- Cleanliness comes from management of the work site. The pipe end to be jointed must be scraped to remove its oxidized outer layer along with any physical contamination that is present on the outside surface of the pipe. Care is then taken to prevent dust being attracted, splashing on the pipe end, sweating on, or physically touching the prepared pipe, the types of things that could interfere with Jointing.
- Visual Examination Of Pipe & Fitting Assembly Gap (Methodology)
1. The pipe end should be squarely cut.
2. The pipe end should be round.
3. The pipe should be inserted until it reaches the end of the socket in the fitting area, likely to minimize voids.
4. The pipe should be roughly centered in the fitting and not misaligned. - Heat is applied by electrical current flowing through the wires in the fitting which in turn heat up the surrounding material. It is a feature of electro fusion that it automates the step of heating the material but this relies on the correct output voltage being maintained by the electro fusion control unit (i.e. in calibration) and the correct voltage and welding time being selected. Things that go wrong are pipes being misaligned in the fitting which move during the heating process and displace the wires so that they do not work in the intended manner which is preventable.
- Pressure is a design feature that is generated by the fitting once the melt from the fitting contacts the pipe surface. The outer edges of the weld area furthest from the wires tend to freeze off creating containment of the melt which as it continues to heat increases the pressure on the materials being joined. Care is taken to prevent the gap between pipe and fitting being excessive (due to pipe end reversion, pipe ovality, overscrapingof the pipe end, pipe not fully inserted, pipe misaligned in the joint) which can act reduce welding pressure.