Thermal Expansion on Piping Systems

[jyanes]

Can anyone offer a literature reference regarding thermal expansion of piping systems? I am interested in reading up on how the use of a linear coefficient compares with using an area coefficient when accounting for diameter expansion.

Thanks.

 

[Q_Goest]

Hi jyanes,

Can anyone offer a literature reference regarding thermal expansion of piping systems?

Most piping systems in the US must conform to ASME B31.3 "Process Piping Code". Para. 319 covers concepts, requirements and equations to be used for piping flexibility analysis, especially those stresses and deflections due to thermal expansion/contraction.

I am interested in reading up on how the use of a linear coefficient compares with using an area coefficient when accounting for diameter expansion.

Can you be more specific? Are you referring to the coefficient of thermal expansion/contraction?

Also, diameter expansion is of little concern when doing a piping stress analysis, since we are most concerned with bending loads created when pipes grow or shrink in length as a consequence of temperature change.

 

[jyanes]

I was trying to figure out if the same linear coefficient for expansion/contraction can be used to estimate a diameter change as well as a length change (which I have seen done in the past). This does not sound quite right though.

Based on your answer, however, the real concern is with the bending loads due to length expansion.

 

[Q_Goest]

I was trying to figure out if the same linear coefficient for expansion/contraction can be used to estimate a diameter change as well as a length change (which I have seen done in the past).

Metals can be modeled as isotropic materials, so yes, the coefficient of thermal expansion/contraction will be the same for both length and diameter of a pipe.

... the real concern is with the bending loads due to length expansion.

Right, and of course how the piping system will react also depends on how it is supported - for example: where the pipe is anchored (fixed point) or allowed to slide or otherwise supported.

There's a tremendous amount of stress analysis that goes into piping systems.