BPVC Sec. VIII vs. ASME B31.3 2

[cocky2001]

Does anyone know if Section VIII supersedes B31.3. Or is there a hiearchy for these standards.

I have a customer who wants to re-rate a ASME Section VIII pressure vessel to meet B31.3. I am not sure if the design will change or just the inspection and NDE requirements.

Any thoughts here would be helpful.

Thanks.

 

[rustbuster]

They are two seperate codes. A section VII vessel is a vessel. You can de-rate within its limits.

Never heard this one before

 

[Guest102023]

Unless this pressure vessel walks, talks and looks like piping, it will not be possible.

The two codes are different, parallel construction codes, applicable to different categories of pressurized equipment, with rules defining where the border between them lies.

 

[vpl]

I have known of situations where former vessels became "fat sections of pipe." However, those were cases where the vessels were already installed and the function changed, not that a vessel was being designed under a piping code.

However, since only you and your customer know the details, it's really incumbent on you to read the scope section for both Codes and determine which one applies.

Patricia Lougheed

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[bhushan76]

I have seen some materials having different allowable stresses in ASME B31.3 as compared to ASME Sec VIII Div.1.
B31.3 has higher allowable stresses for some materials.

As regards to inspection and testing ,hydro test per B31.3 is 1.5 times MAWP (or design pressure) while in Sec VIII it is 1.3 times MAWP multiplied by stress ratio. But there are some additional clauses in B31.3 which if applicable ,allow hydro test at lower pressure.

 

[Shmulik]

Definitely, a pressure vessel will never become a pipe to meet a process piping code.
However, since pressure vessels are not infrequently come as a part of a system, they may be tested altogether with piping acc. To B31.3:

"
345.4.3 Hydrostatic Test of Piping With Vessels as a System
(a) Where the test pressure of piping attached to a vessel is the same as or less than the test pressure for the vessel, the piping may be tested with the vessel at the piping test pressure.
(b) Where the test pressure of the piping exceeds the vessel test pressure, and it is not considered practicable to isolate the piping from the vessel, the piping and the vessel may be tested together at the vessel test pressure, provided the owner approves and the vessel test pressure is not less than 77% of the piping test pressure calculated in accordance with para. 345.4.2(b).

"

I hope this helps.