Test pressure in Sec VIII division 2, how to calculate bending stresses?

[Minamtungekar]

Dear all,
I have designed an exchanger according to division 2, regarding hydro test pressure, the code writes.. "when a hydrostatic test is performed, the hydrostatic
test pressure of a completed vessel shall not exceed that value which results in the following equivalent stress limits:
General Primary membrane stress <= 0.95 yield stress
and also,
A calculated shall not exceed the applicable limits given below:
Pm+Pb<=1.43Sy for Pm<0.67Sy
Pm+Pb<=(2.43Sy-1.5Pm) for 0.67Sy<Pm<0.95Sy

How do I calculate Pm and Pb??
Pb is general primary bending stress.. Please help

Note: I got the test pressure formula from para 8.2.1 but that is the lower limit of the test pressure value, I need to check them at upper limit of the test pressure value which, if am not wrong is 0.95 times the yield ay hydrotest temp. for div 2
Please help me calculate Pb in order to check whether the stresses are with the limits specified above (which is taken from para 4.1.6.2 of the code)

 

[TGS4]

Pb only exists in a flat plate. You can calculate the bending in a flat plate - in your situation it will be a perforated plate. Voila.