Thanks for the reply, but wouldn't ASME VIII be overdesigning the tank? Why couldn't API 620 design formulas be used as long as the allowable stresses don't exceed those listed in ASME VIII for the same material at the design temperature?
Why does API 620 limit itself to 250°F?
Why does API 620 only go to 250 deg F? For a low pressure tank (5 psig) designed to 320 deg F, API 620 still seems like the best fit (this doesn't fall perfectly into any code). Since the allowable stress for 320 deg F is not significantly lower than that for 250 deg F can the API 620...