ASME Section VIII Division 2 Allowable Stresses Limit

[Emily0929]

I am performing a calculation for a vessel according to ASME Section VIII Div 2. I got to the park of calculating the Combined Loadings and Allowable Stresses (4.3.10) and got all the way to the last step (Step 3) that states "At any point on the shell, the following limit shall be satisfied." Unfortunately, the limit given by equation (4.3.44) was not satisfied using all the primary stresses calculated.

I am assuming the way of going about this is de-rating the vessel. I know in Div 1 you go back and reverse engineer to find a new Maximum Allowable Working Pressure (MAWP), but in Div 2 I am not sure how this would be done.

Can anyone help me on how to go about finding a new MAWP for the vessel so that it may satisfy per Div 2 specs?

 

[TGS4]

Sometimes, with some of the equations, it may not be possible to work backwards to arrive at a revised MAWP. You may just be stuck iterating.

 

[Emily0929]

Okay, yes that is what I started to do. I just wanted to make sure there was not another known way to do a de-rating.

THANKS!