Is this wet vent of a toilet OK? Theoretical.

[Stuff]

From IRC saying not allowed: Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent.

 

[wwhitney]

From IPC saying not allowed: Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent.

Can you give a reference, year number and section number? Because I can't find that text in any version of the IPC from 2006 to 2021.

Cheers, Wayne

 

[Sponsor]

 

[Reach4]

From IPC saying not allowed: Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent.

Do you have a link for that in IPC?

I find that in a circuit venting section,
SECTION P3110 CIRCUIT VENTING
for IRC, but not IPC. IPC does not use P prefix for code sections.

 

[Stuff]

Can you give a reference, year number and section number? Because I can't find that text in any version of the IPC from 2006 to 2021.

Cheers, Wayne

912.1 of 2015 IPC: https://up.codes/viewer/alabama/ipc-2015/chapter/9/vents#912

 

[wwhitney]

912.1 of 2015 IPC: https://up.codes/viewer/alabama/ipc-2015/chapter/9/vents#912

OK, but that link and that section don't have the words you quoted.

Cheers, Wayne

 

[Reach4]

912.1 of 2015 IPC: https://up.codes/viewer/alabama/ipc-2015/chapter/9/vents#912

I find 912.2.1 Horizontal Wet Vent

The dry-vent connection for a horizontal wet-vent system shall be an individual vent or a common vent for any bathroom group fixture, except an emergency floor drain. Where the dry-vent connects to a water closet fixture drain, the drain shall connect horizontally to the horizontal wet-vent system. Not more than one wet-vented fixture drain shall discharge upstream of the dry-vented fixture drain connection.​

I think that says that if the vent for the wet venting connects to the toilet drain line, then the toilet line has to be horizontal. I think that would not apply to what we are discussing -- except that if the toilet fixture drain had to be horizontal, then this section would be pointless, right?

 

[Jeff H Young]

Go to International code counsel website and type in the search bar " Bob scott plumbing venting: decoding chapter 9 of the IPC". His book shows a picture of that very thing that is not allowed. You have to own the book to see it. The picture was to large to upload. Try to find a diagram online of a wet vent that shows a toilet entering vertically. It would be similar to a drain entering a wet vent vertically. I am not bothered either way if anyone disagrees with this I am just trying to be helpful.[/QUOTE
Thanks James very much appreciate trying to be helpful. wont purchase the book because its the wrong code for me. Im unable to see his view explaining the code but havent seen anything prohibiting it. trying to understand it. Im a little stubborn Ive been burned so many times beliving blindly others that were wrong. I must see it in the code. no matter how much of an Einstien it is if it aint in the book it aint true. . What matters most to me is UPC. any way thanks to all as well

 

[Stuff]

OK, but that link and that section don't have the words you quoted.

Cheers, Wayne

You are correct. I got lost jumping between versions. IRC only.

 

[wwhitney]

Hmm, so it is in 2018 IRC P3108.1. I wonder why the IRC and the IPC diverge like that, and if it is really intentional.

Cheers, Wayne

 

[Jeff H Young]

Hate to beat a dead horse but racked my brain on this the IRC and IPC looked Identical to me and wording confusing but not conclusive and clear but might mean w/c must come in flat.
But in my code UPC does anyone take issue or think that its not permited to come in verticaly?

 

[wwhitney]

Compare 2018 IPC 912.1 https://codes.iccsafe.org/content/IPC2018P3/chapter-9-vents#IPC2018P3_Ch09_Sec912 to 2018 IRC P3108.1 https://codes.iccsafe.org/content/IRC2018P3/chapter-31-vents#IRC2018P3_Pt07_Ch31_SecP3108

They are almost identical, the main difference is that the IRC has inserted the sentence "Each fixture drain shall connect horizontally to the horizontal branch being wet vented or shall have a dry vent." before the common sentence about each fixture drain connecting independently to the horizontal wet vent.

As to the UPC, by my reading of (2015) 908.2 the configuration in the OP is allowed. 908.2.3 even says of the connection of a trap arm to the horizontal wet vent "The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap." That basically requires the connection to come in on the horizontal (as expected for non-siphoning traps) but it specifically excludes water closets.

Cheers, Wayne

 

[Reach4]

Hmm, so it is in 2018 IRC P3108.1. I wonder why the IRC and the IPC diverge like that, and if it is really intentional.

Another divergence is that P3108.1 allows wet venting two bathroom groups with horizontal wet venting. Whoops again.

 

[wwhitney]

Another divergence is that P3108.1 allows wet venting two bathroom groups with horizontal wet venting.

So does the IPC. It's the UPC that restricts it to one bathroom group.

Cheers, Wayne

 

[Jeff H Young]

Yea IRC 2018 seems to require all things including w/c to come in on side.
The IPC wording does seem a bit uncertain . Good to go on UPC though.

 

[James Henry]

The trap weir on a shower and bathtub will always be below the wet vent opening and the trap weir on a toilet will always be above the floor even if the drain connects horizontally to the wet vent........ Back to the drawing board.

 

[Jeff H Young]

The trap weir on a shower and bathtub will always be below the wet vent opening and the trap weir on a toilet will always be above the floor even if the drain connects horizontally to the wet vent........ Back to the drawing board.

Yes thats all true . nothing to do with all drains coming in horizontal on a wet vent I dont think? but its a possible arguement for allowing the toilet to dump verticaly into the horizontal drain.

 

[James Henry]

Yes thats all true . nothing to do with all drains coming in horizontal on a wet vent I dont think? but its a possible arguement for allowing the toilet to dump verticaly into the horizontal drain.

Yes. After I reread my statement I realized I must be confused or tired or both. I'm reminded of the saying, " baffle them with bull####".

 

[Jeff H Young]

Ha Ha Thanks James, One thing about code is ... Sometimes just because somethng would make sence dosent make it so. the other thing I thought of is bringing the drains in horizontal wouldnt be to help the W/C in any way but possibly some how to protect the other traps from siphonage.
Another thought Ive had is some of that wording in the codes I might not be understanding the intended meanings

 

[Cool Blue Harley]

Reach4.

Your diagram as illustrated would not pass inspection in California which follows the UPC.
The WC is not vented in an approved manner.

Section 905.2 allows venting to be installed in a horizontal position. However, the invert of the vent connection must be above the centerline of the drainage piping to which it is connected. The objective of this code is to keep the vent opening above the flow of effluent. The way you have drawn it is not code compliant. (UPC)

Your vent takeoff must be downstream from a 1/4 bend, or a herco bend, which serves the toilet. Within six feet by measuring from the closet flange, a wye and 1/8th bend on its back will vent the WC. It must be installed as described above.

Wet venting as detailed in section 908.0 regarding fixture trap arm connections can then be discussed. (UPC)

Thanks for the provocative post.

 

[wwhitney]

Section 905.2 allows venting to be installed in a horizontal position. However, the invert of the vent connection must be above the centerline of the drainage piping to which it is connected. The objective of this code is to keep the vent opening above the flow of effluent. The way you have drawn it is not code compliant. (UPC)

While not explicit, horizontally wet vented fixtures under UPC 908.2 are clearly exempt from 905.2. With a horizontally wet vented fixture, the invert of the vent connection is the invert of the drainage piping, so it would be impossible to comply to 905.2 and have wet venting. 908.2.1 tells you that the dry vent connection to a horizontal wet vent has to comply to 905.2; the implication is that the wet vent connections do not.

I have found nothing in the UPC that prohibits the configuration in the OP. Nor do I see a performance reason to prohibit it.

Cheers, Wayne