This document specifies requirements and test methods for flexible, factory made, buried district heating pipe systems with plastic service pipes and no bonding between the layers of the pipe assemblies. It is only applicable in conjunction with prEN 17878-1. This document is applicable to pipes, fittings, their joints and to joints with components made of non-plastics materials intended to be used for district heating installations. This document is applicable to a maximum operating temperature of 80 °C and maximum operating design pressure up to 1,0 MPa for a design service life of at least 50 years. This document does not apply to cover surveillance systems. For higher temperatures or for the transport of other fluids, for example potable water, additional requirements and testing is needed. Such requirements are not specified in this document.