# Vent fittings direction



## drsplumbing (Nov 20, 2009)

sry it's been a while sence I posted but I had a question for you guys. I'm from mass and in our buildings our vents must be connected so that the flow of the fitting must match the direction of the air. I was wondering if international code calls for this as well? Like if you were to put two vents up into the attic and connect the two with the run of the fitting and send a pipe straight up from the branch through the roof? Imo this looks retarded. will it work sure but our inspectors can fail you for it. Can inspectors in states that just use inernational building code do the same?
Thanks


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## Redwood (Sep 8, 2008)

IPC 

905.2 Grade. All vent and branch vent pipes shall be so graded and connected as to drain back to the drainage pipe by gravity.
905.3 Vent connection to drainage system. Every dry vent connecting to a horizontal drain shall connect above the center- line of the horizontal drain pipe.


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## plumbdrum (Nov 30, 2013)

Use a twin ell (double 90)You are correct, you could also use a tee (not TY) I nail guys on this all the time, I'll usually let it go the first time ( nobody's gonna die senario) but that's it.


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## Tommy plumber (Feb 19, 2010)

I was taught to pitch to the roof.


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## Plumbus (Aug 4, 2008)

Air up, waste down.


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## paultheplumber1 (May 1, 2014)

plumbdrum said:


> Use a twin ell (double 90)You are correct, you could also use a tee (not TY) I nail guys on this all the time, I'll usually let it go the first time ( nobody's gonna die senario) but that's it.


What's with the no twye on its back? That's a fairly new code update for mass isn't it? I'm struggling through the new gas updates right now


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## plumbdrum (Nov 30, 2013)

paultheplumber1 said:


> What's with the no twye on its back? That's a fairly new code update for mass isn't it? I'm struggling through the new gas updates right now





Not really, look at your diagrams in the back of the code book. The section on fittings used for change of direction shows a wye and 1/8", it's considered to be a drain until it's 6" above flood level, so still considered a drain. If your tight for room for a shower or tub with an individual vent and the trap, I would never fail on thst


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## plumbdrum (Nov 30, 2013)

I'm liking the gas modifications and code.


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## pianoplumber (Apr 19, 2014)

Vent piping should be installed in a way so that moisture can drain out of all parts of the system. We don't want to create water traps. Keep in mind that DWV fittings have pitch built into them. Example: a "90" is more like 88 or 89 degrees. same goes for sanitary tees. When you keep this in mind, and pitch your vent piping as if it were an "upside down" drainage system, your pipes and fittings go together so much easier.


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