Thanks for your expediant response, where I am obviously confused is, (and I am only referring to R/T) in para. 6.17.3.2, yes, I am going to paraphrase it due to the confusion..."When (steel backing is) required by Para 5.10, the steel backing SHALL be removed, and the surface shall be finished flush by grinding prior to radiography" It does not leave room for an option.
What I have is, an old Andrex (200 kVp) machine/tubehead (5 MA, due to limits of tubehead) but I have a hard time getting through 1" coupons with a 1/4" backing bar. During my research, (of which I am quite certain I CAN remove the backing bar without hindering the speciman and keep within the AWS standards) I came across this issue regarding "in service" radiographs of welds on site. My cohorts here seem to believe no requirement exist to remove the backing. While I understand the excess labor involved in removing the plate may not justify it, when you may have a live source that can easily punch through it...but I must say...WHAT IS REQUIRED BY THE BOOK...and what has been done for the pass 21 years is the apple and oranges here.
thanks again,,,,,mike