How often do I need to use an expansion coupling for HDPE?
For pipe sizes up to 63mm there should be an expansion coupling every 5m. We would suggest one every floor on a vertical stack. For pipe sizes above 63mm, so 75mm and above an expansion coupling should be installed every 2m. However, any change in direction where the maximum distance between fixed points exceeds 1m you should install an expansion coupling.
For a more detailed answer and for further reference please see our Technical Bulletin below on Terrain FUZE HDPE Thermal Expansion.