Steve Thomas/Post-Gazette

Pittsburgh's brand new 1.4 million-square-foot David L. Lawrence Convention Center has won accolades for Rafael Vinoly's striking design, with its sail-like roof that suggests the arcs of the nearby bridges over the Allegheny River.

The Convention Center also is on the cutting edge of the green building movement, an approach to design and construction that creates buildings that are environmentally friendly, profitable to operate and healthy places to work and live.

Pittsburgh's is the first convention center in the world to be built according to green building principles. It will likely become the largest building to be certified as "green" by the U. S. Green Building Council through its Leadership in Energy and Environmental Design Green Building Rating System.

LEED certification is based on criteria such as site selection, water and energy efficiencies and use of nontoxic and recycled building materials, and the new Convention Center meets all the criteria.

The Pittsburgh region already has more than 30 buildings that either have been LEED-certified or are being evaluated for LEED certification. LEED certification for the Convention Center, a major public building, offers Pittsburgh the opportunity to assert its leadership as an emerging center for environmentally conscious design.

In November, the Convention Center will be the site -- and a focus of attention -- of the Greenbuild International Conference and Expo, which will bring thousands of green building professionals -- architects, engineers, developers, building owners, academics and urban planners -- from around the world to take a close look at the center's design.

Conference attendees will see close up three sustainable design strategies that local architecture and engineering firm Burt Hill Kosar Rittelmann employed to cut energy consumption 30 percent compared to similar facilities that use conventional engineering: natural ventilation; natural lighting; water efficiency.

The total energy saved is equal to the electricity consumed annually by 1,900 Pittsburgh households; the water saved is enough to supply 132 Pittsburgh households for a year.

Natural ventilation means that the heating, ventilation and air-conditioning systems work less, consuming less water and energy.

To create natural cross ventilation, the Convention Center takes advantage of the chimney effect created by the sweeping roof and of convection currents from Allegheny River flowing next to the building.

Vents in the building's north and south facades allow outside air to flow through the building without using fans or other mechanical systems. This provides efficient air circulation when outdoor temperatures are between 45 degrees F and 65 F, about one-third of the time in Pittsburgh.

The building has a weather station near the roof to measure air temperature, humidity and wind speed and direction.

When conditions are right, the 20 air-handling units serving the exhibit halls shut off, the vents open and outside air flows into the exhibit area.

The Convention Center also uses natural ventilation to flush air from the exhibit halls at night during warmer periods, which further reduces cooling system operating time.

Natural ventilation saves 3.8 million kWh of energy a year.

In natural lighting, clerestory windows where the walls and roof meet and long, 6-foot-wide ribbon skylights covering 10 percent of the roof area provide natural daylight for 75 percent of the Convention Center's exhibition space and save 9.5 million kWh of energy a year. Aside from the aesthetic appeal of natural light, natural daylight can boost business too.

A recent study for Pacific Gas and Electric Co. suggests that using day lighting in trade or commercial exhibits can increase sales on a convention floor by about 40 percent.

In water efficiency, the Convention Center taps Pittsburgh's "fourth river," the aquifer that runs beneath Downtown, providing makeup water for the Center's refrigeration system cooling towers, reducing the demand for water from the city water system.

Pulsed-power treatment of the cooling tower water to eliminate bacteria without chemicals further reduces the demand for city water. This design saves an estimated 1.8 million gallons of water annually.

The Convention Center uses recycled water for toilet and urinal flushing. The water is conditioned by an aerobic digestion and submicron filtration system.

The effluent is totally colorless and odorless. With final ultraviolet light treatment, the effluent has been treated for everything but viruses. The system recycles 50 percent of the Center's water and saves an estimated 6.4 million gallons annually.

The new Convention Center is not only an architectural landmark of international significance, but also is an important milestone in Pittsburgh's evolution from environmental nightmare as recently as 50 years ago to a city committed to a green, clean environment.