The following terms are defined as used in this chapter:
1. “Ambient sound level” means the noise associated with a given environment, exclusive of a particular noise being tested, being usually a composite of sounds from many sources near and far, exclusive of intruding noises from isolated identifiable sources.
2. “A-weighted sound level” means the sound pressure level in decibels as measured on a sound level meter using the A-weighting network. The level is designated dB(a) or dBa.
3. “Construction” means any site preparation, assembly, erection, substantial repair, alteration, or similar action, for or of public or private right-of-way, structures, utilities or similar property.
4. “Decibel (dB)” means a logarithmic and dimensionless unit of measure often used in describing the amplitude of 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).
5. “Demolition” means any dismantling, intentional destruction or removal of structures, utilities, public or private right-of-way surfaces, or similar property.
6. “Emergency” means any occurrence or set of circumstances involving actual or imminent physical or psychological trauma or property damage which demands immediate action.
7. “Emergency work” means any work performed for the purpose of alleviating or resolving an emergency.
8. “Equivalent A-weighted sound level (L
eq
)” means the constant sound level that, in a given situation and time period, conveys the same sound energy as the actual time-varying A-weighted sound. For the purpose of this chapter, a time period of one hour shall be used, unless the likely duration or intensity of the sound being measured makes a shorter time period reasonable.
9. “Impulsive sound” means sound of short duration, usually less than one second, with an abrupt onset and rapid decay. Examples of sources of impulsive sound include explosions, drop force impacts, and the discharge of firearms.
10. “Motorboat” means any vessel which operates on water and which is propelled by a motor, including, but not limited to, boats, barges, amphibious craft, water ski towing devices and hovercraft.
11. “Motorcycle” means any motor vehicle having a saddle or seat for the use of the rider and designed to travel on not more than three wheels in contact with the ground. The term includes motorized bicycles and motor scooters.
12. “Motor vehicle” means any motor-operated vehicle licensed for use on the public highways, but not including a motorcycle.
13. “Noise” means any sound which disturbs humans or which causes or tends to cause an adverse psychological or physiological effect on humans.
14. “Noise disturbance” means any sound which endangers or injures the welfare, safety, or health of a human being, or disturbs a reasonable person of normal sensitivities, or devalues or injures personal or real property.
15. “Noise sensitive activities” means activities which should be conducted under conditions of exceptional quiet including, but not limited to, operation of schools, libraries open to the public, and churches.
16. “Noise sensitive area” means any area designated by the City Council for the purpose of ensuring exceptional quiet and clearly posted with “Noise Sensitive Area” signs, because of the noise sensitive activities conducted therein.
17. “Powered model vehicle” means any self-propelled airborne, waterborne, or land borne model plane, vessel, or vehicle, which is not designed to carry persons, including (but not limited to) any model airplane, boat, car, or rocket.
18. “Public right-of-way” means any street, avenue, boulevard, highway, sidewalk, or alley or similar place which is owned or controlled by a governmental entity.
19. “Public space” means any real property, including any structure thereon, which is owned or controlled by a governmental entity.
20. “Pure tone” means any sound which can be distinctly heard as a single pitch or a set of single pitches.
21. “Real property boundary” means an imaginary line along the ground surface, and its vertical extension, which separates the real property owned by one person from that owned by another person, but not including intra-building real property divisions.
22. “Receiving land use” means, for the purposes of this chapter, the use or occupancy of the property which receives the transmissions of sound as hereinafter defined.
23. “Recreational vehicle” means any racecar, motorcycle, snowmobile, or any other motorized vehicle equipped for use in racing or other recreational events or uses off of public right-of-way on public or private property.
24. “Residential” means any property on which is located a building or structure used wholly or partially for living or sleeping purposes.
25. “RMS sound pressure” means the square root of the time averaged square of the sound pressure, denoted P
rms
.
26. “Sound” means an oscillation in pressure, particle displacement, particle velocity or other physical parameter, in a medium with internal forces that cause compression and rarefaction of that medium. The description of sound may include any characteristic of such sound, including duration, intensity, and frequency.
27. “Sound equipment” means any radio, record player, stereo, television, tape deck or player, loud speakers, amplifier, sound truck or other device for producing, reproducing, or amplifying sounds.
28. “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 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.
29. “Sound level meter” means an instrument which includes a microphone, amplifier, RMS detector, integrator or time average, output or display meter, and weighting networks used to measure sound pressure levels, which complies with American National Standards Institute Standard 1.4-1971.
30. “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.
31. “Sound pressure level” means 20 times the logarithm to the base 10 of the ratio of the RMS sound pressure to the reference pressure of 20 micronewtons per square meter (20 x 10
-6
N/m2). The sound pressure level is denoted L
P
or SPL and is expressed in decibels.
32. “Used” and “occupied,” when used in this chapter, both shall be deemed to include the words “intended, designed, or arranged to be used or occupied.”