Shower and Toilet Vent - 3 Options - which one works?

[PeterT]

Governed by UPC in CA. The 2" vent location is fixed as it falls in a wall.

Option A - I presume doesn't work because the toilet drains the shower trap, correct?
Option B - will meet code, correct?
Option C - this is the best solution for me: tie shower trap arm into WC drain line at the same location that the 2" vent takes off vertically. However, I don't believe there's a way to do this and meet code. I don't have the vertical height to tie the shower trap arm into the 3" WC drain from above.

Am I missing a different solution here?

.

 

[wwhitney]

(A) No good, as you can't join two unvented fixture drains
(B) Also no good, as while the WC is dry vented and in some jurisdictions (IPC or Washington state's amended UPC) could wet vent the shower, the UPC requires the WC to be the last fixture on a wet vent, so it can't wet vent the shower.
(C) Closer, see below.

What you need to do is dry vent the shower via the 2" vent you have (that connection must be within in 60" of pipe run and 2" maximum vertical fall from the 2" shower trap outlet). Then the 2" shower drain needs to join the WC drain line within 72" of pipe run from the WC closet flange; that wet vents the WC via the shower.

In (C) you've drawn all four pipes coming together at once. Note that the vent takeoff has to be vertical (at most 45 degrees from plumb) and of a drainage pattern (no san-tees on their back or wyes with straight side inlet). So I don't think there exists a fitting that would let you join all four pipes in the necessary pattern. If there was, I think it would be OK, but it's a bit unclear. Better to take the 2" dry vent off the shower trap arm, then join the shower drain to the WC drain.

E.g. Use a horizontal (2% slope) 3x3x2 wye for the WC to shower drain connection. On the 2" inlet, use a (street) 2" wye, with the branch inlet as the vent connection pointed up, and a (street) 2" 45 on that branch inlet for your plumb 2" dry vent connection. That would be the most compact way to bring everything together at almost one point.

Cheers, Wayne

 

[Sponsor]

 

[John Gayewski]

I'll just add the shower trap arm can only be "60 long, so from the vent pipe opening to the trap you've got a maximum of 5'. Will your current setup conform to this?

 

[PeterT]

(A) No good, as you can't join two unvented fixture drains
(B) Also no good, as while the WC is dry vented and in some jurisdictions (IPC or Washington state's amended UPC) could wet vent the shower, the UPC requires the WC to be the last fixture on a wet vent, so it can't wet vent the shower.
(C) Closer, see below.

What you need to do is dry vent the shower via the 2" vent you have (that connection must be within in 60" of pipe run and 2" maximum vertical fall from the 2" shower trap outlet). Then the 2" shower drain needs to join the WC drain line within 72" of pipe run from the WC closet flange; that wet vents the WC via the shower.

In (C) you've drawn all four pipes coming together at once. Note that the vent takeoff has to be vertical (at most 45 degrees from plumb) and of a drainage pattern (no san-tees on their back or wyes with straight side inlet). So I don't think there exists a fitting that would let you join all four pipes in the necessary pattern. If there was, I think it would be OK, but it's a bit unclear. Better to take the 2" dry vent off the shower trap arm, then join the shower drain to the WC drain.

E.g. Use a horizontal (2% slope) 3x3x2 wye for the WC to shower drain connection. On the 2" inlet, use a (street) 2" wye, with the branch inlet as the vent connection pointed up, and a (street) 2" 45 on that branch inlet for your plumb 2" dry vent connection. That would be the most compact way to bring everything together at almost one point.

Cheers, Wayne

Thanks Wayne. See the modified image - I moved the dry vent to the shower drain and now the WC will wet vent adhering to the distances you outlined. Only question is: since a portion of the shower drain now becomes a wet vent, does that wet vent section need to be upsized to 3" ?

 

[wwhitney]

since a portion of the shower drain now becomes a wet vent, does that wet vent section need to be upsized to 3" ?

No. A 2" horizontal wet vent is allowed to carry 4 DFUs; a shower is 2 DFUs. In contrast a horizontal 2" drain that is not serving as a wet vent is allowed to carry 8 DFUs.

Latest drawing looks good if all the distance limits are met.

Cheers, Wayne

 

[PeterT]

Perfect. Does the below drawing also work provided that the distance limits are met?

 

[wwhitney]

Yes, so long as the pipe labeled cleanout is just a cleanout. If you ever added a fixture there, it would need to be a bathroom fixture that was dry vented with at least a 2" vent; it would then become the wet vent for the WC.

Cheers, Wayne

 

[Jeff H Young]

3x3x2 combi on back with 2 inch spigot santee works for venting of cource we dont know if this on ground work, crawspace or in a joist bay? he said he wants vent to hit a wall Isee posts have added since I started my reply looking at those vents drawn need to be verticle if dry

 

[PeterT]

Yes, so long as the pipe labeled cleanout is just a cleanout. If you ever added a fixture there, it would need to be a bathroom fixture that was dry vented with at least a 2" vent; it would then become the wet vent for the WC.

Cheers

yes just a cleanout. thanks again.

 

[PeterT]

3x3x2 combi on back with 2 inch spigot santee works for venting of cource we dont know if this on ground work, crawspace or in a joist bay? he said he wants vent to hit a wall Isee posts have added since I started my reply looking at those vents drawn need to be verticle if dry

I don't have the height for the 2 inch santee to sit above the 3x3x2. thanks.