Venting Question

[BuilderOKC]

The attached picture is the current configuration for a back to back identical bathroom. The Horizontal main is 3" and is under a slab. My question is if all the 1.5in venting and fittings are changed out to 2" would it pass ipc? I am a GC and am working up an estimate for this remodel and just wondering if we are going to need to tear up the slab at all to bring this up to code. Thanks

 

[MicEd69]

I assume the main stack is downstream of the toilets.?.? Unless you have a really long vent line, a 2" vent for those fixtures should be fine. However, draining your HVAC condensate into the vent line is not per code, and it could lead to sewer smells as the trap will not be continuously full of water.

 

[CT18]

Yes it would pass IPC as long as the overall vent length doesnt exceed 120'

 

[BuilderOKC]

I assume the main stack is downstream of the toilets.?.? Unless you have a really long vent line, a 2" vent for those fixtures should be fine. However, draining your HVAC condensate into the vent line is not per code, and it could lead to sewer smells as the trap will not be continuously full of water.

There is a drain basin in adjoining room should i just have the ac condensate drain into there? What about the p trap for the water heater in the attic should i just have them both drain into the basin? Its not a long run and can run in the attic so would not be hard to maintain a good slope. The Horizontal main just continues to city drainage. The vents are a very short and distance about 6 ft from where they exit the roof. The only thing in the building are these two bathrooms and the pool equipment room. It is bathrooms for a private HOA pool. Thank you very much for your help!

 

[MicEd69]

The water heater drain cannot be discharged into the plumbing vent either. Both should go into the drain basin.

And you may need to check the local city codes as some places require a minimum of a 3" stack. That is mostly for frost protection, which may not be a problem for you in OK, but they may have that as a requirement anyway. That could be just the last vertical section through the roof, provided it starts at least 1 foot below the roof. Or you may want to use a 3" connection to the main on the vent between the showers and the fountain. You also need to be sure to use the proper fittings at all changes in direction.

 

[BuilderOKC]

Thank you for you quick reply. My plumber is out of the country right now on vacation. He would be here figuring this all out for me for my estimate if he was not. I do know that a 3-in stack is not required in Oklahoma. Would it be better practice for him to run an inch and a half drain up into the attic from the floor sink and have the AC condensate and water heater tie into that. Or individual drains for both? I'm not a fan of 3/4 in condensate drains they always clog up so would like the most future proof and maintenance-free solution. Thanks again!

 

[MicEd69]

A 1 1/2" drain with each item having an air gap would be my choice as well.