How far away can the vent be?


Old 12-23-02, 01:46 AM
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How far away can the vent be?

I am creating a new half bathroom (Toilet and sink). out of an old 7' by 8' room. I plan to use 3" PVC for the drain. The location of this new half bathroom is 35 feet away from 4" Cast Iron [The Cast Iron drains into city sewer]. The Vent Stack is more than 35 feet away by the time it exits the building. My question is can I tie into the this vent by running 2" PVC over the 35 feet run. I can route the pipe horizontal above a suspended ceiling with no problem. Do I need to exit the building closer or does it matter?
Old 12-23-02, 09:26 AM
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You need to clear this with your local Building Inspection Department first to comply with local plumbing code.
I'm not a pro plumber, but I "think" that you can do what you're planning to do, although if it were me, I would vent through the roof above that half-bath.
Here is an illustrated article on plumbing half-baths from Reader's Digest "The Family Handyman" magazine that may help you:
Good Luck!
Old 12-23-02, 12:19 PM
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Assuming local code allows for it, would the Studor Vent that we were talking about here not work for this application?
Old 12-23-02, 05:26 PM
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Air admittance valve - studor vent - would work as long as it is fully accessable in it's location.
First you need to talk to local building inspector and find out what code you fall under.
Ask about total developed drain length and then what percentage can be vent.
Ask about air addmittance valves, official may not know Studor vent by name, also called pro vents.

Good luck and happy holidays....
Old 12-23-02, 06:30 PM
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Well, the distance you run that vent is not a problem... You can run that vent up 10 stories if you like... where it exits the building is not an issue... If you make sure that you pull the vent off within a few feet of the toilet, and then run it up to the suspended ceiling and run it horizontally (maintaining the grade of course), you can run it as far as you need to, but it has to get above the fixtures upstairs before it could tie on to the other vent stack, OR it has to go through the roof... In other words, you can't tie the horizontal vent into the other existing vent stack BETWEEN the downstairs and upstairs, it would need to get to the attic first...

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