District heating pipes - Bonded single pipe systems for directly buried hot water networks - Part 1: Factory made steel shut-off valve assembly for steel service pipes, polyurethane thermal insulation and a casing of polyethylene

This document establishes comprehensive technical specifications for prefabricated steel valve assemblies designed for connection within single-pipe underground hot water networks serving district heating systems. The standard specifically addresses assemblies constructed with steel pipes featuring polyurethane thermal insulation and an outer protective layer made of polyethylene, ensuring durability and efficiency in harsh underground environments. It defines critical requirements regarding dimensional tolerances, material properties, and performance criteria necessary to maintain system integrity under high-temperature and pressure conditions. The scope covers design, manufacturing processes, testing methodologies, and marking requirements to guarantee compatibility and safety across various installation scenarios. By adhering to these guidelines, stakeholders can ensure that valve groups function reliably within the broader network infrastructure. The document serves as a foundational reference for engineers and manufacturers involved in the production and deployment of such components, facilitating consistent quality control and operational safety without specifying detailed implementation strategies or regulatory enforcement mechanisms.