i got 2 problems,
1. how much should be the minimum diameter of a circuit vent totaling 55 feet developed length and serving a horizontal drain branch, handling 120 dfu's?
2.a vent stack handling 25 dfu's with a developed lenght of 35 feet, how much should be the minimum of diameter?
1. If you do not already know the answers to these two questions, you may be doing a job you are not qualified for.
2. Your blueprint, which you used to get your permit, should have these sizes specified on its plumbing diagram.