The APS thermal expansion calculator

23 October 2020

It’s physics 101: materials expand when heated and contract when cooled. High-density polyethylene (HDPE) pipes are not immune to this phenomenon. 

HDPE pipes expand and contract when the pipe temperature changes from the installation condition to the operating condition.

When a pipe expands, it can generate enormous force and stress in the system, but, if it is flexible enough, the expansion can be absorbed without creating undue stress.


The importance of addressing thermal expansion at the design stage

It is important that thermal expansion is addressed at the design stage of your project, to avoid significant problems occurring down the track. 

If not calculated correctly, the forces created by the thermal expansion can be large enough to cause pipe bowing and buckling, damage pumps, valves, pipe clamps and fixings, and even fracture the pipe or cause damage to the steel or concrete structure of the building.

Thermal expansion can be compensated for with deflection legs – particularly in above ground installations of PE piping systems. 

The below APS Thermal Expansion Calculator will identify how much your pipeline is going to expand and contract, what you should allow for with deflection legs.