Recently, there was a discussion on the ASPE Open Forum regarding, “Plumbing Pipe Thermal Expansion and Expansion Fitting.” Generally, this topic would be found within your specifications under Section 22 05 16, “Expansion Fittings and Loops for Plumbing Piping;” this topic is under-discussed, and in many cases, poorly understood by many designers and engineers.
All materials expand and contract as the temperature conditions within which they are installed or operate change. Expansion and contraction occurs in all directions; longitudinal and radially. The change in longitudinal (length) is of greater concern, one must also understand that radial (change in diameter) does occur.