Plastic pipes in highway drainage

Flexibility in drainage systems has been recognised by most engineers as essential where ground movement may occur; for this reason flexible joints were introduced and are now cheaper than fully rigid lines Fully flexible pipes was the next development and they are now much more common.

For a long time plastics pipes were considered mainly for pressure pipelines and mains, and the British Standard 3506 reflected this usage. With the publication of BS4660 some of the prejudice against their use in sewers may have been overcome, but this standard mainly deals with house drainage and does not yet provide for main sewers.