1. General

All work shall consist of a sound absorptive, “backless” panels to be fitted to an existing wall or barrier structure. The panels and support mechanisms shall be in close conformity with the dimensions and lines shown on the plans and established by the engineer.

2. Materials

Panels shall be fabricated from sheet steel conforming to the structural quality and galvanized in accordance with ASTM A-653 Class G-90. Each panel shall have a cover width of 24 inches with material thickness of 22 gauge.

The individual panel or cell is available in lengths up to 12 foot nested within “Z” or “J” channels clips horizontally attached to the existing wall or structure. The “Z” channel shall be cold-formed steel galvanized in accordance with ASTM A-653, Class G-90, with two inch legs and 2-5/8 inches deep. The panels and “Z” channels may be galvanized and then pre-coated for aesthetic appeal.

The M-90 panel is made of perforated cold-formed steel. The panel contains 3/16 inch diameter perforations in a 3/8 inch staggered pattern.

Fasteners: Typical fasteners shall be galvanized, self drilling, hexagon washer head screw. Fasteners may be color coated to match panels, or stainless steel as required.

3. Construction

The retro-fitted sound absorption panels shall be installed in accordance with engineering erection plan details. The “Z” or “J” channels shall be plump and true, aligned for either continuous appearance or staggered and spaced per plans and details.

4. Acoustical Performance

The sound absorbing panels shall have a noise reduction coefficient (NRC) of 1.10 when tested by an independent laboratory in accordance with ASTM standard C-423.

5. Acoustical Installation

The panels shall have a mineral rock wool sound absorbing baft behind the perforated face. The rock wool is to be a minimum of ½ inch from the surface of the perforated face and shall fill the panel cavity and be 2 inches thick. It shall have a 6 pounds per cubic foot density 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 2 000 degrees Fahrenheit, have 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 an NRC of 1.1.

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