wet-vented?
Wouln't this be considered a wet-vent? The lavatory drain connects to the vent stack at a point higher than the toilet does, (not shown in picture, but the main floor toilet is 2 feet left of the cast iron stack), and the toilet drain enters the stack approximately 10 inches below the point where the main floor lavatory connects to the stack. how does this configuration present a siphonage problem, and thus, an improper vent situation.
As I see it, with no other fixture draining into the vent stack at a point higher than the lavatory, there is no siphonage issue. And, as I understand it, the siphonage issue is the reason for proper venting.
This is new ground for me, so please excuse my ignorance. However, I understand logic, so knowing why it isn't properly vented helps me understand the reason for the venting codes.
any thoughts?