On May 1st and 2nd of 2010, Nashville, TN experienced nearly 14 inches of rain leading to the worst flood in the city’s history. Many homes and businesses suffered terrible losses, including the Schermerhorn Symphony Center. The Nashville Symphony’s 197,000 s.f., 1900 seat home originally opened September 9th, 2006. The center was designed to be a world-class symphony hall and has been a very successful venue since its opening. The mechanical system design includes eleven custom air handling units. Of these, ten were completely submerged in the flooding along with all of the building’s electrical equipment, instruments, and organ.
Having constructed the building originally, American Constructer’s, Inc. was re-hired by the Nashville Symphony to perform flood remediation and reconstruction. ACI, in turn, hired Lee Company to remove all damaged equipment and reinstall a new mechanical system. The original system utilized single plenum fan AHUs in custom cabinets with large motors. The units serving the performance hall were all stacked top and bottom units. All of the units had to be cut out and removed piece by piece. The replacement AHUs supplied by Tom Barrow Company incorporated FANWALL® Technology for acoustical performance, space savings and for the capability of getting new custom units back into the building.
The original project’s acoustical requirement’s were extremely stringent and required a Performance Noise Criteria (PNC) of PNC-10 in the performance hall and PNC-30 in most surrounding areas. Acoustically, the Huntair units were designed so that they were less than the original AHU’s radiated and discharge sound power levels. Using the 4” thick panels with perforated liner to match previous unit construction and utilizing FANWALL Technology’s direct drive plenum fans, this task was easily accomplished. In most octave bands, the Huntair air handling units were 15+ dB better than the original AHUs! As a result of this better acoustical performance, over 25% of the sound attenuation that was to be replaced was eliminated from the project entirely. This in turn reduced the static pressure on the overall system.
Six of the original ten air handling units were stacked units to account for the space required by large single plenum fans. ALL of these units were reduced to a single level by the Huntair design. The gained vertical space was used for future flood remediation. The Huntair units were set on elevated structural steel that raised the base of the units six feet from the floor of the mechanical room. Turbine pumps have been installed in the space beneath the units so that this space can be used as a sump pit in the event of a future flood. Because of the reduced unit height, enough water can be removed from the building that a flood twice as large as the May flood will not damage mechanical or electrical equipment.
The ten AHU’s that were replaced are located in equipment rooms that are 20-30’ below building grade. The Huntair air handling units had to be delivered completely knocked-down so that all of the pieces could be brought in through a grated outside air opening that ran twenty feet deep. It would have been impossible to bring in motors or fan wheels to match the original units without knocking down one of the Symphony Center’s beautiful Neo-Classical exterior walls. This fact made FANWALL Technology the perfect solution for the project, since all of the fans could be brought down in their cubes individually. After eighteen truckloads of palletized equipment and approximately 6,000 man hours, the units were brought in and completely assembled in the mechanical rooms. Besides the installation benefits FANWALL Technology has provided, the owner is now realizing ease of maintenance and better building performance!