Editor's CommentaryThis short article is a sidebar to a feature article, titled "Cured-in-place pipe: Trenchless trends." To read the feature article, click on its title under "Editor's Picks," at top right.
The American Water Works Assn. (AWWA, Denver, Colo.) divides cured-in-place pipe (CIPP) into four classes based on three primary distinctions in terms of structural function:
Class I: Nonstructural liners; act only as corrosion barriers.
Class II and Class III: Semistructural liners; designed to cover small holes or gaps in the host pipe.
Class IV: Fully structural liners; will carry the full internal pressure without support from the host pipe.