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In a recent article featured in ACHR News, Mike Kelly, TBE, American Testing, shed light on duct leakage, craftsmanship, and the invisible cost of air.
There’s a moment in every building’s life when the air stops flowing like it should. The people inside might not notice right away, but the numbers on the energy bill start creeping up, and someone, somewhere, starts to wonder: Where’s all that air going?
For Mike Kelly, a veteran of the testing and balancing world, the answer is rarely mysterious: just overlooked. “Success is neither magical nor mysterious,” he told an audience of engineers and contractors during a recent Associated Air Balance Council (AABC) webinar. “Success is the natural consequence of consistently applying basic fundamentals. We don’t need to run into the forest. You’ve got to look at the trees sometimes and say, all right, what are we doing here? What’s the basics?”
Kelly’s stories have the ring of repeated experience, and the gentle impatience of someone who’s seen every avoidable mistake—twice. Sometimes, it isn’t a leaky seam or a faulty sealant at fault. Sometimes, it’s a sheet metal worker, early in the morning, bolting together a duct run, who forgets to peel the blue plastic off a protective wrap.
“We’re only getting airflow down half the system. Why don’t we have airflow here?” Kelly recalled. “And you have to cut a hole in the duct and find out, ‘Oh, we didn’t cut the plastic out, whoops,’ or the metal plate, or whatever it may be. It’s a little harder to leave a metal plate in, but I’m sure that’s probably a war story that’s out there.”
He prefers metal plates, always sealed with a gasket. “The protective duct wrap is a possibility. I’m sure I’ve seen it here recently, but I prefer metal.”
The core debate in specifying duct leakage, Kelly says, is: how tight do you make the system? The Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) sets standards based on duct surface area and pressure class. The AABC, which Kelly champions, pushes for percent-of-airflow considerations in design.
“In my building or my facility, I would just say we were going to be better. We’re going to make it better than that requirement. We’re going to be 1%,” he said, noting he is an advocate for specifying that a duct system can lose no more than 1% of its total designed airflow to leakage—an especially strict benchmark compared to industry standards. For context, some cleanroom or specialized manufacturing environments may require duct leakage rates well below 1%, sometimes as low as 0.1% of total airflow, but these are rare outside critical facilities.
“If you wanted to go the extra length and say we’re going to be a half a percent, do your job. Get it done right,” he said.”
Why not just stick to SMACNA’s tried-and-true standard? “There’s nothing wrong with that. It works. It’s worked for decades,” Kelly admitted. But, “why can’t we be better? You know, we’re always looking for things to be better, more efficient. Why can’t we be better?”
The Energy Management Association (EMA), Associated Air Balance Council (AABC) and AABC Commissioning Group (ACG) will exhibit together at the 2027 AHR Expo, taking place January 25–27 at McCormick Place in Chicago.
Recognized as one of the HVACR industry’s leading events, the AHR Expo will bring together more than 1,900 manufacturers and suppliers showcasing the latest solutions in heating, cooling, refrigeration, ventilation, plumbing, indoor air quality, building automation, sustainability, software, and instrumentation.
Attendees can also take advantage of a wide-ranging education program featuring industry seminars, expert panel discussions, new product presentations, live podcasts, and opportunities to earn professional development hours. Topics will include commissioning, testing and balancing, energy efficiency, building management, standards and codes, workforce development, smart controls, decarbonization, and other key issues shaping the industry.
Visit booth #S68110 to meet representatives from EMA, AABC and ACG and learn more about industry-leading certifications, technical education, professional resources, events, and membership opportunities for energy management, testing and balancing, and building commissioning professionals.
We look forward to connecting with members, partners and industry colleagues in Chicago!