Venting Help Please!

Users who are viewing this thread

Johnpstucky4ksu

New Member
Messages
5
Reaction score
0
Points
1
Location
67053
Hello, I was wondering if someone could give me someone help on venting a plumbing stack for a very small living space I am putting in a shed. I've added an overhead plan and sketch drawing. I also have a few physical pictures I can add if its helpful. Basically its 1 toilet (3 inch), 1 sink (2 inch) and 1 shower (2 inch) in a bathroom. Then 1 sink (2 inch), 1 washing machine drain (2 inch) and 1 floor drain (2 inch) outside the bathroom. The main pipe is 3 inch.
Questions I have:
1. Which connections need a vent attached?
2. May I run 2 separate vent pipes 1 from the bathroom and 1 from the sink/washing machine on the other?
3. If I do run two separate vent pipes is 2 inch an acceptable size for each vent?
4. Is the vent required to run out of the roof or can it be ran out of the sidewall?
4. Any other thoughts or recommendations?

Thank you for your help!
 

Attachments

  • plumb.JPG
    plumb.JPG
    77.6 KB · Views: 54
  • plumb 2.JPG
    plumb 2.JPG
    27.2 KB · Views: 50

John Gayewski

In the Trades
Messages
2,696
Reaction score
699
Points
113
Location
Iowa
A couple of notes on this drawing. The whole bathroom group is horizontal unless the line on the drawing is vertical. A vertical line means vertical pipe. You can barely see the toilet riser. The vertical line for the floor drain looks like a tee but it should be a wye with a 45. The floor drain vent goes in your partition wall for the cabinets. You can combine any of the vents but it's usually easier in the attic or roof joists.
Screenshot_20220607-221235_Gallery.jpg
 

Johnpstucky4ksu

New Member
Messages
5
Reaction score
0
Points
1
Location
67053
Thank you very much John
A couple of notes on this drawing. The whole bathroom group is horizontal unless the line on the drawing is vertical. A vertical line means vertical pipe. You can barely see the toilet riser. The vertical line for the floor drain looks like a tee but it should be a wye with a 45. The floor drain vent goes in your partition wall for the cabinets. You can combine any of the vents but it's usually easier in the attic or roof joists.
View attachment 84119
Thank you very much John. To clarify what I am seeing on this drawing. The vent pipes you show are attached to the bathroom sink, the floor drain and the washer drain (with an additional teed in vent from the kitchen sink). Is that correct? No vent pipe on the shower fitting or toilet? Thanks again.
 

John Gayewski

In the Trades
Messages
2,696
Reaction score
699
Points
113
Location
Iowa
Thank you very much John

Thank you very much John. To clarify what I am seeing on this drawing. The vent pipes you show are attached to the bathroom sink, the floor drain and the washer drain (with an additional teed in vent from the kitchen sink). Is that correct? No vent pipe on the shower fitting or toilet? Thanks again.
Yes. As long as the pipe from your shower trap to the 3"is less than 8'long you won't need a vent. The piping would needs to be horizontal (with slope) and the riser from your trap up through the shower floor needs to be less than 2'long.
 

Johnpstucky4ksu

New Member
Messages
5
Reaction score
0
Points
1
Location
67053
Yes. As long as the pipe from your shower trap to the 3"is less than 8'long you won't need a vent. The piping would needs to be horizontal (with slope) and the riser from your trap up through the shower floor needs to be less than 2'long.
Yes. As long as the pipe from your shower trap to the 3"is less than 8'long you won't need a vent. The piping would needs to be horizontal (with slope) and the riser from your trap up through the shower floor needs to be less than 2'long.
Hi John, one more question. The bathroom is not very accessible to the roof (there is a loft directly above it). Is is possible for the vent in the bathroom to be one of those air admittance vents as long as the other ones all vent to the outside?
 

John Gayewski

In the Trades
Messages
2,696
Reaction score
699
Points
113
Location
Iowa
In Kansas I believe you can use an AAV.

But you need to vent at least half of the crossectional area of a 3"pipe through the roof. 3.14xR² is the formula. Since your main is 3" the radius is 1.5". 1.5x1.5=2.25x3.14=7.065÷2=3.5325sq. inches worth of vent through the roof. So two-2" pipes or one 2" and one-1.5" pipes need to go through the roof.
 
Last edited:

Johnpstucky4ksu

New Member
Messages
5
Reaction score
0
Points
1
Location
67053
In Kansas I believe you can use an AAV.
Thanks again for all your help! Yes-I confirmed that Kansas will allow 1 AAV. I was more concerned on whether the AAV would function differently than a vent pipe (or would not suffice as the vent for the bathroom.).
 

John Gayewski

In the Trades
Messages
2,696
Reaction score
699
Points
113
Location
Iowa
Thanks again for all your help! Yes-I confirmed that Kansas will allow 1 AAV. I was more concerned on whether the AAV would function differently than a vent pipe (or would not suffice as the vent for the bathroom.).
I have had them not work. But this was a bad situation. The owner refused to let the plumber run vent piping. There were no other vents other than an AAV. The toilet wouldn't flush. I didn't build this or really have anything to do with it, but some guys at our shop were taking about it and trying to figure out what to do.

I'm personally not a fan of AAV. To me they aren't as good and only do half of the job of a vent. I don't know why someone would want that, but they have their place.
 

Terry

The Plumbing Wizard
Staff member
Messages
29,700
Reaction score
3,257
Points
113
Location
Bothell, Washington
Website
terrylove.com
An AAV allows for negative pressure, but not for positive pressure. That's why you also need an atmospheric vent in the system to handle the positive pressures too.
I often see them used for a kitchen island vent for that reason.
 

Johnpstucky4ksu

New Member
Messages
5
Reaction score
0
Points
1
Location
67053
An AAV allows for negative pressure, but not for positive pressure. That's why you also need an atmospheric vent in the system to handle the positive pressures too.
I often see them used for a kitchen island vent for that reason.
Terry, thanks for the comments. Would you advise against using an AAV on bathroom vent in the drawings? I would still have the 2 other atmosphere vents but they would both be closer to the exit from the house? I could probably figure out a way to get an atmospheric vent to the bathroom fixtures but would be difficult since it is in the middle of the house and has an open loft room above it.
 
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