Development

One & Two Potomac Yard

File Type: Free Content, Case study
Release Date: January 2007
Average Rating:       (0 Ratings)
Potomac Yard buildings

Fast Facts

Address: Arlington, Virginia
Company/Developer: Crescent Resources, LLC
Design/Builder: James G. Davis Construction Corporation
Project Specs: Speculative
Project Type: Office
Square Feet: 645,000 in two towers

Project History: Crescent Resources is the master developer of Potomac Yard, a 300-acre development of the former Richmond Fredericksburg and Potomac Railroad rail transfer station in Arlington and Alexandria. Upon completion, the mixed-use project will include 4.5 million square feet of office, 3,000 residental units, 200,000 square feet of retail, 1,250 hotel rooms and 92.4 acres of open space and parks. One & Two Potomac Yard was the first vertical project. Having the EPA as a tenant was the incentive to build green.

Commitment to Sustainability

Crescent Resources, LLC is a member of the U.S. Green Building Council (USBGC). The company documented the LEED process and produced a case study of the “Greening of One and Two Potomac Yard,” signage package and tour program.  The guide details each credit the building qualified for, concise pictorial illustrations, and how the intent was met.  The signage program was developed to help tenants and vistors learn more about the green features of the building.  Lastly, a tour was developed to demonstrate the benefits of building green.  Over 50 tours were given in the first year.  A green housekeeping plan was also developed. The buildings received a Gold Rating for New Construction and Existing Building.

Green Features

Economic Analysis

  • The project was completed on time and on budget.
  • Sixty-five percent occupancy within a year of building completion.
  • While design costs are usually around three to four percent of the building construction costs, LEED-related design costs were about 33 percent of the corresponding LEED-related construction costs.
  • Crescent paid more than $750,000 in commissioning fees.  The commissioning process involves more than 2,800 control points in the energy management system, with each point tested (up to eight different ways) for accuracy, functionality and reliability.  Tests of each control point occur every 48 hours to compile trend-logging reports to compare future performance tests. Building commissioning procedures occurred throughout construction (24 months) and continued for at least 12 months after construction was finished. However, building commissioning ensures a high-performing building from first occupancy and provides building management with a baseline performance standard to evaluate the building systems for efficiency.
     
EPA lobby in Potomac Yard building

Site Sustainability/Materials Use

  • The buildings are located within one-half mile of the Crystal City Metro Station and on two public bus lines.  A regional rail service has a station within one-half mile as well.
  • Crescent provided 201 bicycle lockers and changing rooms with 28 showers for tenants.
  • The buildings were built in a previously developed, urban area.  Crescent only disturbed what was necessary and stayed with the building’s footprint during construction.  Additional, unused land to the north of the project was preserved, replacing impervious surfaces with native or adapted vegetation.
  • A single sand filter serves One and Two Potomac Yard.  It was calculated that the filter reduces the total suspended solids in runoff by 83 percent and the total phosphous in runoff by 41 percent.
  • To reduce the heat island effect, all the parking is underground or in covered structured parking.
  • Both buildings have two separate roof covering systems - a flat-roof and a curved-roof system.  The flat system is a Carlisle White EPDM system, the curved is a Berridge system with a LEED-compliant, field-applied coating. Using these two systems reduces the radiant heat from the building and keeps the sun from heating the building.  Both buildings also have a green roof on a small portion of the roof.
  • Forty-two percent of the materials were found locally (originated from within a 500-mile raduis of Potomac Yard).
  • Forty percent of the construction products have recycled content. The project recycled 73 percent of the waste from construction.
  • At least 50 percent of the wood-base building materials and products used in the project used Forest Stewardship Council-certified wood. Wood-based building components used were general dimensional framing, flooring, finishes, furnishings and temporay construction applications.
  • The steel used to reinforce concrete (rebar) had 85 percent post-consumer and 15 percent post-industrial recycled content.
     
entrance to Potomac Yard

Energy Efficiency

  • "Daylight harvesting” was implemented with the perimeter overhead lighting dimming automatically based on ambient daylight.
  • Crescent redesigned the HVAC, service hot water and interior lighting systems to fall below baseline use and costs established by the energy code required by ASHRAE/IESNA Standard 90.1-1999.
  • One Potomac Yard was able to save 23.5 percent over baseline.  Two Potomac Yard’s energy savings are 20.7 percent over baseline.
  • Lighting power densities fall between 0.74 and 0.90 watts per square foot.
  • High performance window and entry systems maximize thermal performance, reduce solar gain and minimize air leaks and uncontrolled water infiltration.
  • Light colored materials maximize the affect of daylight and reduce energy use and heat gain from artificial light sources.
  • Building management control systems monitor carbon dioxide, humidity, and temperature and control air movement and temperature.
  • Crescent eliminated CFC refrigerants in HVAC systems and refrigeration systems in the buildings in order to reduce ozone depletion. 

Water Efficiency

  • Crescent reduced water use in the building by over 40 percent.
  • Crescent eliminated an irrigation system and designed the landscape with native plants that did not need much water.
  • Low-flow faucets, showerheads and toilets were installed to reduce water use throughout the building. 

Innovation

  • Potomac Yard has a Transportation Management Association (TMA). The TMA was established to encourage tenants and residents of Potomac Yard to use alternative transportation.  The TMA offers shuttle services, as well as metro and bus discounts.  The only other TMA is in Portland, Oregon.
  • The buildings received an innovation credit for the water savings.