Hi, I am installing a full bath in my basement and I am working on picking up a vent line from a 1st floor bathroom sink. I need to run the new vent line approx. 20 feet to where the 1st floor sink is. This also requires 4 direction changes (90 deg bends) to get from the new bath location up to the floor joist in the basement ceiling and then around pipes and other obstructions in the floor joists (through 5 joist spans) before I get to the existing sink vent location. Are there any restrictions on direction changes in vent lines before I tie into the existing 1-1/2"? Thanks.