The staff issued a certificate of occupancy on November 23, 2010 for the subject property and its use as a "secure GSA data and tracking facility." This certificate was issued after a number of plan reviews in the years from 2000 to 2007 and the subsequent issuance of at least two dozen separate building permits. The most recent plan review occurred in April 2011 to permit the installation of a number of actual artifacts from sites that were affected by the deadly attacks of September 11, 2001, and to serve as a reminder as to why this facility now exists.
Situated atop the building are 23 "dry-cooler units" (manufactured by Liebert Corporation) that were installed during the "top-to-bottom" renovation and are designed to serve as the primary cooling system. Each of these dry-coolers (located behind a substantial screen wall) is as large as a good-sized conference room and each also includes 10 cooling fans -that when operating - sound like a group of helicopters that never leave the rooftop of the building. It is this distinctive sound that has generated a steady number of complaints from those residents who live north and west of the subject property.
Reacting to these noise complaints, the Zoning Administrator first issued a stop work order in September 2010 that remained in place until assurances were provided that the sound issue would be resolved before the next cooling season in 2011. As noted above, the certificate of occupancy was subsequently issued; however, the noise complaints resumed in late spring 2011.
In response to these continued noise complaints, both the property owner and the Town engaged the services of separate acoustic engineers who have performed no less than 6 sound studies since October 2010. Three of these studies have been performed by the Town (in September 2011 and again in June and late July 2012), and in each case it was determined that the operation of the dry-cooler system - with as little as 6 units in operation - exceeded the night-time sound pressure levels as set forth in § 18-117 of the Vienna Town Code. According to the Town-authorized reports, the largest spike above (8-9 dB) the permitted levels occurred in the 125 Hz range.
Desiring to resolve the on-going noise issues, the Director of the Liberty Park facility became personally involved during mid-summer 2012 and assigned a specific staff member with the task of implementing a solution. Moreover, a series of on-site meetings has also occurred to inform the residents and other interested parties as to forward progress in this regard. In each of these meetings, it was noted that a supplemental ground-installed water-cooled system would be used to minimize the use of the rooftop dry-cooled system. The most recent meeting - on December 17, 2012 - also set out a permit review and construction schedule.
Upon review of the permit set and conceptual architectural plans, the Zoning Administrator (in consultation with the Town Attorney) determined that the number of proposed units and the size of the proposed noise attenuation screen wall would require plan review in accord with § 18-116D of the Vienna Town Code and exterior architectural review in accord with Chapter 4 of the Vienna Town Code. These specific review procedures include the formulation of a recommendation by the Planning Commission and respective decisions by the Mayor and Town Council and the Board of Architectural Review.
As depicted on Sheet 4 of 6 of the plan set (originally submitted to the staff on December 21, 2012), two 12-feet-deep by 18-feet-long [216 square feet in areal coverage] cooling towers would be placed at the southeast corner of the building and on the opposite side of the building from the residential areas that have been affected by the noise from the roof-top dry-cooler units. These two proposed units (with possible future expansion of a third unit of the same size) are to be situated in a leveled-off grassy area some 29 feet from the easterly property line and surrounded by the aforementioned screen wall some 22-feet, 2-inches in height. Because this is a water-cooled system, a separate 4-inch water line will be required to operate the units. In addition, a "pipe header screen wall" about 6 feet in width and 3 feet in depth will be placed along the exterior wall of the southeastern building elevation to screen the piping system running from the ground-mounted units to the top of the building. Town Staff also notes that an 8-foot by 12-foot concrete pad is proposed very near the southeast corner of the existing building and is - we have been advised - to support the placement of two 5-foot by 5-foot [25 square feet each; 50 square feet total] equipment "screen sheds" associated with the new cooling system.
A review of the area requirements in § 18-98 of the Town Code indicates that no building setbacks or lot coverage limits have been breached in conjunction with this request (the current lot coverage - apparently inclusive of equipment sheds and assorted concrete pads - has been updated by an additional 50 square feet on Sheet 1 of the plan set.)
The Planning Commission considered this matter at its regular meeting of January 9, 2013. The Commission recommended approval of the entire plan (including the third cooling tower, if necessary) by a vote of 7-0-1 (Gelb absent, Chase abstained).