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All assembly, educational, institutional, residential, and office buildings located within designated noise impact zones shall be designed and constructed to cause isolation against exterior noise with at least the noise level reduction indicated in the zoning ordinance. For each occupancy, the zoning ordinance specifies the minimum sound level reduction required in each airport noise and accident potential zone (ANAP). An intent of these requirements is to have residential, assembly, educational and institutional, and the like, buildings constructed with sufficient sound isolation so that any habitable room, furnished for normal use and with doors and windows closed, shall be constructed with the noise level reduction as required by the zoning ordinance for each occupancy.
('80 Code, § 7-44) (Ord. 1857, passed 7-18-79) Penalty, see § 150-999
Noise zones, for the purpose of this amendment, are defined by contours of the day-night sound level, according to the official zoning map of the city. The ANAP zones are intended to identify those areas in the vicinity of the MCAS and Yuma International Airport which require sound isolation to be included in the design and construction of proposed buildings.
(A) Performance standards. Standards of construction considered acceptable and in compliance with the intent and provisions of this amendment are provided in § 150-128. A building will generally be considered acceptable by the building official if it incorporates the applicable features described in § 150-128. Alternate materials and methods of construction may be permitted, provided such alternates are demonstrated to the satisfaction of the building official to be equivalent to those described.
(B) Acoustical analysis and design report. The applicant may elect to have a qualified architect or engineer examine the noise levels and needed building sound isolation requirements for a specific site. The analysis and design report signed by and prepared under the supervision of a qualified architect or engineer shall be submitted with the application for building permit. The report shall show the topographical relationship of the aircraft noise sources and the building site, identification of noise sources and their characteristics, predicated noise spectra at the exterior of the proposed building structure, basis for the predication (measured or obtained from published data), and effectiveness of the proposed construction showing that the prescribed interior day-night sound level is met.
('80 Code, § 7-45) (Ord. 1857, passed 7-18-79)
The expansion of a nonconforming use shall be designed and constructed in such a manner that the interior sound level does not exceed 45 dB.
('80 Code, § 7-46) (Ord. 1857, passed 7-18-79) Penalty, see § 150-999
Construction as outlined in this section that satisfies the requirements of the zoning ordinance and for purposes of this amendment is considered to meet the interior noise standard specified in § 150-125. Each item indicated in this section shall be identified on the project drawings which are submitted with the permit application. Certification by an acoustical engineer or registered architect shall attest that construction practices and the materials of the structure will achieve the interior noise level reduction required by the prescribed noise attenuation standard. The engineer or architect shall submit relevant information to permit the City Building Official to verify that the proposed measures will achieve the specified interior noise level standards.
(A) Noise level reduction—25 decibels. For a building located where a noise level reduction of 25 decibels is required, the building shall be constructed as follows:
(1) 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 half-inch gypsum wallboard, and the intervening space (studs) shall contain fibrous thermal insulation having a resistance of R-11 or greater.
(2) Arrangements for any habitable room shall be such that any exterior door or window can be kept closed when the room is in use.
(3) Any air duct or connection out-of-doors must contain an interior sound-absorbing lining acoustically equivalent at least to fiberglass duct liner one inch thick and of a length greater than five times the diameter of the duct.
(4) The ceiling below an attic space shall include gypsum board or plaster at least one-half inch thick; fibrous thermal insulation having a resistance of R-19 or greater shall be placed above the ceiling.
(5) 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.
(6) All openable windows shall be sound rated assemblies having sound transmission class (STC) of at least 24. Fixed windows shall be well sealed and at least three-sixteenth-inch-thick glass.
(7) All entry doors shall be solid-core constructed, close-fitting units with weather-stripping seals incorporated on all edges to eliminate gaps. Air gaps and rattling shall not be permitted.
(8) Masonry walls, if used, shall be at least equivalent in weight to eight-inch, lightweight concrete blocks, at least one surface of which is painted or plastered.
(9) The roof deck shall weigh at least seven pounds per square foot with roof sheathing containing a solid core at least one-half inch thick.
(10) Rooms when in use are expected to contain furniture, or other materials that absorb sound equivalent to the absorption provided by wall-to-wall carpeting over a conventional pad.
(B) Noise level reduction—30 decibels. For a building located where a noise level reduction of 30 decibels is required, the building shall be constructed to incorporate the features described in preceding subsections (NLR 25 dB) with the following additions:
(1) Windows, fixed or openable, shall be sound-rated units with a sound transmission class (STC) of at least 32 (double-glazed).
(2) A ceiling or exhaust duct for the forced air ventilation system 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-half inch thick.
(3) The top floor-ceiling construction shall consist of plaster or gypsum board at least five-eighths inch thick.
(4) The floor of the lowest room or area shall be a concrete slab, or shall be sealed against exterior noise.
(5) Masonry walls, if used, shall be at least equivalent in weight to eight-inch, lightweight concrete blocks. At least one surface shall be painted, plastered or covered with gypsum board.
(6) The roof deck shall weigh at least 12 pounds per square foot. Wood roof sheathing shall be continuous (plywood) and at least five-eighths inch thick.
(C) Noise level reduction—35 decibels. For a building located where a noise level reduction of 35 decibels is required, a building shall be constructed to incorporate the features described above (NLR of 25 and 30 dB) with the following additional features:
(1) The use of exposed wood beam ceilings is prohibited unless sound isolating treatment is provided between the ceiling and roofline. The minimum treatment shall consist of rigid fiberglass board, nominally two inches thick placed over the interior ceiling and under at least one-half inch of plywood sheathing. The sheathing shall be nailed only to the beam or major frame members and not to the interior exposed ceiling at points between the beams.
(2) For attic spaces ventilated to the outside, the attic floor shall be decked over with one-half inch plywood or equivalent and all cracks caulked. R-11 insulation shall be placed between the floor joists.
(3) Roof deck shall weigh at least 20 pounds per square foot. Roof sheathing shall be continuous, weighing a total of at least four pounds per square foot.
(4) Wood paneling less than one-half inch thick shall be used only over gypsum board of at least five-eighths inch thick. Interior gypsum board walls shall consist of two layers of one-half-inch board nailed directly to the studs.
(5) Fixed or openable windows must be sound rated units with at least a sound transmission class (STC) of 36.
(D) All residential buildings shall be constructed with minimum R19 exterior walls, R30 roofs, dual-glazed windows, and solid wood, foam-filled fiberglass or metal doors to the exterior.
('80 Code, § 7-47) (Ord. 1857, passed 7-18-79; Am. Ord. O2002-10, passed 2-20-02) Penalty, see § 150-999
When inspection indicates that the construction is not in accordance with the approved design, field testing by the applicant shall be required by the building official. Interior noise measurements shall be taken under conditions of typical aircraft operation. A test report signed by, and prepared under, the supervision of a registered engineer or registered architect of the state showing compliance or noncompliance with the prescribed interior allowable levels shall be submitted to the building official.
('80 Code, § 7-48) (Ord. 1857, passed 7-18-79)
When a written complaint is submitted to the building official alleging noncompliance with the interior day-night sound level standards, the building official shall direct that field testing be conducted. The complainant shall post a bond or adequate funds in escrow for the cost of such testing. Such costs shall be chargeable to the complainant when the field tests show compliance with the standards is in fact present. If such tests show noncompliance, then such testing costs shall be borne by the permit applicant and the structure shall be altered as required to comply with the standards at the expense of the permit applicant.
('80 Code, § 7-49) (Ord. 1857, passed 7-18-79)
The test procedure which is to be followed in the event that an evaluation of the noise level reduction (NLR) of the completed building is required by the building official is provided in this section. Alternates to this procedure may be submitted to the building official prior to the initiation of a field test. Field tests should not be undertaken pursuant to the provisions of the amendment prior to the approval of such alternates by the building official.
(A) Interior sound level. The interior sound level shall be measured within a habitable room or rooms of the building. The room or rooms nearest to the aircraft noise source(s) shall be selected. Indoor measurements shall be made at a point five feet above the floor of the room or rooms, three feet from the window nearest the aircraft noise source(s), with curtain (if any) fully opened. The measurement position shall be midway between the sides of the window. Heaters, air conditioners and other equipment shall be inoperative during the measurement period. Tests shall be conducted in rooms with carpets and furnishings.
(B) Exterior sound level. The exterior sound level shall be measured at location away from the building (at least ten feet from any sound reflecting surface). The location should be in a direction from the building nearest to the aircraft noise source(s). The microphone shall be positioned five feet above the ground.
(C) Analysis of data. The interior and exterior sound level shall be recorded for each aircraft noise event. The difference in level between the exterior and interior sound level shall also be recorded on the data sheet submitted to the building official. At least 100 events shall be measured. The events should be reasonably representative of the various aircraft types which operate at the MCAS and airport. The energy averaged value of the difference in level measured shall be calculated and reported as the noise level reduction (NLR).
(D) Documentation. The report of, findings shall include the following:
(1) Hard copy of instrument printouts of all measurements.
(2) Tabulation of the single event sound levels, sound level differences and calculation of energy averaged value of the sound level differences.
(3) Evidence of calibration of equipment before and after test.
(4) A certification that the measurements are true and accurate.
('80 Code, § 7-50) (Ord. 1857, passed 7-18-79)
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