First of all I would like to thank everyone for thier input and advise for my ASME WPS post.

I am now in the process of writing a prequal wps from D1.1 section 3. A-36 to A-36 Group II V groove w/backing

How are positions and base metal thickness ranges determined for a prequal wps? I know if a welder actually welds in the 3G and 4G on a 1" plate with backing he is qualified to weld in all positions form 1/8" to unlimited, but how do I determine the ranges if no testing is being done. Right now I am just starting up the weld program at my company.

Also do I have to write a seperate WPS to cover fillet welds when in table 4.2 and 4.11 note d says a CJP weld qualification shall qualify any size of fillet or PJP groove weld for any thickness or diameter?

Thanks for all of your help.
Chris