649.01 DEFINITIONS.
For the purpose of this chapter, whenever any of the following words, terms or definitions are used herein, they shall have the meaning ascribed to them in this section. All acoustical terminology shall be that contained in ANSI S1.1 "Acoustical Terminology".
(1) "Ambient" means the all-encompassing sound associated with a given environment without the noise source of interest.
(2) "ANSI" means the American National Standards Institute or its successor bodies.
(3) "ARI" means the Air-Conditioning and Refrigeration Institute or its successor bodies.
(4) "ASHRAE" means the American Society of Heating, Refrigerating and Air- Conditioning Engineers or its successor bodies.
(5) "ASTM" means the American Society for Testing Materials or its successor bodies.
(6) "dBA" means the A-weighted sound-pressure level in decibels, as measured by a sound-level meter complying with the provisions of American Standard for General Purpose Sound Level Meters, American National Standards Institute, properly calibrated, and operated on the "A" weighting network.
(7) "Decibel" means a unit for measuring the volume of a sound, equal to the logarithm of the ratio of the intensity of the sound to the intensity of an arbitrarily chosen standard sound "dB".
(8) "Director" means the Director of Public Safety.
(9) "Discrete tone" means a sound wave whose instantaneous sound pressure varies essentially as a simple sinusoidal function of the time.
(10) "Fluctuating noise" means a noise whose sound pressure level varies significantly but does not equal the ambient environmental level more than once during the period of observation.
(11) "Intermittent noise" means a noise whose sound pressure level equals the ambient environmental level two or more times during the period of observation. The period of time during which the level of the noise remains at an essentially constant value different from that of the ambient is on the order of one second or more.
(12) "IEC" means the International Electrotechnical Commission or its successor bodies.
(13) "ISO" means the International Organization for Standardization or its successor bodies.
(14) "Mobile noise source" means any source (other than an individual) of acoustic energy in motion relative to a fixed position.
(16) "Noise level or sound-pressure level," in decibels, means ten times the common logarithm of the ratio of the time-mean-square pressure of the sound to the reference mean-square sound pressure. The reference mean-square sound pressure shall be 4 x 10- microbars squared (twenty micropascal squared).
(17) "Noise pollution" means the presence of that amount of acoustic energy for that period of time necessary:
A. To cause temporary or permanent hearing loss in persons exposed;
B. To be otherwise injurious, or tend to be injurious, on the basis of current information, to the public health or welfare;
C. To cause a nuisance; or
D. To interfere with domestic tranquility, that is, the comfortable enjoyment of life and property or the conduct of business.
(18) "Noise source" means any person or animal, or mechanical, electrical or thermal device, which radiates acoustic energy. In those instances where Federal noise emission standards are established for any noise source, then those noise emission standards shall also be applicable to the same or similar noise sources existing under conditions, such as noninterstate commerce, where the Federal standards would not otherwise apply.
(19) "Nonsteady noise" means a noise whose level shifts significantly during the period of observation.
(20) "Period of observation" means the time interval during which acoustical data are obtained. The period of observation is determined by the characteristics of the noise being measured and should also be at least ten times as long as the response time of the instrumentation. The greater the variance in indicated sound level, the longer shall be the observation time for a given expected accuracy of the measurement.
(21) "Person" includes all natural and artificial persons, including, but not limited to, partners, servants, principals, agents, employees, public or private officials, associations, societies, clubs, firms, partnerships and all bodies politic or corporate.
(22) "SAE" means the Society of Automotive Engineers or its successor bodies.
(23) "Sound level (noise level)" for air-borne sound, means a weighted sound pressure level, obtained by the use of metering characteristics and the A-weighting as specified in the reference standards (ANSI). When the A-weighting is employed, it shall be indicated.
(24) "Sound pressure level" in decibels, of a sound, is twenty times the logarithm to the base ten of the ratio of the pressure of the sound to the reference sound pressure. Unless otherwise specified, the effective (rms) pressure is to be understood. The reference sound pressure is 20 uN/m2.
(25) "Stationary noise source" means any source (other than an individual) of acoustic energy in a fixed position.
(26) "Steady noise" means a noise whose level remains essentially constant and whose fluctuations are negligibly small during the period of observation.
(27) "Zoning district" means those districts established by the Independence Zoning Code. (Ord. 1999-52. Passed 11-9-99.)