Pearwalk Engineering as responsible manufacturers of expansion joints take every design and manufacturing precaution to ensure the user receives a reliable product. The installer and user have the responsibility to handle, store, install, and apply the expansion joints in a way which will not impair the quality built into them.


Some conditions of outdoor storage may be detrimental to the units and where possible should be avoided; preferably the storage should be in a cool, dry area. Where this cannot be accomplished the expansion joint manufacturer should be so advised either through the specifications or purchase contract. Care must be taken to avoid mechanical damage caused by stacking, bumping or dropping. For this reason it is strongly recommended that covers be specified on all expansion joints to protect the bellows. Certain industrial and natural atmospheres can be detrimental to some bellows materials. If expansion joints are to be stored or installed in such atmospheric environments materials should be specified which are compatible with these environments.

Installation Instructions

Thermosel expansion joints are shipped with documents which provided the installer with full instructions covering the installation of the particular expansion joint. These documents should be kept with the expansion joint until installation is completed.


Metallic bellows-type expansion joints have been designed to absorb a specified amount of movement by flexing of the thin-gauge bellows. If proper care is not exercised in the installation of the expansion joint cyclic life pressure capacity could be reduced leading to premature failure and damage to the piping system.

It is important that the expansion joint be installed at the length specified by Thermosel Solutions. They should never be extended or compressed in order to make up for deficiencies in length nor should they be offset to accommodate misaligned pipe.

Remember that a bellows is designed to absorb motion by flexing. The bellows must therefore be sufficiently thick to withstand the design pressure, whilst being thin enough to absorb the required flexing. Optimum design will always require a bellows to be of thinner material than virtually any other component in the piping system in which it is installed. The installer must recognise this relative fragility of the bellows and take every possible measure to protect it during installation. Avoid denting, weld spatter, arc strikes or the possibility of allowing foreign matter to interfere with the proper flexing of the bellows.

With reasonable care during storage, handling, and installation the user will be assured of the reliability designed and built into the expansion joint.

For further information about installing your expansion joints please click here

Do's and Don'ts of Handling and Installation


DO Inspect for damage during shipment such as: dents, broken hardware, water marks on carton, etc.

DO Store in a clean, dry area where it will not be exposed to heavy traffic or damaging environment.

DO Use only designated lifting lugs when provided.

DO Make the piping system fit the expansion joint. By stretching, compressing, or offsetting the joint to fit the piping, the expansion joint may be overstressed when the system is in service.

DO Leave one flange loose on the adjacent piping when possible, until the expansion joint has been fitted into position. Make necessary adjustments of this loose flange before welding.

DO Install the joint with the arrow pointing in the direction of flow.

DO Install single vanstone liners pointing in the direction of flow. Be sure also to install a gasket between a vanstone liner and flange.

DO Remove all shipping devices after the installation is complete and before any pressure test of the fully installed system.

DO Remove any foreign material that may have become lodged between the convolutions.


DON'T Drop or strike expansion joint.

DON'T Remove the shipping bars until the installation is complete.

DON'T Remove any moisture-absorbing desiccant bags or protective coatings untill ready for installation.

DON'T Use hanger lugs or shipping bars as lifting lugs.

DON'T Use chains or any lifting device directly on the bellows or bellows cover.

DON'T Allow weld spatter to hit unprotected bellows.

DON'T Use cleaning agents which contain chlorides.

DON'T Use steel wool or wire brushes on bellows.

DON'T Force or rotate one end of an expansion joint for alignment of bolt holes. Bellows are not ordinarily capable of absorbing torsion.

DON'T Hydrostatic pressure test or evacuate the system before proper installation of all guides and anchors.

DON'T Use shipping bars to restrain the pressure thrust during testing.

DON'T Use pipe hangers as guides.

DON'T Exceed the manufacturers rated test pressure of the expansion joint.