Mechanimal
Mechanical
- Oct 16, 2006
- 42
Hi,
I'm a little confused with the required ASME markings and data report for a combination unit (jacketed vessel or heat exchanger).
If I had a jacketed vessel I would have 2 chambers (jacket, and inner vessel), the jacket design conditions are internal pressure 150psig@300F, external pressure 15psig@300F and the inner vessel design conditions are internal pressure 40psig@300F, external pressure 15psig@300F.
Based on UG-116(j)(1)(a) and assuming design conditions equal MAWP /MAEWP would the required markings be:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 40psig@300F, MAEWP 15psig@300F
Max. Differential External Pressure on Inner Vessel shell: 165psig@300F
Max. Differential Internal Pressure on Inner Vessel shell: 55psig@300F
In the data report per UG-19(a)(2) Remarks section: Max. Differential Internal Pressure on Inner Vessel shell: 165psig@300F
Max. Differential Internal Pressure on Inner Vessel shell: 55psig@300F
I am asking this because we received a vessel that required modification and the nameplate was marked:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 40psig@300F, MAEWP 15psig@300F
Our AI suggested it should of been marked:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 55psig@300F, MAEWP 165psig@300F
I can understand his reasoning but I suggested to him if you marked the inner vessel with a MAEWP of 165psig then you should design the inner vessel shell for a MAEWP of 165 + 150 = 315psig since in theory (probably not possible) you could produce that pressure difference when the nameplate is written that way. Then is when I dug into the code book and came across the combination unit marking requirements.
I'm a little confused with the required ASME markings and data report for a combination unit (jacketed vessel or heat exchanger).
If I had a jacketed vessel I would have 2 chambers (jacket, and inner vessel), the jacket design conditions are internal pressure 150psig@300F, external pressure 15psig@300F and the inner vessel design conditions are internal pressure 40psig@300F, external pressure 15psig@300F.
Based on UG-116(j)(1)(a) and assuming design conditions equal MAWP /MAEWP would the required markings be:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 40psig@300F, MAEWP 15psig@300F
Max. Differential External Pressure on Inner Vessel shell: 165psig@300F
Max. Differential Internal Pressure on Inner Vessel shell: 55psig@300F
In the data report per UG-19(a)(2) Remarks section: Max. Differential Internal Pressure on Inner Vessel shell: 165psig@300F
Max. Differential Internal Pressure on Inner Vessel shell: 55psig@300F
I am asking this because we received a vessel that required modification and the nameplate was marked:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 40psig@300F, MAEWP 15psig@300F
Our AI suggested it should of been marked:
Jacket MAWP 150psig@300F, MAEWP 15psig@300F
Inner Vessel MAWP 55psig@300F, MAEWP 165psig@300F
I can understand his reasoning but I suggested to him if you marked the inner vessel with a MAEWP of 165psig then you should design the inner vessel shell for a MAEWP of 165 + 150 = 315psig since in theory (probably not possible) you could produce that pressure difference when the nameplate is written that way. Then is when I dug into the code book and came across the combination unit marking requirements.