Case Histories (Real-World Solutions)

A Solution for Leaky Ductwork

Harvard University

Leaky ductwork connected to a new air handling unit in Girguis Lab at Harvard University was fixed with a new approach to duct sealing.

At Harvard University’s Girguis Lab, engineers had just installed a new 8,500 CFM air handling unit that was meant to supply heat to the lab and an adjacent facility. When the unit was brought online, however, its fan was operating at around 97 percent of capacity with little effect—and that was even before the system was connected to the adjacent facility. It was determined that leaks in the ductwork were reducing static pressure to such a degree that air couldn’t reach its destinations. With ducts hidden under insulation and behind layers of pipes, fixing those leaks seemed an impossible task.

Fortunately, the mechanical contractors on the job had heard about a new approach to duct sealing called Aeroseal that worked from the inside of the air shafts to locate and seal leaks.

In just a matter of days, the problem was fixed. The system’s duct leaks were quickly reduced from more than 5,800 CFM down to 429 CFM—a 98-percent reduction. The AHR fan now operated at only 37 percent of capacity. The system was quieter, and university engineers were relieved.

“I would absolutely call this a project saver,” says John Holliser, senior capital project manager for Harvard. “Our only other option was to tear down walls and demolish the building structure in order to access the leaky ductwork. We were very pleased with the results and I honestly don’t know how we would have solved this issue if the Aeroseal technology wasn’t available.”

This article originally appeared in the College Planning & Management July/August 2019 issue of Spaces4Learning.