Spot RT and ERW Pipe

[dskjockey1]

This has probably been asked before but. If I perform spot RT on a circumferential joints of ERW (SA-53B) pipe is my longitudinal JE = 1 or .85?

Thanks!

 

[TomBarsh]

UW-12(e) addresses welded pipe. It directs us to UW-12(d) for seamless pipe, and says to treat the welded pipe same as seamless except to use the allowable stresses for the welded pipe.

UW-12(d) tells us that for calculations involving circ stress (through the longitudinal seam) E = 1.0 if we meet requirements of UW-11(a)(5)(b), which the spot RT does not (unless we use one or two of those spots to meet the UW-11(a)(5)(b) requirements), so we are down to E=0.85 for calculation of required thickness for circumferential stress.

For required thickness for longitudinal stress, E will be based strictly on the RT performed on the circ seams, which is spot. Thus E = 0.85.

But for this material (welded pipe) the allowable stress taken for longitudinal direction benefits from Note G24 from the allowable stress tables, which permits us to divided the tabulated allowable stress by 0.85 when calculating the required thickness for longitudinal stress.

There are a number of Code Interpretations that rather play havoc with UG-116 RT marking when you have welded pipe.