EJMA
EJMA
Standards of the Expansion Joint Manufacturers Association
The design and application standard for metal bellows expansion joints. It covers movement capability, cycle life, and the restraint arrangements — tie rods, hinges, gimbals — that handle pressure thrust. That thrust is the point: an unrestrained bellows pushes its anchors apart with a force equal to pressure times the bellows effective area, which routinely dwarfs the thermal force the joint was fitted to relieve.
This is an explanation, not the standard. PipingInspector is not affiliated with EJMA and reproduces no part of the document. Always work to the current edition of the standard itself and to your project specification.