mabhuBR,
There is so much you are not clear on in your post.
A weld with a root face dimension of zero would be a CJP weld.
It is possible to make a PJP weld with a Root Opening of Zero however.
I would suggest that you look in AWS D1.1 at figure 3.3, Prequalified PJP Groove Weld Details.
You will most likely find what you are looking for.