Nozzle Loadings

[keens]

Hello All,

Does anyone know if it is a good practice to include Nozzle Loadings for Flange Ratings? What I mean is, in COMPRESS there is a check you can perform that will include external nozzle loadings in the Flange Rating. Or it will also use the Nozzle Loadings to limit the MAWP. Please let me know some common practices. Thanks....

 

[TomBarsh]

I will be interested to read what some of the practices actually used by designers are. Codeware's comments on this issue are in a FAQ here:

http://www.codeware.com/faq/1051.html

I suggest you also refer to "Pressure Vessel Design Manual" by Dennis Moss for additional information on this issue.

Regarding limiting MAWP based on nozzle loadings: It is clear that, given some value for nozzle loading, if the pressure is gradually increased then at some point the local stresses in the shell will reach their corresponding allowable stress. Increasing the pressure beyond this point will overstress the shell. By definition then there will be some "MAWP" coincident with the nozzle loads. COMPRESS elects to include this effect as limiting the nozzle MAWP (which in turn may govern the chamber MAWP), while others might say this is a different issue; the result is the same either way. UG-22 requires that these loads be considered in design of the vessle and the external loads may in some cases limit the chamber MAWP.


Tom Barsh
Codeware Technical Support