Glossary of terms

Expansion cushion

An expansion cushion (compensation pad) is a flexible foam element placed around a preinsulated pipe where the network expands thermally — at bends, branches and L/Z/U expansion arms. It creates a zone in the ground into which the pipe can move without excessive stress, absorbing the movement caused by thermal expansion. On the profile and in the documentation its location and thickness are marked along the sections that work in expansion. Sizing the cushions goes hand in hand with the compensation calculation and the layout of fixed points, which decide where and how much the pipe moves.