Pipes expand or shrink due to changes in temperature. How much depends on:
This could have serious consequences for the complete installation and cause damage to the entire building.
Each material (steel, copper, PE, PVC, etc) has its own specific coefficient for expansion. Although metal pipework suffers from thermal movement, it is widely acknowledged that plastic materials expand and contract more than metals. If it is not catered for, expansion of a pipework system can cause compression of the pipe, resulting in buckling and deformation. Equally, contraction of a pipe can cause it to be tensioned again, developing tensile loads in the pipe system.
It is crucial that both expansion and contraction are addressed at the design stage of a project to avoid significant problems occurring, such as snaking pipes or stress on pipe joints that could eventually lead to leaks or burst pipes. It is important to use the right products in order to guide the expansion and contraction in the right direction. The video below shows a PE-pipe expanding when warm water flows through and contracts when the warm water flows ceases. It also shows how to fix such a pipe in the correct way.
There are many product combinations that can be used to deal with expansion. Your requirements will depend on the level of expansion expected and the size, weight and type of pipework being installed. For more significant expansion requirements, Walraven offers various fixing points and sliding devices that can be one solution. Fixing points are applied to pipes with considerable expansion. The fixing point is attached to a neutral point so that the pipe can expand in both directions. Slides are applied in-between the fixing points, so that the pipe is free to expand and contract. The adjacent image shows some slide guides in place.
Read our case study of a pipework installation under a new bridge where thermal expansion was a key consideration to be dealt with.Read case study…
Expansion and contraction can be a complex area and you may need some technical support in order to design an effective solution to deal with the requirements of your installation. We have many years experience designing solutions to deal with expansion.
If you have any questions about expansion and contraction of pipes, please contact our technical advice service at [email protected]
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