I live in NYC and I have a plumbing vent pipe which vents through the roof. The vent pipe however has some "angled" pipes which bring it out into a small section of a bedroom to avoid going through the header between the ceiling and the attic floor, the house is balloon framing. The vent pipe then runs back up into the attic where it vents through the roof. The stack is 12 inches to the right of a window. I have two questions. 1. Can I cut the pipe 7 or 8 inches above the window and vent the pipe to the back of the house? There are no other openings other than the window. 2. If I can, how do I close off the roof opening, I don't want to take the roof apart, just close off the vent pipe to prevent water or birds from getting in. Thank you to all who respond.
You really don't want the vent pipe opening near a window, because of the possibility of the sewer odor coming back into the house. That's why vents are on the roof in the first place — any breeze quickly carries the odors away.
To answer your specific question, yes, vent pipes can have horizontal runs, as long as there is no possibility of them becoming plugged with water. In other words, any water that gets into the vent pipe opening must be able to run freely all the way to the sewer, without creating a "trap".
I'm not sure why you want to divert the vent, as rain and birds are not much of a concern when it comes to plumbing vents.
Getting rain into the vent is not a problem, as the vent leads to the sewer. The amount of water that will end up down the vent during a rain storm is trivial, and won't hurt anything at all.
I've heard of birds falling down chimneys, but never down plumbing vents. While I suppose it's possible, the chances of it are probably fairly low. If you're that worried about it, I'm sure they make caps or cages that could be installed over the pipe.