University of Miami Finds Aeroseal Ideal For Getting Laboratory Exhaust Hoods Up To Code

The 50-year-old Cox Science Building on the University of Miami campus is typically a hotbed of activity. During a typical school semester, hundreds of students and faculty members utilize the facility to attend lectures, take classes and conduct experiments within one of the building’s many laboratories. A recent evaluation by the university’s environmental health and safety (EHS) group determined that many of the dozens of exhaust hoods located throughout the four-floor building were simply not providing enough exhaust to sufficiently and safely remove potentially harmful airborne contaminants used during experimentation. A closer look at the problem found that, in most cases, the poor exhaust was due to leaks in the ductwork connecting the hoods to large exhaust fans located on the building’s rooftop.

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“The problem was pretty clear,” said Gary Tarbe, the senior project manager for the university’s facilities, design and construction department. “We smoke tested several of the units and could see that leaks were running throughout the ducts. Old dried tape was clearly visible on the exposed ductwork, and the risers hidden behind the walls were undoubtedly leaking as well.”

Testing of each exhaust hood underscored the problem.

“We needed to achieve a face velocity of 99 feet per minute for each hood,” said Tarbe. We weren’t even close.”

At the end of the evaluation, some of the hoods were identified for replacement. About 20 exhaust hood systems, located in laboratories throughout the building, were marked for repair. Mike Lorion and his crew at Airmax were called in to evaluate the problem and make recommendations for a fix.

“The 20 or so exhaust hoods in question were connected to nine separate risers that lead to nine different rooftop exhaust fans,” said Lorion. “Most of the leaks were located in areas that were simply impossible to get to without major demolition. The rest of the ductwork was intertwined with other ducts, electrical conduits and piping, making access almost impossible. It was clear to us that there was only one viable solution – sealing the leaks from the inside with aeroseal.”

Lorion explained to others on the project exactly how aeroseal worked. The university engineers had heard about the technology, and after conferring with colleagues, they agreed it was really the only sensible option for repairing the leaks. With a “thumbs up” given by the engineers and University administrators, the Airmax crew arrived with their equipment and began the process of sealing the leaks in the nine risers and connecting ductwork.

“We would typically access each ventilation shaft by removing the rooftop fan and attaching the aeroseal delivery tube to the exposed duct,” said Lorion. “In this case, many of the fans were simply too old to remove without causing further damage, so we found it best to use the rooftop access when convenient and connect the aeroseal equipment to the rest of the shafts via temporary access points created in the ductwork located in the mechanical room.”

Airmax identified each of the nine risers branching out to the 20 or so exhaust hoods and began the sealing process on each.

“I’m fascinated by the type of innovative technology that aeroseal represents,” said Tarbe, “so I was sure to observe the entire process. It was great to watch the computer monitor as aeroseal was injected into the ductwork and the graph showing the amount of leakage quickly decline.”

During the sealing, several major gaps in the ductwork were discovered and repaired by hand. The entire sealing process took about two weeks to complete. In the end, the reports generated by the aeroseal system said it all.

“Before aeroseal, the nine risers together exhibited a leakage rate of well of 1,000 CFM,” Said Lorion. “After the sealing process was completed, that leakage rate dropped to around 215 CFM – more than an 80% reduction.

“We had our TAB guy come in and certify each of the exhaust hoods,” said Tarbe. “Each now passed with flying colors. Everyone was really pleased with the results, and quite honestly, if it weren’t for aeroseal, I can’t imagine how we would have solved this issue.”