# What sort of tee's or wye's should I use?



## wvphysics (Jan 2, 2010)

I have attached a drawing for what I am about to describe. I am finishing a basment bathroom and currently doing the plumbing in a 5 year old house I only recently moved into. Drains were already installed, however someone in charge was inebriated and had the drains arranged backwards (i.e. the wall to the basement where the door goes had the toilet and shower drains against that wall, leaving the only place for adoor to go to the garage) thus I had run a drain from where I am putting the shower to a drain in the wall shared with the garage, which I assume is for a sink. I also plan to connect this drain to the bathroom sink, and while I am at it, install a slop sink in the garage. The diagram shows the drain in the lower right corner and the vent that goes to the main vent stak in the upper left. Of course to each sink and the shower a trap will be installed. Also, the main soil stack is located less than 2 feet from the main drain. I have numbered each connection and was wondering if there will be anything wrong with what I suggest for each.

All piping is 2".

1. A wye followed by a 45 elbow to straighten it out to go vertically down to 2. 

2. Wye. Again a wye followed by a 45 going up to 1.

3. Vent Elbow. It is purely a vent, so a vent elbow, however for "just in case" I could put a regular 90 elbow.

4. Sanitary tee. It is vertical, so my understanding is a sanitary tee is allowed. There is a stud directly next to this vertical section of pipe so a sanitry tee might be easiest without shifting the veritcal pipe over a smidge. If a wye would be better, would two 45's below it work to safely shift the pip away from the stud?

5. Sanitary tee. Goes directly to the garage sink, so could be the same as 4.

6. Sanitary tee. Final connection, connecting shower, drain and the rest of the system. I believe it drains directly to the main soil stack only a few feet away in the garage.

Let me know if there are any problems with this setup.


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## dave53 (Jul 12, 2010)

There is a limit to how far the trap for the shower can be located from the vent and it's not very far - only 5' if IRRC. I've exceeded that by a couple of feet and had no problem, but an inspector wouldn't buy it. 

I'm new to this forum, but I find it interesting. In some cases, it's the blind leading the blind. FWIW, at least I have a mechanical engineering degree (BSME '81). I'm preparing to be the GC on my 3300 sq. ft. retirement home. Hope to do a lot of the electrical, HVAC and plumbing. I'll have to read up on a lot of code issues. I've designed all sorts of piping systems, including steam, chilled water, liquid nitrogen, liquid CO2, fire sprinklers, etc., but I depend on pipe fitters to get all the details correct. Vent piping seems trivial, but it has to be done right, or the traps will siphon off.


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## JDC (Mar 11, 2008)

1) You can use a sanitary tee here. This is a vent so drainage pattern fittings are not required.

2) That is fine. However, you can also 90 up and stack a tee on top of the 90 to hit your sink. Just another way of doing it.

3) Stick with a regular 90. Just easier to deal with when you have all these fittings laying around and you're looking for that ONE vent 90 you bought.

4) Yes use a tee. Using a combo (wye and 45) there cuts off your vent

5) fine, but where is it's vent

6) See #5 above

It looks like you're wanting to use from 5 to 3 as your vent for both the garage sink and the shower. This would be ok as a common vent if you didnt have the bath sink dumping over the top of it and your trap to vent distances were within limits. I believe that if my trap to vent distances were okay I'd individually vent the shower then common vent the bath and garage sinks.


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## benjamincall (Apr 25, 2008)

JDC said:


> 1)5) fine, but where is it's vent
> 
> 6) See #5 above
> 
> It looks like you're wanting to use from 5 to 3 as your vent for both the garage sink and the shower. This would be ok as a common vent if you didnt have the bath sink dumping over the top of it and your trap to vent distances were within limits. I believe that if my trap to vent distances were okay I'd individually vent the shower then common vent the bath and garage sinks.


I believe this setup would be OK under the UPC, right?:

*UPC 908.1 *Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one (1) and two (2) fixture unit fixtures that also serves as a vent for not to exceed four (4) fixtures. All wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed six (6) feet in developed length


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## benjamincall (Apr 25, 2008)

I agree with JDC about all the fittings. No need for the wyes on the vent. Why not use a sanitary tee (oriented vertically of course) to run the branch vent straight up from your lavatory trap arm?


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## wvphysics (Jan 2, 2010)

The shower trap is under the shower below the concrete floor up to the wall and attaches to the drain under the wall, which makes adding any vent for it difficult. If this setup is code compliant under the code Ben pointed out, then I would be inclined to go this route, it's unlikely that the sinks would be running while someone takes a shower, but if they do wouldn't the shower being so close to the main soil stack allow acceptable flow?


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## dave53 (Jul 12, 2010)

Flow won't be an issue. As you've noted, the fixtures won't all be in use at the same time. You still don't want the shower trap too far from the vent or you'll have a dry trap.

As for the sink in the garage, is the garage heated? If not, you risk freeze damage and a potential flood, depending on where you live. I've had a wall mounted faucet in a garage and not had it freeze, but I'm sure it would not be accepted by an inspector. The sink trap might freeze too, unless the trap is relocated to the warm side of the wall.


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## wvphysics (Jan 2, 2010)

Depends on what you mean by "too far". The shower trap is about 16" from the wall, then about 20" below the highest Tee, so the vent is well within the 5' limit. But if by too far you mean too many fixtures draining into it and siphoning off water then that is another problem.

The garage is not heated, but it didn't heat to freezing in there this winter and I've considered adding heating since the ducts run in the ceiling it's a matter if cutting drywall and adding a vent. I assume the trap you are referring to moving to the heated side is the garage sink trap.


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## wvphysics (Jan 2, 2010)

There is one other way I may be able to run the sink drains. The shower would then be on its own drain and vent. Beside the bathroom is the furnace room, and in it there is a stack. The upstairs kitchen sink, the washer, and the ait conditioning all drain into it. I may be able to run the drains through there, but it goes into the concerete and I am not sure if the toilet uses it to vent. Is it safe to assume that draining into it is fine since the washer, upstairs kitchen sink, and air conditioning all drain into it? I wouldnt want adding the sinks to cause a problem with the toilet. It is directly behind the toilet on the other side of the wall, so I didnt know if it was used for venting the toilet. 
On a related note, it appears that the washing machine is not vented, the kitchen sink has its own vent that goes up to the attic, and the A/C has a vent that vents to the furnace room. Din't know if any of that was relevant or bad.


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## Alan (Apr 12, 2006)

benjamincall said:


> I believe this setup would be OK under the UPC, right?:
> 
> *UPC 908.1 *Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one (1) and two (2) fixture unit fixtures that also serves as a vent for not to exceed four (4) fixtures. All wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed six (6) feet in developed length


Check 908.2 regarding sizing. I think you might need to bump it up to 3" to meet code.:whistling2:


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## wvphysics (Jan 2, 2010)

Alan said:


> Check 908.2 regarding sizing. I think you might need to bump it up to 3" to meet code.:whistling2:


If that's the case it won't fit in the wall. Also, the already existing pipe buried under gravel and concrete is only two inches.


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## dave53 (Jul 12, 2010)

I see no problem with a 2" vent. It can handle up to 6 DFU and that's what I see - three fixtures, each rated at 2 DFU.


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## wvphysics (Jan 2, 2010)

I think I'm going to go the safe route and try to drain the two sinks to the stack in the furnace room. It's a few feet further and an extra elbow but seems the safe route.


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## Alan (Apr 12, 2006)

dave53 said:


> I see no problem with a 2" vent. It can handle up to 6 DFU and that's what I see - three fixtures, each rated at 2 DFU.


The 2" vent is fine, it's the drain that needs to be upsized.

Out of the code he is reading : 

908.2 The vertical piping between any two consecutive inlet levels shall be considered a wet vented section. Each wet vented section shall be a minimum of one pipe size larger than the required minimum waste pipe of the upper fixture, or shall be one pipe size larger than the required minimum pipe size for the sum of the fixture units served by such wet vented section, whichever is larger, but in no case less than two inches.

1-1/2" will not take all three fixtures, therefore the required minimum is 2". Upsize one pipe size by code you need at least 2-1/2" if you can find the pipe and fittings anywhere, but for ease of installation, 3" will be fine.


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## benjamincall (Apr 25, 2008)

Sorry, I just realized West Virginia (if that's what the WV in your handle means) uses the IPC. Under the IPC, you're going to have to match the size of the dry vent to largest portion of the wet vent, i.e., 3". Your inspector might let you get away with 2", but you might also have to convince him that your laundry tub constitutes part of your "bathroom group," since it's in another room. On a different note, why don't you try to dry vent all the way?

http://www.terrylove.com/forums/showthread.php?5367-Wet-vent-vs-soil-stack


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## wvphysics (Jan 2, 2010)

benjamincall said:


> Sorry, I just realized West Virginia (if that's what the WV in your handle means) uses the IPC. Under the IPC, you're going to have to match the size of the dry vent to largest portion of the wet vent, i.e., 3". Your inspector might let you get away with 2", but you might also have to convince him that your laundry tub constitutes part of your "bathroom group," since it's in another room. On a different note, why don't you try to dry vent all the way?
> 
> http://www.terrylove.com/forums/showthread.php?5367-Wet-vent-vs-soil-stack


Yes, I am in WV so it's IPC. I haven't tried dry venting all the way because the shower trap connects to the drain under the wall and concrete behind the shower and Already right over top the horizontal line to te main soil stack. Which reminds me, I could swear I saw something about vent or drain requirement if you are within a distance of the soil stack but can't seem to find it now. 
Right now I have the shower drain attached via sanitary tee and that us all, but I put a 2 foot pipe in the top and put a hose in it to simulate draining with no effective vent and it didn't seem to siphon, also pour water from a bucket and drained fine. If it seems to work I may just have to take my chances. I live outside city limits so no local inspection. If I have siphon problems I can maybe raise the shower later to add a direct vent, but don't want to give up the head room if I don't need to.


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