§ 25-12-13. MEASURES TO ACHIEVE A NOISE LEVEL REDUCTION OF 30 DECIBELS.

(A)

This section prescribes the building requirements to achieve a minimum outdoor-to-indoor noise level reduction of 30 decibels.

(B)

This subsection prescribes the requirements for exterior walls.

(1)

A masonry wall must equal or exceed the weight of an equivalent wall constructed of six-inch dense 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, stucco, or brick veneer must be installed on the outside of minimum four-inch nominal deep studs.

(3)

The interior wall surface of an exterior wall must be minimum 5/8 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 minimum ½ inch thick. The weight of the sheathing and facing must be at least four pounds per square foot.

(5)

Sheathing boards or panels must be butted tightly and covered on the exterior with overlapping and airtight building paper. The top and bottom edges of the sheathing must be sealed airtight.

(6)

Glass fiber or mineral wool insulation at least two-inches thick 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)

A single-glazed window may be used if the window is fixed and if the glazing is acoustical glass with a laboratory sound transmission rating of minimum STC-35.

(2)

Glass of a double-glazed window must be minimum 1/8-inch thickness. Panes of glass must be separated by a minimum three-inch air space and may not be equal in thickness.

(3)

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

(4)

A double-glazed or triple-glazed window must contain a fixed sash or efficiently weather stripped operable sash. The sash must be rigid and weather stripped with an efficiently airtight material that is compressed airtight when the window is closed.

(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.

(7)

For a sleeping space, the total area of glass of windows and doors may not exceed 20 percent of the net floor area.

(D)

This subsection prescribes the requirements for exterior doors.

(1)

Double door construction is required for a door opening to the exterior.

(2)

If doors are separated by a vestibule of three-foot minimum depth, each door must be minimum 1½ inch solid core wood or metal clad. One door must be weather stripped in an airtight manner. The other door must be tightly fitted to the door frame or weather stripped.

(3)

If a vestibule is not used, a minimum 1¾ inch solid core wood door may be used in series with a storm door. Both doors must be weather stripped in an airtight manner.

(4)

A single frame sliding glass door may not be used. The glass of a double sliding door must be separated by a minimum four inch airspace. Each sliding frame must be provided with an efficiently airtight weather stripping material.

(5)

Glass of a storm or sliding door must be minimum 3/16 inch. Glass of a double sliding door may not be equal in thickness.

(6)

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

(E)

This subsection prescribes the requirements for a roof.

(1)

Roof sheathing must be minimum ¾ inch thick continuous plywood. Spaced board sheathing may not be used.

(2)

A roof sheathing joint must be sealed airtight and must be covered with overlapping, airtight building paper.

(3)

An exposed roof deck must be minimum two-inch thick wood or concrete, and the total weight of the roof construction must be at least 12 pounds per square foot.

(F)

This subsection prescribes the requirements for ceilings.

(1)

A gypsum board or plaster ceiling at least ½ inch thick is required below attic spaces or below the roof rafters or roof decks less than two inches thick and weighing less than 12 pounds per square foot.

(2)

The ceiling must be a minimum of 12 inches below the roof sheathing.

(3)

Glass fiber or mineral wool insulation at least two-inches thick is required above the ceiling between joists. Insulation in attic spaces may not have paper or foil covering on the face exposed to the attic.

(G)

This subsection prescribes the 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 or through-the-wall ventilation unit may not be used.

(3)

Vent openings in attic or crawl spaces must be the minimum number and size to provide adequate ventilation. The openings must be provided with five-foot long transfer ducts containing at least one 90-degree elbow and internal acoustical lining.

(4)

A ventilation duct connecting an interior space to the outdoors or an attic space must contain at least ten foot long internal duct lining plus one limited 90 degree elbow.

(5)

Coated glass fiber duct liner at least one-inch thick is required.

(6)

A vented fireplace may not be used.

(7)

A building heating unit with a flue or combustion air vent must be located in a closet or room closed off from the occupied space by doors.

(8)

A door to a mechanical equipment area must be minimum 1¾ inch solid core wood or 20 gauge steel hollow metal and must be fully weather stripped.

(H)

This subsection prescribes other requirements.

(1)

Carpeting or an acoustical ceiling is required for a sleeping space.

(2)

A through-the-wall or through-the-door mailbox may not be used.

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