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Design Factor for Pipeline Anchor Flange 1

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mch22112

Mechanical
Mar 3, 2011
38
Hello,
What design factor should be used for a pipeline anchor flange?
Thanks
 
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You have only two factors, Design and Operating. Do the calculations for both and price them out. The Design case should be the more expensive but the system will never actually 'see' it. They may also be the same.
A. If there is not a big cost difference then use the worst case.
B. If there is a big cost difference, then present your figures to your Client and see if they want to be realistic (cheaper) or conservative (more expensive).

prognosis: Lead or Lag
 
By "pipeline anchor flange", do you mean a slip on flange that is welded somewhere in the middle of a pipe joint and around which is poured a block of concrete in order to constitute a "pipeline anchor"?

In such case, I don't know if any design factor would need to apply.
 
Could be one of these. A weldend x weldend anchor flange
anchorflangesimage.jpg


You should use the design factor specified by your design code, 0.72 if it is B31.4, or that specified by your class location, if it is B31.8, probably 0.60, 0.50, or maybe 0.40 if it's in a large city location.

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Which part of the design are you looking for a factor?. For hoop stress see biginch above. For axial force the most common I've seen is 1.5. Best thing is not to have them at all, but that's a different thread....

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way
 
Thanks for the help. Yes, I'm referring to the weld-end type anchor flange pictured by BigInch. I agree that the hoop stress design factor should be in accordance with the pipeline design factor. I'm interested to know about the design factor for axial and combined stresses. An anchor flange vendor told me he will use a design factor of 0.9. I assume he is referring to the combined stress design factor. I'm in the process of clarifying, but any tips would be appreciated. 0.9 seems very high to me.
 
Once again see your design code.
ASME B31.4 Table 403.3.1-1 Allowable stresses allows 0.90 * Sy for additive longitudinal stress S[sub]L[/sub]and for sustained and occasional loads.

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