bath fan vent

[John Arnold]

This is new construction in Philadelphia. They vented one of the bath fans out through this teeny pvc pipe which obviously, besides being way too small, has no back draft damper and will happily allow rain to run down to the fan!
I guess they figured no one would go up there and look? Sometimes I can't believe the stuff I find.

[Richard Pultar]

was a permit issued from the building dept.
I wonder what the connector looks like , from the fan ro that pipe

[Jerry Peck]

John,

That may be worse than you are thinking: maybe the exhaust fan was run to a vent for something else and the exhaust vent is blowing into the venting system, some coming out at top and some going down to wherever.