Allowable Torsional Deflection In A pipeline

[Shahin71]

Hello All

I have done a search on this forum for allowable deflection on a pipe and found all talking about deflection between supports due to weight. What about radial deflection due to thermal growth of the pipe. Is there any limit.

Thanks in advance

 

[DSB123]

Shahin71,
The subject title of your post is "Allowable Torsional Deflection in a pipeline" whereas your question relates to radial thermal growth. Which is it you want to know about??

 

[BigInch]

There are no deflection limits, other than what is suitable for installation without wrinkling, excessive ovalization or other deformations, provided the result is within the stress allowables.

The stress limits are proportional to deflection, or more appropriately deformation, when such stresses are within the elastic range and equal deformation taken over a given unit of measure where such deformations occur, those units depending on if it is bending = radians from the axis/unit length, torsion radians around the pipe axis/unit length, or elongation, length/unit length.

A typical pipeline limit for cold bending a pipe might be 1º of angular deflection from the pipe's axis per length of pipe equal to 1 diameter, for example.

http://virtualpipeline.spaces.msn.com

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