Contractor Meets Tighter Specs, No SweatJonathan at Aeroseal
A growing tech company had recently purchased the seven-story Shattuck office building in downtown Berkeley, California and they were anxious to move in. With a grand opening date scheduled just weeks away, the general contractor in charge of having the renovations completed and approved on time was under pressure to finish the top-to-bottom makeover as quickly as possible. Phase one included a complete overhaul of four floors, including replacing the HVAC system and all of the ductwork.
The contractor had the new duct system laid out and constructed on the ground. Entire sections – about 6,500 square feet per floor – were sealed with mastic and then lifted and installed into place tightly under the ceiling. The TAB team was then called in to test the ducts for compliance.
“For whatever reason, all of the leakage tests failed,” said Mark Avila, president of Bay Area Balancing. “California is now enforcing a 6% leakage rate on commercial buildings, and these ducts weren’t even close. The crew tried to reseal them with more mastic but now that the ducts were installed near the ceiling, getting to all the spots was difficult at best. To make things even more complicated, builders were already framing around the installed ducts, so we couldn’t take them down to do the work. It was chaos.”
So as not to compromise the schedule, the GC brought in several teams of sealers – seven guys in each team – to work on each of the different floors. Each team worked furiously against the deadline to effectively seal the duct leaks. Unfortunately, it was taking the mastic too long to dry, so the sealers switched to using tape.
“The tape helped,” said Avila, “but it looked terrible. Much of the ductwork was exposed and the taping ruined the aesthetics. It also didn’t make enough difference to pass inspection.”
Avila’s TAB team worked right alongside the sealers. After each sealing effort, they would retest, and each time the test would fail and the sealers would try hand sealing some more. All in all, it turned into three weeks of testing, resealing, and failing to meet leakage specifications…until finally, over budget and nearly out of time.
Fortunately, Avila’s TAB company is not only respected for the quality test and balancing work they do, but they are also trained and licensed to provide the Aeroseal duct sealing service. Avila explained to the contractor that there was another easier, faster, and more effective way to ensure the duct system met California’s tight building code requirement for leakage.
“Aeroseal proved to be the right solution, particularly for sealing ductwork where leaks were hard to access.”
Nigel Marcussen, PE CEng
Arup Group Limited
Using the aerosol-based sealing technology, Avila guaranteed the contractor that his team could do the job in a matter of hours rather than weeks. “No one on the crew had heard of aeroseal duct sealing and it’s sometimes difficult to convince people to try something new,” said Avila. “One concern was that the sealant would completely coat the inside of the ductwork. We showed them examples of aerosealed ductwork and photos of past projects to prove the sealant accumulates almost exclusively in and around the leaks themselves. Based upon the information we gave them – and the fact that time was running out – they decided to give aeroseal a try.”
Due to the time pressure and expense resulting from the extensive manual sealing during phase one, the general contractor decided not to even both with traditional sealing during phase two. Instead, the ductwork for the remaining three floors was put in place and then aerosealed.
“The results were immediate,” said Art Vegas of Arves Mechanical, the mechanical contractors on the project. “I particularly liked the fact that we didn’t have to guess whether or not we got the leaks. The computerized sealing process showed us the results as the sealing was in progress. The documentation that the system created when we were done provided the immediate proof we needed for the city inspector. There was no need to guess – no need to retest.”
Phase two of the project was completed in just three days using a small crew of just three aerosealers. All of the ductwork performed below the maximum leakage rates specified by the mechanical contractor.
“Aeroseal proved to be the right solution, particularly for sealing ductwork where leaks were hard to access,” said Nigel Marcussen, Arup Group, the building engineers on the job. “Since it works from the inside to seal, it clearly provided a better alternative to mastic and tape.”
“Specifications pertaining to duct system performance are just getting tighter and tighter,” said Avila. “Whether you are looking at the new California Title 24, ASHRAE 90.1 or any other similar building specification, we found that relying on old manual sealing methods has become a risky, often budget-busting strategy. Energy efficient building is here to stay and innovative technologies such as aerosol duct sealing are helping contractors like me succeed.”
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