Hi Moorthy

Depending on the dia of your pipeline, the temperatures involved and the location of anchors (or linestops) upstream and downstream off your loops, 30mm does not sound an excessive displacement.

We often see axial displacements going into loops much greater than this. You just need to make sure that your loop is sized appropriately for the expansion and that you check your pipe shoe to make sure that your shoe is long enough to make sue that it will not fall off the pipe support as it moves axially.