§ 25-12-12. MEASURES TO ACHIEVE A NOISE LEVEL REDUCTION OF 25 DECIBELS.

(A)

This section prescribes the building requirements to achieve a minimum outdoor-to-indoor noise level reduction of 25 decibels.

(B)

This subsection prescribes requirements for exterior walls.

(1)

A masonry wall must equal or exceed the weight of an equivalent wall constructed of six-inch light-weight concrete block. At least one surface must be painted or plastered. A furred interior wall is not required on the inside of a masonry wall.

(2)

Siding-on-sheathing or stucco or brick veneer must be installed on the outside of minimum 4-inch nominal deep studs.

(3)

The interior wall surface of an exterior wall must be minimum ½ inch gypsum board or plaster installed on the inside of the wall studs.

(4)

Continuous sheathing as required by the Building Code must cover the exterior side of the wall studs behind wood, asphalt or aluminum siding. The sheathing must be at least ½ inch thick.

(5)

Sheathing boards or panels must be butted tightly and covered on the exterior with overlapping and airtight building paper when wood sheathing is used.

(6)

Glass fiber or mineral wool insulation with a minimum thermal resistance (R) factor of 11 is required in the cavity space behind the exterior sheathing and between wall studs.

(7)

A brick veneer, masonry block, or stucco wall must be constructed airtight except as otherwise required by the Building Code. All surface joints must be grouped or caulked airtight.

(8)

A penetration of a wall by a pipe or duct must be caulked or filled with mortar.

(C)

This subsection prescribes the requirements for windows.

(1)

Glass of a single-glazed window must be minimum 3/16 inch thick.

(2)

Glass of a double-glazed window must be of standard manufacturers' thickness and separation.

(3)

An operable window in a dwelling must contain a hinged-type sash or double-hung sash. The sash must be rigid and weather stripped with an efficiently airtight, flexible nonmetallic material that is compressed airtight when the window is closed.

(4)

A horizontally sliding sash window may be used if the sash is weather stripped with an efficiently airtight gasket and if the window has a laboratory sound transmission rating of STC-28 or greater.

(5)

Glass of a fixed-sash window must be set and sealed in an airtight non-hardening glazing compound or in an elastomer gasket.

(6)

The perimeter of a window frame must be sealed airtight to the exterior wall construction.

(D)

This subsection prescribes requirements for exterior doors.

(1)

An exterior door must be minimum 1¾ inch thick solid core wood or metal clad and must be fully weather stripped in an airtight manner.

(2)

A sliding door may be used if the operable sash is weather stripped with an efficient airtight gasket and if the door has a laboratory sound transmission rating of STC-28 or greater. Glass of a sliding door must be minimum 3/16 inch thick.

(3)

The perimeter of a door frame must be sealed airtight to the exterior wall construction.

(E)

This subsection prescribes requirements for ceilings.

(1)

A gypsum board or plaster ceiling at least ½ inch thick is required below attic spaces or roof rafters or roof construction weighing less than eight pounds per square foot.

(2)

Insulation with a minimum thermal resistance (R) factor of 19 is required above the ceiling between the joists. Insulation in attic spaces may not have paper or foil covering on the face exposed to the attic.

(F)

This subsection prescribes requirements for ventilation.

(1)

Mechanical ventilation is required and must be of a type and design that provides adequate environmental comfort with all doors and windows closed during all seasons.

(2)

A window ventilation unit may not be used. A wall-mounted ventilation unit may be used if the unit is insulated to minimize outdoor-to-indoor sound and the wall penetrations are sealed.

(3)

Vent openings in attic or crawl spaces must be the minimum number and size necessary to provide proper ventilation. In this paragraph, "vent" includes a conduit or passageway, vertical or nearly so, for conveying products of combustion to the outside atmosphere.

(4)

Coated glass fiber duct liner at least one inch thick is required for a return air duct.

(5)

A fireplace must be provided with a well-fitted damper.

Source: Ord. 010809-78; Ord. 031211-11.