This part of ISO 18672 specifies definitions, requirements and characteristics of pipes, fittings, joints, materials, test methods and marking for pipes and fittings made from polyester resin concrete (PRC), intended to be used within a drain or sewer system operating without pressure. It applies to products for use in buried installations to be installed by open-trench techniques or pipe jacking. It applies to pipes, fittings and their joints of nominal sizes from DN 150 to DN 3000 for circular cross-sections, from WN/HN 300/450 to WN/HN 1400/2100 for egg-shaped cross-sections and from DN 800 to DN 1800 for kite-shaped cross-sections. The intended use of these products is for the conveyance of sewage, rainwater and surface water at temperatures up to 50 °C, without pressure or occasionally at a head of pressure up to 0,5 bar1), and installed in areas subjected to vehicle and/or pedestrian traffic. The pipes are classified on the basis of the intended method of installation and cross-sectional shape. NOTE It is the responsibility of the purchaser or specifier to make the appropriate selections, taking into account the particular requirements and any relevant national regulations and installation practices or codes.