National Rural Utilities Cooperative Finance Corporation
Sterling, VA
General Contractor:  Whiting-Turner Contracting Company
Architect/Engineer:  Kishimoto, Gordon, Dalaya PC and Flack & Kurtz
Contract Amount:  $8,562,647.00
Contract Start Date:  3/1/2010
Contract Completion Date:  8/31/2011
Actual Completion Date:  8/31/2011

Challenge
This project required the full range of mechanical equipment and systems available on the market today.

Solution
Mechanical system components included:

  • Magnetic bearing chiller, multi-stage scroll chiller, and absorption chiller to generate chilled water and to make ice in off-hours.
  • Four custom air handlers to distribute air to fan-powered variable air volume (VAV) boxes and to shut-off VAV boxes in the office and public spaces.
  • Six computer room air conditioning units that make use of both geothermal water and glycol chilled water in the data center. The absorption chiller provides chilled water to the data center; it is driven from waste heat generated by two roof mounted electric micro-turbines.
  • HVAC hydronic piping systems using multiple plate heat exchangers to take advantage of free cooling and alternate sources for cooling. Each of the hydronic systems is pumped using vertical pumps.
  • Three separate water booster systems in the building; one for domestic water, one for reclaimed water and one for irrigation water.
  • More than 25,000 feet of HVAC piping in the building.

System also features:

  • Main atrium with a radiant heated and cooled floor including 13,000 feet of imbedded piping. Exterior walkways at entrances include 3,700 feet of imbedded radiant snow melt systems.
  • Reclaimed water furnished to the building from the local jurisdiction for use in flushing toilets and urinals, for cooling tower make-up water and for irrigation purposes.
  • Exterior to the building, a six-tank ice bank and a 5,000 gallon domestic water storage tank to provide water to the building in case of service outages.

Result
This was a highly complex project with numerous operating sequences not typically found in an office building. Now that the project is completed, we have a very happy and appreciative client.

We are proud to note that this project won the 2012 Craftsmanship Award for Plumbing Systems from the Washington Building Congress (WBC). WBC created the Craftsmanship Awards Program in 1950 to honor craftsmen who have provided exceptional workmanship on buildings throughout the Washington, D.C. area. Only 25 to 28% of the entries received each year are recognized with Craftsmanship Awards.

According to the project description on the WBC Craftsmanship Awards web page, "The National Rural Utilities Cooperative Finance Corporation Headquarters Building’s plumbing system exhibits several unique features with its use of reclaimed water, low water consumption fixtures, siphonic roof drainage, high pressure gas and potable water storage. The building is one of the first in Loudoun County to make use of Loudoun Water’s reclaimed water distribution system and the only one to use it for fire suppression."