Question: Usage of Sani instead of Wye on old-build main stack

[thenextdon13]

Hello-

If i have read everything correctly, including posts on this forum and 'helpful hints' by Bert Polk (noted by Terry Here), the Sani-T is only to be used when going from trap-arm to vertical drain pipe.

Where a horizontal branch joins a vertical branch, a combination Wye -1/8 bend should be used.

I'm working on a house I purchased that appears to use a double sani-t to join quantity 2x 1 1/2" galvanized to the 4" main. Directly above the main is the 4" closet arm and a 4" vent stack for the toilet.
Attached is a picture:


Yes, I know that the installation of the closet arm hacking up the floor joist is _really_ bad.

I have a few questions about the tie ins to the main:
1. Is this improper use of this double tee?
2. Is a combination wye - 1/8 bend the 'correct' fixture to use in this location?
3. There is very little vertical space between the joists and where the horizontal main is. This means that if I were to retrofit with a combination wye - 1/8 bend, I don't think there would be sufficient pipe grade on the new 2" horizontal lines. In addition I would like to fix up that closet arm so it doesn't have the joist all hacked up. So- is there such a thing as a fitting that does 3" sani-t with 2" combination wye - 1/8 bend into a 3" or 4" stack?

On another note;
If i cannot fix the drain properly, I would like to tie 2" into the main. Would this tee appear to accept 2" with the proper donut? The I/D of the Tee appears to be about 2 7/8", while the O/D of 2" abs appears to be about 2 3/8"



Many thanks for any insight that someone can provide

 

[Tom Sawyer]

It is the correct fitting in the correct position.

 

[Sponsor]

 

[hj]

A sanitary tee can be used in most situations when a horizontal line connects to a vertical one.

 

[Houptee]

What about that sani tee at the bottom on its back (with the cleanout behind it).
Isn't that supposed to be a WYE at that change of direction?
The Bert Polk guide says that is the most common mistake, sani tee on its back.

 

[tlarson]

Yes, that sani tee looks to be illegal. FYI: Bert Polk's guide shows sani tees on their backs on pages 5, 9, 10 (two places), and 14, all as vent connections. Perfectly legal here in Oregon, at least in the Portland area.

 

[hj]

A cast iron sanitary tee on its back, like that one, was VERY common in the 50s and 60s.

 

[thenextdon13]

Thank you all for the responses and explanations!

I am on to reading about 'side inlet sanitary tee' that would be 3x3x3x2 to allow me to drop the closet arm to under the floor joist (to patch up the floor joist), and still tie in a 2" Drain (in place of the two 1 1/2's. Tiny house maxed out would be 11 or 12 fixture units).

(example product link)

I have seen mention that these are legal in UPC, and my understanding is that Oregon uses UPC.

 

[Terry]

The previous 1.5" pipe was pulled from the hub, and the lead pried out.

The hub is now ready for a Fernco hub insert and 2" ABS pipe.

 

[Tom Sawyer]

Technically the San tee on its back won't meet code anymore but as HJ said, it was a very common way to add a clean out at the time. It also let the plumbing run higher. It wouldn't pass today. Well except in California lol

 

[Houptee]

You can download most state codes, plumbing, building, electrical, free on this site.

https://law.resource.org/pub/us/code/safety.html

Oddly Oregon is blank under the plumbing, fuel/gas, and electrical columns, so you better check the city or state website for the current code they use where you live. Oregon is pretty progressive state so they probably have them downloadable on their website.

NJ has read only versions of all the NJ codes on the state website, you cant print or even copy n' paste its very annoying.
That's public information that taxpayers funded so why cant they let you download it and at least print it?

 

[tlarson]

Just to be clear: The sani tee on it's back is only legal here for a vent on a trap arm. It is never legal here for a drain line. Combo or wye/45 must be used for vertical to horizontal drains.

 

[thenextdon13]

Thank you all for the notes, they help me understand a lot of what is going on.

If allowed, I think I am going to go to 3" ABS with a 3x3x3x2 sani-t. This will allow me to drop the closet arm to under the horridly notched joist, which I can then patch.

So the overall configuration would be:
-- 3" ABS vent (sufficient vent area on shower [2"], vanity [1.5"], and kitchen [1.5"] to sum with this 3" and be more than the 4" area of the main)
-- 3x3x3x2 sani-t, with closet arm on 3" and combined drain for kitchen/bath on 2" inlet.
-- 3"-4" bushing
-- 4" donut
-- Existing cast iron 4x4x4 sani-t on back

This would allow me to:
1. Scab the floor joist where the current closet arm is
2. Narrow a 1" step-out in the bathroom wall that was put in to allow 4" vent pipe
3. Fix a roof truss that was chopped then supported on a wall to allow 4" vent pipe to exit roof

 

[thenextdon13]

OK, i wanted to be sure about side inlet sani tee on the Oregon code.
The only mention of 'side inlet' i can find in the 2011 Oregon code is in chapter three, from here:


"311.0 Prohibited Fittings and Practices.
311.1 No double hub fitting, single or double tee
branch, single or double tapped tee branch, side inlet
quarter bend, running thread, band, or saddle shall
be used as a drainage fitting, except that a double
hub sanitary tapped tee shall be permitted
"

The way i'm reading it, the sani-t with tapped inlet would be legal as it is:
1. Is Double hub (disallowed), but but also is sanitary tapped tee, permitted by last phrase
2. not a double tee branch (as the two are different sizes and not opposite each other?)
3. Not a tapped tee branch (i think)
4. Not a 1/4 bend (although is side inlet)
5. not a running thread, band, or saddle

Does this sound accurate?

[edit]
@ Terry (or someone else, perhaps)
Would you be concerned with the 3" flush valve toilets on a fitting like this? I see from this thread (and others) that the manufacturers and seattle disallow 2 way sani tees where the inlets are across from each other for the toilets...