API 650 Roof Nozzles

[cherocks]

Anyone have experience with nozzle reinforcement design for ROOF nozzles 30"? API 650 5.8.4 references a table showing only 20" and 24" nozzles (manways) and 5.8.5.6 only includes 12" and smaller nozzles.

I've tried to examine the reinforcements and determine what correlation, if any, exists, and I have been unsuccessful. I cannot locate anything within API which explains their rationale for reinforcement areas.

 

[JStephen]

That's an area on which API is simply not clear, it's not just you.
They include details with and without reinforcement, but don't say when to use either detail.
Generally, if you try to check reinforcing areas like a shell opening, the required thickness is very small and you won't need reinforcing.
Even where reinforcing is not required by design, it may be advantageous just for fit-up.