This Technical Specification (CEN/TS) specifies recommended practices for the underground installation of piping systems made of glass-reinforced thermosetting plastics based on unsaturated polyester resin (GRP-UP), intended to be used for pressure or non-pressure water or sewerage applications and complying with, as applicable, EN 14364 and/or EN 1796. It is applicable to GRP-UP piping systems of nominal sizes from DN 100 to DN 4000 which are intended to be used for the conveyance of liquids at temperatures up to 50 °C and at pressures of 0,5 bar and greater.

Design procedures, the determination of long-term safety factors based on a semi-probabilistic approach, surge allowance and allowable negative pressures for buried GRP pipe applications are addressed in CEN/TS 14807 [1].

Piping systems conforming to EN 1796 or EN 14364 can also be used for above-ground applications provided the influence of the environment and the supports is considered in the design of the pipes and joints. It is recommended to refer to ISO/TR 10986 [4] for guidelines for the installation of above-ground flexible jointed pipes.