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

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DW85745

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https://terrylove.com/forums/attachment.php?attachmentid=16470&d=1338214054

Terry: From the YES picture I think I see what you mean.
Let me confirm please.

The Wye is on it side with the 45 at the same level as the Wye outlet.
The "P" trap weir appears to be slightly above center line of the 45 in order to obtain the "1/4 to 1" required slope.

So I ASSUME I should consider the center line of 2 inch branch pipe to its top to be the vent area.
Using the - rule - that:

"The bottom of the pipe at the trap weir may Not be higher than the top of the pipe at the vent opening"

should keep one out of trouble.
So if I run a string line from the top of the branch pipe to the trap weir and make sure the bottom is not higher
than I should be OK ? Is this CORRECT ?

=============

COMMENT: I guess the code makes this presumption (example):
Using the wet vent from the lav with a San-Tee at its end and the vent located on top of the San-Tee, its easy to
see how the vertical pipe gets vented. However since the fixture arm slopes downward gas IMHO could collect there.
The code must ASSUME (??) the pipe will never be full with water, hence that any gas will escape from the fixture arm by the draft
of the vertical pipe pulling it out even though we have a downward slope.
 
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Tom Sawyer

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Hey Terry, we should get a consulting fee for teaching plumbing 101

Maybe add a Tip Jar to your signature. :)
Terry Love
 
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hj

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quote; So, general consensus is that if I can go with a Y (rotated upward at 45 degrees and a 45 attached to the P trap exit pipe rotated downward at 45, "I think" I can make the connection further downstream.

The "genereal consensus" is that you do "NOT GET IT". You CANNOT "roll" ANYTHING downward UNTIL you have gone past the vent connection. When I worked in a grocery store a lady complained about spoiled milk even though her table was only 2' from the refrigerator. We told her that the milk had to be IN the refrigerator if she did not want it to spoil. You are the same way with your vent. It may be only 1' away from the connection, but it has absolutely NO effect or bearing on your shower drain IF you are "dropping it" into the line.

Citing the paragraphs on venting is only beneficial when you understand what they are saying. Your postings so far indicate that this is not the case.
 

DW85745

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Your postings so far indicate that this is not the case.

I don't disagree a little knowledge is dangerous. Hence climbing the learning curve on drainage.
As Terry pointed, looking at a drawing can be misunderstood UNLESS the viewer understands what's behind that drawing.
Also reading code can also leaves one guessing --based on forum posts different people interpret the code differently.
So bear with me!!
FWIW, I did find some white papers on the history of UPC codes which discuss some of this conflict. Will try and post
as most probably of interest to you at your level.

==================

The area I'm struggling with most is where the venting is in relationship to the drainage.
If you can vent a branch line using one vertical vent tied in at the end of the branch

https://terrylove.com/forums/attachment.php?attachmentid=16470&d=1338214054

then the only thing I can figure out is that the vent must be considered to extend though out the
entire branch drain from the branches center line to the top of the branch pipe. Since the branch line slopes
upward toward the end of the line where the vent goes vertical, gases will move in that direction.

Based on Terry post, my ASSUMPTION is that you then apply the rule (for every fixture arm -- shower and toilet in my case)

"The bottom of the pipe at the trap weir may Not be higher than the top of the pipe at the vent opening"

///////////// QUESTIONS

1)
ASSUMING I'm correct regarding the horizontal venting --OR -- do I have it WRONG again?
(this is a question not a defensive statement) If Wriong, please explain why?

2)
Where does one consider the trap weir for the toilet (from a vent perspective)?
Once the line leaves the toilet "S" trap and goes vertically down, and then runs
horizontal from the closest bend into the horizontal branch line -- how are gases routed (vented) with only
the vertical vent at the end of the branch line???




Hey Terry, we should get a consulting fee for teaching plumbing 101

Probably so.

====================
Here the white papers:

Appears they are too big to upload. Will try and locate the web links to access.
 
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