Minimum DWV sizing

[cedarglen]

I have found info on the minimim sizing of drains and vents, what I have not found is info on how many fixtures can share a vent? Any limit? The system I have worked out and would like to install would have the 1st floor bathroom sink and tub, 2nd floor bathroom sink, tub, and toilet all venting through one 2 inch roof vent. This is a strict code enforcement area of California, so it will be inspected. Is there any problem with that?

Chuck

[glenn kangiser]

I believe the total vent area has to equal the area of the pipe going to the septic tank so you need one 3" stack if one vent or enough smaller ones to equal that area, and I think there are only so many fixture units on each size pipe so that can't be exceeded.  I haven't done it for a while, but Scott has.