LA Unified School District’s Pilot Aeroseal Project Receives Top GradeVicki
This story was published on Facility Executive in October 2016.
With more than 900 schools and 14,000 building structures spread out over 800 different sites in and around the greater Los Angeles area, LA Unified is the second largest school district in the nation. Given its size, district administrators learned long ago that having a sensible energy savings strategy was critical to keeping utility costs down. So it was up to Adrian Tylim, the district’s sustainability manager, to be on the lookout for emerging technologies that could potentially reduce overall energy costs.
- Building: 93rd St. Elementary School – LA Unified
- Location: Los Angeles, California
- General Contractor: Internal – LA Unified
- Aeroseal Contractors: Penn Air Group
- Goal: Duct code compliance / energy savings
- Before Aeroseal: 2,766 CFM of leakage (total/3 ducts)
- After Aeroseal: 207 CFM of leakage
- Results: Reduced leakage by approximately 92%
“We first learned about aerosol duct sealing at a trade show at which time we invited Aeroseal to give a presentation to our design group,” said Tylim. “The concept was straightforward enough and the potential for substantial energy savings was clear. We were excited about conducting a pilot test of the technology once we got it approved by our office of education health and safety.”
Aeroseal worked with the school district to get the necessary approvals. MSDS documents were sent to the OEHS and reviewed by district engineers. Aeroseal also provided a number of case studies and references related to similar projects where the technology was used to great success.
“We met with more than a dozen engineers working throughout the school district,” said Aeroseal’s John Reese. “We were able to share examples where aerosealing the ductwork not only reduced energy use, but also proved to be safe in the most sensitive environments – from elementary school buildings to laboratories and hospitals.”
Soon after aeroseal duct sealing was officially added to the district’s list of approved technologies, school administrators identified and approved a pilot project that would allow district engineers to observe first hand, the duct sealing process and measure results. A bid went out for the work and Penn Air Group, a commercial HVAC services company specializing in aeroseal duct sealing won the contract.
“This initial project involved the sealing of three sections of ductwork serving the 93rd Street Elementary School, one of the district’s showcase facilities,” said Penn Air’s project manger, Victor Gonzales. “The building was undergoing HVAC renovation and they wanted to see if they could save the existing ducts. Initial TAB results showed that leakage rates for the three duct systems to be around 2,874 CFM – well above regulatory levels, so our objectives were two-fold; compliance and energy savings.”
Gonzales and his small team of expert sealers had quite a crowd of observers on hand for the first day of the sealing project. M&O personnel, inspectors and district engineers were all there asking questions, watching the process and judging the outcome. They witnessed the aeroseal crew insert foam blocks in the registers of the targeted duct system. The aeroseal equipment was connected to the ductwork using a long flexible tube that was attached via a temporary entranceway cut into the system’s plenum. Now, when the sealing equipment fan was turned on and the sealant was blown into the interior of the ductwork via the flexible tubing, the only escape route for the sealant was through the leaks. Here the microscopic particles of sealant would cling to the edges of the leaks and then to each other until the holes were completely sealed tight.
The district observers watched the computer monitor as the sealing process took effect. A moving graph showed, in real time, the leakage rate of the supply duct quickly plummet from 1,340 CFM down to 73.2 CFM. Aerosealing the return duct showed similar results. It took less than an hour for Penn Air to seal the two sections targeted for the first day of the project.
“With manual sealing, you don’t know if it’s effective until you are finished and the duct system is retested,” said Doug Orndoff, one of the school district’s observing engineers. “This process showed results in real time. They were also able to access the entire duct system without having to tear into the walls or otherwise disrupt the existing building structure. The entire process was fast and effective.”
Similar results were observed on the second and final day of the project when the aeroseal team sealed the return duct servicing some of the classrooms. When all was completed, results showed an overall drop in leakage down to a total of 207 CFM – a 92% reduction.
“The systems are now under compliance – that I can tell you for a fact,” said Tylim, “and while I haven’t yet calculated the exact amount of energy savings we gained with aerosealing, I’m confident it is substantial. Now multiply that amount times all the other buildings we have that could benefit from duct sealing, and you’re looking at quite a considerable amount of savings.”
Given the overwhelming success of this initial pilot project, the school district is looking at other properties that may benefit from similar work.
“We have quite a bit of HVAC projects on the horizon and this approach to duct sealing really changes the scope of the work,” said Orndoff. Imagine the addition savings we can realize simply from not having to tear out and replace the old ductwork.”