Greetings,In reference to maintaining the integrity of an air barrier, best practice requires all penetrations be properly air sealed. Specifically, when HVAC ducts penetrate the air barrier between…Continue
"As I have read through everyone's excelent responses, it has caused me to reassess my assumptions. Tim O'Brien made a observation that is rightly relevant when he provided,
"I believe most A/C system evaporators running at part load…"
At least in the mid-Atlantic, there is no place in single family detached housing three stories and under that needs to be fire stopped. There are plenty of areas needing fire BLOCKING, but not fire STOPPING, and single part foam is fine…"
"I think this is one of those areas where compromise is used to have a type of "solution" and move on to bigger issues.
But back to you specific comments -
By code, flex duct alone CANNOT pass thru a fire rated barrier. If it does, that is…"
When we find one of these (more and more rare these days) we use single part foam around the perimeter and are very generous with the amount. The hope is that it will compress the insulation enough to reduce any air leakage through that area.…"
"If flex duct/duct board/foam board duct goes though a fire wall for air flow must change to steel and then fire damper at fire wall. I have been though this a lot with powers that be known as code pros. Now I do my…"
Greetings,In reference to maintaining the integrity of an air barrier, best practice requires all penetrations be properly air sealed. Specifically, when HVAC ducts penetrate the air barrier between conditioned and conditioned space, both code and Energy Star require the annular space between the hole and the duct be air sealed. Since flex duct seems to be the among the HVAC community favorite material, most of these penetrations is made with flex duct. And in all cases, I see the air sealing…See More
The Healthy Indoors group is focused on indoor air quality (IAQ), mold, moisture control, radon, lead, air duct cleaning & HVAC hygiene, and building performance/ building science-related topics that affect the healthiness of our indoor environments, like air leakage.See More
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