Please help with Small bathroom DWV in floor on slab ... no wall space

I am in sunny California...... We are required to have a vents through the roof equal to the sewer pipe serving the building. 4" sewer equals 4 -2" vents or any combination of vents equal to the aggregate area of the main sewer. What is required in your neck of the woods?
George

well maybe I don't have that right - I had been reading this:

P3102.1 Required vent extension. The vent system serving each building drain shall have at least one vent pipe that extends to the outdoors.
P3102.3 Size. The required vent shall be sized in accordance with Section P3113.1 based on the required size of the building drain.
P3113.1 Size of vents. The minimum required diameter of individual vents, branch vents, circuit vents, vent stacks and stack vents shall be at least one-half the required diameter of the drain served.

But your question made me find this:
P3109.3 Stack vent. A stack vent shall be installed for the waste stack. The size of the stack vent shall be not less than the size of the waste stack.

So unless I am getting tangled in definitions you are right...?
Btw, I am from your neck of the woods - enjoy the weather (esp in winter)
Thank you
John

In NY and anywhere else under the IRC/IPC you only need one vent that is half the diameter of the building drain. The minimum building drain diameter is generally 4" for residential so that means you need at least one 2" vent through the roof.

Thank you again!
How about the height of the tub Ptrap, what are the constraints?

Maybe now you are beginning to realize that a building's DWV system is more than just a few pipes screwed together. Your "plan view" drawing does NOT give a lot of the information, such as building component locations and sewer depth, needed to optimize the design. Your design is getting more and more complicated, but without some more data, any simplification would be guessing.

jrol22 said:

Thank you again!
How about the height of the tub Ptrap, what are the constraints?

Click to expand...

If the trap is above the water line of the recieving drain then it will have to be individually vented. Rule of thumb. If waste goes down a vent usually is required to go up.

So am I just thinking to much -
if the trap is close to the toilets entry to the drain line
and the trap weir is level with the low side of the 1 1/2 outlet of a 3x1 1/2 wye laying flat in the drain line
than it would not take much to backflow a touch of waste into the trap water - it seems fairly standard though, or am I forgetting about a minimum horizontal run from the trap to drain line
Thank you
John

If the pipes are properly pitched the toilet will not back onto the tub trap unless there is an obstruction downstream of the toilet which by the way happens and yes when it does the toilet backs up into the tub.

Thank you Tom
Hj:
I am not clear on why I have rubbed you the wrong way - I have made no statements to the effect that plumbing is easy or that a building's DWV system is just a few pipes screwed together. I just trying to put my bathroom together so that it works - I have thought a great deal about the details and am well aware of how difficult it is to put it all together with my constraints.
The building has no components in place so far and the sewar depth is just that it comes in to the area I am working at slab height. It goes downhill into a basement after that (to the right on the drawing.) I am having trouble getting it all to work in that 8" space - but it seems possible. I sure hope It doesn't leak later, I'll have to tear up the floor - I see why building usually have at least a crawl space!
john