During the floor-to-ceiling renovation of the Gallego Intermediate School, contractors removed the existing ceiling tiles to find ductwork that was in such bad shape, replacing the entire duct system seemed to be the only option. The building’s HVAC included 34 individual units, each with its own supply and return ducts, all made of duct board that was literally falling apart at the seams. Some of the ducts were in such disrepair that they made leakage testing impossible.
Unfortunately, the Tucson, Arizona-area school district couldn’t afford either the additional expense or time necessary to replace the existing duct system. Beyond the estimated $200,000 dollars it would have cost for the work, the school was set to open in three months and replacing the ductwork would have taken twice that time.
Consulting Contractor: Kelly Wright & Associates
Aeroseal: GreenSeal / Div. of Excel Mechanical
Before / After Aeroseal: 49k CFM of leakage vs 8k CFM
Results: Two weeks to attain 5% leakage rate at ¼ cost of replacement.
Faced with this project-halting dilemma, a consulting engineer on the project suggested they look at aeroseal, a new duct sealing technology he had seen demoed at a recent industry seminar. The aeroseal experts at GreenSeal were called in to share information about the new technology and in just a matter of days, they began the work.
Given the poor condition of much of the existing ductwork, the GreenSeal crew began re-connecting and repairing the most dilapidated portions using tape and mastic. Even after this work, testing showed a total system leakage rate of about 49,000 CFM. Then the aerosealing began.
It took GreenSeal less than two weeks to aeroseal all 34 duct systems – both supply and return. The final results showed total leakage down to 8,000 CFM – an 85% reduction and well below the 5% leaka ge rate they were targeting. The total cost for aerosealing was a fraction of the estimate for duct replacement and best of all, the school opened on time.