Under the SIF's and TEE's side window in the input spreadsheet, there is a drop down list to select the type of connection.

What is the effective difference between the type 8 and type 9 for socket weld fittings? I see socket fittings coded both ways (I generally use type 9) and I find that either one will give you the 2.1 SIF's as indicated in B31.3.

I've looked through the documentation and the help on the input screen and it's not very clear, other than the "as welded" and "no undercut".