Fresh air vent

[fixit123]

I have a basement that I am looking to re-finish. approx. 12ft x 22ft.
There is a 4in. cast iron pipe (extra Heavy) jutting out approx 3ft away from the back wall. The pipe goes up about 4 ft then over 3ft at 1/8in per ft. pitch. Currently a little 3ft x 3ft storage closet is made to hide the cast iron pipe and sub pit area. Adjacent to the sub pit area is a rectangle pit for access to the "clean out" for the main drain. I found the hub that the pipe is attached to, approx. 1ft 3in. down from the slab.

What I'm Proposing to do is:
1. remove the lead and oakum from the hub that is below the slab.
2. Remove the section jutting up and over to the side wall.
3. apply a neoprene doughnut (heavy) to a 4in pvc pipe into the cast iron hub.
4. apply a 4in 90 with a 30in pipe pitched at 1/4 in per foot towards the side wall. (below the slab)
5. the pipe will then hit another 90 to go straight up, and the last 90 to go out.

this could potentially open the basement up greatly.

Question:
1. will with project still let the necessary gasses out and fresh air in to the main drain line even though (3) 90's are added vs. the one?

2. will the 1/4in. per foot upward pitch of the vent still meet plumbing code for the proposed?

3. would this job even meet plumbing codes?

[phishfood]

If it is a drain pipe, then the arrangement you are proposing would meet code in my area. If it is a vent pipe, then it possibly/probably would not. You need to figure out what this pipe does. Does it drain fixtures above, or is it a relief vent for the main drain?