PVC pipe is a PolyVinylChloride combination to create the material. In uPVC, the "U" is for "unplasticised". This makes uPVC a stiffer material. Regular PVC is used in plumbing or sprinkler systems where a some flexibility is required. On the other hand, uPVC would be used in projects where you need a solid, unbending pipeline.
answered Aug 20 '11 at 20:50