eekpod, im glad you see it some what the way i do. that is what i get out of reading the code myself.

I think if you’re skillful and able to fuse the side wall (groove face) then to fuse to the backing is not a problem. The problem may arise if you have a poor backing preparation especially if you don’t have an appropriate root gap and the backing is not fit snugly.

~Joey~

welder performance test has to be welded with a backing unless you welded pqr from one side without backing and backgouging.

my answer to question 2, is with a plate welded with a single vee and a backing plate you can weld any joint  in prequalified wps sections fig 3.3 and 3.4 and fillets , i dont know what a backgouged pqr gets you. i know it is done all the time i just dont think it is what they are wanting. i think that is how people interpit the code. and everybody is differant in the way they see things.