Part 1 -Symbols of the Modern World
Part 2 -57 Stories of Light
Part 3 -Pride of Nashville
Part 4 -A Labor of Indecision
Part 5 -World Title Champion
Part 6 -A Building that Breathes

When Liberty Property Trust began planning a 57-story, 975-foot tower in Philadelphia in 2002, the firm had no partners, no anchor tenants and no thematic design. But Liberty did have a hunch that Class-A office vacancies, then running about 13% in the central business district of Philadelphia, were going to tighten up.

The hunch was correct. Downtown office vacancies have narrowed to 7%. Liberty signed on Comcast Corp. to fit its new world headquarters into the high rise, and has leased up 97% of its 1.2 million sq. ft. of space. Tenants began moving in during the fall of 2007 and an official ribbon cutting is planned for early June. The building sits on a site above the Suburban Station underground-railroad concourse. Building costs totalled $540 million.

In 2006, Liberty sold off an 80% stake in its new building to Commerzbank AG in Germany. By then the theme was clear: Comcast Center would be a green building, with the goal of winning a Silver LEED rating from the U.S. Green Building Council. When it opens this year, it could be the tallest LEED-certified structure in the nation.

What makes Comcast so green? Start with the floor heights. Robert A.M. Stern Architects of New York has set the floor to ceiling heights at 11 feet, compared with an average 9 feet or less elsewhere in Philadelphia. The floor-to-floor measurements are 15 feet, and then the mechanicals are placed in the ceiling.

“Sunlight penetrates much deeper into the middle of the building,” says Robert Stern, the principal partner of his eponymous firm and one of the legends of the design community. “That means you don't need as much electric light.” Stern's second job is dean of the school of architecture at Yale University.

John Gattuso, a senior vice president with Liberty Property, says that office workers are happier in natural light environments. “A company like Comcast could get 20% more productivity out of its employees in an environment like this,” he asserts.

If the higher ceilings recall a design style prevalent a century ago, so does the radiant heat that the Comcast Center employs.

That has allowed the developer to reduce the amount of ductwork required throughout, according to Stern, and provides more flexibility in moving air to various zones in and out of the sun.

“Overall, the air moves better in a building with higher ceilings. That makes for a more comfortable office workspace,” Stern says.

The architects put a trio of stacked atriums on the lower floors — each three stories in height — to make the bottom of the building more appealing to tenants. Every urinal in every washroom employs a waterless design, saving more than 1 million gallons a year in consumption.

“Many jurisdictions don't permit waterless urinals, and we had to get a variance on the local Philadelphia building code to do this,” Stern explains.

He adds that stormwater will be captured and stored in cisterns on the roof, then used to water trees planted in a spacious half-acre plaza below.

The Comcast building is noted as the tallest in Philadelphia, higher than One Liberty Place at 945 feet and Two Liberty Place at 848 feet — both developed by Liberty. It's notable, too, for its lack of parking, with just 100 car spaces in the building.

“There are now 100,000 people living downtown,” says Gattuso of Liberty. “People are going to want to live close to a big employment center like Comcast.”