The following words, terms and phrases, when used in this chapter, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:
"A" weighted sound level"means the sound pressure level in decibels as measured on a sound level meter using the A-weighting network, using a sound level meter meeting the standards set forth in American National Standards Institute specifications for sound level meters (ANSI S1.4-1983 or the latest approved revision thereof). The unit of reporting is dB(A). Sounds measured with the "A" weighting network approximates the response of human hearing when measuring sounds of low to moderate intensity.
"Ambient sound level"means that measured value which represents the summation of the sound from all the discrete sources affecting a given site at a given time, exclusive of extraneous sounds and those from the source under investigation. Ambient sound level is often referred to as neighborhood residual sound level or background sound level. Ambient sounds are differentiated from extraneous sounds by the fact that the former are more steady state, although they may not be continuous.
"Amplified sound"means the operation or playing of any radio, television, DVD, cassette player, compact disk, boom box, phonograph, drum, other musical instruments, sound amplifier or similar device that produces, reproduces or amplifies sound, including music.
"C" weighted sound level"is the sound level as measured using the "C" weighting network with a sound level meter meeting the standards set forth in ANSI S1.4-1983 or its successors. The unit of reporting is dB(C). The "C" weighting network is more sensitive to low frequencies than is the "A" weighting network.
"Commercial"means of or relating to commerce, engaged in commerce, involved in work designed or planned for the mass market; or designating products, often unrefined, made and distributed in large quantities for industrial use; or having profit as a primary aim; or paid for by an advertiser or advertising.
"Commercial area"means any parcel of land zoned as commercial district, downtown district, or mixed-use district under title 21. It also means any development area within a planned community development district under title 21 where the designated land use is commercial, business, or mixed use - commercial/residential. Areas zoned residential-office under title 21 are excepted from the commercial area definition (see residential area).
"Construction"means site preparation, assembly, erection, drilling, substantial repair, alteration, demolition, or similar action or activity for or on: Public or private rights-of-way; structures; utilities; or similar property. For the purposes of this chapter, off-site fabrication and/or manufacture of materials used in construction including but not limited to modular housing fabrication, asphalt or concrete operations, sand/gravel extraction and truss manufacture are not construction.
"Construction season"means the period from April 1 through October 31, both dates inclusive, of each year.
"Continuous sound"means any sound with a duration of more than one second, as measured with a sound level meter set to the "slow" meter response.
"Demolition"means any dismantling, intentional destruction or removal of structures, utilities, public or private right-of-way surfaces or similar property.
"Department"means the Municipal Department of Health and Human Services.
"Director"means the Director of the Anchorage Health Department or his or her designee.
"Emergency work"means any work performed for the purpose of preventing or alleviating the physical trauma or property damage threatened or caused by an emergency.
"Extraneous sound"means a sound which is transient in nature and is neither part of the ambient sound, nor comes from the sound source under investigation. Examples of extraneous sound include automobile horns and brakes, air transport vehicles, people shouting and dog barking.
"Gross vehicle weight rating (GVWR)"means the value specified by the manufacturer as the recommended maximum loaded weight of a single motor vehicle. In cases where trailers and tractors are separable the gross combination weight rating (GCWR), which is the value specified by the manufacturer as the recommended maximum loaded weight of the combination vehicle, shall be used.
"Impulsive sound"means sound of short duration, usually less than one second and of high intensity, with an abrupt onset and rapid decay, examples of which include explosions, drop forge impacts and the discharge of firearms.
"Industrial area"means any parcel of land zoned as industrial district under title 21. It also means any development area within a community development district where the designated land use is industrial.
"Lmax"means a single event metric used to describe the greatest sound level in decibels during a given time period and location.
"Motor vehicle"means any motorized vehicle which is self-propelled including but not limited to automobile, motorcycle, snow mobile, mini-bike, go-cart, motor scooter and off-road vehicle but excluding railroad trains as defined under AMC section
9.04.010.
"Motorboat"means any vessel that operates on water and is propelled by a motor, including but not limited to boats, barges, amphibious craft, water ski towing devices and hovercraft, but excluding vessels engaged in international commerce.
"Noise"means any sound that annoys or disturbs humans or causes or tends to cause an adverse psychological or physiological effect on humans.
"Noise disturbance"means any sound that endangers or injures the safety or health of humans or animals, annoys or disturbs a reasonable person of normal sensitivities, or endangers or injures personal or real property.
"Person"means a corporation, company, partnership, firm, association, organization, business trust, or society, as well as a natural person.
"Powered model vehicle"means any self-propelled airborne, waterborne or landborne plane, vessel or vehicle that is not designed to carry persons, including but not limited to any model airplane, boat, car or rocket.
"Public right-of-way"means any street, avenue, boulevard, highway, sidewalk, alley, public use easement or similar place owned or controlled by a governmental entity.
"Public space"means any real property or structures thereon owned or controlled by a governmental entity.
"Pure tone"means any sound that can be distinctly heard as a single pitch or a set of single pitches. For the purposes of this chapter a pure tone shall exist if the one-third octave band sound pressure level in the band with the tone exceeds the arithmetic average of the sound pressure levels of the two contiguous one-third octave bands by five dB for center, frequencies of 500 Hz and above and by eight dB for center frequencies between 160 and in 400 Hz and by 15 dB for center frequencies less than or equal to 125 Hz.
"Real property boundary"means an imaginary line along the ground surface and its vertical extension or between separate apartments or condominiums that separates the real property owned, rented or leased by one person from that owned, rented or leased by another person.
"Residential area"means any parcel of land zoned as residential district, residential office district, public lands and institutions district, parks and recreation or recreation reserve district, development reserve district, watershed district, the turnagain arm district, girdwood commercial recreation or resort use district, or the girdwood institutions and parks or open space districts under title 21. It also means any development area within a planned community development district under Title 21 where the designated land use is residential.
"RMS sound pressure"means the square root of the time averaged square of the sound pressure, denoted Prms.
"Sound"means an oscillation in pressure, particle displacement, particle velocity or other physical parameter in a medium with internal forces that causes compression and rarefaction of that medium. The description of sound may include any characteristic of such sound, including duration, intensity and frequency.
"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.
"Sound level meter"means an instrument that includes a microphone, amplifier, RMS detector, integrator or time averager, output meter and weighting networks used to measure sound pressure levels.
"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.
"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 micropascals (20 micronewtons per square meter). The sound pressure level is denoted Lp or SPL and is expressed in decibels.
"Total sound level"means that measured level which represents the summation of the sounds from the sound source under investigation and the ambient sounds which affect a given place at a given time, exclusive of extraneous sound sources.
"Vibration"means a rapid linear motion of an elastic solid described by displacement, velocity, acceleration, or as measured with respect to a given reference point or equilibrium position.
"Vibration perception threshold"means the minimum ground-or structure-borne vibrational motion necessary to cause a normal person to be aware of the vibration by direct means such as but not limited to sensation by touch or visual observation of moving objects.
"Weekday"means any day Monday through Friday that is not a legal state holiday.