§ 16-179. Definitions and standards.
The following words, terms, and phrases, when used in this article, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning. All terminology used in this article and not defined in this section shall be in conformance with applicable publications of the American National Standards Institute (ANSI), or its successor body.
A-weighted sound pressure level means the sound pressure level in decibels as measured on a sound level using the A-weighting network. The level so read shall be designated db(A) or dbA.
Ambient (background) sound pressure level means the all-encompassing sound associated with a given environment, being usually a composite of sounds from all sources, excluding the alleged offensive sound, at the location and approximate time at which a comparison with the alleged offensive sound is to be made.
Construction means any site preparation, assembly, erection, substantial repair, alteration, or similar action excluding demolition, for or on public or private rights-of-way, structures, utilities or similar property.
Decibel (dB) means a unit for measuring the volume of a sound, equal to 20 times the logarithm to the base ten of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micropascals (20 micronewtons per square meter), denoted as dB.
Device means any mechanism which is intended to produce, or which actually produces, noise when operated or handled.
Emergency vehicle means a motor vehicle used in response to a public calamity or to protect persons or property from an imminent exposure to danger.
Emergency work means any work performed for the purpose of preventing or alleviating physical trauma or property damage threatened or caused by an emergency.
Energy equivalent sound level (Leq) means the sound level corresponding to the average sound energy during a specified period of time. Its calculation involves the conversion of decibels (a logarithmic quantity) to corresponding intensities (a linear quantity), performing the averaging, and finally changing the average back to decibels.
Land use district means those classifications established by the city Unified Development Code (i.e., the term "residential" means all residential classifications; the term "commercial/agricultural" means all commercial and/or agricultural classifications; and the term "industrial" means all industrial classifications). For purposes of this article, planned development districts shall be considered as residential, commercial, or industrial according to the primary use.
Motor vehicle means any vehicle propelled by mechanical power, such as, but not limited to, any passenger car, truck, truck-trailer, semitrailer, camper, motorcycle, minibike, go-cart, dune buggy or racing vehicle.
Noise means any sound which annoys or disturbs humans or which causes or tends to cause an adverse psychological or physiological effect on humans.
Noise disturbance means any unreasonably loud, disturbing and unnecessary noise which is offensive to an adult person within the city, which noise renders the enjoyment of life or property uncomfortable or interferes with public peace and comfort.
Percentile sound pressure level:
(1)
Unit percentile level means the A-weighted pressure level that is exceeded one percent of the time in a measurement period. It is denoted as L 1 .
(2)
Tenth percentile level means the A-weighted sound pressure level that is exceeded ten percent of the time in any measurement period (such as the level that is exceeded for one minute in a ten-minute period). It is denoted as L 10 .
(3)
Ninetieth percentile level means the A-weighted sound pressure level that is exceeded 90 percent of the time in any measurement period (such as the level that is exceeded for nine minutes in a ten-minute period). It is denoted as L 90 .
Property boundary means an imaginary line exterior to any enclosed structure, at the ground surface, and its vertical extension, which separates the real property owned by one or controlled by a governmental entity.
Public property means any real property or structures thereon which are owned or controlled by a governmental entity.
Public right-of-way means any street, avenue, boulevard, highway, sidewalk, alley, or similar place which is owned or controlled by a governmental entity.
Sound means a temporal or 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 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 the American National Standards Institute specifications for sound level meters. If the frequency weighting employed is not indicated, the A-weighting shall apply.
Sound level meter means an instrument for the measurement of sound, including a microphone, amplifier, RMS detector and integrator, time averager, output meter and weighted networks, that is sensitive to pressure fluctuations. The instruments read sound pressure levels when properly calibrated and is of Type II or better so specified in ANSI Publication S1.4-1971 or its successor body.
Sound pressure level means, expressed in decibels, 20 times the logarithm to the base ten of the ratio of the pressure of the sound to a reference pressure, which reference pressure shall be explicitly stated.
Stationary sound source means any device, fixed or movable, which is located or used on property other than a public right-of-way.
(Code 1982, § 18-5(b); Ord. of 10-5-1953, § 2; Ord. No. 91-31, § 1, 8-19-1991; Ord. No. 95-6, § 1, 3-20-1995; Ord. No. 03-19, § 1, 7-7-2003; Ord. No. 05-45, § 1, 10-3-2005; Ord. No. 09-21, §§ 1, 2, 5-4-2009)