General Installation Instructions for Metal Bellows and Expansion Joints

Bellows Systems (BSI) standard expansion joints are designed to for specific movements and fatigue cycles life per calculated design data. Please confirm that the combined movements due to thermal or mechanical loading do not exceed the specified design data for the expansion joint. Proper installation and handling during installation and maintenance is necessary for safe and reliable operation of the expansion joint. Failure to follow proper installation procedures can be adversely affect its operational capacity and service life and can void the manufacturer warranty.


Bellows Systems standard expansion joints are shipped with shipping bars and protective wrapping in either cardboard shipping boxes, pallets or wooden crates. The shipping bars are usually identified by yellow paint. Upon receipt of the expansion joints, we highly recommend that a visual inspection is performed to confirm it has not been damaged during shipping.

What to look for during receiving visual inspection?
  • Visible damage to packaging
  • Visible damage to expansion joint components like, shipping bars, tie rods, hinges, cover, liner lugs, flanges, weld ends, etc.
  • Visible signs of corrosion due to exposure to moisture or other corrosive elements.
Storage and Handling Precautions
  • Do not lift expansion joints using slings or chains around the bellows elements. BSI technical staff provide guidance for correcting lifting procedure to prevent damage due to lifting loads.
  • Standard expansion joint should not be subjected to torsional loads during handling and installation.
  • Expansion Joints should be stored in a dry moisture proof environment.
  • Store expansion joints on an even surface and do not stack expansion joints on each other without proper supports. The weight of the end fitting and other features can damage the bellows during storage if not properly stored.

Equalizing Expansion Joints are shipped with wooden or metal spacers between the equalizing rings. Other shipping expedients may consist of wooden or metal braces or stays, painted a contrasting color for identification. These shipping expedients must be removed before installation to allow for correct precompression of Expansion Joints.


Expansion joints are designed for specific working parameters. Do not try to correct for alignment mismatch using expansion joints unless specifically designed for it. Following checks should be performed prior to installation,

  • The expansion joint should be free from any damage, dirt or debris.
  • The sealing faces on flanged expansion joints are flat and square.
  • Ensure the Beveled weld ends on expansion joints with weld necks are not damaged and are square.
  • Verify the face to face gap in the piping where the expansion joint is to be installed matches the face to face design dimension of the expansion joints. Note, BSI ships expansion joints tied back ( pre-compressed) for easy installation. Refer to notes below, for guidance on pre-compression of bellows to compensate for temperature variation during installation and operation.

When an Expansion Joint is installed at a temperature above the lowest temperature at which the line will operate, the Expansion Joint must be pre-compressed by an amount calculated by the following expression. This compensates for the thermal growth from minimum expected temperature to the actual installation temperature.
(5) Precompression = Rated movement of Expansion Joint x (Ti – Tmin./Tmax. – Tmin.)
When (Ti – Tmin./Tmax. – Tmin.) ≤ .15 Precompression is not necessary.
When (Ti – Tmin./Tmax. – Tmin.) ≥ .16 Precompression is essential.

Adjustments for precompression can be made at the factory, or they can also made in the field where accurate temperature of pipe at time of installation is known.It is imperative that anchors and alignment guides be installed in any pipe line in which Expansion Joints are installed. The only exception to this rule is in cases where anchor loads are absorbed by some other form of suitable restraining hardware, such as tie rods or hinges, etc. Even in these cases adequate guiding is necessary.

An Expansion Joint should never be bent or mis-aligned to compensate for mis-alignment of the piping. Any such alignment adjustments must be made to the piping.


Installation should be carried out by suitably trained personnel following standard work safety requirements.

Prior to installation, all shipping expedients must be removed. Precompression of the Expansion Joint must be made as per instructions above. All anchor bases, anchors, and guides must be installed and secured to some rigid part of the installation. Only after these instructions have been complied with, can Bellows Systems Expansion Joints be hydrostatically tested at 1-1/2 times their rated working pressure.

The preferred location of single Expansion Joints is next to an anchor. When installed in the center of the line, a greater number of guides will be necessary.

  • The expansion joint should be sufficiently protected when welding or grinding near it from weld spatter or grinding debris.
  • For expansion joints with a flow liner the direction of flow is usually stenciled on the ID of the liner. Make sure the expansion joint is assembled in the correct direction.
  • For expansion joints with Vanstone flanges, the floating flange side is downstream of flow. Make sure the upstream flanges are torqued first and the expansion joints is installed in the correct orientation.
  • When installing hinged expansion joints, make sure the hinge pin orientation is correct.
  • Do not remove components such as tie rods, hinge pins, covers during installation as they could be damaged and are integral to the functioning of the expansion joint.
  • Take care not to damage the bellows convolutions during installation using tools such as spanners or wrenches.

Before completing the installation and commissioning be sure to perform a thorough visual inspection of the expansion joints and the piping.