Is this a "P" or "S" Trap or which is the better alternative?

[dw85745]

1)

The shower tailpiece is a straight drop to the "P" trap.
At the "P" trap exit I can go 90 degrees for about 6 inches, then use a short sweep 90 to drop to the 2 inch drain line.
FWIW - the vent (wet) is upstream about 15 inches where the shower will connect.

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2)
As a alternative:

The shower tailpiece is a straight drop to the "P" trap.
At the "P" trap exit I can insert a street 45 into the 90 degrees (P Trap Exit) fitting
then run a longer 2 inch line (about 12 inches) to a Y.


Thanks
David

[hj]

#1 is a definite No-No!

We would have to know more about the line you are connecting to in order to say whether #2 is correct or not. How you do it is as important as what you do. My impression is that it would also NOT be a proper connection, given the little you describe about it.

[cacher_chick]

The key point is that upon leaving the trap, the horizontal pipe cannot exceed 1/4" per foot of pitch before the vertical vent take-off.

[dw85745]

We would have to know more about the line you are connecting to

The existing line is a 2 inch which is "horizontal and hangs from the existing floor joints. (1/4 to 1 slope).
The existing vent (wet) for the lav is at the end of the the 2 inch line.
Need to insert a shower drain on the downstream side of where the lav and wet vent are located.

Normally would go with a San T at the "P" trap exit if a vent was also needed.
However, no vent needed here.
So the issue becomes, what's best to use at the "P" trap exit -- or short distance from it --
so that I get a vertical drop to the existing 2 inch line without creating an "S" trap.


<<<<<<<< Existing 2 inch <<<<<< Shower <<<<<<<<<<< Lav Wet Vent (ties into the 2 inch with a long sweep 90)

The key point is that upon leaving the trap, the horizontal pipe cannot exceed 1/4" per foot of pitch before the vertical vent take-off.

Agree - However is this case no vertical vent, just a drop (vertical in #!) to the other 2 inch line.


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One other option I could do is use the San T and the run a short piece of 2 inch (like a normal vent pipe) and put a cap on it.
Would be simplier with a short sweep 90, but not sure whether this creates an S trap with the short piece of 2 inch inserted
after trap exit ??

[Tom Sawyer]

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[cacher_chick]

To answer the question headlining your post, S-traps are strictly prohibited in U.S. plumbing codes.

[dw85745]

Tom Sawyer:

Don't agree a vent is needed on the vertical since the vent (wet) is upstream and services the lav, the shower and the toilet.

cacher_chick

S-traps are strictly prohibited

Agree. Hence the basis of my post. That is at what point does one consider going from a "P" trap to an "S".

For example:
1) I think we are in agreement that Tom Sawyer's graphic is a "P" trap.
2) I also think we can agree that if a Ell (90) was put at the "P" trap exit that it would constitute an "S" trap.
3) So where the debate arises is whether putting a Ell (90) some distance X from the "P" trap exit still makes it an "S" trap or
can it be considered a "P" trap?
If a "P" then what is that X distance?

[hj]

quote;

The key point is that upon leaving the trap, the horizontal pipe cannot exceed 1/4" per foot of pitch before the vertical vent take-off.

NOT true, but the slope cannot be such that the vent connection occurs below the weir fo the trap. There is NO distance that will convert an "S" trap to a "P" trap without adding a vent. IF there is no vent then it is NOT a "P" trap regardless of what YOU call it. You also CANNOT connect it to the "drain line" with a sanitary tee since it is a horizontal line.

[dw85745]

Here's a picture. I'm venting the bathroom from the end with a wet vent. FWIW there is also an existing vent downstream from the toilet.
The fixture arm for the shower is my PROBLEM because of the space available. Since the vent is at the end I do NOT need and cannot work in
a separate vent for the shower. So this leaves me trying to get a "P" trap in with only six inches left before I am directly over the 3 inch horizontal branch line
(which is below the sub-floor about 12 inches) . So as I see it I have two options available to connect to the 3 inch line.
1) Bring the the "P" trap end into a San-Tee which will give me a vertical drop to the 3 inch Y Combo and Cap the top of the 2 inch San-Tee since there is NO VENT.
2) Bring the "P" trap end into a 45 and then drop to my 3 inch line.

Personally I don't see the difference in one or two (both make the connection).
Any feedback on (1) or (2) with advantages / disadvantages explained would be appreciated.
Any alternative also appreciated.


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Here's a good diagram re: "P" Trap slope issue:



On the above example, I disagree with the maker of the drawing that a San-Tee can NOT be used in a horizontal. From my reading it can be used on the
horizontal for a VENT PIPE ONLY -- however, it can NOT be used as a drain. So in the top picture, the Y Combo could be a San-Tee since it just services a vent.
However, if this was a wet vent then it would NOT be acceptable.

Thanks
David

[cacher_chick]

We still cannot see what YOU have to work with. From what you are describing, the solution might be to make the connection further downstream instead of so close to the shower drain.

The drawings above fail under code, as they show a 1-1/2" wet vent, which is not allowed.

The sanitee on the horizontal is strictly prohibited except on a DRY vent connection to a horizontal vent (above the flood rim of the highest fixture served). A wye or combo is the only proper fitting for a vent take-off on a horizontal drain.

[hj]

Options 1 & 2 BOTH mention a "drop". Without a vent you CANNOT "DROP" the line into the main line, PERIOD! You can run from the trap into a horizontal "Y" in the main line as long as the trap outlet and main line are at the same elevation. I am not sure WHY you posted the "P" trap drawings because they have little bearing on what you are describing. FYI, the toilet's "trap weir" is at the poing INSIDE the toilet where the waterway turns downward, NOT in the closet bend, which is why ALL toilets, (except "blow out" bowls which are a separate category), are "S" traps.

[dw85745]

First let me THANK All for the feedback and your time.

Let it be known that NONE of these are my drawings. Just some examples I found to help describe the situation.

cacher_chick

The drawings above fail under code, as they show a 1-1/2" wet vent, which is not allowed.

FWIW I'm using a 2 inch wet and dry vent and where it shows 1 1/2 I'm also using a 2 inch.

The san-tee on the horizontal is strictly prohibited except on a DRY vent connection to a horizontal vent (above the flood rim of the highest fixture served). A wye or combo is the only proper fitting for a vent take-off on a horizontal drain.

Will double check SAN-TEE can NOT be used for a dry vent on the horizontal.
Logically -- to me -- this doesn't make sense since whether you use a Y combo to vent vertically from the horizontal or a SAN-TEE,
both are only carrying air.

Add: Look at the bottom Note which supports SAN-TEE use for venting. https://ibcode.com/uploads/Aug_24_Sanitary_Tee.pdf
The bottom pictures show waste into SAN-TEE and I agree NOT TO CODE.

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Without a vent you CANNOT "DROP" the line into the main line, PERIOD!

Question:

Then how are you supposed to make the connection from the shower to the 3 inch line ?
Some how some where the 2 inch line has to get from the shower drain to the 3 inch branch line
with a "P" trap in the line.

I am not sure WHY you posted the "P" trap drawings because they have little bearing on what you are describing.

Posted to show that with the "P" trap connection to the shower, and that at the "P" trap exit, my only alternatives is some kind of drop to the main (in my case branch) line.
(similar to FIg B as described in Option #1)

FYI, the toilet's "trap weir" is at the poing INSIDE the toilet where the waterway turns downward, NOT in the closet bend

NOTED. As indicated NOT my drawings.

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The floor joists are 3 x 9's. From the bottom of the floor joints to the 3 inch branch line is approx. 10 inches. From the bottom the 3 inch branch line to the concrete
crawl space floor is approx 6 inches. The 3 inch line runs perpendicular to the floor joints.

So as you see I have approx 19 inch crawl space under the joints in which to work. On top of that, this was a solar home that had river rock originally as the crawl
space floor which was flooded with self leveling concrete to fill the voids in the rock to keep the rattlesnakes out. The concrete is NOT level, but has rock BUMPS throughout
on which I have to crawl over or lay on to work. NOTE: This has nothing to do with the plumbing issue other than the difficulty of the working conditions.

[Tom Sawyer]

See post #5

Cacher, Under the IPC we can now wet vent not one but two bath groups with a single 1 1/2" wet vent.....woooopee

Here's the rule for venting be it wet, circuit, individual or stack. Anytime crap goes down air goes up. Again see post #5

[cacher_chick]

Cacher, Under the IPC we can now wet vent not one but two bath groups with a single 1 1/2" wet vent.....woooopee

I hate to think that you are right about that, but I don't doubt that you are.
I don't fall under the IPC, so am not completely in the know.


If the OP would show us some decent pictures of what he has, I'm sure there is a solution.

The trap can be turned to give you a little more room. The trap can be lowered so that the trap arm is properly pitched to a wye facing out the side of the main line. Again, without seeing it, all we can do is speculate.

[dw85745]

cacher_chick:

If the OP would show us some decent pictures of what he has, I'm sure there is a solution.

As the original OP there is nothing to show other that the floor joists and a concrete floor. Guess I could show the 3 and then the 2 inch line sloping upward to where the shower will connect.
I'll try an post a picture or two.

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Regarding using of a Y combo, a sanitary tee, and capping the top of the sanitary T since NO vent (as part of the fixture arm).

In re-reading IPC 704.5, I believe it would be considered a "dead end" and therefore would be prohibited. This makes sense in that gas
could rise and get trapped in this area.

So guess my only alternative is go with a 90 to tie into the Y combo or a Y with a 45 which ties in further down the line.

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Referencing Tom Sawyer's post #5 -- my plan is to just put a long sweep 2 inch 90 where the sanitary T is shown and tie that into a Y combo that is sitting vertical.
This way I can get my "P" trap in and a 1/4 to 1 slope prior to making the 90 degree bend downward. Don't personally like the short distance from the P trap exit to where
the 90 makes it down turn.

Trying to go flat, then using a 45 to tie into a Y further down the line may pose a problem (will double check)

>>> Feedback appreciated re use of 90.