As used in this chapter:
(a) “Acceleration” means the time rate of change of velocity.
(b) “Ambient noise” means the all encompassing noise associated with a given environment, being usually a composite of sounds from many sources.
(c) “ANSI” means the American National Standards Institute or its successor bodies.
(d) “Construction noise” means the noise emanating from construction activities, as described in Sections 633.11 and 633.17.
(e) “Critical construction equipment” means construction equipment required to operate twenty-four hours a day to protect the health and safety of the public and the workmen.
(f) “Cycle” means the complete sequence of values of a periodic quantity that occur during a period and is referred to as cycles per second or Hertz.
(g) “dbA” means the A -weighted sound pressure level obtained by the use of metering characteristics in the A-weighting network specified in ANSI S1.4-1971 or a later approved revision thereof.
(h) “Decibel (db)” means a unit of measure, on a logarithmic scale to the base ten, of the ratio of the magnitude of a particular sound pressure to a standard reference pressure, which, for the purposes of this chapter, shall be twenty micronewtons per square meter (MN/m2).
(i) “Displacement” means the magnitude of the motion.
(j) “Emergency work” means 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 or work by private or public utilities when restoring utility services or protecting from imminent danger.
(k) “Fixed source” means a machine or device capable of creating a noise level at the property upon which it is regularly located, including, but not limited to, air conditioning and refrigeration apparatus, industrial and commercial process machinery, fans, etc.
(l) “Impulsive sound” means a noise characterized by brief excursions of sound pressure, significantly exceeding the ambient noise, the duration of a single impulse of which is less than one second and which requires, for accurate measurements, a specifically designed instrumentation.
(m) “Impulsive vibration” means vibration resulting from an impact source, e.g. blasting or pile driving.
(n) “Motor vehicle” includes, but is not limited to, automobiles, trucks, motorcycles, minibikes, go-carts and snowmobiles.
(o) “Noise” means any undesired sound.
(p) “Noise level” is synonymous with “sound level.”
(q) “Particle velocity” means the time rate of change of displacement.
(r) “Person” means any person, association, copartnership, joint venture, corporation or other entity, public or private in nature.
(s) “Sound” means an oscillation in pressure in the air.
(t) “Sound analyzer” means a device for measuring a specific band pressure level or pressure spectrum level of a sound as a function of frequency.
(u) “Sound level” means, in decibels, a weighted sound pressure level, measured by the use of metering characteristics and frequency weightings specified in ANSI S1.4-1971 “Specification for Sound Level Meters.”
(v) “Sound level meter” means an instrument including a microphone, an amplifier, an output meter and frequency weighting networks for the measurement of noise and sound levels in a specified manner. The meter must satisfy the applicable requirements for a Type 2 sound level meter as defined in ANSI S1.4-1971 or the most recent revision thereof.
(w) “Sound pressure level” means, in decibels, twenty times the logarithm to the base ten of the ratio of the magnitude of a particular sound pressure to a standard reference pressure, which, for the purposes of this chapter, shall be twenty micronewtons per square meter (20 MN/m2).
(x) “Steady state vibration” means continuous earthborne oscillations.
(y) “Unnecessary, excessive or offensive noise” means any offensive sound or noise which annoys, disturbs, injures or endangers the comfort, repose, health, peace or safety of others, or a noise level which exceeds the fixed source noise level for the zone by 10 dbA or more, when measured at the nearest property line. (See Section 633.14.)
(z) “Zoning districts” means those zoning districts established by the City Zoning Code.
(Ord. 83-54. Passed 10-13-83.)