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Building Solutions: A Lesson Learned in HVAC

A Lesson In HVAC Retrofiting at Princeton University

When an establishment has been around as long as Princeton University, renovations to its buildings’ infrastructure become an on-going process. That process was recently focused on the school’s physics department, and Aeroseal was in attendance.

Jadwin Hall was first built in the late 1960s and currently serves as the headquarters for the University’s Department of Physics. The six-story building includes ninety laboratories, eighty-four offices and eight classrooms. After more than fifty years of operation, the building’s HVAC system was due for an upgrade.

In Brief

  • Building: Princeton University, Jadwin Hall
  • Contract Engineers: Irwin Leighton Inc.
  • TAB Company: RCC Engineering
  • Aeroseal Company: Aeroseal of Philadelphia
  • Goal: Reduce leakage in two exhaust shafts
  • Before Aeroseal: 533 CFM of leakage
  • After Aeroseal: 8 CFM of leakage
  • Results: A 98% reduction of leakage

This included upgrading the VAVs, replacing the exhaust fans and even replacing much of the ductwork.

Two of the building’s main exhaust shafts could not be replaced. Made of masonry block and brick veneer, these six-story shafts were part of the building itself. Removing them would mean actually tearing down the walls and rebuilding.  Unfortunately, early testing showed that both shafts – one venting offices and labs and the other used to exhaust bathrooms – both had significant leakage. As a result, the exhaust fans were running much hotter than they should have been and heating and cooling costs were escalating. At the same time, air quality issues remained a concern.

“The $70 million dollar renovation project began about five years ago and included replacing windows, new paint and flooring and other areas of concern with special attention given to the building’s HVAC. The aging HVAC system wasn’t working as well as it should, so to increase performance and decrease our carbon footprint, we focused much of the project on updating the system”

Aric Duvalla
Assistant Facilities Supervisor

“We were clearly loosing a substantial amount of CFM in these two shafts,” said Russ Campbell, owner of Campbell Engineering, Princeton’s TAB contractor on the project. “To properly balance the system and to optimize performance, we knew we needed to seal these leaks. But how?”

Fortunately, one of the contract engineers on the job, an HVAC professional at Vanderweil Engineers, was in contact with a local Aeroseal dealer regarding the use of the duct sealing technology on his own home. He talked to Doug Meyers at Aeroseal of Philadelphia about the prospect of using Aeroseal on the masonry duct system at Jadwin Hall.  After an initial review of the technology, Aeroseal of Philadelphia was brought on campus to tackle the leakage problem.

The duct sealing process took about two and a half days to complete – a half day to set up, a day to seal one of the shafts and a second day to complete the second shaft. The work was done while classes were in session and without major interruption to normal building operations.

“We decided the best way to access the interior of the shafts was from the top down,” said Meyers. “Before we arrived, the engineers had removed the connector to the exhaust fans and replaced them with a temporary plate. Then we were able to cut a hole into the plate and access the interior of the shafts. From there, it was a fairly straightforward process, with actual sealing taking just hours per shaft to complete.”

“Frankly, I don’t know of any other way we could have accomplished this goal short of tearing down walls and rebuilding. This was really a project saver.”

Dan Sabatino
General Contractor
Irwin Leighton

Metal ducts, aluminum, fiberglass, flex duct or even stone cold masonry walls – Aeroseal can seal them all. The aerosol mist of sealant seals around the leak and leaves the actual shaft walls virtually sealant free.

The end results: a pre-sealing test showed the exhaust shaft was loosing about 533 cubic feet per minute (CFM). After sealing the ductwork with Aeroseal, leakage was down to 8 CFM – a 98% leak reduction.

“After Aerosealing the ductwork we were able to balance the system and maximize the performance of the building’s exhaust,” said Dan Sabatino, the general contractor with Irwin Leighton. “Frankly, I don’t know of any other way we could have accomplished this goal short of tearing down walls and rebuilding. This was really a project saver. I took a special trip to the work site to see this new technology in action for myself and found it was exactly as the Aeroseal team described it. It worked out well. No glitches. No Issues.”

“We noticed a considerable improvement in the building’s exhaust system,” said Duvalla. “I know there are other projects on campus that would benefit from this new approach to duct sealing.”

About Aeroseal Technology

Before/After Aeroseal
  • Developed at Lawrence Berkeley National Laboratory in 1994.
  • Research for aeroseal technology was partially funded by the U.S. Department of Energy.
  • Aeroseal is the only duct sealant technology that is applied from the inside of the duct system. It is delivered as a non-toxic aerosol mist that seeks out and plugs leaks.
  • Aeroseal has proven to be 95% effective at sealing air duct leaks.

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