I have searched the forum for info on backing rings. My question is do you have to requalify the welders under B31.1 if you are going to use backing rings? They are certified on open butt SMAW pipe. The only variable is the backing. I'm thinking we do not have to recertify and the only previous post on this matter agrees. I have B31.1 but not ASME IX. Is that where I would find this info? Thanks in advance.