ASTM E1375-90(1994)e1

Standard Test Method for Measuring the Interzone Attenuation of Furniture Panels Used as Acoustical Barriers

SCOPE
1.1 This test method covers the measurement of the interzone attenuation of furniture panels used as acoustical barriers in open-plan spaces to provide speech privacy or sound isolation between working positions.
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.
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 conversions 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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: E 1375 – 90 (Reapproved 1994)
Standard Test Method for
Measuring the Interzone Attenuation of Furniture Panels
Used as Acoustical Barriers
This standard is issued under the fixed designation E 1375; 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.
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 relevant acoustical characteristics of one component of the open-plan space, furniture
panels used as acoustical barriers.
1. Scope C 634 Terminology Relating to Environmental Acoustics
E 795 Practices for Mounting Test Specimens During
1.1 This test method covers the measurement of the inter-
Sound Absorption Tests
zone attenuation of furniture panels used as acoustical barriers
E 1110 Classification for Determination of Articulation
in open-plan spaces to provide speech privacy or sound
Class
isolation between working positions.
E 1130 Test Method for Objective Measurement of Speech
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.
S1.4 Specification for Sound Level Meters
1.2.1 Unless otherwise qualified, all dimensions specified in
S1.6 Preferred Frequencies and Band Numbers for Acous-
this test method shall be understood to have a tolerance of 625
tical Measurements
mm (61 in.), even though the indicated approximate conver-
S1.11 Specification for Octave Band and Fractional-Octave
sions of the numerical dimensions given will not always be
Band Analog and Digital Filters
accurate to this extent. All measurements shall be made in SI
S1.12 Specification for Laboratory Standard Microphones
units or the corresponding exact foot-pound units.
1.3 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Definitions—For definition of terms used in this test
responsibility of the user of this standard to establish appro-
method see Terminology C 634. The term source point is
priate safety and health practices and determine the applica-
defined in Specification E 1179.
bility of regulatory limitations prior to use.
3.2 Definitions of Terms Specific to This Standard:
2. Referenced Documents 3.2.1 furniture panel—a furnishing that does not extend to
the ceiling, and that is used to subdivide an open-plan space
2.1 ASTM Standards:
and provide some degree of visual and acoustical privacy.
C 423 Test Method for Sound Absorption and Sound Ab-
Furniture panels include interlocking systems furniture and
sorption Coefficients by the Reverberation Room Method
freestanding screens.
3.2.2 interzone attenuation—at a specified position, for a
one-third octave-band, the difference between the sound pres-
This test method is under the jurisdiction of ASTM Committee E-33 on
Environmental Acoustics and is the direct responsibility of Subcommittee E33.02 on
sure level at a nominal reference position 0.9 m (3 ft) from the
Open Plan Spaces.
sound source and the sound pressure level at the point in
Current edition approved July 27, 1990. Published September 1990.
question.
This test method is similar to a procedure developed by the United States
Government General Services Administration, Public Buildings Service, desig- 3.2.3 nominal interzone attenuation—for a one-third
nated“ PBS-C.2, Test Method for the Sufficient Verification of Speech Privacy
Potential Based on Objective Measurements including Methods for the Rating of
Functional Interzone Attenuation and NC-Background, August 1972.” Available from American National Standards Institute, 11 W. 42nd St., 13th
Annual Book of ASTM Standards, Vol 04.06. Floor, New York, NY 10036.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1375
octave-band, at a specified point, the arithmetic mean interzone may be reflected around the panel by furniture or fixed
attenuation calculated using the interzone attenuation for the constructions, such as walls or columns. Providing adequate
point in question and for two adjacent positions 0.3 m (1 ft) to speech privacy in open-plan spaces requires the use of an
either side. (See Figs. 1 and 2.) For example, in Fig. 1, the acoustically absorbent ceiling and often the use of controlled
nominal interzone attenuation at the 3.0-m (10-ft) position is background masking sound, in addition to partial height
the arithmetic mean of the interzone attenuations at the 2.7, 3.0, acoustical barriers.
and 3.3-m (9, 10, and 11-ft) positions. 5.2 This test method measures one of the relevant acoustical
properties of one component of the open office environment:
4. Summary of Test Method
the effectiveness of furniture panels as acoustical barriers. The
4.1 The test facility is a room constructed such that sound
method measures the degree to which sound is diffracted over
reflections from the walls and ceiling are negligible. The test the top edge and transmitted through the panel. Other test
specimen is a furniture panel arranged as an acoustical barrier,
methods deal with the evaluation of the degree to which
that is, arranged such that it blocks the direct path of sound
reflected sound is attenuated by open-plan components, such as
from the sound source to the measuring microphones. Sound
the ceiling system, furniture panels, and wall finishes. Test
generated by the sound source on one side of the furniture
Method E 1130 is available to evaluate the overall speech
panel under test reaches the other side chiefly by diffracting
privacy between workstations that results from a specific
over its top edge. A potential secondary path is transmission
configuration of components.
through the panel. The differences in sound pressure levels
6. Apparatus
measured on each side of the furniture panel provide a measure
of its effectiveness as an acoustical barrier. 6.1 A sound source meeting Specification E 1179 is re-
quired.
5. Significance and Use
6.2 Microphones shall meet the requirements in ANSI
5.1 In open plan spaces, furniture panels are often used in S1.12.
lieu of full height walls to visually and acoustically separate
6.2.1 The microphones shall satisfy the requirements of
workstations. The use of these units, compared to full-height
11.1.
walls, can significantly lower the degree of speech privacy or
6.3 Electronic instruments used to process the microphone
noise isolation afforded between workstations. The degree of
signals shall conform to the relevant sections of ANSI S1.4 and
speech privacy or noise isolation depends upon many factors.
shall meet Type 1 requirements.
In travelling from one workstation to another, sound may be
7. Test Facility
reflected from the ceiling system, may be diffracted over or
around intervening furniture panels that act as acoustical 7.1 The preferred test facility is a hemi-anechoic room, a
barriers, may be transmitted through the furniture panels, or room with negligible reflections from the walls and ceilings, in
NOTE 1—See Fig. 2 for near survey line measurement positions.
NOTE 2—See Fig. 3 for measurement positions for reference levels.
FIG. 1 Plan of Test Arrangement
E 1375
FIG. 2 Plan of Test Arrangement Showing Near Survey Path Positions
standards should be consulted so that for newly engineered facilities, an
the frequency range of the measurements. A room meeting the
optimum design is achieved.
requirements of 7.2 is satisfactory. The floor shall be made
from a hard, sound-reflective material, such as concrete or
8. Test Specimens
wood, covered with carpet as specified in 7.3.
8.1 Furniture panels to be tested shall be assembled in
7.2 The wall and ceiling coverings shall have random
accordance with the manufacturer’s instructions and shall be
incidence sound absorption coefficients of at least 0.95 at all
arranged as they would normally be arranged in an open office.
frequencies at which measurements are to be made.
Joints between panels shall be sealed by no other means than
NOTE 1—Since reflections from the walls and ceiling of the facility may
those provided or recommended by the manufacturer.
reduce the measured attenuations, it is important to eliminate these
8.2 In order to prevent flanking around the ends of a panel,
reflections as much as possible.
the width of the specimen shall be at least twice its height or its
7.2.1 The random incidence sound absorption coefficients of
width may be the same as the width of the test facility. Two or
the wall and ceiling coverings shall be measured following Test
more panels may be placed or joined edge to edge to meet these
Method C 423 and Practices E 795. The mounting used shall
recommendations. Normal installation procedure shall be fol-
be those that will be used in the actual test facility.
lowed.
7.3 The floor shall be of solid material such as concrete or
8.3 The height of the specimen should not exceed 2.4 m (8
plywood. It shall be covered with carpet, without underpad,
ft). If the specimen is higher than 2.4 m (8 ft), the height shall
typical of those used in open-plan spaces. The carpet shall have
be completely documented in the test report as discussed in
a noise reduction coefficient (NRC) in the range of 0.20 to 0.40
13.2.1.
when measured in a Type A mounting (see Practices E 795)
8.4 Furniture panels may be tested with accessories attached
according to Test Method C 423. The carpet may be installed
to them. The accessories and the positions where they are
and tested using tape or adhesive in the mounting.
attached shall be fully described in the test report.
7.4 The ceiling of the test facility should be at least 0.3 m (1
8.5 Furniture panels that are significantly asymmetrical,
ft) from the edge of the test specimen. (See also 7.5 and 8.3.)
such as curved screens, shall be tested twice, once with each
7.5 The dimensions of the facility will limit the size of
face toward the sound source. The test results for each
specimens that can be tested. The required minimum set of
orientation shall be reported separately.
plan-view room dimensions is 4 by 6 m (13 by 20 ft) measured
to the inner face of the absorptive coverings. The height of the 9. Test Signal
facility, measured from the floor to the inner face of the
9.1 Signal Spectrum—The electrical signals used to gener-
sound-absorptive covering on the ceiling, shall be 2.7 m (9 ft).
ate the sound signals used for this test shall form a series of
bands of random noise containing an essentially continuous
NOTE 2—The facility may be intended for use with other test proce-
dures whose requirements may be more or less stringent than these. These distribution of frequencies over each test band.
E 1375
9.1.1 The generated sound shall be adequate to maintain, at 10.1.2.3 Measure the electrical signal fed to the source and
each of the desired measurement locations, one-third octave- maintain it at the same level during the measurement of the
band sound pressure levels at least 10 dB above the back- sound transmitted beyond the test specimen. This may be
ground noise levels of the test facility and the measuring accomplished by measuring the voltage fed to the loudspeaker.
instrumentation.
NOTE 3—Some precision sound level meters may be used as wide-band
9.2 Bandwidth—The measurement bandwidth shall be one-
voltmeters by removing the microphone and driving them directly with an
third octave. Specifically, the overall frequency response of the
electrical signal. (Consult instruction manual for applicability.)
electrical system, including the filter or filters in the source or
10.1.3 Measurements With the Test Specimen: Standard
sound measurement sections, shall for each test band meet the
Survey Path (see Fig. 1):
requirements of ANSI S1.11 for one third octave band filters of
10.1.3.1 Position the sound source so that the loudspeaker
Order 3 or higher, Type 1 or better.
axis is parallel the floor and 1.2 m (4 ft) above it with the
9.2.1 Filters in the sound measurement system serve to filter
source point 1.8 m (6 ft) from the centerline of the specimen.
out extraneous noise lying outside the test bands, including
In plan view, center the loudspeaker axis on the specimen (see
possible distortion produced in the source system.
Fig. 1).
9.3 Standard Test Frequencies—The minimum range of
10.1.3.2 Make measurements on the side of the panel away
measurements shall be a series of contiguous one-third octave
from the sound source on the loudspeaker axis at distances of
bands with center frequencies from 200 to 5000 Hz conforming
2.1, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, and 4.2 m (7, 8, 9, 10, 11, 12,
to ANSI S1.6. If desired, the range may be extended provided
13 and 14 ft) from the source point (see Fig. 1). Additional
that the requirements of 7.1 and 7.2 are met.
measurements may be made at greater or smaller distances, as
desired.
10. Procedure
10.1.3.3 Make all measurements with the microphone or
10.1 Measurement of Sound Pressure Levels:
microphones positioned 1.2 m (4 ft) above the floor.
10.1.1 Orient microphones so that for each frequency band
10.1.4 Measurements With Test Specimen: Near Survey
they have a uniform directional response within 61dBinthe
Path—(see Fig. 2):
plane that is perpendicular to the floor and that passes through
10.1.4.1 Additional measurements are made as described in
the source point and the microphone. A vertical orientation of
10.1.4.2-10.1.4.5 to assess the direct transmission of sound
the microphone axis is preferred. (Measure the directional
through the specimen or through specimen joints. These
responses of the microphones under laboratory-empty condi-
additional measurements are made at positions on the near
tions, not with the specimen in place, or take them from the
survey line parallel to the specimen and 0.3 m (1 ft) from the
manufacturer’s literature.)
specimen on the side away from the sound source (see Fig. 2).
10.1.1.1 Individually calibrate multiple microphones where
10.1.4.2 Leave t
...