ASTM E1376-90(1994)e2

Standard Test Method for Measuring the Interzone Attenuation of Sound Reflected by Wall Finishes and Furniture Panels

SCOPE
1.1 This laboratory test method measures the degree to which reflected sound is attenuated by the most commonly found vertical surfaces in open-plan spaces. Reflection of sound from vertical surfaces is a concern in open-plan spaces because it can reduce speech privacy. The vertical surfaces covered by this test method include wall finishes such as sound-absorbent panels, and furniture panels or screens. It does not cover such items as window finishes or furniture other than panels.
1.2 This test procedure was originally developed using the foot-pound system of units for prescribing measurement positions and distances. However, the use of SI units is preferred by ASTM. For this reason, dimensions are provided in SI units, with approximate foot-pound conversions indicated in parentheses.
1.2.1 Unless otherwise qualified, all dimensions specified in this test method shall be understood to have a tolerance of ± 25 mm (± 1 in.), even though the indicated approximate conversion of the numerical dimensions given will not always be accurate to this extent. All measurements shall be made in SI units or the corresponding exact foot-pound units.
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.

General Information

• Status: Historical
• Publication Date: 26-Jul-1990
• Technical Committee: E33 - Building and Environmental Acoustics
• Drafting Committee: E33.02 - Speech Privacy

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
e2
Designation: E 1376 – 90 (Reapproved 1994)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Measuring the Interzone Attenuation of Sound Reflected by
Wall Finishes and Furniture Panels
This standard is issued under the fixed designation E 1376; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Keywords were added editorially in December 1994.
e NOTE—Fig. 1 was corrected in November 1996.
INTRODUCTION
This test method is one of a series for the measurement and evaluation of acoustical components
affecting speech privacy in open-plan spaces. This test method provides a means of objectively
measuring the degree to which sound reflected by furniture panels and wall finishes is attenuated.
1. Scope 2. Referenced Documents
1.1 This laboratory test method measures the degree to 2.1 ASTM Standards:
which reflected sound is attenuated by the most commonly C 423 Test Method for Sound Absorption and Sound Ab-
found vertical surfaces in open-plan spaces. Reflection of sorption Coefficients by the Reverberation Room Method
sound from vertical surfaces is a concern in open-plan spaces C 634 Terminology Relating to Environmental Acoustics
because it can reduce speech privacy. The vertical surfaces E 795 Practices for Mounting Test Specimens During
covered by this test method include wall finishes such as Sound Absorption Tests
sound-absorbent panels, and furniture panels or screens. It does E 1110 Classification for Determination of Articulation
not cover such items as window finishes or furniture other than Class
E 1130 Test Method for Objective Measurement of Speech
panels.
1.2 This test procedure was originally developed using the Privacy in Open Offices Using Articulation Index
foot-pound system of units for prescribing measurement posi- E 1179 Specification for Sound Sources Used for Testing
tions and distances. However, the use of SI units is preferred by Open Office Components and Systems
ASTM. For this reason, dimensions are provided in SI units, 2.2 ANSI Standards:
with approximate foot-pound conversions indicated in paren- S1.4 Specification for Sound Level Meters
theses. S1.6 Preferred Frequencies and Band Numbers for Acous-
1.2.1 Unless otherwise qualified, all dimensions specified in tical Measurements
this test method shall be understood to have a tolerance of 625 S1.11 Specification for Octave Band and Fractional-Octave
mm (61 in.), even though the indicated approximate conver- Band Analog and Digital Filters
sion of the numerical dimensions given will not always be S1.12 Specification for Laboratory Standard Microphones
accurate to this extent. All measurements shall be made in SI
3. Terminology
units or the corresponding exact foot-pound units.
3.1 Definitions—For definitions of terms used in this test
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the method, see Terminology C 634. The term source point is
defined in Specification E 1179.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 3.2 Definitions of Terms Specific to This Standard:
3.2.1 furniture panel—a furnishing that does not extend to
bility of regulatory limitations prior to use.
the ceiling, and that is used to subdivide an open-plan space
and provide some degree of visual and acoustical privacy.
This test method is under the jurisdiction of ASTM Committee E-33 on
Furniture panels include interlocking systems furniture and
Environmental Acoustics and is the direct responsibility of Subcommittee E33.02 on
freestanding screens.
Open Plan Spaces.
3.2.2 interzone attenuation—at a specified position for a
Current edition approved July 27, 1990. Published September 1990.
This test method is similar to a procedure developed by the U.S. Government
General Services Administration, Public Buildings Service, designated “PBS-C.2,
Procedure X, Test Method for the Sufficient Verification of Speech-Privacy Potential Annual Book of ASTM Standards, Vol 04.06.
Based on Objective Measurements Including Methods for the Rating of Functional Available from American National Standards Institute, 11 W. 42nd St., 13th
Interzone Attenuation and NC-Background,” April 1980. Floor, New York, NY 10036.
E 1376
NOTE 1—See Fig. 2 for measurement positions for reference levels.
FIG. 1 Plan of Test Arrangement
one-third octave-band, the difference between the sound pres- lieu of full height walls to visually and acoustically separate
sure level at a nominal reference position 0.9 m (3 ft) from the workstations. The use of these units, compared to full-height
sound source and the sound pressure level at the point in walls, can significantly lower the degree of speech privacy or
question. noise isolation afforded between workstations. The degree of
3.2.3 nominal interzone attenuation—for a one-third speech privacy or noise isolation between workstations de-
octave-band, at a specified position, the arithmetic mean pends on many factors. Sound may travel from one workstation
interzone attenuation calculated using the interzone attenuation to another by reflecting from the ceiling elements, or from
for the position in question and for two adjacent positions 0.3 columns, walls, windows, or furniture. It may also be diffracted
m (1 ft) to either side. For example, the nominal interzone over or around a furniture panel, or be transmitted through it.
attenuation at the 3.0-m (10-ft) position is the arithmetic mean Thus, in designing or evaluating open-plan spaces, all possible
of the interzone attenuations at the 2.7, 3.0, and 3.3-m (9, 10, propagation paths must be considered. The provision of ad-
and 11-ft) positions. (See Fig. 1.) equate speech privacy in open-plan spaces requires the use of
an acoustically absorbent ceiling and often a masking sound
4. Summary of Test Method
system, in addition to partial height acoustical barriers.
4.1 The test facility is a room constructed so that sound
5.2 This test method assesses the sound reflected from
reflections from the walls and ceiling are negligible. Sound is
vertical surfaces, such as furniture panels or wall finishes. This
generated on one side of a standard barrier that extends from
test method does not cover the testing of window finishes or
floor to ceiling, with a gap at the end facing the test specimen,
other furniture. The measurement of the performance of other
and is partially reflected by the test specimen to reach the other
open-plan components, such as ceilings, is addressed by other
side. The difference in magnitude of the sound pressure levels
test methods. Test Method E 1130 is available to evaluate the
measured on the source and receiving side of the barrier
overall speech privacy between workstations that results from
provides a measure of to what degree sound energy reflected
a specific configuration of components.
from the specimen is attenuated (see Fig. 1). Sound-absorbent
specimens will reflect less energy around the barrier than
6. Apparatus
sound-reflective specimens. Two test conditions are established
6.1 A sound source meeting Specification E 1179 is re-
in this test method. Specimens that are wall finishes are applied
quired.
over a sound-reflective side wall, whereas specimens that are
6.2 Microphones shall meet the requirements in ANSI
furniture panels are placed against a sound-absorptive side
S1.12.
wall.
6.2.1 The microphones, as used, shall satisfy the require-
5. Significance and Use
ments of 11.1.
5.1 In open-plan spaces, furniture panels are often used in 6.3 Electronic instruments used to process the microphone
E 1376
signals shall conform to the relevant sections of ANSI S1.4 and 7.5.2 The standard barrier shall be constructed to meet the
shall meet Type 1 requirements. requirements of 8.1.3 and 8.2.2. (See also Note 4 and Note 6.)
8. Test Specimens
7. Test Facility
8.1 Wall Finishes:
7.1 The preferred test facility is a hemi-anechoic room, a
room with negligible reflections from the walls and ceiling, in
NOTE 3—It is anticipated that wall finishes tested using this test method
the frequency range of the measurements. A room meeting the
will be chiefly sound absorbent and intended to attenuate reflected sound.
requirements of 7.2 is satisfactory. The floor shall be made However, hard, sound-reflective finishes such as gypsum board or wood
paneling may also be test specimens. While it might appear unnecessary
from a hard, sound-reflective material, such as concrete or
to install a sound-reflective specimen over a sound-reflective panel that is
wood, covered with carpet as specified in 7.3.
part of the test facility, it is not always possible to clearly distinguish in
7.2 The wall and ceiling coverings shall have random
advance whether a specimen is reflective enough to require no backing.
incidence sound absorption coefficients of at least 0.95 at all
For this reason, all wall finishes are to be installed over a hard reflecting
frequencies at which measurements are to be made.
surface.
NOTE 1—Since reflections from the walls and ceiling of the facility may
8.1.1 Mount specimens that are wall finishes on an imper-
reduce the measured sound attenuations with the specimen in place, it is
vious, hard-vertical reflecting surface such as gypsum board or
important to eliminate these reflections as much as possible. 2 2
plywood, with a surface mass of at least 10 kg/m (2 lb/ft ).
7.2.1 The random incidence sound absorption coefficients of The mounting surface shall be perpendicular to the plane of the
the facility wall and ceiling coverings shall be measured in
standard barrier and shall extend at least 1.5-m (5-ft) on either
accordance with Test Method C 423 and Practices E 795. The side of it (see Fig. 1).
mountings used for the test shall be those that will be used in
8.1.2 The specimen mounting surface shall extend from the
the actual test facility. floor to the ceiling of the test facility.
7.2.2 Because specimens that are wall finishes are to be
8.1.3 The perpendicular distance from the edge of the
mounted on a hard, sound-reflecting wall surface, the sound standard barrier to the nearest point of the specimen shall be
absorbing material on this wall should either be demountable
1.8 m (6 ft) (see Fig. 1).
or be covered with a hard surface when the requirements of 8.1
NOTE 4—To satisfy the requirements of 8.1.3 and 8.2.2, it may be
are being satisfied.
necessary to have an adjustable edge on the standard barrier or a
7.3 The floor shall be of solid material such as concrete or
removable hard mounting surface.
plywood. It shall be covered with carpet, without underpad,
8.1.4 The specimen, whether applied as a continuous layer
typical of those used in open-plan spaces. The carpet shall have
or an array of patches, should be mounted on the hard surface
a noise reduction coefficient (NRC) in the range of 0.20 to 0.40
so that it is disposed symmetrically on either side of the
when measured in a Type A mounting (see Practices E 795)
centerline of the standard barrier. Small specimens may be
according to Test Method C 423. The carpet may be installed
butted together to form a larger specimen. If an interlocking
and tested using tape or adhesive.
method is normally used to join sections of the specimen, the
7.4 The dimensions of the facility will limit the size of
specimen should be so mounted.
specimens that can be tested. The required minimum set of
NOTE 5—Unless patches or spot treatments are being tested, the
plan-view room dimensions is 4 by 6 m (13 by 20 ft) measured
specimen should cover the full hard mounting surface. Otherwise, the
to the inner face of the absorptive coverings. The height of the
sound-reflective properties of the exposed portion of the mounting surface
facility, measured from the floor to the inner face of the
may influence the test results.
sound-absorptive covering on the ceiling, shall be 2.7 m (9 ft).
8.1.5 If the specimen to be tested extends beyond the normal
NOTE 2—The facility may be intended for use with other test proce-
limits for the mounting surface, then the mounting surface
dures whose requirements may be more or less stringent than these. These
must be extended so that it has at least the same lateral
standards should be consulted so that for newly engineered facilities, an
dimensions as the specimen.
optimum design is achieved.
8.2 Furniture Panels:
7.5 The standard barrier shall extend from the floor to the
8.2.1 Furniture panels shall be tested with all walls of the
ceiling of the test facility and shall be no greater than 200 mm
test facility acoustically absorptive in accordance with 7.2.
(8 in.) thick. It shall comprise a septum of rigid, impermeable
There shall be no hard mounting surface present.
material having a surface weight of approximately 10 kg/m (2
8.2.2 The perpendicular distance from the edge of the
lb/ft ) such as 13 mm (0.5 in.) gypsum board or plywood, and
barrier to the nearest point of the specimen shall be 1.8 m (6 ft).
sound-absorbing material on both sides of the septum. This
sound absorbing material shall have a minimum noise reduc- NOTE 6—To satisfy the requirements of 8.1.3 and 8.2.2, it may be
necessary to have an adjustable edge on the standard barrier or a
tion coefficient of 0.8 when measured in a Type A mounting
removable hard mounting surface.
(see Practices E 795) in accordance with Test Method C 423.
7.5.1 The bottom edge of the barrier shall fit snugly against 8.2.3 The vertical midline of the specimen shall coincide
the floor when installed in the test chamber. If the barrier is with the centerline of the standard barrier. The specimen shall
assembled in sections, care shall be taken to minimize sound be at least 2.0 m (6.5 ft) wide. If the specimen comprises
leaks at the joints. At the end remote from the specimen, the sections joined together, a joint should not coincide with the
barrier should be extended to meet the wall of the test chamber vertical midline.
to prevent sound transmission. 8.2.4 The lower edge of the specimen shall be no more than
E 1376
0.5 m (1.5 ft) above the floor of the test chamber. The upper standard barrier, 0.9 m (3 ft) from its edge (see Fig. 1).
edge of the test specimen shall be at least 1.5 m (5 ft) above the 10.1.3.4 In plan view, the loudspeaker axis passes t
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