B31.3, Cl.302.2.4 (f)1a, allows 33%

[nzoldun]

B31.3, Cl.302.2.4 (f)1a, allows 33% overstress for up to 10 hrs per instance. Apart from the Wind and/or Seismic allownces, ASME VIII does not appear to have any similar provisions. Since a very considerable amount of 31.3 piping is connected somewhere to an ASME vessel, would anyone care to comment or shed some light on this apparent inconsistency?

 

[prex]

In my opinion this simply means that the vessel and the connected piping might have different design conditions: the vessel with a higher design pressure or temperature, to include in it also the occasional variations that might be unrelevant for the piping.
Of course it's not that simple, as always: pipe reactions used for vessel calculations should then be determined for those extreme conditions that are not used in piping calculations! prex

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