Maximum Thickness of Pressure Vessel?

[chaulklate]

Colleagues;

Is there a maximum thickness a vessel head/shell can be under the rules of ASME Section VIII, Div.1? If so, is it further limited by material selection (ie; P1 may be thicker than P8)?

I don't know why, but I am under the impression that 8" is the maximum permitted for butt welding (forged vessels may be different) and you would have to consider going to a Div.2 or Div.3 design beyond that.

If anyone has a code paragraph to steer me towards will be appreciated.

 

[chaulklate]

Never mind, I figured it out, although my answer is not entirely reflective of my original post. Here it is for anyone who was interested in this...

I have worked primarily with carbon steel and SA-516-70. Section II, Part A, SA-516, paragraph 1.3 limits this steel thickness to 8". This is the number that was stuck in my mind.

 

[Mr168]

Just something else to consider - qualifying welding procedures per ASME IX, a 1.5"-6" thick PQR (1.5" being the norm) will only qualify you up to 8 inches in thickness. Beyond 6 inches, your PQR is qualified to 1.33T, and material availability and cost becomes substantial. Typically, one would have to have spare material ordered at the same time as the vessel components are ordered from the mill/supplier.

 

[vesselfab]

I would consider going to division 2 around 2" thick.

We like to save money on material and labor to put that material together. Just a little more NDE stuff, but doing it anyway.

And engineering is cheap!