Maximum design pressure for Vessel design on sct VIII DivI
Maximum design pressure for Vessel design on sct VIII DivI
(OP)
I got a request for quotation for a Pressure Vessel. The design pressure is 5000 psi and required for Lethal service. I reviewed the ABSA website and found that ASME section VIII Div I is normally up to 3000 psi. Also found statement in ASME section VIII Div I U-1(d) (Introduction), applicable to Vessels designed for pressure not exceeding 3000 psi
Will you kindly clarify this to me.
Thanks
Will you kindly clarify this to me.
Thanks





RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
The rules of Section VIII-1 were formulated primarily for vessels intended to operate at pressures of 3000 psi less. If you use VIII-1 instead of VIII-2, that is your choice as a designer. Remember that if you choose to use VIII-1 as the design basis, the vessel must comply with all of the requirements of this Division before it may it be stamped with the applicable Code Symbol Stamp.
As always, consult with your AI
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RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
Thanks for the help.
RE: Maximum design pressure for Vessel design on sct VIII DivI
The pressure vessel design is based on calculating the minimum required thickness for a every component retaining pressure and that minimum thickness is obviously proportional to the design pressure. That is, the higher the design pressure is, the thicker is the minimum required thickness. The ASME code has made provisions for a reasonable engineering design, for the most common materials used in the industry. It has been established that the Division 1 method of design is most economical and sufficiently safe up to around 3000 psi. Above that pressure, the design method may not be as economical as it should be, hence a Division 2 method of design has been created, to help the design engineers, fabricators and end users to build a safe equipment, but allowing some thickness reduction in comparison with Division 1 by applying more stringent design/fabrication/testing requirements.
Nothing will prevent you designing and stamping your equipment subject of 5000 psi pressure to Division 1. However, it could be more feasible for you to take advantage of the Division 2 allowances.
This days, if in doubt, you can run some quick numbers on the major components of your vessels, to estimate if the design to Division 2 would be beneficial to you (or to estimate the losses if you will use the Division 1 instead of Division 2. I assume that you are using some PV Elite software or similar. As per the above, you could quote on the Division 1 basis, but you might not be competitive as the Division 2 fabricators.
cheers,
gr2vessels
RE: Maximum design pressure for Vessel design on sct VIII DivI
Out of curiosity, what is the contents of the vessel and on what design basis are you designating it "Lethal"...???
-MJC
RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
RE: Maximum design pressure for Vessel design on sct VIII DivI
I have attended several classes or seminars that were taught by members of ASME Code Committees (including one fellow who was on the Division 3 committee for extremely high presssures) where it was also said that Division 1 does not prohibit pressures above 3000 psi.
Use of Division 1 for high pressures may result in excessive thickness as compared to other design Codes. Use of Section VIII Divisions 2 and 3 could result in lesser required thickness, but they will also result in more extensive testing and QA requirements. Depending on the complexity of the vessel, a Div 1 design might be more economical than a Div 2 design, or vice versa.
I suggest discussing with ABSA before proceeding, or before declining to bid.
RE: Maximum design pressure for Vessel design on sct VIII DivI
The rules of this Division constitute requirements for the design, construction, inspection, and overpressure protection of metallic pressure vessels with design pressures generally above 10 ksi (70 MPa). However, it is not the intent of this Division to establish maximum pressure limits for either Section VIII, Division 1 or 2, nor minimum pressure limits for this Division.
Although it could go Div. 1, Div. 2 would most likely be a better application. The question then becomes "new" or "old" Div. 2?
jt