings 4.1 The laboratory test facility consists of an outer shell
E413 Classification for Rating Sound Insulation
divided into two rooms by a partition and a suspended ceiling
E691 Practice for Conducting an Interlaboratory Study to (the test specimen). The partition between the two rooms may
Determine the Precision of a Test Method
extend up to, or through, the suspended ceiling, depending
E3091 Specification for Systems to Measure Sound Levels upon whether the specific test specimen is designed to be
continuous or interrupted at the partition line. The rooms are
2.2 ANSI Standards:
built so that the only significant sound transmission path
S1.11 Specification for Octave-Band and Fractional-Octave
between them is that provided by the test specimen and the
Band Analog and Digital Filters
ceiling plenum. All other sound transmission paths must be
2.3 Other Standards:
negligible. The ceiling attenuation is determined in each of the
AMA 1-II-1967 Method of Test, Standard Specification for
test frequency bands, by placing a sound source in one room
Ceiling Sound Transmission Test by Two Room Method
and then calculating the difference of the average sound
IEC 61672-1: 2013 Electroacoustics - Sound level meters —
pressure levels in both rooms. For the purposes of this test
Part 1: Specifications
method,theroomcontainingthesoundsourceisdesignatedthe
source room and the other, the receiving room.
3. Terminology
4.2 The measurement of a normalized ceiling attenuation
3.1 Definitions—For definitions of terms used in this test
requires that the value of a normalization term dependent upon
method see Terminology C634.
the amount of sound absorption present in the receiving room
3.2 Definitions of Terms Specific to This Standard:
be known. Two alternate methods are used for the determina-
3.2.1 ceiling attenuation (D )—the noise reduction between
c
tion of this normalization term.
the source and receiving rooms where flanking transmission by
allpathsareatleast10decibelslowerthanthepaththroughthe
5. Significance and Use
ceiling and plenum.
5.1 Modern offices and other multipurpose buildings com-
¯ ¯
D 5 L 2 L (1)
c 1 2
monly have suspended acoustical ceilings installed over room
¯ dividing partitions. The test facility prescribed in this test
where L is the average one-third octave band sound pres-
¯ method is useful for providing ceiling attenuation data on the
sure level in the source room; L is the average one-third
relevant ceiling/partition elements and systems, to ensure that
octave band sound pressure level in the receiving room.
the transmission of sound through the ceiling and plenum
3.2.2 normalized ceiling attenuation (D )—the ceiling at-
n,c
space, or through the combination of ceiling, plenum space,
tenuation adjusted to account for receiving room absorption.
and partition systems, provides a suitable degree of acoustical
D 5 D 1N (2)
n,c c f
isolation.
where N is the normalization term defined in 3.2.3.
5.2 This test method is useful for rating and specifying,
f
under standardized conditions, the sound attenuation perfor-
3.2.3 normalization term(N)—the adjustment term deter-
f
mance of ceiling materials when mounted in a specified
mined in 9.3 which normalizes the ceiling attenuation to
suspension system.
account for receiving room absorption.
5.3 This test method may be useful for selecting a wall-
3.2.4 ceiling attenuation class (CAC)—a single figure rating
ceiling system for probable compliance with a performance
derived from the normalized ceiling attenuation values in
specification for overall sound isolation between rooms.
accordance with Classification E413, except that the resultant
However, the actual field performance may differ significantly,
rating shall be designated ceiling attenuation class.
particularly if the field plenum depth is not within the limits
3.2.5 plenum space—the whole of the void above the
specified in this test method or if the plenum space contains
suspended ceilings in both rooms. Its dimensions are to be
large ducts, beams, etc., or both. (See Test Method E336.)
measured, discounting the thickness of any sound absorbing
5.4 The flexibility inherent in the test facility enables
material either adhered to walls or laid on the back of the test
evaluationoftheeffectsofpenetrations,inducedleakagepaths,
ceiling.
luminaire, and air diffuser installations and discontinuities in
3.2.6 direct sound field—the sound that results from an
the ceiling suspension system at the partition line, including
acoustical source without reflection from boundaries.
penetration of the partition into the ceiling plenum. The effect
of installing plenum barriers at the partition line may also be
investigated.
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org.
5.5 With the concentration of sound absorbent area offered
MethodoftheAmericanBoardProductsAssoc.,(formerlyAcousticalMaterials
by a suspended sound absorbent ceiling installed in a room, it
Assoc.) available from Ceiling and Interior Systems Contracting Assoc., 1800
Pickwick Ave., Glenview, IL 60025. is not possible to obtain a good approximation to a diffuse
E1414/E1414M − 21a
sound field in that room. The plenum dimensions prevent the
maintenance of a diffuse sound field above the test specimen.
These factors affect the values of the measured ceiling sound
attenuation and thus the measurements are not a fundamental
property of the ceiling. The test method measures the acousti-
cal properties attainable under the prescribed test conditions,
which have been arbitrarily selected. The conditions must be
adheredtoineverytestfacilitysothatthemeasuredresultswill
beconsistent.Twomethodsforobtaining A,thereceivingroom
FIG. 1 General Dimensions of the Test Room
absorption, are given without preference. One method, known
as the steady state method, has been used to obtain an estimate
for A in the AMA 1-II-1967 standard. The other method
ft [3.65 6 0.15 m]. All dimensions shall be measured inter-
follows the procedures used in Test Methods E90 and C423;
nally. Fig. 1 shows the major dimensions of the test rooms.
justification for the use of this method may be found in
5 7.1.2 Separating Wall—The separating wall shall be of such
reference (1) . Persons wishing to further investigate the
designthatthesoundpowertransmittedthroughitisatleast10
limitations imposed by this test method are advised to read
dB less than the total sound power transmitted through the
references (2), (3), (4) and (5).
ceiling specimen. This requirement may be checked by mea-
5.6 Notwithstanding the above limitations, this type of test
suring the D with the calibration ceiling referenced in A1.2,in
c
method has been used successfully for a number of years to
an interrupted configuration, and an effective gypsum board
rank order commercial ceiling systems and the test results are
plenum closure above the partition. All of the separating wall
commonly used for this purpose.
exterior surfaces shall be acoustically reflective. The wall shall
be tapered at its upper extremity so that its overall thickness at
6. Test Signal
the top, with the cap installed, is 73 6 0.1 in. [6 6 2.5 mm ].
6.1 Signal Spectrum—The sound signal used for this test The taper angle shall be not less than 45° from the ceiling
plane. The height of the wall shall be such that the top exactly
shall constitute a band or bands of random noise with a
continuous distribution of frequencies over each test band. meets the lower surface of the ceiling specimen. In the case of
interrupted ceiling systems a 50 6 2 6 0.1 in. by 3 6 0.1 in.
6.2 Bandwidth—The measurement bandwidth shall be one-
[2.5 mm by 75 6 2.5 mm] wooden adaptor cap shall be
third octave. Specifically the overall frequency response of the
installed. The length of the adaptor cap shall be identical to the
filter or filters, in the source and microphone amplifiers, shall
width of the wall. The capping should be designed to simulate
conform to ANSI Specification S 1.11-2004 (R2009) for class
a practical header condition typical of the type used for the
1, ⁄3 octave band filters.
ceiling being tested. The wall shall be installed near the
6.3 Standard Test Frequencies—The minimum frequency
mid-point of the test room so that two rooms are formed. The
range shall be a series of contiguous one-third octave bands
two rooms shall not differ in length by more than 15 %.
with geometric center frequencies from 125 to 4000 Hz.
NOTE 1—One wall design which has been found to be effective is
shown in Fig. 2.
7. Test Arrangement
7.1.3 Plenum Depth—The plenum depth shall be 30 6 1 in.
7.1 Theessentialfeaturesofthetestfacilityaregivenbelow.
[760 6 25 mm] at the separating wall. At other places within
7.1.1 Room Construction—The rooms shall be rectangular
the room, the plenum depth tolerance may be relaxed to 62.5
in shape and cross-section. The walls, floor, doors, and roof
in. [664 mm].
should provide sufficient acoustical isolation to reduce external
7.1.4 Plenum Width—The plenum width shall be 14.1 6 0.1
noise levels to at least 10 dB below the lowest test signal level.
ft [4.3 6 0.02 m] at the separating wall (Fig. 3).At other points
The sound absorption in each of the rooms should be made as
in the room, the plenum width should be the same as the full
low as possible in order to achieve the best possible diffuse
room width (see 3.2.5). The restriction in plenum width at the
field condition. The average sound absorption coefficients of
separating wall may be achieved by means of suitable pilasters
the floor and all vertical surfaces below the test ceiling should
installed either from floor to roof or from the level of the
not exceed 0.1 at any of the octave band center frequencies
ceiling underside to the roof.
given in 7.1.5.1. It is recommended that a structural disconti-
7.1.5 Plenum Lining:
nuity be provided close to the mid-point between the rooms to
7.1.5.1 All side walls of the plenum shall be lined with
minimize flanking sound transmission, allowing high values of
suitable sound absorbing material not less than 76 mm (3 in.)
ceiling attenuation to be measured. The total length of each
thick. This material, shall when tested in accordance with Test
side wall, including the vibration break (if any), shall be 25 6
Method C423 in a Type A mounting, have random incidence
5 ft [7.5 6 1.5 m] and the width of the room shall be 15.25 6
sound absorption coefficients not less than those shown below:
0.75 ft [4.65 6 0.23 m]. The overall height shall be 12 6 0.5
Octave Band Center 125 250 500 1000 2000 4000
Frequency, Hz
Absorption Coeffi- 0.65 0.80 0.80 0.80 0.80 0.80
cient
The boldface numbers in parentheses refer to the list of references at the end of
this standard. NOTE 2—A suitable plenum lining has been found to be a 6-in. thick
E1414/E1414M − 21a
least10dBbelowthetestsignalwheneacharemeasuredinthe
receiving half of the room.
8. Test Specimen
8.1 Installationoftheceilingspecimenshouldconformwith
recommended practice for the product.The test ceiling suspen-
sion system should be installed in accordance with the provi-
sions of Practice C636. In cases where the normal practice
would result in custom fit pieces of ceiling panels smaller than
4 in. [10 cm] in length installed between the supporting ledge
on a wall opposite the partition and the adjacent parallel grid
member, a filler material that has a higher TL than the
specimenmaybesubstituted.Fillermaterialsmayonlybeused
at the laboratory end walls farthest from the common partition.
No filler materials may be used in grid areas adjacent to the
side walls or the common partition.
NOTE 1—Except for the adaptor cap, all English units are standard
NOTE 3—Small custom fitted pieces of ceiling panels around the
lumber dimensions.
perimeter of the test room may not load the grid properly, allowing excess
FIG. 2 Vertical Section Through a Partition Found to Satisfy the
leakage of sound between the plenum and the test room. Such situations
Requirements of 7.1.2
can be avoided along the side walls of the test rooms by shifting the grid
system parallel to the partition. Along the end walls of the test rooms it
maynotbepossibletoavoidsmallcustomfittedpieces.Inthiscaseitmay
be appropriate to use a filler such as gypsum board to fill these small
sections of the ceiling.
8.2 The area of the ceiling system under test shall equal the
area formed by the room’s length and width, less the following
areas:
8.2.1 The area of the supporting ledge around the perimeter,
8.2.2 The area of the adapter cap when the ceiling is
interrupted, and
8.2.3 the area of any fillers as described in 8.1.
9. Procedure
FIG. 3 Horizontal Section Through the Test Rooms at the Ceiling
9.1 Test Signal—The test signal shall satisfy the require-
Level
ments of Section 6.
9.1.1 The sound pressure level of the test signal shall be
glass fiber bat with a thin impervious membrane at a depth of 1 ⁄2 in.
sufficient so that the resultant averaged sound pressure level in
below the exposed face.
the receiving room is at least 10 dB above the background
7.1.5.2 Aledgeorshelf,aswideastheplenumliningbutnot
noise in any test frequency band.
extending beyond the pilaster, may be constructed at ceiling
9.1.2 If more than one sound source is used, each source
height around the perimeter of both test rooms to support the
shall be powered by a separate random noise generator.
plenum lining. For the upper surface of the plenum, the sound
Multiple drivers in a single loudspeaker enclosure are
absorption coefficients measured in accordance with Test
permitted, provided the drivers are in phase. The maximum
Method C423 shall be less than 0.10 at all the above frequen-
volume of each loudspeaker enclosure shall not exceed 1 % of
cies.
the source room volume.
7.1.6 Diffusers—A sufficiently diffuse sound field, to meet
¯
9.2 Measurement of Average Sound Pressure Levels L and
the precision requirements of 11.3, shall be established. This
¯
L :
may be achieved by installing obliquely oriented stationary
sound reflecting diffusers, or by the introduction of rotating 9.2.1 Measurement System:
vanediffusers.Itisrecommendedthatthreestationarydiffusers 9.2.1.1 The measurement system shall meet Section 5 and
2 2
with a total single side area of at least 85 ft [8 m ], each either Section 6 or Subsections 7.1 and 7.5 of Specification
diffuser having a minimum width of 2.3 ft [0.7 m], be installed E3091.
in each room half. Alternately, one rotating vane diffuser 9.2.1.2 If multiple microphones are used:
2 2
having a minimum single side area of 43 ft [4 m ] and (1) The deviation in adjusted sensitivity between channels
minimum width of 5 ft [1.5 m] may be substituted for each set shall be no greater than 0.5 dB in all one-third octave bands
of three stationary diffusers. Care should be taken to ensure specified in 6.3, and
that placement of the diffusers does not shield the ceiling (2) The channel gains shall be adjusted at a single fre-
specimen or the sound source. Background noise from rotating quency before testing by following Subsection 7.5.2 of Speci-
vane apparatus together with other noise sources shall be at fication E3091 each day that test
...

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: E1414/E1414M − 21 E1414/E1414M − 21a
Standard Test Method for
Airborne Sound Attenuation Between Rooms Sharing a
Common Ceiling Plenum
This standard is issued under the fixed designation E1414/E1414M; 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 test method is designed to measure the sound attenuation provided by a suspended ceiling in
the presence of a continuous plenum space under prescribed laboratory test conditions. The test
method is an adaptation of AMA 1-II-1967 Method of Test. This modified test method may give results
differing from the AMA-1-II procedure.
1. Scope
1.1 This test method utilizes a laboratory space so arranged that it simulates a pair of horizontally adjacent small offices or rooms
separated by a partition and sharing a common plenum space. The partition either extends to the underside of a common plenum
space or penetrates through it. In the prescribed configuration, special design features of the facility ensure that the only significant
sound transmission path is by way of the ceiling and the plenum space.
1.2 Within the limitations outlined in the significance statement, the primary quantity measured by this test method is the ceiling
attenuation of a suspended ceiling installed in a laboratory environment. By accounting for receiving room sound absorption, the
normalized ceiling attenuation may be determined.
1.3 The test method may also be used to evaluate the attenuation of composite ceiling systems comprised of the ceiling material
and other components such as luminaires and ventilating systems.
1.4 The field performance of a ceiling system may differ significantly from the results obtained by this test method (see Section
5, Significance and Use, and Test Method E336).
1.5 The procedures may also be used to study the additional sound insulation that may be achieved by other attenuation measures.
This would include materials used either as plenum barriers or as backing for all or part of the ceiling.
1.6 The facility may also be used to study the performance of an integrated system comprising plenum, ceiling, and partition,
tested as a single assembly.
1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
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 Feb. 1, 2021May 1, 2021. Published February 2021June 2021. Originally approved in 1991. Last previous edition approved in 20162021 as
E1414/E1414M – 16.E1414/E1414M – 21. DOI: 10.1520/E1414_E1414M-21.10.1520/E1414_E1414M-21A.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1414/E1414M − 21a
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.8 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.
1.9 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.
2. Referenced Documents
2.1 ASTM Standards:
C423 Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
C634 Terminology Relating to Building and Environmental Acoustics
C636 Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels
E90 Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E336 Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
E413 Classification for Rating Sound Insulation
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E3091 Specification for Systems to Measure Sound Levels
2.2 ANSI Standards:
S1.11 Specification for Octave-Band and Fractional-Octave Band Analog and Digital Filters
2.3 ANSIOther Standards:
S1.11 Specification for Octave-Band and Fractional-Octave Band Analog and Digital Filters
2.3 Other Standards:
AMA 1-II-1967 Method of Test, Standard Specification for Ceiling Sound Transmission Test by Two Room Method
IEC 61672-1: 2013 Electroacoustics - Sound level meters — Part 1: Specifications
3. Terminology
3.1 Definitions—For definitions of terms used in this test method see Terminology C634.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 ceiling attenuation (D )—the noise reduction between the source and receiving rooms where flanking transmission by all
c
paths are at least 10 decibels lower than the path through the ceiling and plenum.
¯ ¯
D 5 L 2 L (1)
c 1 2
where L¯ is the average one-third octave band sound pressure level in the source room; L¯ is the average one-third octave
1 2
band sound pressure level in the receiving room.
3.2.2 normalized ceiling attenuation (D )—the ceiling attenuation adjusted to account for receiving room absorption.
n,c
D 5 D 1N (2)
n,c c f
where N is the normalization term defined in 3.2.3.
f
3.2.3 normalization term(N )—the adjustment term determined in 9.3 which normalizes the ceiling attenuation to account for
f
receiving room absorption.
3.2.4 ceiling attenuation class (CAC)—a single figure rating derived from the normalized ceiling attenuation values in accordance
with Classification E413, except that the resultant rating shall be designated ceiling attenuation class.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Method of the American Board Products Assoc., (formerly Acoustical Materials Assoc.) available from Ceiling and Interior Systems Contracting Assoc., 1800 Pickwick
Ave., Glenview, IL 60025.
E1414/E1414M − 21a
3.2.5 plenum space—the whole of the void above the suspended ceilings in both rooms. Its dimensions are to be measured,
discounting the thickness of any sound absorbing material either adhered to walls or laid on the back of the test ceiling.
3.2.6 direct sound field—the sound that results from an acoustical source without reflection from boundaries.
3.2.7 reverberant sound field—the sound in an enclosed or partially enclosed space that has been reflected repeatedly from the
enclosure boundaries.
4. Summary of Test Method
4.1 The laboratory test facility consists of an outer shell divided into two rooms by a partition and a suspended ceiling (the test
specimen). The partition between the two rooms may extend up to, or through, the suspended ceiling, depending upon whether the
specific test specimen is designed to be continuous or interrupted at the partition line. The rooms are built so that the only
significant sound transmission path between them is that provided by the test specimen and the ceiling plenum. All other sound
transmission paths must be negligible. The ceiling attenuation is determined in each of the test frequency bands, by placing a sound
source in one room and then calculating the difference of the average sound pressure levels in both rooms. For the purposes of
this test method, the room containing the sound source is designated the source room and the other, the receiving room.
4.2 The measurement of a normalized ceiling attenuation requires that the value of a normalization term dependent upon the
amount of sound absorption present in the receiving room be known. Two alternate methods are used for the determination of this
normalization term.
5. Significance and Use
5.1 Modern offices and other multipurpose buildings commonly have suspended acoustical ceilings installed over room dividing
partitions. The test facility prescribed in this test method is useful for providing ceiling attenuation data on the relevant
ceiling/partition elements and systems, to ensure that the transmission of sound through the ceiling and plenum space, or through
the combination of ceiling, plenum space, and partition systems, provides a suitable degree of acoustical isolation.
5.2 This test method is useful for rating and specifying, under standardized conditions, the sound attenuation performance of
ceiling materials when mounted in a specified suspension system.
5.3 This test method may be useful for selecting a wall-ceiling system for probable compliance with a performance specification
for overall sound isolation between rooms. However, the actual field performance may differ significantly, particularly if the field
plenum depth is not within the limits specified in this test method or if the plenum space contains large ducts, beams, etc., or both.
(See Test Method E336.)
5.4 The flexibility inherent in the test facility enables evaluation of the effects of penetrations, induced leakage paths, luminaire,
and air diffuser installations and discontinuities in the ceiling suspension system at the partition line, including penetration of the
partition into the ceiling plenum. The effect of installing plenum barriers at the partition line may also be investigated.
5.5 With the concentration of sound absorbent area offered by a suspended sound absorbent ceiling installed in a room, it is not
possible to obtain a good approximation to a diffuse sound field in that room. The plenum dimensions prevent the maintenance
of a diffuse sound field above the test specimen. These factors affect the values of the measured ceiling sound attenuation and thus
the measurements are not a fundamental property of the ceiling. The test method measures the acoustical properties attainable
under the prescribed test conditions, which have been arbitrarily selected. The conditions must be adhered to in every test facility
so that the measured results will be consistent. Two methods for obtaining A, the receiving room absorption, are given without
preference. One method, known as the steady state method, has been used to obtain an estimate for A in the AMA 1-II-1967
standard. The other method follows the procedures used in Test Methods E90 and C423; justification for the use of this method
may be found in reference (1) . Persons wishing to further investigate the limitations imposed by this test method are advised to
read references (2),(3),(4) and (5).
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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FIG. 1 General Dimensions of the Test Room
5.6 Notwithstanding the above limitations, this type of test method has been used successfully for a number of years to rank order
commercial ceiling systems and the test results are commonly used for this purpose.
6. Test Signal
6.1 Signal Spectrum—The sound signal used for this test shall constitute a band or bands of random noise with a continuous
distribution of frequencies over each test band.
6.2 Bandwidth—The measurement bandwidth shall be one-third octave. Specifically the overall frequency response of the filter
or filters, in the source and microphone amplifiers, shall conform to ANSI Specification S 1.11-2004 (R2009) for class 1, ⁄3 octave
band filters.
6.3 Standard Test Frequencies—The minimum frequency range shall be a series of contiguous one-third octave bands with
geometric center frequencies from 125 to 4000 Hz.
7. Test Arrangement
7.1 The essential features of the test facility are given below.
7.1.1 Room Construction—The rooms shall be rectangular in shape and cross-section. The walls, floor, doors, and roof should
provide sufficient acoustical isolation to reduce external noise levels to at least 10 dB below the lowest test signal level. The sound
absorption in each of the rooms should be made as low as possible in order to achieve the best possible diffuse field condition.
The average sound absorption coefficients of the floor and all vertical surfaces below the test ceiling should not exceed 0.1 at any
of the octave band center frequencies given in 7.1.5.1. It is recommended that a structural discontinuity be provided close to the
mid-point between the rooms to minimize flanking sound transmission, allowing high values of ceiling attenuation to be measured.
The total length of each side wall, including the vibration break (if any), shall be 25 6 5 ft [7.5 6 1.5 m] and the width of the
room shall be 15.25 6 0.75 ft [4.65 6 0.23 m]. The overall height shall be 12 6 0.5 ft [3.65 6 0.15 m]. All dimensions shall be
measured internally. Fig. 1 shows the major dimensions of the test rooms.
7.1.2 Separating Wall—The separating wall shall be of such design that the sound power transmitted through it is at least 10 dB
less than the total sound power transmitted through the ceiling specimen. This requirement may be checked by measuring the D
c
with the calibration ceiling referenced in A1.2, in an interrupted configuration, and an effective gypsum board plenum closure
above the partition. All of the separating wall exterior surfaces shall be acoustically reflective. The wall shall be tapered at its upper
extremity so that its overall thickness at the top, with the cap installed, is 73 6 0.1 in. [6 6 2.5 mm ]. The taper angle shall be
not less than 45° from the ceiling plane. The height of the wall shall be such that the top exactly meets the lower surface of the
ceiling specimen. In the case of interrupted ceiling systems a 50 6 2 6 0.1 in. by 3 6 0.1 in. [2.5 mm by 75 6 2.5 mm] wooden
adaptor cap shall be installed. The length of the adaptor cap shall be identical to the width of the wall. The capping should be
designed to simulate a practical header condition typical of the type used for the ceiling being tested. The wall shall be installed
near the mid-point of the test room so that two rooms are formed. The two rooms shall not differ in length by more than 15 %.
NOTE 1—One wall design which has been found to be effective is shown in Fig. 2.
7.1.3 Plenum Depth—The plenum depth shall be 30 6 1 in. [760 6 25 mm] at the separating wall. At other places within the room,
the plenum depth tolerance may be relaxed to 62.5 in. [664 mm].
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NOTE 1—Except for the adaptor cap, all English units are standard lumber dimensions.
FIG. 2 Vertical Section Through a Partition Found to Satisfy the Requirements of 7.1.2
7.1.4 Plenum Width—The plenum width shall be 14.1 6 0.1 ft [4.3 6 0.02 m] at the separating wall (Fig. 3). At other points in
the room, the plenum width should be the same as the full room width (see 3.2.5). The restriction in plenum width at the separating
wall may be achieved by means of suitable pilasters installed either from floor to roof or from the level of the ceiling underside
to the roof.
7.1.5 Plenum Lining:
7.1.5.1 All side walls of the plenum shall be lined with suitable sound absorbing material not less than 76 mm (3 in.) thick. This
material, shall when tested in accordance with Test Method C423 in a Type A mounting, have random incidence sound absorption
coefficients not less than those shown below:
Octave Band Center 125 250 500 1000 2000 4000
Frequency, Hz
Absorption Coeffi- 0.65 0.80 0.80 0.80 0.80 0.80
cient
NOTE 2—A suitable plenum lining has been found to be a 6-in. thick glass fiber bat with a thin impervious membrane at a depth of 1 ⁄2 in. below the
exposed face.
7.1.5.2 A ledge or shelf, as wide as the plenum lining but not extending beyond the pilaster, may be constructed at ceiling height
around the perimeter of both test rooms to support the plenum lining. For the upper surface of the plenum, the sound absorption
coefficients measured in accordance with Test Method C423 shall be less than 0.10 at all the above frequencies.
7.1.6 Diffusers—A sufficiently diffuse sound field, to meet the precision requirements of 11.3, shall be established. This may be
achieved by installing obliquely oriented stationary sound reflecting diffusers, or by the introduction of rotating vane diffusers. It
2 2
is recommended that three stationary diffusers with a total single side area of at least 85 ft [8 m ], each diffuser having a minimum
width of 2.3 ft [0.7 m], be installed in each room half. Alternately, one rotating vane diffuser having a minimum single side area
2 2
of 43 ft [4 m ] and minimum width of 5 ft [1.5 m] may be substituted for each set of three stationary diffusers. Care should be
taken to ensure that placement of the diffusers does not shield the ceiling specimen or the sound source. Background noise from
rotating vane apparatus together with other noise sources shall be at least 10 dB below the test signal when each are measured in
the receiving half of the room.
8. Test Specimen
8.1 Installation of the ceiling specimen should conform with recommended practice for the product. The test ceiling suspension
system should be installed in accordance with the provisions of Practice C636. In cases where the normal practice would result
in custom fit pieces of ceiling panels smaller than 4 in. [10 cm] in length installed between the supporting ledge on a wall opposite
the partition and the adjacent parallel grid member, a filler material that has a higher TL than the specimen may be substituted.
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FIG. 3 Horizontal Section Through the Test Rooms at the Ceiling Level
Filler materials may only be used at the laboratory end walls farthest from the common partition. No filler materials may be used
in grid areas adjacent to the side walls or the common partition.
NOTE 3—Small custom fitted pieces of ceiling panels around the perimeter of the test room may not load the grid properly, allowing excess leakage of
sound between the plenum and the test room. Such situations can be avoided along the side walls of the test rooms by shifting the grid system parallel
to the partition. Along the end walls of the test rooms it may not be possible to avoid small custom fitted pieces. In this case it may be appropriate to
use a filler such as gypsum board to fill these small sections of the ceiling.
8.2 The area of the ceiling system under test shall equal the area formed by the room’s length and width, less the following areas:
8.2.1 The area of the supporting ledge around the perimeter,
8.2.2 The area of the adapter cap when the ceiling is interrupted, and
8.2.3 the area of any fillers as described in 8.1.
9. Procedure
9.1 Test Signal—The test signal shall satisfy the requirements of Section 6.
9.1.1 The sound pressure level of the test signal shall be sufficient so that the resultant averaged sound pressure level in the
receiving room is at least 10 dB above the background noise in any test frequency band.
9.1.2 If more than one sound source is used, each source shall be powered by a separate random noise generator. Multiple drivers
in a single loudspeaker enclosure are permitted, provided the drivers are in phase. The maximum volume of each loudspeaker
enclosure shall not exceed 1 % of the source room volume.
¯ ¯
9.2 Measurement of Average Sound Pressure Levels L¯L and L¯L :
11 22
9.2.1 Measurement System:
9.2.1.1 The measurement system shall meet Section 5 and either Section 6 or Subsections 7.1 and 7.5 of Specification E3091.
9.2.1.2 If multiple microphones are used:
(1) The deviation in adjusted sensitivity between channels shall be no greater than 0.5 dB in all one-third octave bands specified
in 6.3, and
(2) The channel gains shall be adjusted at a single frequency before testing by following Subsection 7.5.2 of Specification
E3091 each day that testing is performed and
...