Exhaust & Fresh Air tied together

[sanzelc (Steven Anzelc - RETIRED, CPI CCI)]

On this home the high efficiency furnace vents were tied together (exhaust and fresh air) right before they exited building.

Is there any circumstance where this is allowed?

Thanks

Steve

[ccurrins (Christopher Currins, CMI)]

https://www.google.com/search?q=concentric+venting&ie=utf-8&oe=utf-8

[sanzelc (Steven Anzelc - RETIRED, CPI CCI)]

Thank you so much Christopher Currins. That is perfect explanation. Your Googling skills beat mine tonight. Thanks again

Steve

[belliott (Bob Elliott, 450.0002662)]

Next time you see a mushroom cap you will know.