Definitions. All terminology used in this chapter
and not defined below shall be in conformance with applicable publications
of the American National Standards Institute (ANSI) or its successor
body. As used in this chapter, the following terms shall have the
meanings indicated herein:
AMBIENT SOUND LEVEL
The composite or normal or existing sound from all sources
measured at a given location for a specific time of the day or night.
CYCLICALLY VARYING NOISE
Steady, fluctuating or impulsive noise which may or may not
contain a pure tone and which varies in sound pressure level such
that the same level is obtained repetitively at reasonably uniform
intervals of time.
DECIBEL
The logarithmic and dimensionless unit of measurement often
used in describing the loudness of sound. Decibel is denoted as dB.
DEVICE
Any mechanism which is intended to produce, or which actually
produces, noise when operated or handled.
EMERGENCY WORK
Work made necessary to restore property to a safe condition
following a public calamity, or work required to protect persons or
property from an imminent exposure to danger.
EMERGENCY VEHICLE
A motor vehicle used in response to a public calamity, or
to protect persons or property from an imminent exposure to danger.
IMPULSIVE NOISE
A noise characterized by brief excursions of sound pressure
whose peak levels exceed the ambience by 10dB. The duration of a single
impulse is usually less than one second and requires the use of a
sound level meter specially adapted for its measurement. Examples
of impulsive sound include but are not limited to gun shots, blasting
and hammering.
MOTOR VEHICLE
Any vehicle which is self-propelled by mechanical power,
or propelled by human power or electric power from overhead wires
or electrified rails, including, but not limited to, passenger cars,
trucks, trucktrailers, trains, semi-trailers, campers, motorcycles,
minibikes, go-carts, snowmobiles and racing vehicles.
NOISE
Any sound which annoys or disturbs humans or which causes
or tends to cause an adverse psychological or physiological effect
on human, or which endangers personal or real property.
PLAINLY AUDIBLE NOISE
Any noise for which the information content of that noise
is unambiguously transferred to the listener, such as, but not limited
to, understanding of spoken speech, comprehension of whether a voice
is raised or normal, or comprehension of musical rhythms.
PURE TONE
Any sound which can be distinctly heard as a single pitch
or a set of single pitches. For the purposes of this chapter, a pure
tone shall exist if the 1/3 octave band sound pressure level in the
band with the tone exceeds the arithmetic average of the sound pressure
levels of the two contiguous 1/3 octave bands by five dB for center
frequencies of 500 Hz and above, 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
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. The description of sound may include any characteristic
of such sound, including duration, intensity and frequency.
SOUND LEVEL
The weighted sound pressure level 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.4-1983), or the latest approved revision
thereof. If the frequency weighting employed is not indicated, the
A-weighting shall apply (dBA).
SOUND LEVEL METER
An instrument, including a microphone, amplifier, RMS detector
and integrator, time averager, output meter and/or visual display
and weighting networks, that is sensitive to pressure fluctuations.
The instrument reads sound pressure level when properly calibrated.
The sound level meter used for testing purposes in accordance with
this chapter shall meet the current American National Standard Institute
specifications.
SOUND PRESSURE
The instantaneous difference between the actual pressure
and the average or barometric pressure at a given point in space due
to sound.
STATIONARY NOISE SOURCE
Any device, fixed or movable, which is located or is being
used on geographically defined real property other than a public right-of-way.