All terminology used in this chapter, not defined
herein, shall be in conformance with applicable publications of the
American National Standard Institute (ANSI) or its successor body.
As used in this chapter, the following terms shall have the meanings
indicated:
A-WEIGHTED SOUND-PRESSURE LEVEL
The sound-pressure level as measured on a sound-level meter
using the A-weighting network. The level so read shall be designated
dB(A) or dBA.
AMBIENT NOISE LEVEL
The all-encompassing background noise associated with a given
environment without the sound contribution of the specific source
in question.
DECIBEL
A standard unit for measuring the sound-pressure level. It
is equal to 20 times the logarithm to the base 10 of the ratio of
the pressure of the sound measured to a reference which is 20 micropascals
denoted as dB.
EMERGENCY
Any occurrence or set of circumstances involving actual or
imminent physical trauma or property damage which demands immediate
actions.
EMERGENCY VEHICLE
A motor vehicle used in response to public calamity or to
protect persons or property from imminent danger.
EQUIVALENT SOUND LEVEL (A-WEIGHTED)
The constant sound level that, in a given situation and time
period (x) conveys the sound energy as the actual time-varying A-weighted
sound. Designated Leq(x) dB(A).
MOTOR VEHICLE
As defined in the Motor Vehicle Code of the State of Delaware,
or any vehicles which are propelled or drawn by mechanical equipment,
such as but not limited to passenger cars, trucks, truck-trailers,
semitrailers, campers, motorcycles, minibikes, go-carts, snowmobiles,
mopeds, amphibious craft on land, dune buggies or racing vehicles.
MUFFLER
Any apparatus whose primary purpose is to transmit liquids
or gases while causing a reduction in sound emission at one end.
NOISE
Any sound which is unwanted or which causes or tends to cause
an adverse physiological effect on human beings.
NOISE DISTURBANCE
Any sound which:
A.
Endangers or injures the safety or health of
humans or animals;
B.
Annoys or disturbs a reasonable person of normal
sensibilities;
C.
Jeopardizes the value of property and erodes
the integrity of the environment; or
D.
Is in excess of the allowable noise levels established in §
143-5 herein.
NOISE, PLAINLY AUDIBLE
Any noise for which the information content of that noise
is communicated to the listener, such as but not limited to understandable
spoken speech or comprehensible musical rhythms, including bass tones
with a repetitive and impulsive sound.
POWERED MODEL VEHICLES
Any powered vehicles, either airborne, waterborne or landborne,
which are designed not to carry persons or property, such as but not
limited to model airplanes, boats and rockets, which can be propelled
by mechanical means.
PROPERTY BOUNDARY
An imaginary line at the ground surface, and its vertical
extension, which separates the real property owned by one person from
that owned by another person, or institution, corporation, business
or governmental entity.
PURE TONE
Any sound which can be distinctly heard as a single pitch
or set of single pitches. For the purpose of this section, a pure
tone shall exist if the 1/3 octave band sound-pressure level and the
band with the tone exceeds the arithmetic average of the sound-pressure
level of the two contiguous 1/3 octave bands by 15 dB for bands with
center frequencies less than 160 Hz, eight dB for bands with center
frequencies greater than 400 Hz.
SOUND
A temporal and spatial oscillation in pressure, or other
physical quantity, in a medium with internal forces that causes compression
and rarefaction of that medium, and which propagates at finite speed
to distant points.
SOUND LEVEL
The sound-pressure level (SPL) obtained by the use of a sound-level
meter and frequency weighting network, such as A, B or C, as specified
in American National Standards Institute specifications for sound-level
meters (ANSI SI.4-1971, or the latest approved revision thereof).
The unit of measurement is the decibel. If the frequency weighting
employed is not indicated, the A-weighting shall apply.
SOUND PRESSURE
The instantaneous difference between the actual pressure
and the average or barometric pressure at a given point in space.
WEEKDAY
Any Monday, Tuesday, Wednesday, Thursday or Friday which
is not a legally designated holiday.
For the purpose of the enforcement of the provisions
of this chapter, when used, a sound-level meter shall meet or exceed
the requirements of the American National Standard Institute specifications
for sound-level meters (ANSI SI.4-1971), approved April 27, 1971,
and issued by the American National Standard Institute for Types I,
II, or S sound-level meters. A sound-level calibration instrument
of the coupler type shall be used to calibrate the sound-level meter
in decibel units, and such instrument shall produce a calibration
sound-pressure level having a tolerance no greater than plus 0.5 dB
with a reference sound-pressure level of 20 micronewtons per square
meter.