Credit: Payne Rowlett
A 49-STORY OFFICE TOWER IN THE PLANNED, MIXED-USE SOUTH STATION AIR RIGHTS PROJECT is the first Boston building to be pre-certified in the Washington, D.C.-based U.S. Green Building Council’s LEED Core and Shell development program. If all goes as planned, the building will earn LEED Core and Shell Silver certification when completed in 2012.
Once built, the office tower also will be the tallest building in Boston’s financial district. The tower will be curved to reflect the train station façade below. It will be clad with textured spandrel glass panels and taper toward the architectural crown, designed with glass and metal accents.
“Boston is underwhelming in terms of the architecture of tall buildings,” says David Perry, senior vice president of Houston-based Hines, the owner/developer of the project. “Tall buildings here tend to be rectangular and monochromatic, but this building will be neither of those things. It will have a large illuminated feature on top that will be quite striking at night. I think this building will take the Boston skyline to another level.”
Pre-certified at the LEED Silver level in 2006, the 1 million-square-foot (93000-m2) office tower proposed by Hines and TUDC, a subsidiary of Tufts University, Medford, Mass., predated a January 2007 Boston zoning code change that requires all projects of more than 50,000 square feet (4645 m2) to be designed and planned to at least achieve a LEED Certified rating.
According to USGBC, to date there are 117 pre-certified projects nationwide; three of those, including this office project, are in Boston. Construction of the tower is scheduled to begin in early 2009.
MAKING THE GRADE LEED
Core and Shell certification covers base building elements, such as the structure, envelope and HVAC system. It is designed to complement the LEED for Commercial Interiors rating system. LEED pre-certification, which is not necessary for certification, is based on declared goals and intent to achieve green features, not the actual achievement of these features. However, Perry is confident the building will achieve Silver—if not Gold—status when it gets its final certification. The design also earned the Washington-based U.S. Environmental Protection Agency’s Designed to Earn the Energy Star label in May. (To learn more about Designed to Earn the Energy Star, see “perspectives,” July/August issue, page 60.) The office tower is the first part of a threephase project. Phase two will include a hotel and residential building and phase three will feature the construction of a 9-story office building.
The developer applied for pre-certification for the office tower because, Perry says, “We believe in getting credit when credit is due. Tenants are interested in sustainability; investors are interested in sustainability; and we're interested in tenants and investors, so there is a mutuality of interest there.” The developer pursues LEED certification on all its projects. “It’s a qualitative and a quantitative decision,” Perry says. “We shoot for as high a LEED certification as we think the market will support and as high as necessary to differentiate us in the marketplace. So it can vary depending on the project and the market [the project] is in.” Perry admits achieving these sustainability goals can take a bit more time, but says it is a worthy endeavor.
He estimates about 5 percent of the overall design effort goes toward achieving LEED certification, though he has noticed that with each project the design team’s expertise increases and the time spent planning green features decreases. Many sustainable practices, like dedicated recycling collection and storage facilities or using low-emitting materials, now are standard practice for the development firm. Building with LEED certification in mind adds a 5 to 10 percent premium on the cost, Perry says, but doing so makes potential tenants, investors and city planners look more favorably on the project.
LOCATION, LOCATION, LOCATION
The location of the office tower was of key importance in terms of LEED pre-certification and gathering early interest from potential tenants. The project occupies the air rights between the rear of the historic South Station train station building and the end of a bus terminal. It already is a transportation hub for Boston, but the developers agreed to spend approximately $40 million on transportation-related improvements for South Station, including an increase of the bus terminal’s capacity by nearly 40 percent. “This project uses an innovative approach to combine the creation of new space with one of Boston’s most important transportation assets,” Boston Mayor Thomas Menino said in a written statement.
“We’re talking about putting offices, homes and hotel rooms literally right on top of public transit.” The office tower’s location above the transit hub means future tenants will be able to easily access the building and the rest of Boston without automobiles, a benefit that earned LEED points and also enabled the developers to get by with less parking than an office tower this size might otherwise require. “This building will be one of the most accessible buildings to public transportation in New England,” Perry asserts. In addition to the location, which encourages public transportation, one section of the roof is vegetated and the parking lot is a sheltered garage to minimize contribution to the urban heat-island effect.
AN ENERGY STAR IS BORN
Credit: Payne Rowlett
Plans include the use of low-E glass and an energy- efficient curtainwall, as well as water-efficient fixtures and landscaping. An energy-efficient HVAC system will bring in outside air at a rate of 18 cubic feet per minute (0.5 m³ per minute) in winter and summer and approximately 20 cfm (0.6 m³ per minute) in spring and fall, supplying a higher percentage of outside air than most Boston office buildings. The air will be purified by a highly efficient filtration system and controlled by a carbon-dioxide monitoring system. Low-emitting building materials, including adhesives, agrifiber or composite-wood products, paint and coatings, and carpet, will be specified. Hines also has created tenant interior design guidelines, which will help guide tenants through similar green considerations for outfitting their interior spaces.
A score of 75 is required to earn the Energy Star label. With an anticipated Energy Star rating of 90, the developers project an energy savings of 152,587,263.2 thousand Btu per year compared with the average energy usage for a similarly sized building with a rating of 50. However, since a cost/benefit study couldn’t support it, there will be no renewable-energy generation, such as photovoltaics, on site. “We consider LEED certification standard now,” Perry says. “Pretty soon designing for LEED certification will be seamless and all the design discussion will centered on aesthetics.”
LISA ANDERSON MANN writes about architecture and sustainability from Petaluma, Calif.
OWNERS AND DEVELOPERS / Hines, Houston, www.hines.com, and TUDC (a subsidiary of Tufts University), Medford, Mass.
DESIGN ARCHITECTS / Pelli Clarke Pelli Architects, New Haven, Conn., www.pcparch.com
ARCHITECT OF RECORD / Kendall/Heaton Associates, Houston, www.kendall-heaton.com
MECHANICAL ENGINEER / Cosentini, Cambridge, Mass., www.cosentini.com