1. General

All work shall consist of finishing 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

Panels shall be fabricated from 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 inches or 3¾ inches.

The individual panels shall be “nested” either vertically or horizontally into structural members. The panels may be installed vertically or horizontally in heights up to 14 feet before intermediate girths may be required. The panels may be galvanized or pre-coated for aesthetic appeal. The panel system can be either galvanized or a combination of galvanized and pre-coated elements depending on customer requirements; i.e. galvanized face panel and pre coated back tray or pre-coated face panel and galvanized back tray.

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. The back trays will be 16 gauge.

Bolts and nuts shall be the sizes as shown in the plans and conforming to ASTM A-307 and galvanized per ASTM A-164.

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 be aligned to maintain a continuous appearance. Joints and connections shall be constructed in such a manner to achieve maximum noise reduction.

4. Acoustical Performance

Sound absorptive 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 sound absorption material such as fiberglass.