When the nozzle loads are a little bit over allowable values, can I use hot modulus for equipment nozzle loads as per 319.4.4(a) and 319.2.2 (b) in B31.3? Of course, stress check shall be done based on the highest values.

Is there any limitation to apply it to piping system? To be honest, I have not used it before though.

Thanks,

You can try to make a nozzle calculation with WRC 107/297 , usualy the hot modulus is use for high temperature ( I think more that 650 F, but not for stress ) .

Best regards
Marian

NewPiper - Yes you can. Just setup an additional OPE load case but on "Load Case Options" select the corresponding hot modulus. This should lower your nozzle loads, reducing the values you input into WRC107.

As was mentioned above, you don't want to use the results from this load case for anything else.

Thanks Marian and Richard,

Everybody considers mainly WRC-107/297. Is there any problem to apply it to rotating equipment and heaters? Basically the reaction forces are reduced by the ratio of Hot Modulus/Cold Modulus.

Thanks again!

No, you're still ok - you just wouldn't use WRC107, but API-610 (or whatever).

Perhaps I'm too picky here but the stress check is not performed using "the highest value" (of moment). The stress check should be made with the Code-defined value for Young's modulus. It usually IS the highest value.