§ 93.001  DEFINITIONS AND STANDARDS.
   All terminology used in this subchapter and not defined in this section shall be in conformance with applicable American National Standards Institute publications. For the purposes of this subchapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
   A-WEIGHTED SOUND PRESSURE LEVEL. The sound pressure level as measured with a sound level meter using the A-weighting network. The standard notation is dB(A) or dBA.
   AMBIENT SOUND PRESSURE LEVEL. The sound pressure level of the all-encompassing noise associated with a given environment, usually a composite of sounds from many sources.
   CONTINUOUS SOUND. Any sound which exists, essentially without interruption, for a period of ten minutes or more.
   CYCLICALLY VARYING NOISE. Any sound which varies in sound level so that the same level is obtained repetitively at reasonably uniform intervals of time.
   DECIBEL. A logarithmic and dimensionless unit of measure often used in describing the amplitude of sound. DECIBEL is denoted as “dB.”
   DEVICE. Any mechanism which is intended to produce, or which actually produces, noise when operated or handled.
   DYNAMIC BRAKING DEVICE (COMMONLY REFERRED TO AS JACOB’S BRAKE). A device used primarily on trucks for the conversion of the engine from an internal combustion engine to an air compressor for the purpose of braking without the use of wheel brakes.
   EMERGENCY VEHICLE. A motor vehicle used in response to any emergency or to protect persons or property from imminent exposure to danger.
   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.
   IMPULSIVE NOISE. A sound of short duration usually less than one second with an abrupt onset and rapid decay.
   MOTOR VEHICLE. Any vehicle which is self-propelled by mechanical power, including, but not limited to, passenger cars, trucks, truck-trailers, semitrailers, campers, helicopters, motorcycles, minibikes, go-carts, snowmobiles and racing vehicles.
   MUFFLER. An apparatus consisting of a series of chambers or baffle plates designed for the purpose of transmitting gases while reducing sound emanating from the apparatus.
   NINETIETH PERCENTILE NOISE LEVEL. The A-weighted sound pressure level that is exceeded 90% of the time in any measurement period (such as the level that is exceeded for nine minutes in a ten-minute period) and is denoted L90. The measurement period shall not be less than ten minutes unless otherwise noted in this chapter.
   NOISE. Any sound which is unwanted or which causes or tends to cause an adverse psychological or physiological effect on human beings.
   NOISE DISTURBANCE. Any sound which annoys or disturbs reasonable persons with normal sensitivities, or which injures or endangers the comfort, repose, health, hearing, peace and safety of other persons.
   PEAK. A sound level with a brief occurrence within a sound event which is characterized by a quick onset, an above average sound amplitude, and a rapid return to a lower sound level.
   PERSON. Any human being, firm, association, organization, partnership, business, trust, corporation, company, contractor, supplier, installer, user, owner or operator, including any municipal corporation or its officers or employees.
   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.
   PROPERTY BOUNDARY. Any imaginary line exterior to any enclosed structure, at the ground surface and its vertical extension, which separates the real property owned by one person from that owned by another person.
   PUBLIC RIGHT-OF-WAY. Any street, avenue, boulevard, highway or alley or similar place which is owned or controlled by a public governmental entity.
   PURE TONE. Any sound which can be distinctly heard as a single pitch or a set of single pitches.
   RECEIVING LAND USE CATEGORY. The principal use of the receiving property regardless of the zoning use established by city zoning ordinances.
   REPETITIVE IMPULSIVE NOISE. Any noise which is composed of impulsive noises that are repeated at sufficiently slow rates so that a sound level meter set at fast meter characteristic will show changes in sound pressure level greater than 10 dB(A).
   SOUND. A temporal and spatial oscillation in pressure, or other physical quantity, in a medium with interval forces that causes compression and rarefaction of that medium, and which propagates at finite speed to distant points.
   SOUND LEVEL METER.
      (1)   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.
      (2)   The instrument reads sound pressure level when properly calibrated and is of type 2 or better as specified in American National Standards Institute publication S1. 4-1971 or its successor publication.
   SOUND PRESSURE. The instantaneous difference between the actual pressure and the average or barometric pressure at a given point in space due to sound.
   SOUND PRESSURE LEVEL. Twenty times the logarithm to the base ten of the ratio of the RMS sound pressure to the reference pressure, which shall be 20 micropascals, denoted LP or SPL.
   STATIONARY NOISE SOURCE. Any device, fixed or movable, which is located or used on property other than a public right-of-way.
   STEADY NOISE. A sound pressure level which remains essentially constant during the period of observation; i.e., does not vary more than six dB(A) when measured with the slow meter characteristic of a sound level meter.
   USE DISTRICT. Those districts established by the city zoning ordinance.
(1972 Code, § 9-1; 1992 Code, § 25.5-1)  (Ord. 72-78, passed 7-10-1978; Ord. 22-86, passed 3-31-1986; Ord. 57-98, passed 6-15-1998; Ord. 6-10, passed 2-10-2010)
Cross-reference:
   Definitions and rules of construction generally, see § 10.002