Kitchen Drain Size IPC in CT

Can someone tell me if in CT, we use IPC/IRC if the kitchen drain can be 1.5" or if 2" is required. Tried searching but couldn't find the answer.

Just trying to help a fellow co-worker who is preping for his rough inspection and realized he used 1.5" for the drain line.

I found this PDF,

Here's a quote

"The IPC and UPC both require 1-1/2" minimum traps on kitchen sinks. The
IPC permits a 1-1/2" branch drain. However, the UPC requires a 2" drain
beyond the trap on any sink, as there may be food waste now or in the
future."

We googled the definition of "branch line" but were 50/50 on whether it would apply in this case. Basically the Kithchen drain goes down the wall and then hang a 45 to the left and makes a connection over to the 3" vertical main stack. That is only a couple feet away from the main stack. Do you think that means the "IPC Exception" would apply.

Thanks
Rem

drain

Why are you so concerned with the "minimum" size you can install? Use 2", regardless of what you can "get away with", and you will eliminate a lot of future problems.

I know, I used 2" for mine, but he already this this all and I was just checking it for him. I feel bad telling him to redo it, esp since he actually did it in copper.

Just trying to see if he can get by with what he has, even though the AHJ will have the ultimate say. I know it will all work b/c old drains were 1.5" including his old one.

Just was trying to see if he would be able to use that IPC exception in case his inspector pushes him to redo it in 2".

The code is a minimum, and where you live will choose one (and not mix them)...they often also ammend it with local 'enhancements'. So, it depends on where you live...minimum doesn't leave much margin for error.

This kitchen drain done in the 60's and then with me tweaking it a bit in 1983.
It was done with 2" to the kitchen, 1.5" on the trap and venting.



Moving the venting down for the new larger window that went down to the countertop.