We have a stand for fluid steam demostration. There is steam traps with glass body and steel. I need know "theorical" equation for determinate the thickness o allowable pressure(Relief Valves) in a tube (cylindrical) of glass, specifically borosylicate 33. We working, in the laboratory with 30 psig max pressure.
A tube thickness 2.5 mm (0.098 inch) is enough for 30 psig?

You need to give a lot more information about your assembly to help provide any assistance.
Is it a cylinder?
If cylinder what is the diameter?
How is it attached to the metal?
What is the temperature?
Is there is thermal shock?

Based on the size of glass pipe we used your thickness sounds a might thin. 

oh excuse please. Well, the cylinder is made in borosilicate 3.3 or Pyrex.
diameter is 90 mm (3.54")
thickness= 2.5 mm (0.098")
the working pressure is 30 psig. (max)
temperature  max= 120?C (248?F )
Referent to thermal shock, the inicial temperature is 32?C and the final is 120?C in a aproximately 20 minutes.  
the  fluid is steam, assume saturate.
thanks advance unclesyd  and someothers.

i want to know the mawp or the minimal thickness.

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