Industrial noise control projects are typically addressed with heavy-duty fabrications attached to or encapsulating process machinery to meet sound attenuation requirements. But, not infrequently, there are factory interior workspaces that need reduced noise levels as well. SysTech was contacted by an industrial client with a need for noise reduction in a “noisy” lunch/meeting room. The room was 30′ x 12′ x 8’, with block walls, glass windows, a hard tile floor and a coated dry wall ceiling. All these hard surfaces resulted in indirect source sound levels approaching 85 to 87 dBA making it difficult for workers to hear and communicate during meetings or lunch breaks.
Indirect noise is defined as noise energy, not in a direct line of sight to the receiver (often referred to as reverberated noise). The best approach for attenuating indirect source noise is with absorption materials, and this application was a perfect fit for wall mounted, acoustical absorber panels.
Design of Absorptive Surface Treatment
The design “rule of thumb” for sound absorption applications is, where possible, to cover 60% to 70% of the reflective wall and ceiling hard surfaces with absorption material.
SysTech selected Noise Suppression Technologies, Inc (NSTI) Decorative Acoustical Absorber (DCA) panels, which were mounted on the walls and on the ceiling. The panels are 2-inch thick and are comprised of a semi-rigid fiberglass core completely encapsulated with client option of a cover fabric and fabric color. The wall and ceiling mounted panels have an Noise Reduction Coefficient (NRC) of 1.0. The NRC is a single number rating system that indicates a material’s ability to absorb reverberated noise energy. The higher this number, the more effective the material.
Stategic location of the panels was designated by SysTech and installation was by the owner. Detailed installation instructions were included with the NSTI panels minimizing install time requirements.
“Results were significant” per clients review, with room sound levels reduced to 70 – 73 dBA. Meetings now enable discussion and lunch break conversations are in a relaxed environment.