Venting two toilets

[Shavinghorse]

Hi everyone, I’m new to the forum but a fairly accomplished d.i.yer and I’m making two bathrooms out of one on the second floor of my house. The picture shows the proposed new DWV layout and given the distances shown in the picture from the toilets to the main stack, I think this will serve as the toilet vents. I do have some concerns that the toilet closest to the main stack will siphon the toilet farthest from the main stack. Just for added reference, there’s a wall between the toilets and the horizontal portion of the waste line is running under the floors joists.

 

[James Henry]

It looks like the 2" line and the toilets enter the 3" line vertically, if that's the case you have problems. also, a floor plan with wall locations are needed for anyone to make comments on your proposed layout.

 

[Sponsor]

 

[Shavinghorse]

The 2” and the toilets enter the 3” on a wye and a 45 so there is a slight drop because the 3” runs under the floor joists. The bad drawing just makes it look like they enter vertically, they don’t. The 3” stack and drain are on the inside of an exterior wall and there is a partition wall running between the two toilets separating the two bathrooms. I should mention too that the 3” stack and drain to the septic are existing. Not sure if this is of anymore help with the siphoning question but any feedback is greatly appreciated. Thanks.

 

[Shavinghorse]

Sorry, I had said that the 2”and 3” enter the 3” drain with a wye and a 45.....I meant a wye and a 90.