ASTM E1014-84(1995)e1
(Guide)Standard Guide for Measurement of Outdoor A-Weighted Sound Levels
Standard Guide for Measurement of Outdoor A-Weighted Sound Levels
SCOPE
1.1 This guide covers the measurement of A-weighted sound levels outdoors at specified locations or along particular site boundaries, using a general purpose sound-level meter.
1.2 Three distinct types of measurement surveys are described:
1.2.1 Survey around a site boundary,
1.2.2 Survey at a specified location,
1.2.3 Survey to find the maximum sound level at a specified distance from a source.
1.3 Since outdoor sound levels almost always vary with time over a wide range, the data obtained using this guide may be presented in the form of a histogram of sound levels. The data obtained using this guide enables calculations of average or statistical sound levels for comparison with appropriate criteria.
1.4 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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e1
Designation: E 1014 – 84 (Reapproved 1995) An American National Standard
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 Guide for
Measurement of Outdoor A-Weighted Sound Levels
This standard is issued under the fixed designation E 1014; 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 November 1995.
1. Scope discharge of a firearm, or a shout.
3.2.3 measurement set—the set of data obtained at a mea-
1.1 This guide covers the measurement of A-weighted
surement location during a specific time period. For the types
sound levels outdoors at specified locations or along particular
of measurements covered by this guide, evaluation of a site
site boundaries, using a general purpose sound-level meter.
may require several measurement sets. The time period is
1.2 Three distinct types of measurement surveys are de-
flexible but should not extend beyond the time when the
scribed:
conditions influencing noise, or atmospheric conditions affect-
1.2.1 Survey around a site boundary,
ing noise propagation, are reasonably uniform. As an example,
1.2.2 Survey at a specified location,
a significant change in traffic density or start-up of a machine
1.2.3 Survey to find the maximum sound level at a specified
indicate the beginning or end of a measurement set.
distance from a source.
1.3 Since outdoor sound levels almost always vary with
4. Significance and Use
time over a wide range, the data obtained using this guide may
4.1 There are numerous situations for which outdoor sound
be presented in the form of a histogram of sound levels. The
level data are required. These include, but are not limited to,
data obtained using this guide enables calculations of average
the following:
or statistical sound levels for comparison with appropriate
4.1.1 Documentation of sound levels before the introduction
criteria.
of a new sound source (for example, assessment of the impact
1.4 This standard does not purport to address all of the
due to a proposed use).
safety concerns, if any, associated with its use. It is the
4.1.2 Comparison of sound levels with and without a
responsibility of the user of this standard to establish appro-
specific source (for example, assessment of the impact of an
priate safety and health practices and determine the applica-
existing source).
bility of regulatory limitations prior to use.
4.1.3 Comparison of sound levels with criteria or regulatory
2. Referenced Documents limits (for example, indication of exceedence of criteria or
non-compliance with laws).
2.1 ASTM Standards:
2 4.2 This guide provides a means for selecting measurement
C 634 Terminology Relating to Environmental Acoustics
locations, operating a sound level meter, documenting the
2.2 ANSI Standard:
3 conditions under which the measurements were performed, and
S1.4 Specification for Sound Level Meters
recording the results.
3. Terminology 4.3 This guide provides the user with information to (1)
make and document the sound level measurements necessary
3.1 Definitions—For definitions of terms used in this guide,
to quantify relatively steady or slowly varying outdoor sound
see Terminology C 634.
levels over a specific time period and at specific places and (2)
3.2 Definitions of Terms Specific to This Standard:
make and document the physical observations necessary to
3.2.1 barrier—any obstacle that blocks the line-of-sight
qualify the measurements.
between a source and a receiver or a measurement location.
4.4 The user is cautioned that there are many nonacoustical
3.2.2 impulse noise—a brief, intrusive sound, such as that
factors that can strongly influence the measurement of outdoor
associated with a tire blowout, operation of a power press, the
sound levels and that this guide is not intended to supplant the
1 experience and judgment of experts in the field of acoustics.
This guide is under the jurisdiction of ASTM Committee E-33 on Environ-
The guide is not applicable when more sophisticated measure-
mental Acoustics and is the direct responsibility of Subcommittee E33.09 on
Community Noise.
ment methods or equipment are specified. This guide, depend-
Current edition approved July 27, 1984. Published September 1984.
ing as it does on simplified manual data acquisition, is
Annual Book of ASTM Standards, Vol. 04.06.
necessarily more appropriate for the simpler types of environ-
Available from American National Standards Institute, 11 W. 42nd St., 13th
Floor, New York, NY 10036. mental noise situations. As the number of sources and the range
Terminology C 634 – 81a was used in the development of this guide.
E 1014
of sound levels increase, the more likely experienced special- time. Calibration shall also be verified if the sound level meter
ists with sophisticated instruments are needed. is abused (dropped, etc.). If the change in the calibration
4.5 This guide can be used by individuals, regulatory reading, as shown on the sound level meter, is 1 dB or greater,
agencies, or others as a measurement method to collect the data gathered since the preceding calibration are considered
acoustical data for many common situations. The data are invalid and should be discarded.
obtained in the form of a histogram, a graph, or a table 6.2 The sound level meter and the acoustical calibrator shall
indicating the number of occurrences of each sound level have been thoroughly calibrated with equipment traceable to
observed during the measurement. Criteria for evaluating or the National Institute of Standards and Technology within 1
analyzing the data obtained are beyond the scope of this guide. year before the survey. Included in this calibration shall be
4.6 Note that this guide is only a measurement procedure checks of frequency response, amplifier sensitivity, internal
and, as such, does not address the methods of comparison of noise, and verification of correct operation of meter circuits
the acquired data with the specific criteria. No procedures are and microphone.
provided for estimating or separating the influences of two or
7. Interference
more simultaneously measured sounds. This guide can be
7.1 Wind may influence sound level measurements, even
useful in establishing compliance when the measured data are
with a windscreen in place, particularly at wind speeds above
below a specified limit.
20 km/h (12 mph). Manufacturers’ instructions shall be fol-
4.7 Paragraph 8.2.1 outlines a procedure that can be used for
lowed with respect to meter limitations under windy condi-
a survey of the site boundary; paragraph 8.2.2 for a survey of
tions. When wind speeds approach or exceed 20 km/h, head-
specified monitoring points; and paragraph 8.2.3 for determin-
phones shall be used to monitor the sound level meter output or
ing the location and magnitude of maximum sound level.
the sound level meter indicator shall be carefully observed to
5. Apparatus
determine if fluctuations correspond to wind speed or actual
sound sources. Data obtained during intervals when wind is
5.1 Acoustical Measurements:
influencing the measurements shall not be used. No measure-
5.1.1 Sound Level Meter (required), Type 2, as defined by
ments shall be made when steady wind speeds exceed 20 km/h.
ANSI S1.4–1971 preferably with an a-c output port to permit
7.2 Measurable precipitation almost always influences out-
the use of headphones.
door sound levels. For example, tires rolling on a paved surface
5.1.2 Microphone Windscreen (required), recommended by
the sound level meter manufacturer. result in higher sound levels when the pavement is wet. Also,
fallen snow may affect the propagation of sound so that sound
5.1.3 Acoustical Calibrator (required), with adaptors nec-
essary to fit the microphone. levels may be different with and without fallen snow. For these
reasons, making measurements during precipitation or when
5.1.4 Set of Headphones (desirable), compatible with and
electrically connected to the a-c output of the sound level pavement is wet or snow covered is discouraged. If it is
necessary to obtain data when ground surfaces are wet or snow
meter. Monitoring the output of the sound level meter with
covered, the conditions shall be carefully described in the
headphones may enable the operator to detect equipment
report. High humidity can influence certain microphones;
malfunctions or anomalies in the data caused by wind, humid-
manufacturers’ instructions should be closely followed under
ity, and electrical interference.
these conditions.
5.1.5 Tripod (desirable), to ensure a steady and repeatable
7.3 This guide is not intended to evaluate impulse noise
microphone position.
because Type 2 sound level meters operating in “fast” or
5.2 Physical Measurements:
“slow” modes do not accurately or precisely measure impulse
5.2.1 To assure an accuracy of 1 dB in values derived from
noise. If occasional impulses occur during the survey, estima-
these measurements, the accuracy of distance measurements
tion of their magnitude may be attempted using the fastest
must be within 5 %. Any instrument that provides this degree
available meter response, either “fast,” “peak,” or “impulse.”
of accuracy is satisfactory.
The maximum meter reading, the meter response setting, and
5.2.2 Pocket Compass (desirable), used for site layout work
the repetition rate within the measurement set shall be reported.
and for determination of wind direction.
Whenever most of the sound level meter readings in any
5.2.3 Site Map (optional).
measurement set are influenced by impulse noise, this guide
5.3 Meteorological Measurements—Any of the many avail-
shall not be used.
able general-accuracy meteorological instruments may be used
in order to enable the measurement of: 7.4 Occasionally it is necessary to measure sources of pure
tone noise perceived as a “buzz,” “hum,” or “whistle.” Since
5.3.1 Wind speed (5-km/h or 2.5-mph increments),
5.3.2 Wind direction (in octants), both the operator’s body and reflections can significantly
influence the sound level meter indication when tones are
5.3.3 Relative humidity (in 10 % increments),
present, the report must include observations of tonal noise
5.3.4 Dry bulb temperature (in 2°C or 5°F increments).
when present.
6. Calibration
7.5 Electromagnetic radiation from high voltage transmis-
6.1 The calibration of the sound level meter shall be sion lines, or strong television or radio signals may affect the
checked using an acoustical calibrator immediately before and sound level meter indication. The operator should use caution
after each measurement set, in a manner prescribed by the when these are nearby. Such electrical interference problems,
manufacturer. Adjustments, if required, shall be made at this when they occur, might result in wild and unexpected swings
E 1014
of the sound level meter indicator or upward indications even and without the source present, as two different measurement
when the instrument is turned off. These effects may be audible sets.
through monitoring headphones. This is the most effective way
8.2.1.2 The sound level meter may be used in selecting the
to detect these conditions and other anomalies. locations on the basis of sound level. For each time period,
7.6 Temperature inversions and other meteorological condi- walk the site boundary, measure and note the trend of sound
tions may strongly influence the propagation of sound over levels. Select a minimum of two locations to meet one or more
long distances. Therefore, when sound from sources at hori- of the following:
zontal distances of about 500 m (1600 ft) or more need to be (1) Local maximum, the location where the highest
measured, an acoustical specialist should be consulted. A-weighted sound level is observed.
(2) Local minimum, the location where the lowest
7.7 During certain times of the year, naturally occurring
sounds such as from birds or insects (crickets, locusts) may A-weighted sound level is observed.
dominate A-weighted sound levels particularly during evening 8.2.1.3 Alternatively, locations may be selected for other
and nighttime periods. Such noises should be noted in the reasons:
report. Where possible, an effort may be made to document
(1) Sensitive Locations, considering sound sources and
their influence by making measurements at different times or receivers either inside or outside the site, including upper floors
different locations to document conditions with and without
of nearby structures.
such naturally occurring sounds. (2) Locations Nearest to a Community, considering sound
sources within the site.
8. Procedure
(3) Intermediate Locations, locations selected so that the
indicated sound level at adjacent locations might not differ by
8.1 Preparation of Equipment—Prepare the sound level
more than 5 dB.
meter for use as follows:
(4) Other Locations: (1) so that locations are separated by no
8.1.1 Check the battery condition indicator (recheck every
more than one-half the site perimeter; (2) so that such
15 to 30 min during the measurement set).
conditions as variable terrain, acoustical barriers adjacent to
8.1.2 Verify calibration of the sound level meter in accor-
site activities, and presence of adjoining structures are consid-
dance with the manufacturer’s instructions.
ered.
8.1.3 Place the windscreen over the microphone.
8.1.4 Set the weighting to “A.”
NOTE 1—The location of the microphone, relative to barriers and large
reflecting surfaces influences the indicated sound level. It is extremely
8.1.5 Set the response to “slow” or as required in 7.3 (unless
important to record the location of the microphone relative to other
otherwise specified).
objects.
8.1.6 Select a range so that the sound level meter reading is
on scale.
(5) Measurement locations should be chosen so that they are
8.1.7 Support the instrument and orient the microphone in
at least 1.5 m (5 ft) apart.
accordance with the manufacturer’s instructions. In the ab-
8.2.1.4 Measure the sound levels at each location in accor-
sence of a specified height, position the microphone between
dance with 8.3.1.
1.2 m (4 ft) and 1.5 m (5 ft) above the ground.
8.2.1.5 Measure the meteorological conditions in accor-
8.2 Selecting Measurement Locations and Times: dance with 8.3.2.
8.2.1 Survey Around a Site Boundary—Follow procedures 8.2.2 Survey at a Specified Location—Follow procedures in
in 8.2.1.1-8.2.1.5 when it is necessary to measure A-weighted 8.2.2.1-8.2.2.3 for
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