Where damage to the pipe could occur as a result of movement of the pipe relative to its surroundings, the pipe should be protected by a compressible membrane such as PE, PVC, petrolatum tape or felt.
Where expansion joints are provided in the concrete slab, expansion joints should be provided at the same point in the pipeline. At these points a flexible membrane should be provided to prevent shear stresses developing across the joint.
PE pipes behave as flexible structures when externally loaded, and care needs to be exercised by the designer when using concrete encasement so that the effective strength of the pipeline is not reduced.
