VIII-1: Can you use the higher stress values for alloy tubesheets? 1

[Christine74]

I understand that you shouldn't use the alternative higher allowable stress values in Section IID for alloy flanges because of possible dimensional changes, but is it OK to use them for alloy tubesheets? Why or why not?

Thanks.

 

[kyong]

The reason why not to use higher allowable stress for flange design is to minimize flange leak due to deformation. If deformation of a tubesheet is not to be causing critical problems, higher stress value may be used. Actually I use higher value for tubesheet design. When tube sheet has extended flange area, I use lower value only for that flange area.

kyong