Collected Mechanical Ex Vents prior to exit

[Mike Gault]

Home this am had collected the exhaust from two bathrooms in a circular plenum of sorts that is attached to the termination through the ceiling...

Roof Gabled at top, So I'm thinking wind from the same side as the termination could keep air from being vented outside the home and forced down the far vent piping back into the guest bathroom...

Anyone ever seen this??? New Construction...

[David McGuire]

Never saw 2 combined into one, not around here.

[Jerry Peck]

Home this am had collected the exhaust from two bathrooms in a circular plenum of sorts that is attached to the termination through the ceiling...

Roof Gabled at top, So I'm thinking wind from the same side as the termination could keep air from being vented outside the home and forced down the far vent piping back into the guest bathroom...

Anyone ever seen this??? New Construction...

Yep, I've seen it.

Yep, I've called it out for correction for the very reason you gave. I've seen this when I was doing home inspections, but not often then, and just a couple of weeks ago I saw this in a new construction house at code mechanical inspection, which I failed for the above reason along with other reasons. The contractor came back and corrected the interconnected bath fan exhausts and their other problems.

[Matthew Steger]

Interestingly, I saw something similar about 2 months ago. 4 unit apartments that someone had connected all of the bathroom vent fans to into a 4" PVC pipe and terminated above a rear soffit. Had never seen bathrooms share a vent before but it just looked wrong and I could foresee air from one bathroom getting into another bathroom. Called it out for repair into separate vent systems.

[bob smit]

Not to mention condensation collecting in the collector:p