Doing a trial for fusion welding of HDPE pipesElectrofusion is a method of joining MDPE, HDPE and other plastic pipes with special fittings that have built-in electric heating elements which are used to weld the joint together.
The pipes to be joined are cleaned, inserted into the electrofusion fitting (with a temporary clamp if required) and a voltage (typically 40V) is applied for a fixed time depending on the fitting in use, the built-in heater coils then melt the inside of the fitting and the outside of the pipe wall which weld together producing a very strong homogeneous joint. The assembly is then left to cool for a specified time. The joints produced tend to be more reliable than threaded fittings sealed with O-rings.
These pipelines deal with an enormous amount of pressure so the Electrofusion way of welding provides for the reliability required.