Nozzle reinforcement 1

[dbday]

Hi,

If I have a set-on nozzle on the side of a cylindrical vessel where the hole in the vessel is smaller than the internal diameter of the set-on nozzle, do I use the actual hole diameter for the reinforcement calculations or do I stick with the internal diameter of the nozzle that is set on, or something in between ?

Any comments would be appreciated.

 

[mk3223]

By definition, the nozzle reinforcement is based on the pipe branch intersection where the branch opening is a projection of the branch pipe inside diameter, instead of the "actual" hole diameter inside the branch.

 

[r6155]

You need to compensate the hole in the shell.

Regards

 

[dbday]

mk3223 - So if, for example, I have a nozzle with a 6" i.d. but only a 1" hole in the shell then do I design as though there is a 6" hole in the shell ?

r6155 - Taking my example above of a nozzle with a 6" i.d. - if the hole in the shell was 6" and it worked out that that this needed a reinforcing pad to pass code, could I consider reducing the size of the hole in the shell to the point where the need for a reinforcing pad was eliminated ?

 

[r6155]

@ dbday
1) NO
2) Yes
Did you read ASME VIII Div1?

Regards

 

[Christine74]

First I think it's a good idea to specify which Code you're using for the design of the vessel in order to get more precise answers.

Second the situation you describe is so uncommon that I doubt that any Code would have explicit rules for how to address it. I would just be conservative and assume that the diameter of the opening is equal to the ID of the nozzle.


-Christine

 

[david339933]

If you need to eliminate a repad, increase the nozzle thickness. You really need to get into the Code and start understanding what the areas available for reinforcement are and there limits.

 

[Cobra17]

UG-36(c)(3) Openings in vessels. AKA the size of the hole in the shell, not the ID of the connection.


I reduce the opening all the time on NPT 2" OLets. if I limit the opening in the shell to 2.125", with 1/8" corrosion the opening gets exempt.