Pipe Welded - Calculating Max Temp & Pressure

you can consult B31.3 for max pressure and max temperature. for pressure check part 304 of B31.3, from this you will get design pressure and from design pressure you can conclude max or working pressure (as you ll have pipe data such as OD, thickness etc) for design temperature consult 301 of B31.3, may it will be helpful for you.

For piping codes, we have a variety of codes and standards. Therefore you have to define which code you shall apply. For ASME B31.1, you can follow the following example Re: High Pressure Steam Pipe which demonstrates the calculations of pipe wall thickness.

But if the intent is to demonstrate the max. allowable working pressure P, you can extract the required equation from the main equation of ASME B31.1, Para. 104.1.2 : t_m = P D_o / (2 SE + 2y P) + C (Eqn. 3), where the unknown is the thickness t_m.

From that equation, you can easily derive an equation with the unknown is the max. allowable working pressure, P = 2 SE (t_m – C) / [Do – 2y (t_m – C)] (Eqn. 4).

Note. For defining the max. temperature (design temp.), you have to know that the value of S is selected based on that design temp., and we have to differentiate between design temp. and operating temp.