§ 34-84. Definitions.

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:

Acoustic specialist means a person or persons trained in acoustic sampling, qualified to measure sound levels in A-weighted and C-weighted networks and one-third octave band frequencies.

Ambient noise level means the all-encompassing noise level associated with a given environment, being a composite of sounds from all sources, excluding the alleged offensive noise, at the location and approximate time at which a comparison with the alleged offensive noise is to be made.

A-weighting means the standard A-weighted frequency response of a sound level meter, which de-emphasizes low and high frequencies of sound in a manner similar to the human ear for moderate sounds.

C-weighting means the standard C-weighted frequency response of a sound level meter, which de-emphasizes high frequencies of sound in a manner similar to the human ear for relatively loud sounds.

Cumulative period means an additive period of time composed of individual time segments which may be continuous or interrupted.

Decibel and dB mean a unit which denotes the ratio between two quantities which are proportional to power; the number of decibels corresponding to the ratio of two amounts of power is ten times the logarithm to the base of ten of this ratio.

Emergency work means the use of any machinery, equipment, vehicle, human power or other activity in an effort to protect, maintain, provide or restore safe conditions in the community or for citizenry, or work by private or public utilities when restoring utility service.

Equivalent hourly sound level ("Leq") means the sound level corresponding to a steady state A-weighted sound level containing the same total energy as the actual time-varying sound level over a one-hour period.

Hertz means a unit of measurement of frequency, numerically equal to cycles per second.

Impulsive noise means a noise characterized by brief excursions of sound pressures the peak levels of which are very much greater than the ambient noise level, such as might be produced by the impact of a piledriver, punchpress or a drop hammer, typically with one second or less duration.

Low frequency noise means a noise which occurs in the frequency range of 160 Hertz or less.

Noise level means the sound pressure level in decibels obtained by using a sound level meter using A-weighting and C-weighting networks, or one-third octave band frequency at slow response (or fast response when required by this article for the measurement of impulsive sounds or low frequency noise) with a reference pressure of 20 micropascals. The unit of measurement shall be designated as dBA or dBC, as appropriate. The meter setting for slow or fast response shall be noted.

One-third octave band means a band of frequencies, in Hertz, which is one-third of an octave wide, as defined by the current version of the American National Standards Institute (ANSI) Standard S1.11. Examples of one-third octave band center frequencies in the range of audible sound include 20, 25, 31.5, 40 and 63 Hertz. Describing sound pressure levels in one-third octave bands provides information as to the tone or pitch, of noise (low frequency versus high frequency), as well as the amplitude of the sound.

Residential property means a parcel of real property which is developed and used either in part or in whole for residential purposes, other than transient uses such as hotels and motels.

Simple tone noise and pure tone noise mean a noise characterized by the presence of a predominant frequency such as might be produced by whistle or hum.

Sound level meter means an instrument meeting ANSI Standard S1.4-1983 for type 1 or type 2 sound level meters or an instrument and the associated recording and analyzing equipment which will provide equivalent data.

Sound pressure level means a sound pressure level of a sound, in decibels, as defined in ANSI Standard S1.4-1983; that is, 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.

Zone means any of the zones specified in the zoning code of the city, as such zones are presently identified therein and as they may be subsequently modified or altered.

(Ord. No. 2015-011, § 1, 1-14-2016)