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How To Install Expansion Joints

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At Stourflex, offering the right product to provide the right solution is hugely important to us and therefore we offer a complete range of pipework expansion & anti-vibration equipment all supported by a comprehensive range of technical services, that includes specialist site surveys, technical advice and a reliable aftersales service.

We are amongst the UK’s foremost providers of complete pipework flexibility designs and solutions, including of course, expansion joints.

What exactly are expansion joints?

Expansion joints are designed to safely absorb the movement in pipework systems due to heat-induced expansion and contraction of pipework. When a pipeline is subject to a change in temperature it will expand or contract in direct proportion to that change. Expansion joints are primarily designed to compensate for thermal expansion but it is not the only movement being imposed on the pipeline system. Other types of movements can occur that need to be taken into account when providing a pipework flexibility solution such as building settlement, wind loading, vibration from rotating and reciprocating machinery.

Expansion joints – sometimes called expansion bellows, flexible joints or compensators – are devices that comprise of a flexible element known as the bellows membrane that is fitted to end connections that are best suited to the pipework they are to be installed in. Most bellows membranes are manufactured from stainless steel and are made up of a series of convolutions manufactured to withstand the pressure of the system but also must be suitable to accept the movements for which they are designed.

Expansion joint installation

The use of expansion joints is rigid and correct installation is governed by a strict set of rules. All Stourflex expansion joints are supplied with a comprehensive set of installation instructions and in order for our products to provide the service for which they were designed the detailed information must be strictly adhered to.

In summary these rules are

  • Before installation remove the packaging, shipping devices and inspect the bellows for any

damage to the bellows convolutions.

  • Expansion joints can only be used in anchored pipework – omitting anchors will result in


  •  Pipe runs must be straight.
  •  Only one axial expansion bellows may be place between two anchors
  •  If the movement capacity of one axial expansion bellows is not sufficient for the movement of the pipe, the pipe will need to be subdivided by anchors.
  •  The pipe adjacent to the expansion joint must be guided to control the movement as per Stourflex installation instructions.
  • Make sure you install expansion joints so that the arrow is pointing with flow

It is essential that before installation that the correct expansion joint has been selected for the operating conditions that exist. Temperature, pressure and movement should all be confirmed and also ensuring the expansion joint has the correct end fittings for the pipework it is to be installed in.

Omitting anchors and insufficient guides on and around the expansion joint will result in failure. It is also important that full length of the pipework is sufficiently guided to prevent buckling.

Expansion joint Storage & Handling Do’s and Don’ts.


  •  Expansion Joints should be stored under cover
  •  Store the expansion joints so that the mating surfaces are not damaged such as the flanges faces are free from debris.
  •  Protect convolutions from mechanical damage and cement, plaster and concrete mixtures.
  •  Store expansion joints so that they are not piled one on top of another as to compress the bellows and alter the free length.


  •  Do not roll expansion joints on the convolutions
  •  Avoid wire brushes or steel wool on bellows
  •  Don’t over-rotate the expansion joint.
  •  Do not sling from hinges or tie bar arrangement

Always refer to the instructions of the manufacturer and the designer of the original system.