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B y Den ise Deveau

Sealing the deal Duct sealing options range from the rudimentary to the sophisticated. Here are some of the available options, along with HVAC consultant Dara Bowser’s take on their pros and cons:

PAINT-ON DUCT SEALER This does a really good job, says Bowser. And the contractor can tell that a joint is sealed with a visual inspection.

FOIL TAPE This is approved for use on ducts. While good for some joints, it falls short of the mark for complex hidden joints and take-offs. “You can’t really seal those with that kind of tape,” says Bowser. “All you’re doing is covering up a leak.”

AEROSOL IN-DUCT SEALANTS For existing installations, this technology, which works from the inside to seal leaks, is becoming an increasingly popular choice because it eliminates the need to remove finishes to get at the ductwork.

COMMON GREY CLOTH DUCT TAPE This is not a good choice because it w as never meant for ducts. “It actually disintegrates in less than five years. It’s not good for sealing at all,” Bowser explains.


leakage from within Y

ou would think that a luxury residential complex would have everything signed and sealed. But for the upscale MuseumHouse in Toronto, the sealing part was an issue. Within a few months of completion of the project, it was discovered that duct leakage was a problem. In order to pass a performance audit and meet air handling specifications, the owners of MuseumHouse decided to invest in duct sealing.

“The building was only two years old when the decision was made,” says Kenneth Kwasniak, service operations manager for the John W. Danforth Company, an HVAC contractor and duct sealing specialist. “When the original contractor put the ductwork in they performed preliminary tests and drywalled everything. Because nobody had thoroughly tested the ducts, there was leakage above the drywall once everything was closed up.” continued on page 62


M e c h a n i c a l

B u s i n e s s

1 2 . 1 2

November/December 2012  

Entrepreneur and philanthropist Brett Wilson on finding balance; Pipes—Sizing them right; Pumps—The heart of the system; Ducts—Tackling leak...

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