Horizontal Dry Vent, what is 'horizontal'

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StephK

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Yes, I know this question has been covered, alot. Just wanted to verify my understanding before slapping the glue on, hopefully today.

I have a toilet draining to a 90-bend with an inlet. I've got the inlet facing up and is used as a dry vent for the toilet. I need to get the vent about 12 inches to the wall before it can rise vertically. I know it needs to rise vertically up to 42", and I THINK vertical means anything less than 45 degrees from vertical.

My plan is to use a 60 street coming out of the 90 inlet (ya, took awhile to find that part), but it rises to above the finished floor before reaching the wall. So, I'd like to add a 22.5 degree to get it a little flatter. My calculations tell me this is now 52.5 from vertical and NOT OK. Even though it's only about 4 inches of this angle before going vertical in the wall, may not pass inspection.

Is my assessment correct? Any other ideas?? And no, I can't drain another fixture thru this vent - not easily at least.

I'm in Richmond, VA. We use the IPC Virginia Edition. Thanks in advance!!
 

StephK

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So you're thinking that if it's sloped the minimal 1/4 / foot, they'd leave it alone? Even though it's a dry vent, under the floor, NOT 42' above highest fixture?
 

Cacher_Chick

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It might be useful to see a diagram and/or or photos of what you are dealing with. It would be common for closet bend to be angled towards a wall for the vent to be piped.
Under the IPC the vent take-off can be up to 12 feet from the trap at 1/8" per foot of pitch. Reduce this to 8 feet for the standard 1/4" per foot of slope.
 

StephK

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OK, here are 3 annotated pics. 2 from below and 1 from above.
 

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Stuff

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Any issue with instead of a low heel 90 use a regular 90 then put a 3x3x2 reducing wye below.
 

Cacher_Chick

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1/4" per foot, or any other, 'nominal pitch' would NOT do it. The pipe has to have a clearly defined "slant" to not be "horizontal.
If it wasn't clear, I was referring to the pitch of the trap arm, and how it changes the permitted trap to vent distance.
 

Cacher_Chick

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It is not easy to see the big picture of things there, but it would appear the arm off the closet bent could have run parallel to the joist instead of through it, allowing the vent to come straight up in the adjacent wall. Where the drain must come down into the lower level is not always the most direct path.
 

StephK

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Cacher_chick. I have to go up the wall as shown, the adjoining wall is just brick, the outside of the house. Plus there's a window right there.

HJ - That is my question. What is a 'clearly defined slant'? Right now, I have a 60 degree slant. If I add the 22, my slant would be 38. Is that 'clearly defined' ??
 

StephK

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Any issue with instead of a low heel 90 use a regular 90 then put a 3x3x2 reducing wye below.
this is exactly what I initially had. But, city required us to have the plumbing designed by an engineer, who told me that was not vented properly. I had to cut it all out.
 

Cacher_Chick

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Cacher_chick. I have to go up the wall as shown, the adjoining wall is just brick, the outside of the house. Plus there's a window right there.

HJ - That is my question. What is a 'clearly defined slant'? Right now, I have a 60 degree slant. If I add the 22, my slant would be 38. Is that 'clearly defined' ??

Everything I have ever read and been told says 45 degrees or greater.
 
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