proper venting for new toilet install

[amp]

working on an old house that has only 1 full bath on the 2nd floor. so i'm installing a half bath on the 1st floor. my issue is with the venting of the new toilet i'm installing. once the 3" pvc is connected to the flange and goes through the floor it will wind around a bit before it attaches to a wye that was installed to the main stack with the idea of future renovation (half bath). the wye is capped until i attach to it. once the 3" pvc pipe finishes winding around just a little bit as i mentioned before (to avoid some boiler lines) it will run parallel with the main stack (only about 3" apart). After a few feet it will do a 90 to get over to (maybe 3' horizontal run...sloped of course) the capped wye. by the way, if you couldn't tell already...the main stack is very close to where i'm installing the half bath..it's just that the stack is fairly buried in the wall. although, since i'm within 10' of the main stack is venting required? hopefully i explained this well enough....but from what i've read, the main stack will act as the vent if you're close enough to it...........that is before you start having problems like sucking your traps dry. does this sound right?...any code, thoughts, etc? thanks!!

[homebild]

Section P3105.1 of the International Residential Code 2003 states:

"The developed length of the fixture drain from the trap weir to the vent fitting for self-siphoning fixtures, such as water closets, shall not be limited..."

In brief, there is no limiting distance that a toilet must be from it's vent.

[amp]

so does mean that the vent is optional since there is no limiting distance? or does this mean i have to install another vent specific to the new toilet?

[homebild]

The stack is the vent.

You need to do nothing else for vent purposes but connect the toilet drain to it.