Pipe re-rounding:
ElectroFusion fittings are designed to work on a round pipe.
PE pipes, being manufactured from a flexible material, have the tendency to become out of round due to various reasons.
Such reason may include the following examples:
• Manufacturer: Process conditions will affect the pipe roundness. The pipe manufacturer is obliged to check this parameter, but this should be confirmed by the installer in the field. • Pipe coiling: A coiled pipe left in coil shape for a long period of time will become oval due to the bending forces applied onto it. • Storage conditions: Pipes are often stacked on top of one other during storage. Such stacking will result in the pipes on the lower part of the stack becoming out of round due to the mass applied on them. • Time: PE pipes have residual stresses induced into them during the manufacturing process. As function of time, these stresses will “relax” and pipes may loose their initial dimensions. • Installed pipe: Pipes that have already spent time under ground might loose roundness due to the ground loads, ground movement and internal pressure
In order for the EF process to work properly, it is essential that the pipe is as round as possible.
The success of the EF process is based among other things on the ability of the fitting to close the gap between the fitting and the pipe and building up an even interfacial pressure for the fusion to take place.
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