Pressure Vessel Corrosion Allowance

[Jharper361]

My employer has thrown me into the world of QA/QC inspection after years of never inspecting their fleet. I am questioning our U1a's. They state a Minimum thickness of .680 on 96'' heads but allowable CA of .0625. Do I subtract .0625 from the minimum thickness or is the minimum thickness when we call it a dead vessel or downgrade MAWP?

 

[LittleInch]

Any other thicknesses it quotes?

Min should be minimum. then you add CA to get to your required as built or more thickness, but depends how they've calculated minimum.