For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
ANCI. The American National Standards Institute or its successor bodies. All acoustical terminology shall be that contained in ANSI A1.1 “Acoustical Terminology”.
ARI. Air Conditioning and Refrigeration Institute or its successor bodies.
ASHRAE. The American Society of Heating, Refrigerating and Air Conditioning Engineers or its successor bodies.
ASTM. The American Society for Testing Materials or its successor bodies.
DECIBEL. A logarithmic unit of measurement which indicates the ratio between two quantities (commonly electrical or sound energy levels, or pressure levels). (See-sound pressure level).
DIRECTOR. The City Manager or his or her duly authorized representative.
DISCRETE TONE. A sound wave whose instantaneous sound pressure varies essentially as a sinusoidal function of time.
ESSENTIAL SERVICES. The erection, construction, alteration or maintenance by public utilities, municipal departments or commissions, or any governmental agencies, of underground or overhead gas, electrical, steam or water transmission or distribution system, collection, communication, supply or disposal system, including poles, wires, mains, drains, sewers, pipes, conduits, cables, public safety (police and fire) vehicles and equipment, fire alarm boxes, police call boxes, traffic signals, hydrants, towers, electric substations, telephone exchange buildings, gas regulator stations, and other similar equipment and accessories in connection therewith, reasonably necessary for the furnishing of utility service by such public utilities, municipal departments, commissions or any governmental agencies, or for the public health, safety or welfare.
FLUCTUATING NOISE. A noise whose sound pressure level varies significantly but does not equal the ambient environmental level more than once during the period of observation.
IEC. International Electrotechnical Commission or its successor bodies.
IMPULSE NOISE. Characterized by brief excursions of sound pressure which significantly exceed the ambient environmental sound pressure. The duration of a single impulse is usually less than one second.
INTERMITTENT NOISE. 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 noise level is on the order of one second or more.
ISO. International Organization for Standardization or its successor bodies.
MOTOR VEHICLE. Any passenger vehicle, truck, truck-trailer or semitrailer propelled or drawn by mechanical power.
OCTAVE BAND. A frequency band with lower and upper cut-off frequencies having a ratio of two. The cut-off frequencies of 707 hertz and 1,414 hertz define an octave band in common use.
PERIOD OF OBSERVATION. 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 must be the observation time for a given expected accuracy of the measurement.
PERSON. Every natural person, partnership, association or corporation which may own, operate or control those devices or facilities herein described.
REPETITIVE IMPULSE NOISE. More than five impulses per hour.
SAE. Society of Automotive Engineers or its successor bodies.
SOUND LEVEL or NOISE LEVEL. For airborne sound, a weighted sound pressure level, obtained by the use of metering characteristics and A-weighting as specified in the referenced standards. When the A-weighting is employed, it must be indicated.
SOUND PRESSURE LEVEL OF A SOUND. In decibels, is 20 times the logarithm to the base ten of the ratio of the pressure of this sound to the reference sound pressure having the value of two by 10.4 dynes per square centimeter.
STEADY-NOISE. A noise whose level remains essentially constant.
ZONING DISTRICT. Districts established by the zoning ordinance of the city and found in Chapter 50 of this code.
(Prior Code, § 9.402)