1. The problem statement, all variables and given/known data Problem: find the thickness of a Pressure Vessel. Given: Operating Pressure, Operating Temperature, Material type and Grade, and OUTSIDE Diameter/Radius 2. Relevant equations q1. how to calculate Design Pressure/Temp. from Operating Pressure/Temp.? q2. how to calculate INSIDE Radius using OUTSIDE Radius (note that thickness is needed)? 3. The attempt at a solution I tried to obtain the thickness of that pressure vessel using (ASME Code SEC.VIII, DIV.2, ARTICLE.2)'s formula, but it only takes INSIDE Diameter, so how can i obtain Inside Diameter to get the thickness. Or is there any other way that doesn't require INSIDE Diameter to get the thickness.