DWV vent questions...

Long story short... I am an architect playing owner / builder... My plumber bailed on me 'cause he lost two of his guys... All plumbers in the area are booked for months. I can do the work myself since I'm O/B. I've done a bunch of remodel stuff in the past, but not much new work.

I've read the IPC on vents many times, but am still a little foggy. For vent diameter, I need to use the FU capacity of the drain as the vent also?
1-1/2"=3 FU max
2"=6 FU max
2-1/2"=12 FU max
3"=20 FU max

Finally, on a circuit vent I can have up to 8 fixtures, but is there a limit on a stack vent? (I have 17 fixtures for one 3" stack vent and 6 fixtures on the other)

Thanks!!!

Bump... ;-)

well i'm just a DIY'r myself to preface this:

stack vents are limited, naturally, by stack diameter. according to the IRC - with a (2.5" - 4") Stack Vent, there is no limit to DFU discharge into a single branch interval BUT there is a limit for the total DFU's into the stack.

IRC code
Total Discharge for Stack in DFU's by Vent Diameter would be:
1.5" = 1
2.0" = 4
2.5" = 8
3.0" = 24
4.0" = 50

now let me suffix this by saying i'm another diy with even less experience - but my forum experience tells me that misinformation gets corrected faster than the question it refers to gets answered
Tom