API 650 Flush-Type Cleanout and Shell Connection Supporting Research

[jimmyhutmacher]

Hello,

In many parts of API 650, footnotes have been added to show which papers and research formed the basis for the equations given. However, nothing is provided for Flush-Type Cleanouts and Shell Connections. Is anyone aware of any paper(s) or research that the API 650 Flush-Type Cleanouts and Shell Connections sections were based on?

Thank you!

 

[JStephen]

There's a good chance it was developed by CBI or PDM back in the day and the research just wasn't published, therefore no reference provided.
I've never tried to work through and see if there was any way to derive those equations.
FYI, the equations for the thickness of the cover plates are based on rectangular-plate equations in Formulas for Stress and Strain, if I remember correctly.

 

[Geoff13]

The oldest code I have is the final (1958) edition of API 12C (replaced by API 650 in 1961), and the flush type equations and graphs are remarkably similar. There has been some slight reduction in the reinforcing required over the years but generally identical.

I expect JStephen is correct on the source, but this is before computers so we're talking smart engineers using slide rules and working from first principles.