It seems that I've resurrected an old thread. I am having a great deal of difficulty getting some preliminary modeling to pass the NEMA allowables. The main reason is that NEMA makes no provision for class or schedule. Many times the main steam line will be CL2500 with sch 160 piping. This system is incredibly stiff in addition to usually having a forced displacement at the nozzle connection. Getting my sustained case and thermal case to pass is a pain (dare I say, impossible) let alone the occasional cases. This is with an SIF of 1. NEMA allowables seem ridiculously conservative even compared to simple API pump allowables. Can you elaborate on this NEMA factor? I must of missed it...