Electrofusion is the joining of two polyethylene or other plastic pipes using electrical energy. A copper coil built into the fitting itself is heated using an external fusion machine. Electrofusion is an alternative to other coupling methods such as butt fusion. It is often necessary to create piping joints onsite during trenchless construction operations.
Trenchlesspedia Explains Electrofusion
If you’ve ever thrown a piece of plastic into a fire, you know that it melts. That’s the idea behind the heating of polyethylene pipes to join their ends together. With electrofusion pipe joining, special fittings are used to create a permanent coupling between two pipe segments.
The methods may vary, but certain steps are common to all electrofusion procedures. Using special tools, the ends of pipes are peeled to a certain depth. This creates a rough surface that makes coupling easier. The pipe ends should be peeled to match the length of the fitting.
The joint is specially made for electrofusion. The heating element inside the fitting is what welds the pipes together. Once the pipes are inserted into the ends of the joints, the operator will attach leads from the electrofusion machine. The machine is turned on and the coil in the pipe fitting heats up. Following instructions from the manufacturer, the operator will allow for designated heating and cooling times for the joint. Once the joint is established, markings on the pipe detailing a joint number and the date and time of the operation will be helpful for future pipe inspections.