When ASME SEC VIII Div 2 Required in ARAMCO

Probably in here someplace....

https://cae-cube.ru/literatura/literatura-sosudy/sosudy-prochnost/ASME/ASME_PTB-1-2014.pdf

Is this for a project already underway or are you tendering for a project? If you are tendering I would say submit a clarification stating your intentions and you need to clarify if these guidelines are only for guidance or are compulsory.

If this is on a live project then contact the lead engineer in Saudi Aramco and ask them. Submit a technical query to allow for traceability of the answer.

I don't deal with Saudi Aramco but the oil and gas companies I deal with almost universally use the word "shall" when something is mandatory and "should" when it is advised but not compulsory. These definitions are usually stated at the start of the document.

But if thickness difference is a mere 2-3 mm, then we should use div-1, and I think ARAMCO is trying to say the same thing right? Because, for very high pressure, maybe around 3000 psi thickness difference will be sizable. In my case pressure is around 1000 psi.

It sounds to me like they are saying if any of the parameters are close, div II specs should prevail (if it doesn't cost much more). So you're not cutting any corners, you're just erring on the side of safety (if the cost is minimal). So don't be penny wise and pound foolish, use the common sense approach to fabrication.

The original statement indicates division 2 should be considered and that the following conditions should be considered when deciding whether to use division 2. Sounds like it's at the discretion of the contractor whether to consider it or not. Looks like a wonderful liability issue just waiting to happen. BTW, economically justified for whom? Sounds like a risk assessment is called for with customer approval necessary to cover the contractor's a$$.

With respect to a liability issue in selection, the responsibility lies with the user or his agent. It is his responsibility to select the Code.

To complicate the situation, with the 2017 Edition, ASME split Div. 2 into Class 1 and Class 2. Div. 2 / Class 2 vessels require that the user provide a certified design specification and the fabricator needs a U2 scope of authorization. Div. 2 / Class 1 does not require a certified design specification, but there cannot be any fatigue or analysis required. A fabricator with a U scope of authorization can provide a Div. 2 Class 1 vessel, just like a Div. 1 vessel.