B31.3 External Pressure + Thermal Stress Limits?

[JayZ]

Per B31.3 the limits of max. code stress = Sustained Loads+ Displacements Loads & When Sh>SL then,

Max. Code Stress = f[1.25(Sh+Sc)-SL] or
Sa + SL = f[1.25(Sh + Sc)]

What Sa + SL would be if we have external pressure? Algor pipePlus solution for 304 SST (Sc =Sh = 20,000 psi)& f =1
is 25,000 psi? Why is that?

Thank you,
Jay

 

[prex]

That equation is not meant for checking stability issues, if this is what worries you. Moreover that equation is used to check longitudinal stresses, and the first thing to do with external pressure is to check stability against circumferential stress under external pressure. Once this is done it might be of course also necessary to check stability against longitudinal stresses under external pressure and other loads.
There are no rules in B31.3 for structural stability checks: ASME VIII Div.1 should be used.

prex

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