ASME.BPVC.VIII.1 fig UG-37.1 F correction factor.

[tigny]

Hello,

in an opening reinforcement calculation, according to ASME.BPVC.VIII.1 fig UG-37.1, for a circular opening in a cylindrical shell, without reinforcing element added, when checking the 90° theta to longitudinal axis location,

is it enough to modify the correction factor F (value become 0,5) in A "Area required" and A1 "Area available" formulas before comparing the A1+A2+A41 to A?

best regards,

Cyril

 

[SnTMan]

tigny, yes, if you look at the equations, F only appears in A & A1. For a radial, circular, integrally reinforced opening in a cylinder, you will find checking in the circumferential direction to be a trivial exercise.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[david339933]

Yes, but not much point for a radial connection.

 

[tigny]

Thank you SnTMAn and david339933.

Does it imply that, for checking at 90° theta to longitudinal axis location instead of 0°, only F must be modified, and all other data can be left unchanged?

Since at the bottom of Fug. UG-37.1 there is the NOTE (2) "This formula is applicable for a rectangular cross-sectional element that falls within the limits of reinforcement.", I'm not sure whether changing only F is correct, because the sections at 90° for the vessel are not "rectangular" when looked at like on the illustration below.

example when only changing the value of F (in the following calcs. A41 is the same in both locations):
[ul]
[li]at theta = 0°, A = 144,4 cm²; Area = 147 cm² > reinforcement OK (98% of needed area A)[/li]
[li]at theta = 90°, A = 72,2 cm²; Area = 198 cm² > reinforcement OK (36% of needed area A)[/li]
[/ul]
(I extracted calculations results from COMPRESS and changed only the value of F from 1 to 0,5.)

Illustration of the locations:

best regards,
Cyril

 

[david339933]

Not sure I see the problem...

Note 2 is referring to the rectangular cross-section of the repad....see A5 calc.

 

[SnTMan]

tigny, I don't find it written as such, but the limits are considered to follow the contour of the vessel in the plane of interest. If you have an old Appendix L, or whatever it's currently called, see the examples for hillside nozzles.

So, to answer your question, yes, I believe only the F factor needs be changed.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[tigny]

david339933, thank you, this is right. I thought this note applied to the whole content of the Figure UG-37.1.
SnTMan, I will check the Appendix L in previous versions of the Code (2010; 2011a) or PTB-4.

best regards,
Cyril

 

[tigny]

Hi,

I went through example L-7.7 (hill side) nozzle, and I checked my model in COMPRESS with an added Offset of 1 mm CL to CL, so that the reinforcement check is first done in the plane perpendicular to the vessel axis and also in the plane parallel to the longitudinal axis.

In the plane perpendicular to the longitudinal axis, the A41 can be zeroed.

So we would only resquest that "tc" of Figure UW-16.1 (a) is present at the location perpendicular to the longitudinal axis.

Thank you for you help.

best regards,

 

[david339933]

Have no idea what you are stating, but something seems fishy.

 

[SnTMan]

Not certain either, but maybe a variable fillet weld around the nozzle?

Good luck with that

The problem with sloppy work is that the supply FAR EXCEEDS the demand