Umm, I believe there is a bit of a difference in the interpretation of post answers from both Lawrence and Brent.... Because if you look at both responses and compare what is written between the two within different parts of each answer... You will notice this:
Yes, provided all conditions for a prequalified weld are met. Backing other than steel
is not a prequalified substitute where steel backing is required....
That is the reply from Brent... Now will look at Lawrence's post where the exception to the rule is noted plain as the day...
AWS D1.1 2015, 3.13.2.1
Prequalified CJP groove welds detailed without steel backing or spacers may use backing other than steel as listed in 5.9.3 when the following conditions are met:
(1) The backing is removed after welding, and,
(2) The back side of the weld is backgouged to sound metal and back welded.
Welding procedures for joints welded with backing other than steel in which the weld is to be left in the as-welded
condition without backgouging and welding from the other side are not prequalified.what I take from both answers is both yes & no are noted with respect to what is allowable depending that ALL conditions are met producing what can be called an exception to not being allowed... So you're both right! I completely understand why your initial response was no Lawrence...It was a no because the original qualification was produced according to section 4...Therefore the substitution and use of ceramic backing without documentation noted in the original WPS/PQR is not allowed and yet, can be easily addressed via qualification... Bottom line is it all depends on the details... Time to go see one of my many doctors who are keeping me living with good quality of life so far even though some might beg to differ, but hey
as long as I'm grateful it will be good... Gotta go!
Respectfully,
Henry