In order to control the ambient acoustic noise on
the ISS, acoustic emission limits are levied on the
various ISS hardware depending on the hardware's classification.
The most basic classification is the element-level
or "Module" classification. Please see Module
Acoustic Requirements for a listing of these requirements.
These Module requirements include noise created by
integrated hardware that is required for the Module's
basic functioning. An example of this integrated hardware
for the U.S. Lab is the Common Cabin Air Assembly
(CCAA) air conditioning system which is a piece of
Government Furnished Equipment (GFE).
Science experiments are classified as "Payloads"
and have requirements that depend upon the classification
of the payload. The three basic classifications of
payload hardware are Payload Racks, Sub-rack Payloads,
and Aisle-mounted Payloads. The Plant Generic Bioprocessing
Apparatus (PGBA) is an example of a Sub-rack Payload.
The PGBA is installed inside an Expedite the PRocessing
of Experiments to Space Station (EXPRESS) Payload
Rack. Please see
Payload Acoustic Requirements* for a listing of
Payload requirements
The final classification includes Non-Integrated
Equipment, which includes non-integrated Government
Furnished Equipment (GFE) or Contractor Furnished
Equipment (CFE). Examples of GFE include the ISS Vacuum
Cleaner as well as the various exercise hardware.
Please see Non-Integrated
GFE and CFE Acoustic Requirements for a listing
of Non-Integrated Equipment requirements.
Definition of Terms used in Acoustics Requirements:
Significant Noise Source: A significant
noise source is any individual item of equipment,
or group of equipment items, which collectively function
as an operating system, that generates an A-weighted
sound pressure level (SPL) equal to or in excess of
37 decibels (dBA), measured at 0.6 meters distance
from the noisiest part of the equipment.
Continuous Noise Source: A significant
noise source, which exists for a cumulative total
of eight hours or more in any 24-hour period, is considered
a continuous noise source.
Intermittent Noise Source: A significant
noise source, which exists for a cumulative total
of less than eight hours in any 24-hour period, is
considered an intermittent noise source.
Acoustic Reference: All sound pressure
levels in decibels are referenced to 20 micropascals.
Human Spaceflight, Mission Analysis and Design,
Larson, M. and Pranke, L., McGraw-Hill, 2001.
Noise and Vibration Control Engineering,
Baranek, L. L.. and Ver, I. L., John Wiley &
Sons, Inc., 1992.
Handbook of Acoustics, Crocker, M. J.,
John Wiley & Sons, Inc., 1998.
Engineering Noise Control, Theory and Practice,
Bies, D. A. and Hansen, C. H., E&FN Spon, 1988.
Criteria for a Recommended Standard, Occupational
Noise Exposure, Revised Criteria 1998, DHHS (NIOSH)
Publication No. 98-126.
BBN Job No. 157160, “Recommendations for
Noise Levels in the Space Shuttle”, Bolt Beranek
and Newman, Inc., February 28, 1975.
SSP 57000, Revision B (Include. PIRN 0062), “Pressurized
Payloads Interface Requirements Document, International
Space Station Program”, NASA/JSC, May 1998.
TSS30671, “Space Station Freedom Vibroacoustic
Control Plan”, NASA/JSC, March 1992.
Int’l. Std. Book No. 0-9622072-0-9, “Noise
and Vibration Control”, Revised Edition, Edited
by Leo L. Beranek, Institute of Noise Control Engineering,
1988.
ANSI-S12.23, “Method for the Designation
of Sound Power Emitted by Machinery and Equipment”,
1996.
ANSI-S12.34, “Engineering Methods for the
Determination of Sound Power Levels of Noise Sources
for Essentially Free-field Conditions over a Reflecting
Plane”, 1993.
ANSI-S12.36, “Survey Methods for the Determination
of Sound Power Levels of Noise Sources”, 1990.
ANSI-S12.31, “Precision Methods for the
Determination of Sound Power Levels of Broad- band
Noise Sources in Reverberation Rooms”, 1996.
ANSI-S12.32, “Precision Methods for the
Determination of Sound Power Levels of Discrete
Frequency and Narrow-band Noise Sources in Reverberation
Rooms”, 1996.
ANSI-S12.33, “Engineering Methods for the
Determination of Sound Power Levels of Noise Sources
in Special Reverberation Test Room”, 1990.
ANSI-S12.35, “Precision Methods for the
Determination of Sound Power Levels in Anechoic
and Hemi-anechoic Rooms”, 1996.
ANSI-S12.12, “Engineering Method for the
Determination of Sound Power Levels of Noise Sources
using Sound Intensity”, 1992.
ISO 9614-2, “Acoustics - Determination
of Sound Power Levels of Noise Sources using Sound
Intensity - Part 2: Measuring by Scanning”,
1996.
