TWI Frequently asked questions
by Felicity Chipperfield
There are several factors that will influence the decision on whether to use butt fusion or electrofusion for the joining of PE pipes -
- Accessibility - electrofusion is particularly suited to installations where access is difficult, such as in trenches or around other pipes.
- Pipe size - electrofusion is applicable to pipe sizes from 16mm to 710mm, whereas butt fusion is applicable to pipe sizes from 50mm to 2000mm.
- Pipe material - electrofusion can be used to join different grades of the same material e.g. MDPE to HDPE.
- Pipe structure - whereas in butt fusion welding the pipes to be joined must have the same wall thickness, with electrofusion a difference in wall thickness can be accommodated. Electrofusion can also be used to join certain typesof multiple layer pipes, e.g. nylon lined polyethylene pipe for the conveyance of fuel.
- Installation method - if the pipe is to be installed using a 'no-dig' technique such as directional drilling, then electrofusion cannot be used. Similarly, if the pipe is to be used as a close-fit lining in an existing pipeline,then butt fusion is the only viable technique.
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