Main Stack Vent Requirements

I think I missed something in my DWV design....

It is required that I have a minimal 3" vent on my main stack? I was planning on a vent for my main stack.

The fixtures runs are all vented independently.

I am in the Chicago Area (Illinois Plumbing Code).

Thanks,
Steve

Placement of Bored Wholes

I have to bore a whole for a 2" PVC DWV line in two 2x8 flloor joists. The general contractor has already beefed it up (added a second 2x8. The only loading on the joists is simply floor loading.

As the general left on Friday, I thought he said that I could aim for the midsection of the beam. I'm thinking I misheard him. Should large bores and notches be in the far ends of the beams.

The wholes will be dead center along the horizontal center line of the beam.

Thanks,
Steve

If you are going to bore a hole, you want it in the middle 1/3'rd of the joist. The top and bottom edges are the parts that are doing the most work...the middle is keeping there. Seme idea along the length, you don't want to bore holes in the middle 1/3'rd.