Handling and installation of expansion joints need particular care and shall be carried out by experienced staff. Damage to expansion joints, especially the bellows, shall be avoided, in order that the full pressure reliability and service life is achieved. The manufacturer’s authorisation shall be obtained before any repairs are carried out. Transport safety devices or pretension or shipping bars shall not be removed before installation.
Care shall be taken to ensure that lifting chains or other lifting devices do not damage the bellows or the bellows outer cover. Care shall be taken to ensure that the expansion joints are installed at the correct location and the right way round, indicated by the flow direction arrow. Expansion joints shall be installed at the correct length and any cold spring (pre-stressing) shall be agreed with manufacturer. During installation the bellows shall not be stretched, compressed, bent or twisted, unless such movements are within the design envelope. Gaskets and seals shall be positioned correctly. A check shall be made to ensure that no foreign objects or media inside or outside of corrugations will affect the working of the bellows. During welding no electrical current shall be conducted through the bellows. The expansion joint shall not be used for an earthing connection.
After installation transport safety devices and pretension bars shall be removed if any. Anchors and pipe guides shall be firmly installed prior to pressure testing. Consideration shall be given to the inclination of the expansion joint in order to provide for drainage.
Unrestrained expansion joints under pressure will exert a considerable axial force on the pipeline, i.e. anchors. It is essential that checks are carried out when the expansion joint is first pressurized to ensure that there is no unforeseen stretching of the bellows. If unforeseen movement is apparent then the pipe guides or anchors shall be examined to ensure that they have been installed correctly and sufficiently designed for the duty. The distance between the bellows and the first support as well as the distances between the supports shall be such that any buckling of the pipework is avoided. Only one expansion joint shall be installed between each set of anchors. Only axial pipe guides or anchors shall be used adjacent to an unrestrained expansion joint. Special instructions shall be observed for the installation of hinged expansion joints. It is important
That the direction of the pipe movement is perpendicular to the axis of the pins.
Do not lift the expansion joint by the shipping bars.
Do not lift the expansion joint by the hinges, gimbals, tie rods or any other operative device.
Do not fix any chains or ropes to the bellows section, as the bellows portion of the expansion joint may be easily damaged and cannot usually be repaired.
Do not remove any blocking/transport device (yellow marked and clearly identified) if available until the Expansion Joint has been installed.
Do not stretch or compress the expansion joint in order to absorb any defects along the length of the pipe or to rectify any misalignments unless this was taken into account during the initial design and the manufacturing process.
Do not allow weld splatter to hit unprotected bellows. Protect with an appropriate fire resistance insulation blanket or wet chloride-free insulation.
Do not use cleaning agents that contain chlorides.
Do not use steel wool or wire brushes on bellows. Do not force-rotate one end of an expansion joint for alignment of bolt holes as in most cases bellows are not capable of absorbing rotation.
Do not hydrostatic pressure test or evacuate the system before installation of all guides and anchors. Pipe hangers are not adequate guides.
Do not exceed a pressure test 1-½ times the rated working pressure of the expansion joint.
Do not use shipping bars to retain thrust if tested prior to installation.