Terms defined.
ANSI
American National Standards Institute or its successor bodies.
CONSTRUCTION
Any site preparation, assembly, erection, repair, alteration
or similar activity.
CURTILAGE
The enclosed land surrounding a house or dwelling and includes
all areas maintained in lawn or horticultural plantings and may be
bounded by a fence or wall, but would not typically include areas
more distant than 300 feet from the dwelling unless those areas were
horticulturally maintained and routinely used as areas of personal
refuge, or supported accessory structures that were routinely utilized.
DAY-NIGHT AVERAGE SOUND LEVEL (Ldn)
In decibels, the energy average sound level for a twenty-four-hour
day with a ten-decibel penalty applied to noise occurring during the
nighttime period: i.e., noise levels occurring during the period from
10:00 p.m. one day until 7:00 a.m. the next day are treated as though
they were 10 dBA higher than they actually are. The use of the A-weighting
is understood. The mathematical expression for Ldn is as follows:
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where
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Ld = The daytime average
sound level.
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Ln = The nighttime average
sound level.
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DBA
Abbreviation for the sound level in decibels determined by
the A-weighing network of a sound level meter or by calculation from
octave band or one-third octave band data.
DECIBEL (dB)
A unit of measure equal to 10 times the logarithm to the
base 10 of the ratio of the square of the sound pressure to the square
of a standard reference pressure. For the purpose of this subsection,
20 micropascals shall be the standard reference pressure.
DEMOLITION
Any dismantling destruction, or removal activities.
CITY
The City of Crisfield.
EMERGENCY
Any occurrence or set of circumstances involving actual or
imminent physical trauma or property damage which demands immediate
action.
ENVIRONMENTAL NOISE STANDARDS
The goals for environmental noise, the attainment and maintenance
of which, in defined areas and under specific conditions, are necessary
to protect the public health and general welfare.
EQUIVALENT SOUND LEVEL (ALSO AVERAGE SOUND LEVEL)
The level of a constant sound which, in a given situation
and time period, would convey the same sound energy as does the actual
time-varying sound during the same period. Equivalent sound level
is the level of the time-weighted, mean-square, A-weighted sound pressure.
A numerical subscript may be used to indicate the time period under
consideration; i.e., 1eq 24 or Leq8 for twenty-four-hour and eight-hour periods, respectively.
No subscript indicates a twenty-four-hour period. The mathematical
expression for the Leq is as follows:
Where t1 and t2 are the beginning and ending times, respectively, of
the period over which the average is determined, and LA(t) is the instantaneous A-weighed sound pressure levels fluctuating
with time.
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IEC
International Electrotechnical Commission.
NOISE
The intensity, frequency, duration and character of sound,
including sound and vibration of subaudible frequencies.
NOISE POLLUTION
The presence of noise of sufficient loudness, character,
and duration, which whether from a single source or multiple sources,
is, or may be predicted with reasonable certainty to be injurious
to health or which unreasonably interferes with the proper enjoyment
of property or with any lawful business activity.
PERIODIC NOISE
Noise possessing a repetitive on-and-off characteristic with
a rapid rise to maximum and a short decay not exceeding two seconds.
PERSON
Any individual, group of individuals, firm, partnership,
voluntary association, or private, public, or municipal corporation,
or political subdivision of the state, or department, bureau, agency,
or instrument of federal, state or local government, responsible for
the use of the property.
PROMINENT DISCRETE TONE
Any sound which can be distinctly heard as a single pitch
or a set of single pitches. For the purpose of this regulation, a
prominent discrete tone shall exist if the one-third octave band sound
pressure level in the band with the tone exceeds the arithmetic average
of the sound pressure levels of the two contiguous one-third octave
bands by five dB for center frequencies of 500 Hz and above and by
eight dB for center frequencies between 160 Hz and 400 Hz and by 15
dB for center frequencies less than or equal to 125 Hz.
SOUND LEVEL
In decibels, the weighted sound pressure level measured by
the use of a sound level meter. Sound level and noise level are synonymous.
The weighting employed shall always be specified.
SOUND LEVEL METER
An instrument, meeting International Electrotechnical Commission
and American National Standards Institute standards comprising a microphone,
an amplifier, an output meter, and frequency-weighting network(s)
that is used for the measurement of sound pressure levels in a specified
manner.
SOUND PRESSURE
The minute fluctuations in atmospheric pressure which accompany
the passage of a sound wave. Sound pressure is usually measured in
dynes per square centimeter (dyne/cm2),
or in newtons per square meter N/m2), or
in micropascals.
SOUND PRESSURE LEVEL
In decibels, 20 times the logarithm to the base 10 of the
ratio of a sound pressure to the reference sound pressure of 20 micropascals
(20 micronewtons per square meter). In the absence of any modifier,
the pressure is understood to be that of a root mean-square pressure.
SOURCE
Any person or property, real or personal, contributing to
noise pollution.
VIBRATION
Any oscillatory motion of solid bodies.
ZONING DISTRICT
A general land use category, defined according to local subdivision,
the activities and uses for which are generally uniform throughout
the subdivision. For the purpose of this regulation, property which
is not zoned "industrial," "commercial," or "residential" shall be
classified according to use as follows:
(b)
COMMERCIALProperty used for buying and selling goods and services;