The following definitions are applicable to the environmental performance standards in this article:
(1) A-WEIGHTED SOUND LEVEL means the sound pressure level in decibels as measured on a sound level meter using the A-weighing network. The level so read is designated dB(A) or dBA.
(2) BACKGROUND NOISE means noise from all sources other than that under specific consideration including traffic operating on public thoroughfares, and is established by measuring the noise level over an eight-minute period of time.
(3) BOUNDING LOT LINE means the far side of any street, alley, stream or other permanently dedicated open space from the stationary source when such open space exists between the lot line of the stationary source and adjacent property. When no such open space exists, the common line between two parcels of property shall be interpreted as the bounding lot line.
(4) CONSTRUCTION means any phase of the on-site erection, including excavation, demolition, alteration, or repair, of any building or structure which is designed to be used on that site.
(5) DAYTIME means the hours between 7:00 a.m. and 10:00 p.m. on any given day.
(6) DECIBEL (dB) means a unit for measuring the volume of a sound, equal to 20 times the logarithm to the base 10 of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micropascals (20 Micronewtons per square meter).
(7) EQUIVALENT SOUND PRESSURE LEVEL (Leg) means the time weighted, mean square, A-weighted sound pressure level.
(7.1) LEGAL HOLIDAY means New Year’s Day (January 1), Memorial Day (observed date), Fourth of July (July 4), Labor Day (observed date), Thanksgiving Day (observed date), and Christmas Day (December 25).
(8) MOBILE SOURCE means sound pressure created by motorized vehicles designed to operate on public rights-of-way, including, but not limited to, automobiles and aircraft.
(9) NOISE means any sound which annoys or disturbs humans or which causes or tends to cause an adverse psychological or physiological effect on humans.
(10) NOISE DISTURBANCE means any sound which (a) endangers or injures the safety or health of humans or animals, or (b) annoys or disturbs a reasonable person of normal sensitivities, or (c) endangers or injures personal or real property.
(11) PERMISSIBLE SOUND PRESSURE LEVEL means the equivalent sound pressure level (Leg) averaged over an eight-minute period of time.
(12) PERSON means any individual, association, partnership, or corporation, and includes any officer, employee, department, agency, or instrumentality of a state or any political subdivision of a state.
(13) PROPERTY means all contiguous land and any fixed or moveable object on such land, under common ownership, irrespective of leasehold or other interest.
(14) RETAIL DISTRICTS means the NS, SC, and GR districts.
(15) SOUND means 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 S1.4-1971, or the latest approved revision thereof). If the frequency weighting employed is not indicated, the A-weighting shall apply.
(16) SOUND LEVEL METER means an instrument which includes a microphone, amplifier, RMS detector, integrator or time averager, output meter, and weighting networks used to measure sound pressure levels.
(17) SOUND PRESSURE means the instantaneous difference between the actual pressure and the average or barometric pressure at a given point in space, as produced by sound energy.
(19) SPECIAL EVENTS means all public and private school related activities and all events where a special events permit is issued by the city of Dallas.
(20) STATIONARY SOURCE means the point of origin of any noise emitted from a property. Multiple sources on a property shall be treated as a single source.
(21) TIME WEIGHTED means an established period of time during which the sound pressure levels are averaged. (Ord. Nos. 17501; 18849; 19995; 29424)
Notes
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