For a 1 ½-inc pipe the vent should be 42 inches away at the most while a 2-inch pipe must have a maximum distance of 5 feet. For pipes that have a diameter of 3 inches the distance is 6 feet and for a 4-inch pipe the most it should be away from the vent is 10 feet.
How far can shower drain be from vent stack?
The connection between the fixture drain and the horizontal drain and vent pipe is the only vertical pipe of a combination drain and vent system. 8 feet is the maximum vertical distance.
How far should a vent stack be above the roof?
Unless a roof is to be used for any purpose other than weather protection, extensions of vent pipes through a roof should be terminated at least 12 inches above the roof. The vent should be extended at least seven feet above the roof if it is to be used for something other than weather protection.