ASTM E1780-96
(Guide)Standard Guide for Measuring Outdoor Sound Received from a Nearby Fixed Source
Standard Guide for Measuring Outdoor Sound Received from a Nearby Fixed Source
SCOPE
1.1 This guide covers the measurement of outdoor sound due to a fixed sound source such as a siren, stationary pump, power plant, or music amphitheater. Procedures characterize the location, sound level, spectral content, and temporal characteristics of that sound source at the time of measurement. Users should be aware that wind and temperature gradients can cause significant variations in sound levels beyond 300 m (1000 ft). With appropriate caution, the use of measurements resulting from this guide include but are not limited to:
1.1.1 Assessing compliance with applicable regulations,
1.1.2 Monitoring the effectiveness of a noise reduction plan,
1.1.3 Verifying the effectiveness of measures for mitigation of noise impact,
1.1.4 Validating sound prediction models, and
1.1.5 Obtaining source data for use in sound prediction models.
1.2 This guide may be used according to Guide E1779 and specified in the measurement plan.
1.2.1 This guide can also be used to conduct measurements without a plan provided an operator/observer whose qualifications are satisfactory to both the performing organization and the user of the results is present at all times during the measurements and who complies with the applicable requirements of this guide, including record keeping.
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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Designation: E 1780 – 96
Standard Guide for
Measuring Outdoor Sound Received from a Nearby Fixed
Source
This standard is issued under the fixed designation E 1780; 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.
INTRODUCTION
This is one of a series of standards and guidelines for measurement and evaluation of community
noise. Also in preparation is a standard method for preparing a measurement plan and a guide to
determine the validity and significance of outdoor noise measurement data. Techniques and
precautions in this guide are not fixed or mandatory and cannot replace the judgment of acoustical
professionals. Rather, this guide is a summary of processes found to be productive and useful in
ensuring that meaningful information will be gathered in an efficient manner about fixed sources of
noise in a community as they each may exist. Others in this series include Guide E 1014, which covers
manual A-Weighted measurements of outdoor noise using a simple meter, and Test Method E 1503.
ANSI 12.18 provides a method of obtaining repeatable sound pressure level measurements of the
sound emitted by a source. This document differs in that atmospheric and ground effects are not
controlled. Thus, the results may not repeat if atmospheric conditions or ground conditions between
the source and the measurement position change. This guide provides only a method of accurately
documenting the sound levels occurring at the measurement position at the time of measurement.
1. Scope tions are satisfactory to both the performing organization and
the user of the results is present at all times during the
1.1 This guide covers the measurement of outdoor sound
measurements and who complies with the applicable require-
due to a fixed sound source such as a siren, stationary pump,
ments of this guide, including record keeping.
power plant, or music amphitheater. Procedures characterize
1.3 This standard does not purport to address all of the
the location, sound level, spectral content, and temporal
safety concerns, if any, associated with its use. It is the
characteristics of that sound source at the time of measurement.
responsibility of the user of this standard to establish appro-
Users should be aware that wind and temperature gradients can
priate safety and health practices and determine the applica-
cause significant variations in sound levels beyond 300 m
bility of regulatory limitations prior to use.
(1000 ft). With appropriate caution, the use of measurements
resulting from this guide include but are not limited to:
2. Referenced Documents
1.1.1 Assessing compliance with applicable regulations,
2.1 ASTM Standards:
1.1.2 Monitoring the effectiveness of a noise reduction plan,
C 634 Terminology Relating to Environmental Acoustics
1.1.3 Verifying the effectiveness of measures for mitigation
E 1014 Guide for Measurement of Outdoor A-Weighted
of noise impact,
Sound Levels
1.1.4 Validating sound prediction models, and
E 1503 Test Method for Conducting Outdoor Sound Level
1.1.5 Obtaining source data for use in sound prediction
Measurements Using a Digital Statistical Analysis System
models.
E 1779 Guide for Preparing a Measurement Plan for Con-
1.2 This guide may be used according to Guide E 1779 and
ducting Outdoor Sound Measurements
specified in the measurement plan.
2.2 ANSI Standards:
1.2.1 This guide can also be used to conduct measurements
S1.4 Specification for Sound Level Meters
without a plan provided an operator/observer whose qualifica-
S1.11 Octave-band and Fractional Octave-band Analog and
This guide is under the jurisdiction of ASTM Committee E33 on Environmental
Acoustics and is the direct responsibility of Subcommittee E33.09 on Community Annual Book of ASTM Standards, Vol 04.06.
Noise. Available from American National Standards Institute, 11 W. 42nd St., 13th
Current edition approved Feb. 10, 1996. Published June 1996. Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1780–96
Digital Filters, Specifications for in Section 8, with due consideration for a specific source
operating condition and one or more sound propagation con-
S1.13 Methods for the Measurement of Sound Pressure
ditions.
Levels
3.2.9 noise floor—see self-noise.
S1.40 Specification for Acoustical (Microphone) Calibra-
3.2.10 percentile level—the sound level exceeded during a
tors
specific percent of time in a measurement set. (Also known as
S12.1 American National Standard Guidelines for the
percentile exceedance level.)
Preparation of Standard Procedures for the Determination
3.2.11 self-noise—extraneous signal components, not part
of Noise Emission from Sources
of the sound field to be measured, generated or induced in a
S12.14 Sirens
measurement system which set the lower limit or floor below
S12.18 1994 American National Standards Procedures for
which accurate measurements cannot be made. See Terminol-
Outdoor Measurement of Sound Pressure Level
ogy C 634, definition of background noise.
S12.7 American National Standard Methods for Measure-
3.2.12 time-average sound level—the value obtained by
ments of Impulse Noise integrating and averaging an A-weighted sound level measured
over a specific period of time, or in the case of unweighted
S12.9 American National Standard Quantities and Proce-
(flat) sound pressure and fractional octave bands, time average
dures for Description and Measurement of Environmental
sound pressure level. (Also known as equivalent sound pres-
Sound, Parts 1, 2, and 3
sure level.) See Terminology C 634, definition of average
sound pressure level.
3. Terminology
3.1 For definitions of terms used in this guide see Termi-
4. Significance and Use
nology C 634.
4.1 Situations for which outdoor sound level data are
3.2 Definitions of Terms Specific to This Standard:
required include, but are not limited to, comparison of sound
3.2.1 barrier—any obstacle in the line-of-sight between the
levels with criteria or regulatory limits.
fixed source under test and the measurement microphone that
4.2 This guide provides information to (1) measure outdoor
may reduce or otherwise interfere with the passage of sound
sound level in the vicinity of outdoor fixed noise sources, and
from the fixed sound source to that microphone.
(2) document other observations necessary for the measure-
3.2.2 dummy microphone—a microphone substitute which
ments. This guide provides a standard procedure for a trained
has electrical characteristics identical to a functional micro-
acoustical professional that will produce results and documen-
phone, but which is not sensitive to incident acoustic energy. It
tation which are consistent with the purposes cited in 1.1.1-
is used in place of a functional microphone when evaluating
1.1.5.
the internal noise of an acoustic measuring system.
4.3 These sound measurements should be performed by or
3.2.3 equivalent sound level, Leq—see time-average sound
under the direction of a person experienced in the measurement
level.
and analysis of outdoor sound, and who is familiar with the use
3.2.4 fixed source—any permanently installed equipment
of the required equipment and techniques.
capable of emitting sound on a regular basis such as a pump,
4.4 This guide can be used by individuals, regulatory
power station or warning siren, sound amplification system
agencies, or others as a measurement guide to collect data on
permanently installed or stationary for a concert.
the sound level received from a fixed source within the
3.2.5 impulse sound—a brief, intrusive sound, such as that
constraints cited in 8.1 and Appendix X2.
emitted by impacting metal objects, operation of a punch press
4.5 This guide can be used to establish compliance or
or the discharge of a firearm. (See ANSI S1.13.)
noncompliance at the time, distance, and conditions during
3.2.6 interference—any activity or event occurring near the
which the data were obtained. However, this guide is only a
measurement location that could produce anomalous measure-
measurement procedure and does not address the problem of
ment results or data which are not representative in the context
projecting the acquired data outside those conditions, other
of the measurement objectives. Examples are air turbulence
times of day, other distances, or comparison with specific
generated by the wind at the microphone, people or animals
criteria. In particular, for a given sound source level, distant
making sounds in the vicinity of the microphone, or the
noise levels will often be found to be greater at night than
presence of surfaces which alter the normal sound propagation
during the day.
path. See Appendix X2 for additional details and precautions.
3.2.7 measurement plan—a document covering require-
5. Apparatus
ments unique and specific to the objectives of the measurement
including selection of sound measurement times and locations, 5.1 Acoustical Measurements:
number and length of measurement sets, and directions on 5.1.1 Use a Type 1 or Type 2 sound level meter as defined
actions to be taken in case of major changes in environment
by ANSI S1.4 and with a dynamic range of at least 60 dB. The
while obtaining a measurement set. See Section 8. instrument should have a buffered AC signal output port to
3.2.8 measurement set—the set of acoustical and related permit the use of headphones. If measurements are to be made
data results obtained at a single measurement location during a in fractional octave-bands, the system should include filter sets
specific time period. The time of measurement should be that fulfill the objectives of the measurement plan. Filters
selected based on the purpose of the measurement as specified should meet the requirements of ANSI S1.11.
E1780–96
5.1.2 Outdoor Microphone System—At a minimum the If the data are to be used for modeling, and if the study area is
outdoor microphone system should consist of the following: undulating in nature, and the variation in elevation exceeds 2 m
(6 ft), it is recommended that a topographical map be consulted
5.1.2.1 Microphone and preamplifier recommended by the
manufacturer of the measurement instrument, and compatible for estimating elevation of sound sources, potential receptors,
and potential sound barriers.
with and supporting the ANSI Type 1 or Type 2 requirement of
the sound level meter portion of the system. The microphone 5.2.2 Direction—A pocket compass should be used for site
layout work and determination of wind direction within 45
should also meet the measurement requirements for frequency
response, directional response and internal background noise degrees.
5.2.3 Site Map—A scale map of the measurement site
(self-noise).
environs should be available while preparing for measure-
5.1.2.2 Microphone windscreen compatible with the micro-
ments. The fixed source position and all measurement locations
phone system and meeting the requirements of the measure-
should be annotated on that map.
ment plan and the weather conditions under which measure-
5.3 Meteorological Observations:
ments are made.
5.3.1 Observe and record wind speed, relative humidity, and
5.1.3 The microphone system should include the following
temperature for potential effects on the sound level meter
features as appropriate for the time duration and weather
instruments, and these factors plus wind direction for potential
conditions expected during the measurement set.
effects on sound propagation from the fixed sound source to
5.1.3.1 Microphone and preamplifier system that does not
each measurement location. General accuracy meteorological
experience a sensitivity or frequency response change beyond
instruments should be available to measure:
ANSI Type 1 or Type 2 limits caused by moisture and
5.3.1.1 Wind speed (5-km/h or 2.5-mph increments),
temperature effects during the course of the measurement.
5.3.1.2 Wind direction to the nearest of the eight common
5.1.3.2 Microphone rain shield for use when applicable.
compass directions,
5.1.3.3 A tripod of the type normally used for supporting
5.3.1.3 Relative humidity (in 10 % increments), and
photographic equipment, a mast, or other support sufficiently
5.3.1.4 Dry bulb temperature (in 2°C or 5°F increments).
strong to support the weight of the microphone, possibly the
sound level meter and attached protective equipment.
NOTE 2—NOAA weather reports may be used for wind, temperature,
and humidity data when meteorological instruments are not available on
5.1.3.4 To prevent fouling of windscreens by roosting birds
site.
during long term and unattended measurement, it is recom-
mended that a bird repellant device, known as a “bird spike” be
5.3.2 Site absolute atmospheric pressure may be required
installed on the windscreen.
for the proper use of the microphone calibrator. See Appendix
5.1.4 Acoustical calibrator (required), with adapters neces- X1.
sary to fit the microphone. 5.4 Photographs—A camera should be carried by the mea-
5.1.5 Headphones (recommended)—Headphones for moni- surement team for the purpose of documenting the equipment
setup and surroundings at least once at each measurement
toring the AC output of the sound level meter portion of the
location.
analyzer should have the ability to exclude external sound and
prevent sound from the earphones from reaching the measure-
6. Calibration and Noise Floor
ment microphone. The headphones, with an appropriate
battery-powered driver, should have sufficient frequency re- 6.1 The measurement system should be calibrated and its
sponse to permit detection of anomalies in the data caused by
noise floor determined according to Appendix X1.
wind, humidity, and electrical interference. A frequency re-
7. Interference from Airborne Sound and
sponse of 50–20 000 Hz is adequate. The headphones or other
load should be correctly matched to the source impedance of Electromagnetic Fields
the sound level meter AC output port.
7.1 Sound level meter measurements are subject to interfer-
ence from a number of sources, some of which are discussed in
NOTE 1—Caution: Headphone impedance may not be compatible with
Appendix X2.
the AC output port of some sound level meter instruments. An impedance
matching amplifier (buffer) may be required. Failure to use such an
8. Measurement Plan and Procedure
amplifier, when needed, can cause the meter to produce inaccurate results.
If the sound level meter circuit is modified to use headphones, a functional
8.1 A measurement plan should be establis
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