I have existing plumbing fixture vent pipes exposed. Can I tie into these to vent a new bathroom exhaust or must I drill through my brick exterior wall?

Hey Budvest...

You CANNOT tie a bathroom fan exhaust vent/pipe into a plumbing vent pipe for any reason. If you connect bathroom exhaust fan into plumbing vent then sewer gasses can/will enter into bathroom via fan and create a health hazard to you and family.

Let me know if I misunderstood your question...

MARK

I think 21boat misread the post. The poster is talking about a plumbing vent stack and exhaust fans can not be connected to them. The sewer gas would back fed when the fan is not running, pretty smelly.

I did miss that "exhaust" part. The word vent /bathroom I took as D.W.V. Thanks guys. Apparently I Need to translate better! I have to remember not everybody is in the trades all of time and it never DAWNED on me a person would think of hooking an exhaust fan in a vent stack! Alls I know is I am perfectly imperfect! Ha ha Thanks for not busting me on that. My advice was good except on the wrong application.
Signed 21 boat