Nova Southeastern University is a 380,000 medical education complex and research university focusing on the field of Osteopathic Medicine. Commercial Acoustics was contracted by Baker Barrios Architects to provide detailed design-assist services to identify areas of noise intrusion or concern and speech privacy requirements per ANSI S12, DoDEA and LEED V4 to achieve a LEED Silver certification. The analysis included target STCs and IICs for all rooms and target reverberation times of lecture halls and cafeteria.
Healthcare and Education Acoustic Treatment
Areas reviewed for reverberation control included the primary lecture hall with a footprint of over 8,000 square feet. In rooms of this size, when reinforced speech systems are used, reverberation is of particular concern. RT60 values calculated at the 250 Hz and 500 Hz octave bands drove the requirement for extensive fabric wall systems along the two large parallel side walls. Similar analyses were performed in smaller conference rooms and training areas.
When to Use Sound Masking
One primary area of concern was the sound privacy between adjacent physician offices and medical personnel rooms. In most of these locations, the demising partition did not go to deck and ended at the ceiling grid, or alternatively, the drywall was only extended to deck on one side. This unique condition greatly reduces the composite STC between the rooms (composite STC is the average soundproofing between the full wall below and the one sided wall above. It is heavily weighted toward the lower STC of the partition).
Moss Construction recognized the potential for significant schedule savings if walls could be terminated at the grid entirely. Making it much more efficient for MEP contractors to run duct work and other commodities above without needing to punch through sheet rock layers. This schedule reduction would come at an additional STC cost.
The agreed upon solution was to install sound masking in the plenum above. This is a win-win as it improves the speech privacy more than the single layer of drywall would provide, but it would also greatly improve the cost and schedule on the entire project. As LLED V4 and FGI guidelines denote, properly tuned and balanced sound masking systems can improve speech privacy by an equivalent 5-10 STC points.
Implementation of Sound Masking
The Lencore Spectra i.Net speaker system was installed over the course of 3 weeks. One control panel ran through 3 floors of the facility with a vertical pass through in the IDF. 292 total speakers were installed in various locations including classrooms, offices, and simulation rooms.
The Commercial Acoustics Team completed the installation after the ceiling grid was installed but before ACT. J Hooks were fastened to the bottom of the composite metal concrete deck above, and plenum rated CAT5E was run from speaker to speaker and connected to the system via operating platforms. Zoning was designed to allow precise tuning for various room types. Per sound masking specifications in Spec 275119, dBA levels are defined for open offices semi closed spaces, and conference rooms with tolerance levels of 1-2 dBA. Upon completion of the installation our engineering team provided training support for facilities management and the system was activated 2 weeks prior to the school opening.
Speech Privacy is critical in hospitals to improve patient sleep quality and corresponding HCAHPS scores. Consider Commercial Acoustics if you have questions on how best to design and install Sound Masking systems in your project.
