Please, can any body help me out why E=1 in this case? Base on what? Thank you

This is example L-1.5.1. It is given in the statement that the vessel is in lethal service with full RT. Thus the joint efficiency for the seamless head is E = 1.0.

Why is this so? I assume it's clear by now, but just in case...

Para UW-12(d) applies to the seamless head. It says that for thickness calc for seamless heads use E = 1.0 when the requirements of UW-11(a)(5)(b) are met, otherwise use E = 0.85. The full RT at the round seam (as per the problem statement) meets the UW-11(a)(5)(b) requirement, thus E = 1.0.

Thank you Tom,

But this a type 2 joint to shell

Tony

Why does that make any difference?

if it is right, how to usderstand L-1.5.3(d)? E=07 but not 0.85

Ahhh, the difference is the head configuration. In the first case the head was ellipsoidal; the head-to-shell joint is Category B. But in the second case the head is hemispherical and the head-to-shell joint is Category A.

Be sure to see the definition of "E" in UG-32(b). The rule for hemispherical head includes the head-to-shell seam.

Thank you Tom for your kindest reply. I really appreciate your help.

I read the related code as you indicated, and went through all the examples listed in L-1.5. Alomst all of them are met except L-1.5.5(f). This time, I am pretty sure this was a mistake by editor. The E should be 0.8. Am I right? I guess this question was sold out under your help. Thanks again.

Best regards

Tony