ASTM E1014-84(2000)
(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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Designation:E1014–84 (Reapproved 2000)
Standard Guide for
Measurement of Outdoor A-Weighted Sound Levels
This standard is issued under the fixed designation E1014; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.2 impulse noise—a brief, intrusive sound, such as that
associated with a tire blowout, operation of a power press, the
1.1 This guide covers the measurement of A-weighted
discharge of a firearm, or a shout.
sound levels outdoors at specified locations or along particular
3.2.3 measurement set—the set of data obtained at a mea-
site boundaries, using a general purpose sound-level meter.
surement location during a specific time period. For the types
1.2 Three distinct types of measurement surveys are de-
of measurements covered by this guide, evaluation of a site
scribed:
may require several measurement sets. The time period is
1.2.1 Survey around a site boundary,
flexible but should not extend beyond the time when the
1.2.2 Survey at a specified location,
conditions influencing noise, or atmospheric conditions affect-
1.2.3 Surveytofindthemaximumsoundlevelataspecified
ing noise propagation, are reasonably uniform.As an example,
distance from a source.
a significant change in traffic density or start-up of a machine
1.3 Since outdoor sound levels almost always vary with
indicate the beginning or end of a measurement set.
time over a wide range, the data obtained using this guide may
be presented in the form of a histogram of sound levels. The
4. Significance and Use
data obtained using this guide enables calculations of average
4.1 There are numerous situations for which outdoor sound
or statistical sound levels for comparison with appropriate
level data are required. These include, but are not limited to,
criteria.
the following:
1.4 This standard does not purport to address all of the
4.1.1 Documentationofsoundlevelsbeforetheintroduction
safety concerns, if any, associated with its use. It is the
of a new sound source (for example, assessment of the impact
responsibility of the user of this standard to establish appro-
due to a proposed use).
priate safety and health practices and determine the applica-
4.1.2 Comparison of sound levels with and without a
bility of regulatory limitations prior to use.
specific source (for example, assessment of the impact of an
2. Referenced Documents existing source).
4.1.3 Comparisonofsoundlevelswithcriteriaorregulatory
2.1 ASTM Standards:
limits (for example, indication of exceedence of criteria or
C634 Terminology Relating to Environmental Acoustics
non-compliance with laws).
2.2 ANSI Standard:
4.2 This guide provides a means for selecting measurement
S1.4 Specification for Sound Level Meters
locations, operating a sound level meter, documenting the
3. Terminology
conditionsunderwhichthemeasurementswereperformed,and
recording the results.
3.1 Definitions—For definitions of terms used in this guide,
4.3 This guide provides the user with information to (1)
see Terminology C634.
make and document the sound level measurements necessary
3.2 Definitions of Terms Specific to This Standard:
to quantify relatively steady or slowly varying outdoor sound
3.2.1 barrier—any obstacle that blocks the line-of-sight
levels over a specific time period and at specific places and (2)
between a source and a receiver or a measurement location.
make and document the physical observations necessary to
qualify the measurements.
ThisguideisunderthejurisdictionofASTMCommitteeE33onEnvironmental
4.4 The user is cautioned that there are many nonacoustical
Acoustics and is the direct responsibility of Subcommittee E33.09 on Community
factors that can strongly influence the measurement of outdoor
Noise.
sound levels and that this guide is not intended to supplant the
Current edition approved July 27, 1984. Published September 1984.
experience and judgment of experts in the field of acoustics.
Annual Book of ASTM Standards, Vol. 04.06.
Available from American National Standards Institute, 11 W. 42nd St., 13th
Floor, New York, NY 10036.
Terminology C634–81a was used in the development of this guide.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1014
The guide is not applicable when more sophisticated measure- 6. Calibration
ment methods or equipment are specified. This guide, depend-
6.1 The calibration of the sound level meter shall be
ing as it does on simplified manual data acquisition, is
checked using an acoustical calibrator immediately before and
necessarily more appropriate for the simpler types of environ-
after each measurement set, in a manner prescribed by the
mentalnoisesituations.Asthenumberofsourcesandtherange
manufacturer. Adjustments, if required, shall be made at this
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
thedatagatheredsincetheprecedingcalibrationareconsidered
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 Thesoundlevelmeterandtheacousticalcalibratorshall
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
analyzingthedataobtainedarebeyondthescopeofthisguide.
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
provided for estimating or separating the influences of two or and microphone.
more simultaneously measured sounds. This guide can be
useful in establishing compliance when the measured data are 7. Interference
below a specified limit.
7.1 Wind may influence sound level measurements, even
4.7 Paragraph8.2.1outlinesaprocedurethatcanbeusedfor
with a windscreen in place, particularly at wind speeds above
a survey of the site boundary; paragraph 8.2.2 for a survey of
20 km/h (12 mph). Manufacturers’ instructions shall be fol-
specified monitoring points; and paragraph 8.2.3 for determin-
lowed with respect to meter limitations under windy condi-
ing the location and magnitude of maximum sound level.
tions. When wind speeds approach or exceed 20 km/h, head-
phonesshallbeusedtomonitorthesoundlevelmeteroutputor
5. Apparatus
the sound level meter indicator shall be carefully observed to
5.1 Acoustical Measurements:
determine if fluctuations correspond to wind speed or actual
5.1.1 Sound Level Meter (required), Type 2, as defined by
sound sources. Data obtained during intervals when wind is
ANSI S1.4–1971 preferably with an a-c output port to permit
influencing the measurements shall not be used. No measure-
the use of headphones.
mentsshallbemadewhensteadywindspeedsexceed20km/h.
5.1.2 Microphone Windscreen (required), recommended by
7.2 Measurable precipitation almost always influences out-
the sound level meter manufacturer.
doorsoundlevels.Forexample,tiresrollingonapavedsurface
5.1.3 Acoustical Calibrator (required), with adaptors nec-
result in higher sound levels when the pavement is wet. Also,
essary to fit the microphone.
fallen snow may affect the propagation of sound so that sound
5.1.4 Set of Headphones (desirable), compatible with and
levelsmaybedifferentwithandwithoutfallensnow.Forthese
electrically connected to the a-c output of the sound level
reasons, making measurements during precipitation or when
meter. Monitoring the output of the sound level meter with
pavement is wet or snow covered is discouraged. If it is
headphones may enable the operator to detect equipment
necessarytoobtaindatawhengroundsurfacesarewetorsnow
malfunctions or anomalies in the data caused by wind, humid-
covered, the conditions shall be carefully described in the
ity, and electrical interference.
report. High humidity can influence certain microphones;
5.1.5 Tripod (desirable), to ensure a steady and repeatable
manufacturers’ instructions should be closely followed under
microphone position.
these conditions.
5.2 Physical Measurements:
7.3 This guide is not intended to evaluate impulse noise
5.2.1 To assure an accuracy of 1 dB in values derived from
because Type 2 sound level meters operating in “fast” or
these measurements, the accuracy of distance measurements
“slow” modes do not accurately or precisely measure impulse
must be within 5%. Any instrument that provides this degree
noise. If occasional impulses occur during the survey, estima-
of accuracy is satisfactory.
tion of their magnitude may be attempted using the fastest
5.2.2 Pocket Compass (desirable),usedforsitelayoutwork
available meter response, either “fast,” “peak,” or “impulse.”
and for determination of wind direction.
The maximum meter reading, the meter response setting, and
5.2.3 Site Map (optional).
therepetitionratewithinthemeasurementsetshallbereported.
5.3 Meteorological Measurements—Any of the many avail-
Whenever most of the sound level meter readings in any
able general-accuracy meteorological instruments may be used
measurement set are influenced by impulse noise, this guide
in order to enable the measurement of:
shall not be used.
5.3.1 Wind speed (5-km/h or 2.5-mph increments),
5.3.2 Wind direction (in octants),
7.4 Occasionally it is necessary to measure sources of pure
5.3.3 Relative humidity (in 10% increments), tone noise perceived as a “buzz,” “hum,” or “whistle.” Since
5.3.4 Dry bulb temperature (in 2°C or 5°F increments). both the operator’s body and reflections can significantly
E1014
influence the sound level meter indication when tones are to9amandfrom4to6pm)and“non-rush”hoursforpurposes
present, the report must include observations of tonal noise of comparing noise levels with and without peak traffic flow.
when present.
(2)Bothaweekday(MondaytoFriday)andaweekendday
7.5 Electromagnetic radiation from high voltage transmis-
(Saturday or Sunday) should be monitored if a difference in
sion lines, or strong television or radio signals may affect the
sound levels is expected unless otherwise specified. Whenever
sound level meter indication. The operator should use caution
aparticularnoisesourcetendstodominatethemeasuredsound
when these are nearby. Such electrical interference problems,
level only intermittently, the survey shall include periods with
when they occur, might result in wild and unexpected swings
and without the source present, as two different measurement
of the sound level meter indicator or upward indications even
sets.
whentheinstrumentisturnedoff.Theseeffectsmaybeaudible
8.2.1.2 The sound level meter may be used in selecting the
throughmonitoringheadphones.Thisisthemosteffectiveway
locations on the basis of sound level. For each time period,
to detect these conditions and other anomalies.
walk the site boundary, measure and note the trend of sound
7.6 Temperature inversions and other meteorological condi-
levels. Select a minimum of two locations to meet one or more
tions may strongly influence the propagation of sound over
of the following:
long distances. Therefore, when sound from sources at hori-
(1) Local maximum, the location where the highest
zontal distances of about 500 m (1600 ft) or more need to be
A-weighted sound level is observed.
measured, an acoustical specialist should be consulted.
(2) Local minimum, the location where the lowest
7.7 During certain times of the year, naturally occurring
A-weighted sound level is observed.
sounds such as from birds or insects (crickets, locusts) may
8.2.1.3 Alternatively, locations may be selected for other
dominateA-weighted sound levels particularly during evening
reasons:
and nighttime periods. Such noises should be noted in the
(1) Sensitive Locations, considering sound sources and
report. Where possible, an effort may be made to document
receiverseitherinsideoroutsidethesite,includingupperfloors
their influence by making measurements at different times or
of nearby structures.
different locations to document conditions with and without
(2) Locations Nearest to a Community, considering sound
such naturally occurring sounds.
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:
8.1.1 Check the battery condition indicator (recheck every (4) Other Locations: (1) so that locations are separated by
15 to 30 min during the measurement set). no more than one-half the site perimeter; (2) so that such
8.1.2 Verify calibration of the sound level meter in accor- conditions as variable terrain, acoustical barriers adjacent to
dance with the manufacturer’s instructions. site activities, and presence of adjoining structures are consid-
8.1.3 Place the windscreen over the microphone. ered.
8.1.4 Set the weighting to “A.”
NOTE 1—The location of the microphone, relative to barriers and large
8.1.5 Settheresponseto“slow”orasrequiredin7.3(unless
reflecting surfaces influences the indicated sound level. It is extremely
otherwise specified).
important to record the location of the microphone relative to other
8.1.6 Select a range so that the sound level meter reading is
objects.
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
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