1. General

All work shall consist of furnishing metal sound barrier panels in accordance with this provision and in reasonably close conformity with the dimensions, lines and grades shown on the plans and established by the engineer.

2. Materials

Sound Absorptive Panels - Panels shall be fabricated with 22 to 16 gauge sheet steel conforming to the structural quality and galvanized in accordance with ASTM A-653, Class G-90. Each panel shall have a width of 12 inches and a thickness of 2¾ or 3¾ inches.

Galvanized Perforated Face Panel - The face panel of the Empire Acoustical Systems “Silent Screen” absorptive panel is made of 22 gauge perforated cold-formed ASTM A-653 steel. The face panel has 3/16 inch diameter perforations in a 3/8 inch staggered pattern.

Polycarbonate Panel - The monolithic and laminated panel shall be made of high impact ultraviolet light resistant sheets, with a sound transmission loss of STC 31 or higher and manufactured polycarbonate material. The panel shall be a minimum of 3/16 inch (4.8 mm) thick.

Fasteners - Bolts and self-drilling fasteners shall be the size shown on the plans and conforming to ASTM A-307 and galvanized per ASTM A-164 or stainless steel as required.

 3. Construction

The steel sound barrier wall shall be installed in accordance with engineering erection plan details. The top edge of the sound barrier wall shall e aligned to maintain a continuous appearance. Joints and connections shall be constructed in such a manner as to achieve maximum noise reduction.

4. Acoustical Performance

Sound absorbing panels shall have a mineral rock wool sound absorbing baft between the perforated face and solid back panel. The rock wool is to be a minimum of ½ inches from the surface of the perforated panel and shall fill the panel cavity and be 2 inches thick. It shall have a density of 6 pounds per cubic foot and conform to Federal Specifications HH-1-558B and ASTM Standard E-136. The mineral rock wool sound absorbing material shall absorb less than 1% water, be non-corrosive, melt above 2000 Degrees Fahrenheit, have a flame spread of 15 or less and a smoke development of 0 when tested in accordance with ASTM Standard E-84, be rated incombustible by ASTM Standard E-136, be non-hygroscopic, and have a NRC of 1.05 and STC of 35.

When specified, the Empire Acoustical Panels may use alternative absorptive material such as fiberglass.