ISO 16611:2017 specifies the required properties of the piping system and its components made from glass-reinforced thermosetting plastics (GRP) based on unsaturated polyester resin (UP) intended to be used for drainage or sewerage without pressure including culverts.

It is the responsibility of the purchaser or specifier to make the appropriate selections taking into account their particular requirements and any relevant national regulations and installation practices or codes.

ISO 16611:2017 is applicable to non-circular GRP-UP pipes, with flexible or rigid joints, primarily intended for use in buried installations but may also be used to reline existing non-circular pipe lines.

NOTE 1 GRP-UP includes pipes with vinyl ester liners or made entirely from vinyl ester.

NOTE 2 Piping systems conforming to ISO 16611:2017 can be used also for non-buried applications provided the influence of the environment, e.g. from UV-radiation, and the supports are considered in the design of the pipes, fittings and joints.

ISO 16611:2017 is applicable to pipes, fittings and their joints of nominal sizes from DN 150 to DN 4000, which are intended to be used for the conveyance of surface water or sewage at temperatures up to 50 °C.