Venting question - 2nd floor bathroom

[dtms]

I have a 2nd floor bathroom in an older house that i'm remodeling. In the corner of the bathroom there is a 4" cast iron drain\vent that everything in that bathroom currently ties into. Currently there are no individual fixture vents. 2 questions:

1) are fixture vents necessary if the distances for the lav, tub, and toilet are all within 7' of this 3" drain\vent?

2) If vents are needed can i run a 3" pipe over to the toilet and use a 2" wet vent of of that to the lav as the vent for the toilet and shower and then do a 1.5" vent from the top of the san tee for the sink up and then across the wall tie into the 3" vent?

I've attached pics but my drawing skills are not great. Sorry

 

[Reach4]

Find out which code you are under. Is it IPC? If so, see page 12 of https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf

 

[Sponsor]

 

[dtms]

Find out which code you are under. Is it IPC? If so, see page 12 of https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf

Maine State Internal Plumbing Code. The Plumbers’ Examining Board adopted the International Association of Plumbing and Mechanical Officials Uniform Plumbing Code, 2015 edition, as the standard for plumbing installations in the State of Maine. The code may be purchased from:

 

[Reach4]

I don't know Maine rules. I read some cities had adopted IPC. The attached sketch would be acceptable wet venting for more codes. I don't know the distance limits.

 

[dtms]

I don't know Maine rules. I read some cities had adopted IPC. The attached sketch would be acceptable wet venting for more codes. I don't know the distance limits.

Thank you very much for the help! So to clarify I would only need to have the sink vented in this configuration and that would serve as the vent for the entire bathroom group correct?

As an alternative since the shower is closer to the 3” vent would there be a way to vent the shower and have that be the vent for the group?

 

[Reach4]

As an alternative since the shower is closer to the 3” vent would there be a way to vent the shower and have that be the vent for the group?

The lavatory will need to be vented, because it's trap is higher. Some codes permit that venting to be with an AAV, and some don't.

 

[dtms]

The lavatory will need to be vented, because it's trap is higher. Some codes permit that venting to be with an AAV, and some don't.

OK. Thx. So if I don’t go the AAV route if the sink is vented as shown the shower and toilet dont need separate vents because the sink wet vent vents them both, correct?

 

[dtms]

Good morning. I'm finally getting around to this project and figured if I upload a pic it might help. The vent in the corner only serves this bathroom. Nothing else drains into it. It goes out the roof right at the slanted area so no attic space directly above. In the rear of the pic there will be a shower. Then a toilet approximately where the old toilet outline is and in the foreground there will be a vanity\sink. Few updated questions:

1) Vents are still required even though I'm so close to the stack, correct? I know every fixture needs a vent but wasn't sure if there's any exception where these fixtures are so close to the stack.

2)Reach4 had provided me with a pic on how I could vent the group. After seeing the pic does that design still make sense?

3) Are my only options here a) an AAV under the sink b) another vent thru the roof at the wall on the left for the sink? I don't see a way to vent back to this stack because of the fact that there's no attic above the area where the vent is.

Any help is greatly apprectiated!

 

[wwhitney]

0) The pipe in the picture, is it serving as a dry vent for any fixtures in the lower floors? If so, then it can't be a drain for your fixtures on this floor. It could be a vent for this floor's fixtures, and then the fixtures' drain would need to be kept separate and parallel the stack down to an elevation where the stack is already carrying drainage (no longer a vent), at which point the two drains could combine.

Hopefully it is just a drain and vent for this floor's fixtures, and lower floors' fixtures are vented elsewhere.

1) Yes, every trap needs a vent connection within one pipe diameter of elevation of the trap outlet. So if the lav were right next to the stack and the trap arm just ran horizontal to the stack, it could vent the lav that way. Otherwise you need to provide a separate vent connection for the lav.

2) The connectivity in the diagram in post 4 works well. The various requirements: the blue line needs to be a 2" drain with a 2" vent above. The orange line needs to be 2", and the length from the trap to where the orange meets the blue is limited to 60", while the fall over that length is limited to 2". The red line needs to be 3", and the length of the red line from the closet flange to where it hits the orange line is limited to 72" (measured along the pipe, including vertical segments), with no limit on the fall.

3) Your information is that Maine uses the UPC, which does not allow AAVs. I didn't track down the actual text of Maine's plumbing code; if you do, you could check for an amendment that would allow AAVs (likely as a new section under Chapter 9). So absent an AAV allowance, your only option for dry venting the sink (and thereby wet venting the shower and WC) is to take off a 2" dry vent which ultimately goes through the roof. That could be a separate roof penetration, or you could run the vent around the room, at a height at least 6" above the lav flood rim, to connect to your existing vent. For the latter, if the sloped ceiling is the underside of the roof rafters, you'd either have to have to open up the wood-clad wall in your photo to hide the horizontal vent line within it (if the wall is load bearing, checking that the necessary holes in the studs are allowable); or have an exposed horizontal vent line; or fur out the back wall to hide the horizontal vent line.

Cheers, Wayne

 

[dtms]

Wayne,

Thank you so much for your detailed response. Its very helpful. The pipe in the pic is just the drain and vent for this floors fixtures so good there.

Upon further research the town that i'm in now uses MUBEC (Maine Uniform Building and Energy Code) which is made up of a number of codes but one of which is the IRC. It looks like the IRC allows for AAV use with certain parameters that must be followed. So while the other options for venting make sense to me and would work i think i'll go with the AAV under the vanity.

Thank again for your help. It is greatly appreciated.

 

[dtms]

0) The pipe in the picture, is it serving as a dry vent for any fixtures in the lower floors? If so, then it can't be a drain for your fixtures on this floor. It could be a vent for this floor's fixtures, and then the fixtures' drain would need to be kept separate and parallel the stack down to an elevation where the stack is already carrying drainage (no longer a vent), at which point the two drains could combine.

Hopefully it is just a drain and vent for this floor's fixtures, and lower floors' fixtures are vented elsewhere.

1) Yes, every trap needs a vent connection within one pipe diameter of elevation of the trap outlet. So if the lav were right next to the stack and the trap arm just ran horizontal to the stack, it could vent the lav that way. Otherwise you need to provide a separate vent connection for the lav.

2) The connectivity in the diagram in post 4 works well. The various requirements: the blue line needs to be a 2" drain with a 2" vent above. The orange line needs to be 2", and the length from the trap to where the orange meets the blue is limited to 60", while the fall over that length is limited to 2". The red line needs to be 3", and the length of the red line from the closet flange to where it hits the orange line is limited to 72" (measured along the pipe, including vertical segments), with no limit on the fall.

3) Your information is that Maine uses the UPC, which does not allow AAVs. I didn't track down the actual text of Maine's plumbing code; if you do, you could check for an amendment that would allow AAVs (likely as a new section under Chapter 9). So absent an AAV allowance, your only option for dry venting the sink (and thereby wet venting the shower and WC) is to take off a 2" dry vent which ultimately goes through the roof. That could be a separate roof penetration, or you could run the vent around the room, at a height at least 6" above the lav flood rim, to connect to your existing vent. For the latter, if the sloped ceiling is the underside of the roof rafters, you'd either have to have to open up the wood-clad wall in your photo to hide the horizontal vent line within it (if the wall is load bearing, checking that the necessary holes in the studs are allowable); or have an exposed horizontal vent line; or fur out the back wall to hide the horizontal vent line.

Cheers, Wayne

Wayne,

Where the red 3" line comes into the 3" vent line do i use a San Tee or a Y w/ 45? I've read a lot of posts about this topic but i'm still unsure. I bought a Y with a 45 but now i'm questioning if it should be a San tee.

 

[wwhitney]

Where the red 3" line comes into the 3" vent line

I don't follow this. Do you mean where the new 3" horizontal branch drain joins the existing 4" stack?

For that you can use either a san-tee or a combo (wye plus 45). The only time a san-tee is required is when a horizontal drain is turning vertical while a (required) vent comes off the top. [Likewise, the only time you can use a san-tee for drainage is when the side inlet is a horizontal drain and the outlet is vertical.] As your horizontal branch drain is being vented via the lav, you don't need to use a san-tee.

Cheers, Wayn

 

[dtms]

Yes, that's what i was asking. Thank you again!