(a) “Authorized emergency vehicle” means a vehicle equipped with a siren, exhaust whistle or bell necessary to warn other vehicle operators or pedestrians of the approach of the emergency vehicle, including an ambulance, police or fire service vehicle and vehicles of the Water and Power Authority, the Department of Public Works, the Territorial Emergency Management Agency and such other vehicles that may be so designated by the Police Commissioner when these vehicles are being used in actual emergencies.
(b) “Construction activity” means all activity incidental to the erection, demolition, assembling, altering, installation or equipping of buildings, structures, roads or appurtenances thereof, including land clearing, grading, excavating and filling.
(c) “dBA” refers to sound levels measured on the “A” scale of a standard sound level meter. “dB” means decibel, a unit used to measure the level of sound.
(d) “Emergency” means any occurrence or set of circumstances involving actual or imminent physical harm or property damage which demands immediate action.
(e) “Motor vehicles” means all vehicles propelled by power other than muscular.
(f) “Indoor sound amplification device” means any equipment or machine used for the magnification of speech, music or other sound within any roofed structure having more than fifty percent of its floor plan enclosed by walls.
(g) “Noise” means the intensity, frequency, duration and character of sounds from a source or number of sources which annoys or disturbs humans or causes or tends to cause an adverse psychological or physiological effect on humans.
(h) “Noise disturbance” means any sound that is or may be:
(1) harmful or injurious to the health, safety or welfare of any individual;
(2) unreasonably interferes with the enjoyment of life, quiet, comfort or outdoor recreation of an individual of ordinary sensitivity and habits;
(3) endangers or injures the conduct of business;
(4) jeopardizes the value of property and erodes the integrity of the environment; and
(5) exceeds a sound level of 75 dBA.
(i) “Noncommercial purpose” means the installation, use or operation of any outdoor sound amplifying device for other than a commercial purpose, including a charitable, patriotic, philanthropic, political or private purpose.
(j) “Outdoor sound amplification device” means any equipment or machine used for the out-of-doors magnification of speech, music or other sound.
(k) “Person” means any natural person, individual, public or private corporation, firm, association, joint venture, partnership, governmental agency, political subdivision, public officer or any other entity or any combination of entities, jointly or severally.
(l) “Residential zone” means all those districts zoned for residential uses.
(m) “Sound level” means the A-weighted sound pressure level measured with fast response using an instrument complying with the specifications for sound level meters of the American National Standards, Inc.
(n) “Sound level meter” means an instrument that includes a microphone, an amplifier, an output meter and frequency weighing networks for the measurement of noise and sound levels.
(o) “Sound-producing device” means any equipment or machine used for the production or reproduction of speech, music or other sound, including radios, television, phonographs, tape players, musical instruments, compact disc or tape cassette players, walkie-talkies, CD radios or synthesizers.
(p) “Soundproof” means to insulate so as to obstruct the passage of sound.
(q) “Warning device” means a sound emitting device used to alert and warn people.
(r) “Watercraft” means any boat or craft, including a vessel, used or capable of being used as a means of transport on water.
(s) “Noise sensitive zone” means existing quiet zones, if any, and those areas containing noise sensitive activities including, but not limited to, operations of schools, libraries open to the public, houses of worship, hospitals, and nursing homes.
(t) “Weighted average dBA” means the 24-hour energy average of the sound pressure level in decibels (dB), as measured on a sound level meter using the A-weighted network; any readings taken during the period between 10:00 p.m. and 7:00 a.m. the following day are increased by ten dBA before averaging the other readings.