§ 158.318  DEFINITIONS.
   For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
   ACCIDENT POTENTIAL ZONES (APZ). As applied to military airfields, those areas which are identified as being significantly impacted by accident potential from aircraft. APZ-1 is an area normally beyond the Clear Zone that possesses a significant potential for accidents. APZ-2 is an area normally beyond APZ-1 that has a measurable potential for accidents. Both the APZ-1 and APZ-2 are the same width as the Clear Zone. APZ-1 extends from the Clear Zone an additional 5,000 feet. APZ-2 extends from APZ-1 an additional 7,000 feet.
   AIR INSTALLATION COMPATIBLE USE ZONE (AICUZ). A study conducted by the Air Force to evaluate the effect on noise and accident potential on surrounding property and to promote compatible land use that reduces the risks to public health and safety.
   AIR FORCE. The United States Air Force as represented by the Base Community Planner for Scott Air Force Base or such other designee.
   AIRPORT. Any area of land or water that is designed and set aside for the landing and taking off of aircraft and related use associated with Scott Air Force Base or MidAmerica St. Louis Airport and utilized or to be utilized in the interest of the public for such purposes.
   AIRPORT ENVIRONS. The geographic area that is affected by the airport air traffic operations and defined on the basis of those areas immediately affected by noise exposure, Clear Zones, Civilian Clear Zones, Runway Protection Zones, APZ-1 and APZ-2 areas, CPZ-1 and CPZ-2 areas, height hazard zones, and areas of airport influence property. These areas constitute the Airport Overlay (AO) District established in this chapter.
   AIRPORT HAZARD. Any structure or object of natural growth or use of land within the airport environs that obstructs the air space required for the flight of taking off, maneuvering or landing at an airport or which is otherwise hazardous to such landing or taking off of aircraft.
   AIRPORT HAZARD AREA. Any area of land or water, or both, upon which an airport hazard might be established if not prevented by this chapter.
   CIVILIAN PROTECTION ZONES (CPZ). As applied to civilian airfields, those areas which are identified as being significantly impacted by accident potential from aircraft. CPZ-1 is an area normally beyond the Civilian Clear Zone that possesses a significant potential for accidents. CPZ-2 is an area normally beyond CPZ-1 that has a measurable potential for accidents. Both the CPZ-1 and CPZ-2 are the same width as the Civilian Clear Zone. CPZ-1 extends from the Civilian Clear Zone an additional 5,000 feet. CPZ-2 extends from CPZ-1 an additional 7,000 feet.
   CIVILIAN CLEAR ZONE (CCZ). A defined area extending outward from the end of each runway of MidAmerica St. Louis Airport. The CIVILIAN CLEAR ZONES are considered an area of high accident potential. The Clear Zone starts at the end of the runway and extends outward 3,000 feet at a width of 3,000 feet.
   CLEAR ZONE (CZ). A defined area extending outward from the end of each runway of Scott Air Force Base. The CLEAR ZONES are considered an area of high accident potential. The CLEAR ZONE starts at the end of the runway and extends outward 3,000 feet at a width of 3,000 feet.
   DECIBEL (DB). A unit for measuring the relative loudness of sound or sound pressure equal approximately to the smallest degree of difference of loudness or sound pressure ordinarily detectable by the human ear, the range of which includes about 130 decibels on a scale beginning with one for the faintest audible sound.
   DECIBEL A-WEIGHTED SCALE (DBA). The unit of noise level measured in accordance with the “A- weighted scale” which replicates the response characteristics of the ear. This scale is a quantity, in decibels, read from a standard sound-level meter with A weighting circuitry. The A-space weighting discriminates against lower frequencies according to a relationship approximating, and more accurately reflecting the auditory sensitivity and response of the human ear. The A-scale sound level measures approximately the relative “noisiness” or “annoyance” of common sounds.
   DEVELOPMENT APPLICATION. Any request to the local governing body for rezoning, subdivision (major or minor), zoning variance, permit for a non-conformity, final site plan approval, special use permits, sign permits for freestanding or illuminated signs, mobile home permits, or in the case of building permits, permits to increase the existing square footage by 50% or more or over 35 feet in height, or permits otherwise determined by the Director to have any potential impact within the District intended to be addressed by this chapter. A request to approve a change to the future land use map of the approved Comprehensive Plan shall also be considered a development application within this section.
   DIRECTOR. The Director of Community Development, or other designee, as the staff person assigned to administer, interpret and implement the standards, criteria, and procedures of this Zoning Code for their respective elected bodies.
   DNL. Day Night Level. See LEVEL, DAY NIGHT SOUND LEVEL (LDN). Acoustical industry standards often use the abbreviations DNL and Ldn interchangeably.
   ELECTRONIC DISPLAY SIGNS. Signs that show changeable copy, graphic displays or video displays.
   FEDERAL AVIATION ADMINISTRATION (FAA). The federal agency responsible for the safety of civil aviation and the regulation of U.S. commercial space transportation.
   HEIGHT, AIRPORT. In the Airport Environs, for purpose of determining the height of any structure, tree, or other object, including communication towers, the height is the elevation above mean sea level (MSL). For calculation purposes, this is the sum of the elevation of the site and the height of the structure, including any appurtenances.
   LEVEL, DAY NIGHT SOUND LEVEL (LDN). A basic measure for quantifying noise exposure. The day/night average level, or the 24-hour equivalent continuous sound level (time averaged A-weighted sound level) from midnight to midnight, obtained after the addition of ten dBA to sound levels measured from 10:00 p.m. to 7:00 a.m.
   NOISE CONTOUR. A line on the AO-4 Map linking together a series of points of equal cumulative noise exposure based on the day/night average level (Ldn) measurement. Such contours are developed based on aircraft flight patterns, number of daily aircraft operations by type of aircraft, and time of day noise characteristics of each aircraft and typical runway usage patterns.
   NIT. A unit of visible-light intensity, commonly used to specify the brightness of a cathode ray tube or liquid crystal display computer display. One NIT is equivalent to one candela per square meter.
   NOISE LEVEL REDUCTION (NLR). Amount of noise reduction required through construction and incorporation of sound attenuation material to reduce interior noise level. The difference between the exterior and interior sound level, expressed in decibels.
   OWNER. Any person, group of persons, firm or firms, corporation or corporations, commanding officer of any local military base or any other legal entity having legal or equitable title to or sufficient proprietary interest in or to any property subject to this Zoning Code.
   PARTICIPATING LOCAL GOVERNMENTS. The coordinating local governments in the county participating in the RAB and adopting an Airport Overlay Code substantially in the form of or consistent with this chapter.
   PRIMARY SURFACE. A ground surface longitudinally centered on the runway. The dimensions and limits of the primary surface shall be those prescribed in Department of Defense (DoD) height and obstruction criteria for Scott AFB and in Federal Aviation Regulation (FAR) part 77 for MidAmerica St. Louis Airport.
   RUNWAY. A defined area on an airport or airfield prepared for landing and takeoff of aircraft along its length. For purposes of this chapter and compliance with other applicable laws, the RUNWAYS of Scott Air Force Base or MidAmerica St. Louis Airport shall be considered PRECISION INSTRUMENT RUNWAYS unless otherwise hereinafter designated.
   RUNWAY PROTECTION ZONE (RPZ). An area off the runway end of a civilian airport designated by the FAA to enhance the protection of people and property on the ground.
   SLCUM. The Standard Land Use Coding Manual, which provides a general numeric coding scheme that uses two, three, four or more digits to identify land use activities and allow for the flexible categorization of new land uses.
   SOUND ATTENUATION. The reduction in sound level which occurs between the source and the receiver.
   SOUND LEVEL.
      (1)   The level of sound pressure measured with a sound level meter and one of its weighing (frequency) networks.
      (2)   When A-weighing is used, the SOUND LEVEL is expressed as dBA.
   SOUND TRANSMISSION CLASS (STC).
      (1)   An integer rating of how well a building partition attenuates airborne sound.
      (2)   In the United States, it is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations
   STRUCTURE. Any object whether permanent or temporary, including, but not limited to, a building, tower, crane, smokestack, earth formation, overhead transmission line or flagpole; to also include mobile and tethered objects.
   ZONING CODE. The Zoning Ordinance of the city, as amended, set out in Ch. 158 of this code, including this chapter.
(Ord. 3718, passed 6-20-2011)