Height of shower p trap

Users who are viewing this thread

Straight_A

New Member
Messages
1
Reaction score
0
Points
1
Location
Pennsylvania
New to the forum although I use it frequently for reference. I'm running fixture drains from a bathroom to the main drain stack (about 2 ft to the right of the end of the pic.). My question is about the p trap shown. I have a 2" vertical drain from a shower pan, p-trap, 2" vent then it connects to 3" horizontal drain via a combination wye. Upstream I have waste from vented vanity and vented toilet. Is it permissable to have the bottom of the p trap below the height of the horizontal drain? (Or does the p trap need raised and tied into "2 inch vent/drain via sanitary tee with 2" waste then dropping into 3" horizontal waste line?) I am subject to 2015 IRC. Thanks for the help.
 

Attachments

  • Screenshot_2022-08-29-14-48-56-149~2.jpg
    Screenshot_2022-08-29-14-48-56-149~2.jpg
    63.1 KB · Views: 156

Tuttles Revenge

In the Trades
Messages
2,983
Reaction score
934
Points
113
New to the forum although I use it frequently for reference. I'm running fixture drains from a bathroom to the main drain stack (about 2 ft to the right of the end of the pic.). My question is about the p trap shown. I have a 2" vertical drain from a shower pan, p-trap, 2" vent then it connects to 3" horizontal drain via a combination wye. Upstream I have waste from vented vanity and vented toilet. Is it permissable to have the bottom of the p trap below the height of the horizontal drain? (Or does the p trap need raised and tied into "2 inch vent/drain via sanitary tee with 2" waste then dropping into 3" horizontal waste line?) I am subject to 2015 IRC. Thanks for the help.
The way the trap is shown is correct. The new water/waste coming from the shower, pushes or displaces the water already in the trap. The excess waste then becomes higher than the Weir of the trap and begins travelling downstream via gravity. Liquids take the form of the object they occupy and in this instance can never get any higher than that of the weir.

*edit just to add some useless info

The shape and size of a trap also is important. Both are designed to help the trap stay clean by scouring. Too small a diameter and it doesn't drain efficiently. Too large a diameter and the water passes by too slowly and gunks up. Too much angle slows the water. Too deep the waste has time to settle out. Too shallow of a trap and the water that keeps sewer gasses from passing evaporates too quickly.
 

breplum

Licensed plumbing contractor
Messages
1,070
Reaction score
401
Points
83
Location
San Francisco Bay Area
The Tee on it's back is incorrect. The fitting should be a combo, and the air flow direction should be sweeping downstream.
The vent need only be 1-1/2".
 

wwhitney

In the Trades
Messages
5,661
Reaction score
1,467
Points
113
Location
Berkeley, CA
The Tee on it's back is incorrect. The fitting should be a combo, and the air flow direction should be sweeping downstream.
The vent need only be 1-1/2".
Agree with the above in practice, but it's worth noting that on "the fitting should be a combo," that doesn't have the strength of code under the IPC. It has no requirement like the UPC that all vent fittings below the fixture flood rim are of a drainage pattern.

And PA uses the IPC.

Cheers, Wayne
 

Jeff H Young

In the Trades
Messages
5,720
Reaction score
1,281
Points
113
Location
92346
I had bad teachers we used to put santee on back routinely or always and never a combi but got set straight a few years in by inspector Mr Whipple city of Long Beach.
I suppose other than santee backwards its ok.
My code calls for tailpiece as short as practical but not over 24 inches (unless some verbiage has been changed) , I could Imagine my old inspector calling me on it or just giving me a hard time . I think a long sweep 90 under vent hole and a 2x1 1/2 x 2 santee pointed toward drain be better than a long tailpiece. but I'm being a bit nit picky
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks