It was not intended for that purpose but more for center islands or peninsular sinks and such. It is accepted by building inspectors and I do not think it shows anywhere that you cannot do it.

However I have found it before and wrote it up. I do things like that because I think what they did was foolish. Is not the roof right over that pipe. Someone else posted similar to this.

Again the intent was when fixtures were added somewhere that a vent was further away than allowed by code and a wall was also out of rach to add a vent.

__________________
Ted Menelly
"Castle"
Home Inspection Services