Shower pan drain connection to vented stack

[Ivan Blackford]

Hi all. I'm in Ontario, so I'm looking for advice relevant to the Ontario Building Code. I have a shower drain connection that is about 5' from the trap to a 3" wet-vented stack. This isn't a conventional stack, but rather it would be tied in below a toilet, the configuration I would like to do is as follows:



Blue: 3" Wet vented Toilet drain
Green: 2" wet vent line from vanity
Red: Proposed 2" drain line shower pan.

A few other comments/questions:
1) I did run a dedicated 1.5" vent line into the basement for this, but I am trying to keep the 2" trap as tight into the joist cavity as possible to avoid a large bulkhead.
2) the 2" connection to the stack is made with a WYE instead of a sanitary tee, but given the changes in height between the trap line and the connection to the stack, I didn't think a sanitary tee would work. Would using this wet-vented stack configuration be ok, if I could somehow change the height of the shower drain to work with a sanitary tee?

My end goal is to have a legal setup without dropping the shower trap down too much.

Thanks, Ivan

 

[Jeff H Young]

2x1 1/2x2santee in joist bay with vent going through floorv and connecting with lav vent at 42 minimum above floor.
I cant make it out but looks like youve already built it? did you forget the vent (i cant tell) whats the issue? of cource the shower wont be wet vented ittl be dry vented

 

[Sponsor]

 

[Ivan Blackford]

I dry-fitted everything and took a picture...nothing has been glued up yet. I'm trying to avoid a direct connect dry vent, as that makes the trap sit down too far, and means I need a bulkhead. Can a shower not be wet vented?

 

[Jeff H Young]

you dont need the trap low it can go in joist bay easily santee on top vent goes through the floor ?

 

[Jeff H Young]

you might be thinking of having no vent there is no vent the way it is now it appears. unless its going through the floor above joist bay

 

[Ivan Blackford]

The joists are 2"x8" only, and do not allow enough depth for the 2x1.5x2 Sanitary tee + elbow, without dropping the trap down very far. Below is what it looks like if I try to dry vent without dropping the trap down, there isn't enough room for my sanitary tee + elbow:

Green: Top/Bottom of joists
Black: Drain line
Red: Dry Vent line
If i drop the trap down a bunch, then yes, I can achieve a dry vent, but then i'm looking at building a bulkhead.

Green: Top/Bottom of joists
Black: Drain line
Red: Dry Vent line

I'm looking at *wet* venting from the 3" wet vented stack, and I would like to know if this is legal in my jurisdiction:

Green: Top/Bottom of joists
Black: Drain line
Red: 2" Wet vent line
Blue: 3" wet-vented toilet stack

Hope this helps illustrate what i'm trying to achieve!

Thanks in advance, Ivan

 

[wwhitney]

Does your proposed configuration involved a single stack serving as both the drain for a fixture on one story, and a vent for a fixture on a story below? If so, it doesn't comply with any of the US plumbing codes for wet venting. Some US codes allow stack venting, which has allowances for that.

As to the Canadian plumbing code, I'm unsure. Look up the section on wet venting and see if it mentions that all fixtures have to be on the same story. I do know that the Canadian plumbing has a few wet venting related allowances not present in the US codes, so it's possible it has an explicit limited permission for interstory wet venting.

Cheers, Wayne

 

[Jeff H Young]

I cant see everything but I dont see that as working

 

[Ivan Blackford]

So I worked a little more on this tonight, and I came up with a solution for my issue. I have rotated the dry vent location to be on a 45degree angle, and moved it as far away from the trap as practical. Here's pictures of my dry-fit installation:

In each picture, Red is the dry vent line, blue is the drain. The connection point after the vertical drop is to a wye into my 3" vertical drain. A few comments/questions:
-My trap arm length is about 48". I believe this allowed under OBC 7.5.6.3. (2.4m is allowed for a 2" drain).
-I have rotated the dry vent location to 45 degrees. I think this still allows the dry vent to be located above the halfway mark of the drain.
-I have the sweep part of my sanitary tee pointing towards the main stack, is this the correct orientation?
-The total drop in from the trap weir to my vent connection is about 1.75", which is right on the edge of acceptable I think.

Any comments on this would be greatly appreciated.
Thanks, Ivan

Any advice would be greatly appre

 

[wwhitney]

-I have rotated the dry vent location to 45 degrees. I think this still allows the dry vent to be located above the halfway mark of the drain.

That's a necessary requirement of dry vents; another is that the dry vent stay vertical (at least 45 degrees above level) until reaching an elevation of 6" above the fixture flood rim.

Cheers, Wayne

 

[Ivan Blackford]

That's a necessary requirement of dry vents; another is that the dry vent stay vertical (at least 45 degrees above level) until reaching an elevation of 6" above the fixture flood rim.

Cheers, Wayne

This is where I struggle a bit....in my configuration, there's going to be about 4.5 ft of very slightly sloped vent pipe until it can go vertical. But my situation isn't unique I think, just about every shower pan venting has *some* length of vent pipe that is pseudo-horizontal as the pipe traverses under the pan? How much is acceptable?

 

[wwhitney]

This is where I struggle a bit....in my configuration, there's going to be about 4.5 ft of very slightly sloped vent pipe until it can go vertical. But my situation isn't unique I think, just about every shower pan venting has *some* length of vent pipe that is pseudo-horizontal as the pipe traverses under the pan?

Nope, the usual solution is to either (a) run the shower trap arm directly under a wall where you can take a dry vent off that can rise directly into that wall or (b) wet vent the shower via a lav drain.

Cheers, Wayne

 

[Jeff H Young]

you have issues cant say I havent seen that before. none horrizontal are acceptable except if its a wet vent also you need drainage fiittings santees on side arent drainage .

 

[Jeff H Young]

Formerly vents were allowed under certain conditions but not like you did it with a san tee so I doubt that meets any code but cant 100 percent but maybe 95 percent confident its a fail as far as being legal

 

[Ivan Blackford]

Nope, the usual solution is to either (a) run the shower trap arm directly under a wall where you can take a dry vent off that can rise directly into that wall or (b) wet vent the shower via a lav drain.

Cheers, Wayne

Ah, I think I understand now...the trap arm stays horizontal (or sloped down at 1/8 to 1/4 per foot) and then ties into the vertical vent connection. I can achieve this...but it would mean that my horizontal drain would zigzag quite a bit (instead of going straight out of the trap, I would head left to pickup the vent, and then right again to hit the main stack). It's not quite as bad as I describe, but it is taking the milk route a bit...

 

[wwhitney]

instead of going straight out of the trap

You always go straight out of the trap, as the trap has a swivel joint in it, so you can point it any direction you want. I think you mean instead of pointing the trap straight at the stack, you will have to point it to the side to get to a place where you can take the vent off, then head to the stack. If you can achieve that with only one LT90 between the trap and the stack, that's par for the course. One LT90 and a 45 is fine. Two LT90s, think hard about whether you can optimize, but if that's the only route to get a dry vent, that's OK.

Cheers, Wayne

 

[Ivan Blackford]

So if I head straight towards the dry vent location, pickup the *completely vertical* dry vent and then head towards the 3" stack, my route (looking down on the horizontal projection) looks something like this:

-I shouldn't need to swivel the P-trap at all, I think I can come straight out
-I will attempt to make the turn with a long sweep 90 or dual 45's (or a combo of 22/45)

What do you think? Assuming I slope everything correctly, should this be a legal way to achieve my vented drain?

Thanks again for any assistance, I swear legally vented drains are amongst the trickiest things to achieve in the plumbing profession.

 

[Jeff H Young]

no question that would be a legal installation, btw it makes no differance how the ptrap is swivele3d or dead straight

 

[Ivan Blackford]

Ok....I think I have a plan now based on my latest drawing. One final question though: when connecting the vertical dry vent to the horizontal branch drain, can I use a horizontally placed sanitary tee, as shown below:

I understand that generally sanitary tees are not permitted when transitioning from vertical to horizontal, but in this case there is no (or there ought not to be) any flow of liquid or solids through the vent pipe, so it should be permitted?

Thanks, Ivan

 

[wwhitney]

Ok....I think I have a plan now based on my latest drawing. One final question though: when connecting the vertical dry vent to the horizontal branch drain, can I use a horizontally placed sanitary tee, as shown below:

The answer to that is going to be specific to your Canadian Plumbing Code. One US code allows a san-tee on its back for a vent takeoff, the other requires a combo.. If you have space for a combo, go ahead and use one; if not, do a little more research on the Canadian Plumbing Code. The US code that prohibits a san-tee on its back for a vent takeoff does so via language in the Venting chapter of the form (to paraphrase from memory) "all fittings below the fixture flood rim shall be of a drainage pattern."

Cheers, Wayne