First Residents To Move Into Drexel University’s New Green Dorm

Drexel University sophomores moved into a new "green" $42 million residence hall this week, a 17-story Millennium Hall housing 482 students in a hybrid suite configuration with a series of shared living areas.

The building, made primarily of glass, features spectacular views of Center City and incorporates many environmentally sustainable features including a “green” roof.

The residence hall will give students transitioning into upperclassmen the opportunity to live together and participate in sophomore-focused events and professional development programs.

Drexel students were consulted for the design of the new residence hall. Erdy McHenry is the architect and Intech Construction is the contractor. The 115,000-sq.-ft. Millennium Hall boasts a 3,000-sq.-ft.-green roof.

The green roof’s major characteristics are:

-- A weight of approximately 27-29lbs/sq. ft. when fully vegetated and saturated.

-- Soil composed of high quality inorganic aggregates, containing a special clay particle to bind nutrients and an acid rain buffering component.

-- Soil formulated with disease-suppressive organic material at a level consistent with ecologically sustainable soil/plant communities.

-- Regional adaptations of engineered soil vary in composition. Each is specifically developed based upon climate, water quality, and regionally available components. Millennium Hall plants have been selected for extreme drought tolerance, disease and insect resistance, long life, low maintenance, and beauty.

-- Plants were selected by local horticulturists in order to meet the local climate preferences. They were planted in modules at a local nursery and cared for until they were transported to the building.

Green roofs have been proven to bring about significant energy savings, particularly during the summer cooling season in which single-story buildings can experience a reduction of greater than 25 percent energy use. Plants transform heat and soil moisture into humidity to create natural evaporative cooling. Each gallon of water that is transpired by the plants or evaporated from the roof surface liberates 8,000 BTUs of thermal energy.

The green roof acts like a protective umbrella to shade and insulate buildings, avoiding the heat island effect associated with traditional rooftops. Millennium Hall’s green roof surface can absorb up to 99 percent of one inch of rainfall, reduce runoff, and lessen the risk of sewer overflows and flooding. When the rainfall is less than an inch and can’t be absorbed by the green roof system, the excess rain that runs through the roof is filtered and delayed until after peak flows.

Plants used on the green roof have extreme drought resistance through some means other than their root system. Succulent, water-holding plants are sedums, alliums, sempervivums, and delospermas. These best plants will store water, and have a special type of metabolism called Crassulacean Acid Metabolism.

CAM plants are unique in that under drought conditions their stomates (leaf pores) are open at night rather than during the day, as is the case with most plants. CAM plants exchange gasses (oxygen and carbon dioxide) in the dark when it is cooler and less windy. CAM plants are up to 10 times more efficient with water conservation than non-CAM plants.

Among Millennium Hall’s other “green” features are restricted flow toilets and shower heads that have been installed to reduce the use of water, and an exterior that incorporates a rain screen panel system to provide solar shading.