Nearing completion of a new 6 - story dormitory complex, the building contractors at Ohio State University were dismayed to find that all 19 ventilation shafts failed pressure tests needed to pass fire code and receive LEED Silver certification. The only solution was to tear down the paint - ready walls, access the shafts and try to seal all the leaks by hand. The project delay was estimated at 6 months. The addition costs were estimated in the hundreds of thousands of dollars. Then, an engineer remembered hearing about a new duct and ventilation shaft sealing technology called Aeroseal. Three weeks later, the problem was solved. Aeroseal sealed the leaks without damaging walls or having to redesign the shafts.