1 “Integral” flanges are designs where the flange is cast or forged integrally with the pipe wall, or otherwise welded in such a manner that the flange and the pipe wall are considered to be the equivalent of an integral structure.
2 “Loose” flanges are designs where the method of attachment of the flange to the pipe is not considered to give the mechanical strength equivalent of an integral flange, or in which the flange has no direct connection to the pipe wall. Slip-on welded flange attached to pipe with fillet welds only is generally considered a loose flange