Need advice on main stack change...?

[vbtalent]

First off, "Hello" to the forum this is my first post...

I would like to make a couple of changes to my current setup but could use some expert advice from those of you in the field.

I have attached some crude pictures of what I'd like to do. My current setup (1st image) incorporates 90 degree streets for the toilets and also has the sinks and showers draining into the main stack after the toilets.

I would like to change 2 things (2nd image).

1) I want the sinks and showers to drain before the the toilets
2) I want to use 90 fittings instead of the sweeps on the toilets

I am trying to get some headroom in the basement which is the reason for the 90's and there will be some short straight lengths between the fittings, the graphic is just a rough idea of what I want to do (lacking connecting pieces).

So, does anyone see any problem with using 90's instead of sweeps and is there some type of code issue that I might be missing, I'm located in Kentucky?

The sinks and showers draining before the toilets doesn't seem to be a problem I was just looking for a second opinion...

Thanks for any help you can give,

VB,

 

[noahlamy]

You don't indicate pipe sizing or run lengths but as a general rule your toilets would be 3" or 4" pipe. using 1/4 bends (short elbows) shouldn't cause problems there. but basins (sinks) and tubs might be 1-1/2" and showers might be 2" and there you might have problems with the shorter fittings. the code calls for sweeps in drains of these sizes. you could use 2 1/8 bend fittings (45 degree elbows) instead of a sweep if it is more compact. also I don't see any indication of sanitary vent piping, also a code requirement and essential for good drainage and protecting the water seal level in your traps.

 

[phishfood]

I don't know what code requirments are in your area, but long sweeps are not required under IPC for 3" drains. Your 2nd graphic appears to show vent ells, which are not allowed in any situation where water flows through the drainage system. Short sweeps are allowed, vent ells are not.

I can't think of any reason that you can't move the sinks, showers, and bathtubs above the water closets.