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-   -   1.5" vent for toilet with 3" drain? (http://www.diychatroom.com/f7/1-5-vent-toilet-3-drain-161766/)

fulmar2 10-31-2012 06:09 PM

1.5" vent for toilet with 3" drain?
 
I've been reading on diychatroom for great advice for a number of years: but now I have my first question.

I installed some plumbing, starting without a permit, and it is now encased in concrete. I now have a permit, and would like to get the under slab plumbing checked off. As long as it meets 2010 UPC, the inspector says he can pass it. Everything looks okay, except there is some hesitation about my use of a 1.5" vent on a 3" toilet drain. In table 7-5, it says that 1.5" vent piping maximum loading is 8DFUs. A 1.6GPF toilet is 3DFUs, and I bought a 1.28GPF toilet (so maybe fewer DFUs?) There is a footnote (#3) next to the 8DFUs that says "except for 6 unit traps or water closets." It does not explicitly say 2" vents are required for water closets, but maybe that is what this footnote means. 8DFUs would allow 2 water closets on a 1.5" vent, so the footnote could also be interpreted to mean fewer DFUs. It does not explicitly say that you need to go to 2" for one water closet...

So, my job is to convince the inspector that the installation meets 2010 UPC, and maybe there is another way to do this. He mentioned "horizontal wet venting" in an attempt to help me out. I suggested saying that the vent for the wet bar (which is 2") be used for the toilet vent (it's less than 6 feet away), but he pointed out that you're restricted to the "bathroom group" when doing this. From my pictures, can anyone see a way to propose that my installation meet 2010 UPC? If not, I'll need to tear up the framing, concrete, and put in no-hubs to fix that one fitting. Three images from different angles to illustrate the situation:

http://gotoes.org/Plumbing/1.png
http://gotoes.org/Plumbing/2.png
http://gotoes.org/Plumbing/3.png

Thanks in advance for any help!

GBrackins 10-31-2012 06:19 PM

I'm not a plumber so I can't help you out on this, but you do know that a water closet and toilet are the same thing right?

fulmar2 10-31-2012 06:25 PM

Thanks Gary - yes, I do know that it's the same; I have changed the wording of my question to reflect that.

Beepster 10-31-2012 06:45 PM

I do not believe you can drop more than an inch for any items being vented.

When in doubt, give a call to your local building inspector.

B

TheEplumber 10-31-2012 06:57 PM

You need a 2" vent as the foot note says and it needs to be within 6' of the flange. This is the way UPC has read since at least the mid 80's

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fulmar2 10-31-2012 07:06 PM

Quote:

Originally Posted by TheEplumber (Post 1042010)
You need a 2" vent as the foot note says and it needs to be within 6' of the flange. This is the way UPC has read since at least the mid 80's

Thanks, Eplumber. I wasn't sure that the footnote actually said that you needed a 2" vent. But if that is truly the case, is there any way that I can state that the 2" vent for the wet bar is my toilet vent? How about horizontal wet venting? The drain for the tub shower is 2", and the inspector suggested looking into horizontal wet venting rules. I didn't completely understand them, which is why I posted here: in the hope that someone could help me find a solution that does not require tearing up the concrete again.

TheEplumber 10-31-2012 07:19 PM

Unfortunately I'm viewing this on my phone so the images are not clear enough. Give me a few hours till I get to a computer or I kill some zombies- which comes first :)

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ben's plumbing 10-31-2012 08:57 PM

no disrespect but ...you can tell the inspector anything you want.....to get it to past.....but if its not plumbed right ..you will have problems down the road.. you should have 2" min vent size on water closet....wet venting some areas permit it ..some don't .....I personally don't like wet venting......your concrete is open all you have to do is cut in a new fitting with 2" instead if 1 1/2...now the time to make it right...ben sr

fulmar2 10-31-2012 09:20 PM

Hi ben's plumbing - no disrespect taken; thank you for taking the time to reply. I should have made it more clear that the concrete has already been poured. If it were open, I would have just changed the fitting - that would be pretty simple!

I have read in a number of places that this vent will work, and I too believe that it will. For example, in the IPC, no vent is required at all for water closets (see figure 906.1).

My challenge is this: Even if my system will work perfectly, I still need to conform to the 2010 UPC. I know from other trades that there is more than one way to skin a cat - and it is my hope that someone will look at my pictures, and make an observation that allows my installation to conform to the code. I hope that makes sense. Thanks!

ben's plumbing 10-31-2012 10:11 PM

off the record..it will work....on the record it won't pass code..my bad thougth concrete was open......I really think you need to take the inspector to dinner get him drunk have him sign off and give you the inspection sticker:laughing::laughing:....just kidding....maybe ask him what he thinks is needed to get you through this.. ..does he seem reasonable....

DannyT 10-31-2012 10:46 PM

in western ny the vent had to be 1/2 the diameter of the drain it served minimum. if you ran 4 inch for the toilet it had to be 2 inch, for 3 inch 1-1/2 was minimum. in the OP case he has vents all over the place. i would be interested in seeing a drawing of how the underground piping is actually run, couldn't really tell where everything tied in looking at the picture.

TheEplumber 10-31-2012 11:35 PM

Your worst case scenario is to chip out the concrete and replace the 3x1.5 combo and 3" 90.
I work off an older UPC and horizontal wet venting is not allowed so I can't address the latest UPC horz. vent regs. But what you have now would not pass my inspectors. Will it work? Yes. Is it per UPC? No. Will your inspector let it slid? Maybe- if he is a plumber and not just a book smart inspector.
BTW I gotta ask- did you wrap the pipes with 3M tape? Looks like it. I'm curious as to why

fulmar2 11-01-2012 09:43 AM

Quote:

Originally Posted by DannyT (Post 1042190)
in western ny the vent had to be 1/2 the diameter of the drain it served minimum. if you ran 4 inch for the toilet it had to be 2 inch, for 3 inch 1-1/2 was minimum.

DannyT - Thank you for your reply. This is my interpretation of the UPC as well. No where does the UPC explicitly say that you need a 2" vent. Unfortunately, all that matters is my inspector's interpretation of the code - so I need a workaround. I am wondering if the 2" vertical pipe for the wet bar could be considered the vent for the toilet. It is less than 6' away, and if I understand the code correctly, toilets HAVE to use horizontal wet venting to at least some degree due to the fact that the trap is in the toilet. I need a way to explain this "alternative" way of looking at it to my inspector. Another alternative would be to use the 2" pipe for the laundry. This one is downstream from the toilet.

@TheEPlumber - I did wrap the pipes in tape, as I thought it was necessary for pipes underground. It was some thick black tape with the UPC shield on it...

TheEplumber 11-01-2012 10:47 AM

Quote:

Originally Posted by fulmar2 (Post 1042373)
DannyT - Thank you for your reply. This is my interpretation of the UPC as well. No where does the UPC explicitly say that you need a 2" vent. Unfortunately, all that matters is my inspector's interpretation of the code - so I need a workaround.

Table7-5, footnote 3 states "Except six unit traps or water closets"
I have worked the UPC for more then 20 yrs. Always had to have a 2" vent for a toilet. You can count a WC as 3 FU when calculating total load on the common vent stack but it still needs to be minimum 2".

Alan 11-01-2012 09:55 PM

Quote:

Originally Posted by TheEplumber (Post 1042010)
You need a 2" vent as the foot note says and it needs to be within 6' of the flange. This is the way UPC has read since at least the mid 80's

I just looked all over, and I can't find it. I know it says it (or at least used to) but my 2008 Oregon Plumbing Specialty Code, does not say that on either of the tables that I can see.

Plz tell me where you see it?

TYIA.


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