Heat and cold causes piping systems to expand and contract. This expansion and contraction can put enormous stresses on the pipe causing it to buckle or fail. A common way for dealing with this is to install expansion joints or expansion loops.
Expansion joints, abbreviated as EXPJT, are designed to withstand pressure and temperatures growth in the piping system. The thermal movement can be angular, axial or lateral. The expansion sometimes must be restricted to a specific length to prevent damage of equipment or piping.