Tanks EJL,

But, according RT-4, I must use E = 0.85 for efficiency of the longitudinal seam in my case, correctly?
According RT-2, if I full radiography the longitudinal joint and spot radiography the circumferential joint, I can use E = 1 for efficiency of the longitudinal seam and E = 1 for efficiency of the circumferential seam too, correctly?
And then, when I can use different efficiency for longitudinal and circumferential joint?

Pedro