3.1 Noise Overlay District

Transcription

1 3.1 A. Purpose The purpose of this District is to establish a Noise Overlay Zoning District within the. B. Special Definitions As used in this Article only, the following terms shall be defined as set forth below. All other terms shall have the meaning set forth in Article XIII, Definitions. DAY-NIGHT SOUND LEVEL (LDN): A cumulative aircraft noise index which estimates the exposure to aircraft noise and relates the estimated exposure to an expected community response. The Day-Night Sound Level noise metric assesses a ten (10) decibel (db) penalty to all noise events occurring between 10:00 p.m. and 7:00 p.m. LDN CONTOUR: A line linking together a series of points of equal cumulative noise exposure based on the Ldn metric. Ldn 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. NAVIGABLE AIRSPACE: The airspace above the minimum altitudes of flight prescribed by regulations issued under the Federal Aviation Act of 1958, Section 101 (24) 49 United States Code 11, including the airspace needed to ensure safety in the take-off and landing of aircraft. C. Noise Compatibility Zones Established Noise compatibility zones for the area around Indianapolis International Airport are hereby established based on the Ldn Contours for aircraft noise developed for conditions forecast to exist in 1996 with noise abated operating conditions. 1. N-1 Zone: The N-1 zone generally corresponds to the area between the sixty-five (65) and seventy (70) Ldn Contours. 2. N-2 Zone: The N-2 zone generally corresponds to the area within the seventy (70) Ldn Contour

2 D. Noise Overlay Zone Boundaries The boundaries of the Noise Overlay Zones are shown on the Official Zoning Map. The boundaries generally correspond to the sixty-five (65) and seventy (70) Ldn Contours prepared as part of the Indianapolis International Airport Noise Compatibility Plan. The N-1 and N-2 zones are based on the sixty-five (65) and seventy (70) Ldn Contours, as shown on the Official Zoning Map. E. Notification of Noise Compatibility Zones The plat of any Subdivision located within the noise compatibility boundaries as described in Section D., above, and approved after the effective date of this Ordinance, shall contain the following statement: This subdivision is located within a Noise Compatibility Zone determined pursuant to Federal Aviation Regulation Part 150 with respect to Indianapolis International Airport. This subdivision will experience aircraft overflights and relatively high levels of noise resulting from such overflights. F. Uses Expressly Prohibited Land uses prohibited in the Noise Overlay Zones are: mobile homes; mobile home parks; hospitals; nursing homes; public and private educational services; auditoriums; concert halls; outdoor music facilities; and, amphitheaters. G. Uses Available as Special Uses Land uses that are allowed in the Noise Overlay Zones only after application for and approval of a Special Exception in accordance with the requirements for a Special Exception as provided for in Article 10.3 of this Ordinance are: resorts; group camps; and, campgrounds, provide, however, that such land uses are indicated as either a Permitted Use or Special Exception Use in the primary zoning District. H. Soundproofing Required Soundproofing shall be required for all new residential uses in each of the Noise Overlay Zones. Soundproofing is required and no Building Permit shall be issued for new Single -Family, Two Family, or Multifamily Dwellings until the builder has demonstrated that the Building design is capable of achieving the Noise Level Reduction required in Table 3.1-A, Land Use Compatibility Standards. This requirement can be met in one of two ways as described in the following subsections: 3.1-2

3 1. Design Standards: The builder may choose to use a design that incorporates the design standards described in Subsection I., and, if so, the design shall be considered to have met the required soundproofing standard. 2. Performance Standards: The builder may choose to use design features other than those described in Subsection I., as long as the final design is capable of achieving the Noise Level Reduction required in Table 3.1-A, Land Use Compatibility Standards. Such noise attenuation capability shall be certified on the Building plans by a registered architect, structural engineer, or acoustician. These soundproofing requirements provided for in Subsection H., 1., and H., 2., are not applicable to Buildings that have already been issued a Building Permit on the effective date of this Ordinance nor to room additions, Garages, storage Buildings, or commercial Buildings. I. Soundproofing Design Standards The construction methods and materials described in this Section shall be considered to satisfy the Noise Level Reduction standards set forth in Table 3.1-A, Land Use Compatibility Standards. 1. Noise Level Reduction of Twenty-Five (25) Decibels (db). a. If wood frame construction is used, all exterior stud walls shall have interior and exterior surfaces of an approved material at least as massive as one-half (0.5) inch thick gypsum wallboard, and the intervening space shall contain fibrous thermal insulation at least three (3) inches thick. b. The design for a habitable room shall be such that any exterior door or window can be kept closed when the room is in use. Means of ventilation shall be available to afford a minimum of two (2) complete air changes per hour. c. Any air duct or connection to out-of-doors shall contain an interior sound absorbing lining acoustically equivalent at least to fiberglass duct line one (1) inch thick and length greater than five (5) times the diameter of the duct. d. The ceiling below an attic space shall include gypsum board or plaster at least one-half (0.5) inch thick; fibrous thermal insulation at least three (3) inches thick shall be laid between the ceiling joists

4 e. A forced air circulation system shall be provided that will give a minimum of two (2) complete air changes per hour, of which at least one-fifth (0.20) is fresh air. f. A ceiling or exhaust duct shall be provided with a bend in the duct such that there is no direct line of sight through the duct from outside to inside. The bend shall be lined with the equivalent of fiberglass duct liner one (1) inch thick. g. There shall be no direct openings, such as mail slots, from the interior to the exterior of the Building. All chimneys shall be provided with well-fitted dampers. h. Exterior hinged doors shall be solid-core construction. Jalousie windows shall not be permitted. The total area of glass windows and of any exterior door to a sleeping space shall not exceed twenty (20) percent of the Floor Area of a room. i. Workmanship on doors and operable windows shall be such that the doors and windows are as close fitting as possible or weather stripping seals shall be incorporated on all edges to eliminate gaps. Air gaps and ratting shall be prevented. j. Masonry walls, if used, shall be at least equivalent in weight to six (6) inch lightweight concrete blocks, at least one (1) surface of which is painted or plastered. k. The roof deck shall weigh at least seven (7) pounds per square foot, containing a solid core at least one and one-half (1.5) inches thick. 2. Noise Level Reduction Thirty (30) Decibels (db). a. Window glass shall be set in an elastomer gasket. Double glazing shall be installed, with an air space of at least three (3) inches between the two (2) panes of glass. Windows or dome skylights shall not be permitted, unless they have a sound transmission class of at least thirty (30). b. The top-floor ceiling construction shall consist of plaster or gypsum board at least five-eighths (5/8) inch thick supported on resilient clips or channels. A non-hardening caulking compound shall be provided around the entire perimeter of the suspended ceiling. c. The floor of the lowest room or area containing the uses to which those insulation requirements apply shall be a concrete slab, or should be similarly sealed otherwise against exterior noise

5 d. Masonry walls, if used, shall be at least equivalent in weight to eight (8) inch lightweight concrete blocks, at least one (1) surface of which shall be painted or plastered. e. The roof deck shall weigh at least twelve (12) pounds per square foot. Wood roof sheathing shall be continuous and at least three-quarters (3/4) inch thick. J. Land-Use Compatibility Standards Table 3.1-A presents the levels of Day-Night Sound Level (Ldn) for the N-1 and N-2 Noise Overlay Zones: 3.1-5

6 TABLE 3.l-A LAND-USE COMPATIBILITY STANDARDS NOISE OVERLAY ZONES/LEVELS IN Ldn SLUCM LAND-USE N-1 N-2 NO. NAME Residential 25 (1) 30 (1) 11 Household Units 25 (1) 30 (1) Single Units- detached 25 (1) 30 (1) Single Units- semi-attached 25 (1) 30 (1) Single Units- attached row 25 (1) 30 (1) Two Units- side by side 25 (1) 30 (1) Two Units- over-under 25 (1) 30 (1) Apartments- walk up 25 (1) 30 (1) Apartments- elevator 25 (1) 30 (1) 12 Group Quarters 25 (1) 30 (1) 13 Residential Quarters 25 (1) 30 (1) 15 Transient Lodgings, Hotels, Motels Y (2) Y (3) 16 Other Residential 25 (1) 30 (1) NOTES: 1. All residences in the N-1 Noise Overlay Zone are marginally noise compatible and shall be soundproofed to achieve a twenty-five (25) db reduction from outdoor noise levels (NLR). All residences in the N-2 Noise Overlay Zone are marginally noise compatible and shall be soundproofed to achieve a thirty (3) db NLR. Soundproofing will not eliminate outdoor noise problems. However, Building location and site planning, design, and use of berms and barriers can help mitigate outdoor noise exposure particularly from ground level sources. Measures that reduce noise at a site should be used wherever practical in preference to measures which only protect interior spaces. 2. Measures to achieve NLR of thirty (30) shall be incorporated into the design and construction of portions of the following Buildings where the public is received: office areas; noise sensitive areas; or, where the normal noise level is low. KEY TO TABLE: SLUCM - Standards Land-Use Coding Manual, U.S. Urban Renewal Administration and Bureau of Public Roads, Y (Yes) - Land Use and related Structures compatible without restrictions. N (No) - Land Use and related Structures are not compatible and should be prohibited. NLR - Noise Level Reduction (outdoor to indoor) to be achieved through incorporation of noise attenuation into the design and construction of the Structure. 25 or 30 - Land Use and related Structures are generally compatible; measures to achieve NLR of twenty-five (25) or thirty (30) db must be incorporated into design and construction of the Structure