Every expansion joint that leaves the factory is provided with installation instructions. These instructions describe the simple, straightforward requirements that must be followed to ensure a trouble-free installation.
Shipping Bars - These are temporary attachments that "hold" the expansion joint at its correct installed length during shipping and installation. Angle iron or channel section is used and is always painted bright yellow. Shipping bars must never be removed until after the unit has been correctly welded or bolted into the piping system. Caution: Tie rods or limit rods are sometimes mistaken for shipping bars. NEVER TAMPER WITH THESE ATTACHMENTS.
NOTE: Great care must be taken when removing the shipping bars. If a welding or burning torch is used, ALWAYS protect the bellows element from burn splatter with a flame-retardant cloth or other shielding material.
UNRESTRAINED EXPANSION JOINTS
Unrestrained expansion joints are not provided with attachments such as tie rods or hinges to restrain pressure thrust. Therefore, they can be used only in a piping system that incorporates correctly designed anchors and pipe alignment guides. These components prevent the bellows from over extension and damage due to distortion under operating conditions.
RESTRAINED EXPANSION JOINTS
Tied expansion joints can be of the Single or Universal Type provided with restraints such as tie rods, hinges or gimbals. Tie rods and gimbals allow the expansion joint to move in all planes. Hinges allow movement in a single plane only. These restraints are designed to absorb the pressure thrust and other external loads like pipe dead weight. For restraints to remain effective, the expansion joint can absorb only lateral offset or angulation in directional changes in the piping system, such as "Z" bends, "U" bends, or "S" bends. Tied units are used where the equipment or adjacent structures cannot accommodate pressure thrust.