A.

The principal purpose of the district is to promote and protect the public health, safety and general welfare in the vicinity of the Laughlin/Bullhead International Airport, by minimizing exposure to high noise levels and accident hazards generated by airport operations and to encourage future development which is compatible with the continued operation of the airports.

B.

In addition, it is the purpose of the district to minimize future conflicts between land uses and excessive noise generated by aircraft.

C.

The district shall be in addition to, and shall overlay, all other zoning district regulations where it is applied, so that any parcel of land laying in the noise and height district shall also lay in one or more of the other zoning districts provided for by the Bullhead City zoning code. The effect is to create a new district which has the characteristics and limitations of the overlaying district. In any situation where a conflict arises, the more strict regulation(s) shall apply.

D.

It is the intent of this district to regulate land uses within designated existing or projected airport noise impact zones by specifying acoustical performance standards. Nothing in this chapter shall be construed as altering building materials or construction methods from those which are specified in the uniform building code.

E.

It is also the intent of this district to prohibit uses in the landing approach zones (clear zones) that, if otherwise permitted, would endanger lives or invite destruction of property.

(Ord. 2006-16 § 1 (part); Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

A.

The following words, terms and phrases, when used in this chapter, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:

"Airport" means any area of land or water designed and set aside for the landing and taking off of aircraft and utilized or to be utilized in the interests of the public for those purposes.

"Airport hazard" means any structure or use of land which obstructs the airspace required for flight or aircraft in taking off or landing in an airport, or is otherwise hazardous to aircraft taking off or landing.

"Approach surface" means a surface longitudinally centered on the extended runway centerline, extending outward and upward from the end of the primary surface and at the same slope as the approach zone height limitation slope set forth in this chapter. In plan the perimeter of the approach surface coincides with the perimeter of the approach zone.

"Conical surface" means a surface extending outward and upward from the periphery of the horizontal surface at a slope of twenty to one for a horizontal distance of four thousand feet.

"Day-night sound level contour (Ldn)" means a noise which uses sound exposure levels (SEL) which are computed by numerically integrating the sound pressure level versus the time history of each operation measured. This data is then converted to Ldn by taking the energy average SEL at reference measurement points for all aircraft. The Ldn methodology defines the day-night level as a series of hourly noise levels for a given day, weighted for time of occurrence.

"Decibel" means the physical unit commonly used to describe noise levels.

"Height" for the purpose of determining the height limits in all zones set forth in this chapter and shown on the zoning map, the datum shall be mean sea level elevation unless otherwise specified.

"High noise levels" means sound levels which equal or exceed that within the sixty-five Ldn noise contour line developed by the application of the day-night average sound level methodology of sound measurement (Ldn).

"Horizontal surface" means a horizontal plane one hundred fifty feet above the established airport elevation, the perimeter of which in plan coincides with the perimeter of the horizontal zone as described in Section 17.34.090(B)(8).

"Larger than utility runway" means a runway that is constructed for and intended to be used by propeller driven aircraft of greater than twelve thousand five hundred pounds maximum gross weight and jet powered aircraft.

"Ldn" means the day-night average sound level.

"Noise level reduction (NLR)" means the difference in decibels of the noise level from outside to inside of a building, wherein such reduction depends primarily upon the construction and materials used in the walls, windows, ceilings, doors, and vents of the building.

"Nonconforming use" means any pre-existing structure, object of natural growth, or use of land which is inconsistent with the provisions of this chapter or an amendment thereto.

"Nonprecision instrument runway" means a runway having an existing instrument approach procedure utilizing air navigation facilities with only horizontal guidance, or area-type navigation equipment, for which a straight-in nonprecision instrument approach procedure has been approved or planned.

"Precision instrument runway" means a runway having an existing instrument approach procedure utilizing an instrument landing system (ILS) or a precision approach radar (PAR). It also means a runway for which a precision approach system is planned and is so indicated on an approved airport layout plan or any other planning document.

"Primary surface" means a surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface extends two hundred feet beyond each end of that runway. The width of the primary surface is set forth in this chapter. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline.

"Runway" means an artificially surfaced strip of ground designed and used at an airport for the landing and taking off of aircraft.

"Structure" means an object constructed or installed by a human including, but without limitation, buildings, towers, and overhead transmission lines.

"Transitional surfaces" means those surfaces extending outward at ninety degree angles to the runway centerline and the runway centerline extended at a slope of seven feet horizontally for each foot vertically from the sides of the primary and approach surfaces to where they intersect the horizontal and conical surfaces. Transitional surfaces for those portions of the precision approach surfaces, which project through and beyond the limits of the conical surface, extend a distance of five thousand feet measured horizontally from the edge of the approach surface and at ninety degree angles to the extended runway centerline.

"Tree" means an object of natural growth.

"Utility runway" means a runway that is constructed for and intended to be used by propeller driven aircraft of twelve thousand five hundred pounds maximum gross weight and less.

"Visual runway" means a runway intended solely for the operation of aircraft using visual approach procedures.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

The boundaries of the noise overlay district for the Laughlin/Bullhead International Airport shall be those areas within the city limits of Bullhead City shown on Map 1* and as adopted as part and parcel to this chapter and any amendments thereto.

(Ord. 2006-16 § 2: Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

* Editor's note: Map 1, "Land Use/Noise Plan," does not appear in this code, but is available in the office of the city clerk or development services.

A.

For purposes of administering these noise regulations, there shall be four airport noise overlay zones, and one clear zone overlay area as identified below, within the noise overlay district for the Laughlin/Bullhead International Airport.

1.

Noise overlay Zone-Zero (NOZ-0): The area between the post-2007 65-Ldn noise contour line developed by the application of day-night average sound level methodology of sound measurement (Ldn) and the noise overlay district boundary.

2.

Noise overlay Zone-One (NOZ-1): The area between the post-2007 65-Ldn and 70-Ldn noise contour lines developed by the application of day-night average sound level methodology of sound measurement (Ldn).

3.

Noise overlay Zone-Two (NOZ-2): The area between the post-2007 70-Ldn and 75-Ldn noise contour lines developed by the application of day-night average sound level methodology of sound measurement (Ldn).

4.

Noise overlay Zone-Three (NOZ-3): The area within the post-2007 75-Ldn and greater noise contour lines developed by the application of day-night average sound level methodology of sound measurement (Ldn).

5.

Clear zone overlay (CZO): The area at the ends of any runway in which there is a high potential for accidents and as depicted on Map 1* and as adopted as part and parcel to this chapter and any amendments thereto.

C.

The purpose of the establishment of five airport noise overlay zones is to distinguish between the severity of the levels of noise impact and accident potential so that appropriate uses and acoustical performance standards can be established to mitigate the adverse impacts of aircraft noise and hazards to protect the public health, safety and welfare.

D.

Whenever a lot of record is divided by an airport overlay zone boundary, the development shall conform to the land use and design criteria of the more restrictive district in accordance with all city codes and regulations.

(Ord. 2006-16 §§ 1 (part), 3; Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

* Editor's note: Map 1, "Land Use/Noise Plan," does not appear in this code, but is available in the office of the city clerk or development services.

A.

Within the noise overlay district, there shall be five overlay zones: NOZ-0, NOZ-1, NOZ-2, NOZ-3, and CZO. The uses permitted in the overlay zones shall be those uses permitted in the underlying zoning district, and shall be subject to all conditions and procedures of the underlying district.

B.

Such uses shall also comply with restrictions of the noise attenuation matrix presented in Table 17.34.050, unless a land use category is specifically not permitted in the matrix, in which case such uses classified in the designated land use category shall not be permitted.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

A.

To obtain a building permit in the NOZ-1, NOZ-2, NOZ-3, CZO zones, the permittee must comply with noise level reduction standards set forth in Table 17.34.060A or Table 17.34.060B, whichever will achieve the interior noise level required in Table 17.34.050 of the noise attenuation matrix.

B.

Failure to comply with these standards shall be cause for rendering null and void any building permit and may result in nonissuance of a certificate of occupancy.

C.

The city of Bullhead City, its employees and officers, shall not be held liable for any permit issued on the basis of false information.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

The boundaries of the height overlay district for the Laughlin/Bullhead International Airport shall be those areas within the city limits of Bullhead City shown on Map 2* and as adopted as part and parcel to this chapter and any amendments thereto.

(Ord. 2006-16 § 4: Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

* Editor's note: Map 2, "Part 77 Airspace Plan," does not appear in this code, but is available in the office of the city clerk or development services.

A.

The construction or establishment of any building structure or use shall comply with the height limits as determined by the zoning district identified by the official zoning map of the city of Bullhead City, or with the height limits specified in this chapter and also identified on the airport runway approach clearance map, "Part 77 Airspace Plan," Map 2*, whichever places the greater restriction and as adopted as part and parcel to this chapter and any amendments thereto.

B.

For purposes of administering these height regulations, there shall be nine height overlay zones, as identified below, within the airport height overlay district for the Laughlin/Bullhead International Airport.

1.

"Utility runway visual approach zone" means the inner edge of this approach zone coincides with the width of the primary surface and is two hundred fifty feet wide at the end of the primary surface. The approach zone expands outward uniformly to a width of one thousand two hundred fifty feet at a horizontal distance of five thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

2.

Utility Runway Nonprecision Instrument Zone. The inner edge of this approach zone coincides with the width of the primary surface and is five hundred feet wide. The approach zone expands outward uniformly to a width of two thousand feet at a horizontal distance five thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

3.

Runway Larger than Utility Visual Approach Zone. The inner edge of this approach zone coincides with the width of the primary surface and is five hundred feet wide. The approach zone expands outward uniformly to a width of one thousand five hundred feet at a horizontal distance of five thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

4.

Runway Larger than Utility with a Visibility Minimum Greater than Three-Fourths Mile Nonprecision Instrument Approach Zone. The inner edge of this approach zone coincides with the width of the primary surface and is five hundred feet wide. The approach zone expands outward uniformly to a width of three thousand five hundred feet at a horizontal distance of ten thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

5.

Runway Larger than Utility with a Visibility Minimum as Low as Three-Fourths Mile Nonprecision Instrument Approach Zone. The inner edge of this approach zone coincides with the width of the primary surface and is one thousand feet wide. The approach zone expands outward uniformly to a width of four thousand feet at a horizontal distance of ten thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

6.

Precision Instrument Runway Approach Zone. The inner edge of this approach zone coincides with the width of the primary surface and is one thousand feet wide. The approach zone expands outward uniformly to a width of sixteen thousand feet at a horizontal distance of fifty thousand feet from the primary surface. Its centerline is the continuation of the centerline of the runway.

7.

Transitional Zone. The transitional zones are the areas beneath the transitional surfaces.

8.

Horizontal Zone. The horizontal zone is established by swinging arcs of five thousand feet radii for all runways designated utility or visual and ten thousand feet for all others from the center of each end of the primary surface of each runway and connecting the adjacent arcs by drawing lines tangent to those arcs. The horizontal zones does not include the approach and transitional zones.

9.

Conical Zone. The conical zone is established as the area that commences at the periphery of the horizontal zone and extends outward therefrom a horizontal distance of four thousand feet.

B.

The development services director shall determine whether the construction and/or existence of any structure, pole, tower, tank or plant material constitutes a hazard to an aircraft operation in the vicinity of the airport.

C.

When such a determination is made, the owner of the structure, pole, tower, tank or plant material shall, at his own expense, reduce in height or install, operate and maintain such markers and lights as may be necessary to indicate to aircraft operators the presence of an airport hazard.

D.

Any activity within this district which may create an electrical interference with communications between the airport facility and aircraft is prohibited.

(Res. No. 2010R-12, § 16, 2-16-2010; Ord. No. 2010-2, § 1, 2-16-2010; Ord. 2006-16 §§ 1 (part), 5; Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

* Editor's note: Map 2, "Part 77 Airspace Plan," does not appear in this code, but is available in the office of the city clerk or development services.

A.

Except as otherwise provided in this chapter, no structure shall be erected, altered, or maintained, and no tree shall be allowed to grow in any zone created by this chapter to a height in excess of the applicable height herein established for such zone. Such applicable height limitations are established for each of the zones in question as follows:

1.

Utility Runway Visual Approach Zone. Slopes twenty feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of five thousand feet along the extended runway centerline.

2.

Utility Runway Nonprecision Instrument Approach Zone. Slopes twenty feet outwards for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of five thousand feet along the extended runway centerline.

3.

Runway Larger than Utility Visual Approach Zone. Slopes twenty feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of five thousand feet along the extended runway centerline.

4.

Runway Larger than Utility with a Visibility Minimum Greater than Three-Fourths Mile Nonprecision Instrument Approach Zone. Slopes thirty-four feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of ten thousand feet along the extended runway centerline.

5.

Runway Larger than Utility with a Visibility Minimum as Low as Three-Fourths Mile Nonprecision Instrument Approach Zone. Slopes thirty-four feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of ten thousand feet along the extended runway centerline.

6.

Precision Instrument Runway Approach Zone. Slopes fifty feet outward for each foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of ten thousand feet along the extended runway centerline; thence slopes upward forty feet horizontally for each foot vertically to an additional horizontal distance of forty thousand feet along the extended runway centerline.

7.

Transitional Zones. Slope seven feet outward for each foot upward beginning at the sides of and at the same elevation as the primary surface and the approach surface, and extending to a height of one hundred fifty feet above the airport elevation which is seven hundred four feet above mean sea level. In addition to the foregoing, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of and the same elevation as the approach surface, and extending to where they intersect the conical surface. Where the precision instrument runway approach zone projects beyond the conical zone, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of and the same elevation as the approach surface, and extending a horizontal distance of five thousand feet measured at ninety degree angles to the extended runway centerline.

8.

Horizontal Zone. Established at one hundred fifty feet above the airport elevation or at a height of eight hundred fifty-four feet above mean sea level.

9.

Conical Zone. Slopes twenty feet outward for each foot upward beginning at the periphery of the horizontal zone and at one hundred fifty feet above the airport elevation and extending to a height of three hundred fifty feet above the airport elevation.

10.

Extended Height Limitations. Nothing in this chapter shall be construed as prohibiting the construction or maintenance of any structure, or growth of any tree to a height up to fifty feet above the surface of the land, except as otherwise restricted by Table 17.38 of this code.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

A.

Nothing in this chapter shall require any change or alteration in a lawfully constructed or established building, structure, in use or in existence at the time of the adoption or amendment of the airport noise and height districts regulations and which are established as "nonconforming uses," of this chapter.

B.

Before any nonconforming structure or use located within the airport noise and height overlay districts may be replaced, substantially altered, repaired or rebuilt, an "airport noise and height overlay district" permit shall be obtained from the development services director.

1.

No permit shall be granted by the city that will allow establishment or creation of an airport hazard as defined in Section 17.34.020, or permits a nonconforming structure or use to be made or to become higher or a greater hazard to air navigation than it was at the time this chapter was adopted.

2.

Except as provided in this section, all applications for an "airport noise and height overlay district" permit shall be granted by the development services director.

C.

Any nonconforming structure or use located within the airport noise and height overlay districts that is replaced, substantially altered, repaired, or rebuilt shall comply with the noise attenuation matrix.

D.

A person desiring to erect or increase the height of a structure, or otherwise use his property in violation of airport zoning regulations adopted under this chapter, may apply to the board of adjustment for a variance from the zoning regulations in question.

1.

Variances shall be allowed where a literal application or enforcement of the regulations would result in practical difficulty or unnecessary hardship and the relief granted would not be contrary to the public interest but would do substantial justice and would be in accordance with the spirit of the regulations and this chapter.

2.

Any variance may be allowed subject to any reasonable conditions the board of adjustment deems necessary to effectuate the purposes of this action.

E.

In granting a permit or variance under this section, the development services director or board of adjustment, if it deems such action advisable to effectuate the purposes of this section and reasonable in the circumstances, may condition the permit or variance, as the case may be, so as to require the owner of the structure in question to permit the city, at its own expense, to install, operate and maintain thereon markers and lights as are necessary to indicate the presence of an airport hazard.

(Res. No. 2010R-12, § 16, 2-16-2010; Ord. No. 2010-2, § 1, 2-16-2010; Ord. 97-905 § 1 (part); Ord. 97-869 §§ 39 — 41; Ord. 91-499 § 2 (part), 1991)

A.

The development services director shall review all requests for building and development within the airport noise and height overlay districts for compliance with this chapter prior to issuance of any permit.

B.

The airport executive management shall be informed of all requests for building and development within the airport noise and height overlay districts. The development services director shall forward a copy of all applications with attendant information, to the airport executive management. The airport executive management shall verify receipt of such information and, within a reasonable time, forward any comments concerning the request to the development services director.

(Res. No. 2010R-12, § 16, 2-16-2010; Ord. No. 2010-2, § 1, 2-16-2010; Ord. 97-905 § 1 (part); Ord. 97-869 § 42: Ord. 91-499 § 2 (part), 1991)

A.

Prior to issuance of any building or installation permits for the construction or maintenance of any structure over fifty feet above the surface of the land within the airport height overlay district, the owner of said property shall provide the city of Bullhead City with proof of the owner's compliance with Part 77 of the Federal Aviation Regulations (14 CFR, Part 77) pursuant to Section 1101 of the Federal Aviation Act of 1958, as amended (49 U.S.C. 1101). Proof of compliance shall be the submission of either a copy of Federal Aviation Administration Form 7460-1 appropriately marked by the Federal Aviation Administration that notice is not required, or a separate acknowledgment from the Federal Aviation Administration indicating approval of the proposed construction or alteration.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

A.

Any person, firm or corporation violating any regulation or provision of this chapter is guilty of a Class 1 misdemeanor. Each and every day during such violation continues is a separate offense.

B.

A violation of any regulation or provision of this chapter shall be punishable by a fine of not more than two thousand five hundred dollars or by imprisonment in the county jail for a term not exceeding six months or by both such fine and imprisonment for each conviction.

C.

All such remedies provided in this section shall be cumulative and not exclusive. The conviction of any person, firm or corporation hereunder shall not relieve such person from the responsibility to correct such violation, nor prevent the enforcement, correction or removal thereof.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

Table 17.34.050

NOISE ATTENUATION MATRIX CODE RESTRICTIONS

NOISE ATTENUATION MATRIX CODE RESTRICTIONS

Blank columns, no restrictions.

N.P. = Uses within this category are not permitted

1. The land use or activity is permitted; however, the level of noise within the principally permitted structures must be reduced by the developer of this land use activity, in accordance with Chapter 35, "Sound Transmission Control," of 1988 edition of the uniform building code.

2. The land use or activity is permitted; however, a noise level reduction (NLR) of 25 decibels must be incorporated into the design and construction of those buildings where people live, work, or are otherwise received, in order to achieve a maximum interior noise level of 45 decibels.

3. The land use or activity is permitted; however, a noise level reduction (NLR) of 30 decibels must be incorporated into the design and construction of those buildings where people live, work, or are otherwise received, in order to achieve a maximum interior noise level of 45 decibels.

4. The land use or activity is permitted when the level of noise does not exceed 45 decibels within the principally permitted structure unless 45 decibels is exceeded by self-generated noise.

5. Uses which produce air pollutants that may obscure vision in any way, or which pose a potential explosive hazard, are not permitted.

6. Aboveground transmission lines are not permitted.

7. In order to minimize public exposure to accident hazard and crash potential as generated by aircraft operations, structures shall not be located within any portion of a clear zone as defined and designated by this chapter. However, such on-site improvements as vehicle parking, storm water retention, landscaping, and yard setbacks, as otherwise required by this chapter or other city regulation, may be permitted within the designated clear zones. No element of any landscaping shall be allowed to penetrate any clear zone slope or other approach surface.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

Table 17.34.060A

TWENTY-FIVE DECIBEL NOISE LEVEL REDUCTION STANDARD

Compliance with the following standards shall be deemed to meet requirements for a minimum noise level reduction (NLR) of twenty-five decibels.

A.

General:

1.

Brick veneer, masonry blocks, or stucco exterior walls shall be constructed airtight. All joints shall be grouted or caulked airtight.

2.

At the penetration of exterior walls by pipes, ducts or conduits, the space between the wall and pipes, ducts or conduits shall be caulked or filled with mortar.

3.

Window and/or through-the-wall ventilation units shall not be used.

4.

Through-the-wall/door mailboxes shall not be used.

B.

Exterior Walls:

1.

Exterior walls, other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-30.

2.

Masonry walls have a surface weight of at least twenty-five pounds per square foot do not require a furred (stud) interior wall. At least one surface of concrete block walls shall be plastered.

3.

Stud walls shall be at least 4 inches in nominal depth and shall be finished on the outside with siding-on-sheathing, stucco or brick veneer.

a.

Interior surface of the exterior walls shall be of gypsum board or plaster at least one-half-inch thick, installed on the studs.

b.

Continuous composition board, plywood or gypsum board sheathing at least one-half-inch thick shall cover the exterior side of the wall studs behind wood or metal siding. Asphaltic or wood shake shingles or plaster (stucco) are acceptable in lieu of siding.

c.

Sheathing panels shall be covered on the exterior with overlapping building paper.

d.

Insulation material at least R-11 shall be installed continuously throughout the cavity space behind the exterior sheathing and between wall studs. Insulation shall be glass fiber or mineral wool.

C.

Windows:

1.

Windows other than as described in this section shall have a laboratory sound transmission class rating of at least STC-28.

2.

Glass shall be at least three-sixteenths-inch thick.

3.

All operable windows shall be weather stripped and airtight when closed so as to conform to an air infiltration test not to exceed 0.5 cubic foot per minute per foot of crack length in accordance with ASTM E-283-65-T.

4.

Glass of fixed-sash windows shall be sealed in an airtight manner with a nonhardening sealant or a soft elastomer gasket or gasket tape.

5.

The perimeter of window frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-0027, TT-S-00230 or TT-S- 00153.

6.

Total area of glass shall not exceed twenty percent of total exterior wall area.

D.

Doors:

1.

Doors other than as described in this section shall have a laboratory sound transmission class rating of at least STC-26.

2.

All exterior sidehinged doors shall be solidcore wood or insulated hollow metal at least one and three-fourth inches thick and shall be fully weather stripped.

3.

Exterior sliding doors shall be weather stripped with an efficient airtight gasket system with performance as specified in subsection (C)3. The glass in the sliding doors shall be at least three-sixteenth inch thick.

4.

Glass in doors shall be sealed in an airtight nonhardening sealant or in a soft elastomer gasket or glazing tape.

5.

The perimeter of door frames shall be sealed airtight to the exterior wall construction as described in subsection (C) 5.

E.

Roofs:

1.

Combined roof and ceiling construction other than described in this subsection and subsection F shall have a laboratory sound transmission class rating of at least STC-39. This requires an acoustical analysis or test.

2.

With an attic or rafter space at least six inches deep, and with a ceiling below, the roof shall consist of one-third inch composition board, plywood or gypsum board sheathing topped by roofing as required.

3.

Open beam roof construction shall follow the energy insulation standard method for batt insulation.

4.

Skylights shall conform to a STC rating of 28.

F.

Ceilings:

1.

Gypsum board or plaster ceilings at least one-half-inch thick shall be provided where required by subsection (E)2, above. Ceilings shall be substantially airtight with a minimum of penetrations.

2.

Glass fiber or mineral wood insulation at least R-19 shall be provided above the ceiling between joist.

G.

Floors:

1.

Openings to any crawl spaces below the floor of the lowest occupied room shall not exceed two percent of the floor area of the occupied rooms.

H.

Ventilation:

1.

A mechanical ventilation system shall be installed that will provide the minimum air circulation and fresh air supply requirements for various uses in occupied rooms without the need to open any windows, doors or other openings to the exterior. The attic inlet and discharge openings shall be fitted with sheet metal transfer ducts of at least 20-gauge steel, which shall be lined with one-inch thick coated glass fiber, and shall be at least five feet long with one ninety degree bend.

2.

Gravity vent openings in attics shall not exceed code minimum in number and size.

3.

All vent ducts (except kitchen and sewer gas ducts) connecting the interior space to the outdoors, excepting domestic range exhaust ducts, shall contain at least a five-foot length of internal sound-absorbing duct lining. Each duct shall be provided with a bend in the duct such that there is no direct line-of-sight through the duct from the venting cross-section to the room opening cross-section. Duct lining shall be coasted glass fiber duct liner at least one inch thick.

4.

Fireplaces shall be provided with well-fitted dampers.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)

Table 17.34.060B

THIRTY DECIBEL NOISE LEVEL REDUCTION STANDARDS

Compliance with the following standards shall be deemed to meet requirements for a minimum noise level reduction of thirty decibels.

A.

General:

1.

Brick veneer, masonry blocks, or stucco exterior walls shall be constructed airtight. All joints shall be grouted or caulked airtight.

2.

At the penetration of exterior walls by pipes, ducts or conduits, the space between the wall and pipes, ducts or conduits shall be caulked or filled with mortar.

3.

Window and/or through-the-wall ventilation units shall not be used.

4.

Operational-vented fireplaces shall not be used.

5.

All sleeping spaces shall be provided with a carpeted floor.

6.

Through-the-wall/door mailboxes shall not be used.

B.

Exterior Walls:

1.

Exterior walls, other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-35.

2.

Masonry walls have a surface weight of at least forty pounds per square foot do not require a furred (stud) interior wall. At least one surface of concrete block walls shall be plastered.

3.

Stud walls shall be at least four inches in nominal depth and shall be finished on the outside with siding-on-sheathing, stucco or brick veneer.

a.

Interior surface of the exterior walls shall be of gypsum board or plaster at least one-half-inch thick, installed on the studs. The gypsum board or plaster may be fastened rigidly to the studs if the exterior is brick veneer or stucco. If the exterior is siding-on-sheathing, the interior gypsum board or plaster must be fastened resiliently to the studs.

b.

Continuous composition board, plywood, plaster (stucco), or gypsum board sheathing at least three-fourths inch thick shall cover the exterior side of the wall studs behind wood or metal siding.

c.

Sheathing panels shall be covered on the exterior with overlapping building paper.

d.

Insulation material at least R-11 shall be installed continuously throughout the cavity space behind the exterior sheathing and between wall studs. Insulation shall be glass fiber or mineral wool.

C.

Windows:

1.

Windows other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-33.

2.

Glass of double-glazed windows shall be at least one-eighth inch thick. Panes of glass shall be separated by a minimum one-half-inch airspace.

3.

Double-glazed windows shall employ fixed sash or efficiently weather stripped, operable sash. The sash shall be rigid and weather stripped with material that is compressed airtight when the window is closed so as to conform to an infiltration test not to exceed 0.5 cubic foot per minute per foot of crack length in accordance with ASTM E-283-65-T.

4.

Glass of fixed-sash windows shall be sealed in an airtight manner with a nonhardening sealant or a soft elastomer gasket or glazing tape.

5.

The perimeter of window frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230 or TT-S- 00153.

6.

Total area of glass shall not exceed twenty percent of total exterior wall area.

D.

Doors:

1.

Doors, other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-33.

2.

Double-door construction is required for all door openings to the exterior. Openings fitted with sidehinged doors shall have one solid core wood or insulated hollow metal core door at least one and three-fourths inch thick separated by an airspace of at three inches from another door, which can be a storm door. Both doors shall be tightly fitted and weather stripped.

3.

The glass of doubleglazed sliding doors shall be separated by a minimum one-half-inch airspace. Each sliding frame shall be provided with an efficiently airtight weather stripping material as specified in subsection (C)3.

4.

Glass of all doors shall be at least three-sixteenths-inch thick. Glass of double sliding doors shall not be equal in thickness.

5.

The perimeter of door frames shall be sealed airtight to the exterior wall construction as indicated in subsection (C) 5.

6.

Glass of doors shall be set and sealed in an airtight nonhardening sealant or a soft elastomer gasket or glazing tape.

E.

Roofs:

1.

Combined roof and ceiling construction, other than described in this section and subsection (F), shall have a laboratory sound transmission class rating of at least STC-44.

2.

With an attic or rafter space at least six inches deep, and with a ceiling below, the roof shall consist of three-fourths inch composition board, plywood or gypsum board sheathing topped by roofing as required.

3.

Open beam roof construction shall follow the energy insulation standard method for batt insulation, except use one inch plywood decking with shakes or other suitable roofing material in place of one-half-inch plywood.

4.

Window or dome skylights shall have a laboratory sound transmission class rating of at least STC-33.

F.

Ceilings:

1.

Gypsum board or plaster ceilings at least five-eighths inch thick shall be provided where required by subsection (E) 2, above. Ceilings shall be substantially airtight with a minimum number of penetrations.

2.

Glass fiber or mineral wood insulation of at least R-19 shall be provided above the ceiling between joist.

G.

Floors:

1.

The floor of the lowest occupied rooms shall be slab on fill, below grade, or over a fully enclosed basement or crawl space. All door and window openings in the fully enclosed basement shall be tightly fitted.

H.

Ventilation:

1.

A mechanical ventilation system shall be installed that will provide the minimum air circulating and fresh air supply requirements for various uses in occupied rooms without the need to open any windows, doors or other openings to the exterior. The attic inlet and discharge openings shall be fitted with sheet metal transfer ducts of at least 20-gauge steel, which shall be lined with one inch thick coated glass fiber, and shall be at least five feet long with one ninety degree bend.

2.

Gravity vent openings in attics shall not exceed code minimum in number and size. The openings shall be fitted with transfer ducts at least three feet in length containing internal one inch thick coated fiberglass sound absorbing duct lining. Each duct shall have a lined ninety-degree bend in the duct such that there is no direct line-of-sight from the exterior through the duct into the attic.

3.

All vent ducts connecting the interior space to the outdoors, excepting domestic range exhaust and sewer gas ducts, shall contain at least a ten foot length of internal sound-absorbing duct lining. Each duct shall be provided with a lined ninety degree bend in the duct such that there is no direct line-of- sight through the duct from the venting cross-section to the room-opening cross-section. Duct lining shall be coasted glass fiber duct liner at least one inch thick.

4.

Domestic range exhaust ducts connecting the interior space to the outdoors shall contain a selfclosing baffle plate across the exterior termination which allows proper ventilation. The duct shall be provided with a ninety degree bend or other mitigating measures approved by the building official.

(Ord. 97-905 § 1 (part); Ord. 91-499 § 2 (part), 1991)