Pipelines & Pipeline Safety - EXPANSION LOOPS (or BENDS)

Most materials, when heated or cooled, will expand or contract. The degree of expansion (or contraction) depends on :

1. The Temperature Change.
2. The Original Size of the Material.
3. The Co-efficient of Linear (length), and Cubical (volume), Expansion of the Material.

As mentioned earlier, hot or cold pipeline contents and extreme changes in ambient temperature, will cause the expansion or contraction of the pipeline. In this case, we are mainly concerned with the change in length of the pipeline. (The longer the line, the greater the change in length).

For this reason, expansion loops or bends are incorporated into some pipeline constructions in order to minimize the forces set up by the changes in length.

Here's video that demonstrate pipeline expansion loop

References :
https://www.youtube.com/watch?v=urW5wE0gEEM
http://articles.compressionjobs.com/articles/oilfield-101/4336-pipelines-safety-joints-bends-shafer-valve?start=5