Piping systems and components in water installations - District heating pipes

District heating networks - District heating pipes

Danish Technological Institute has many years of experience and a thorough knowledge about district heating pipes and components, including testing of pre-insulated district heating piping systems, valves, flow meters, etc.

Through participation in R&D projects and involvement in conferences, we continuously acquire new knowledge for the benefit of the industry.

Pre-insulated pipes (factory-made pipes for district heating networks) consists of a steel pipe or PE-X pipe with polyurethane insulation and a polyethylene casing.

The test methods for these pipes include specification of materials, dimensions and mechanical properties such as compressive strength and thermal conductivity. A particular focus is on the evaluation of the pipes' ability to withstand thermal and mechanical stresses over time, such as stress cracking, non-crystalline linear thermoplastics (NCLT) and criteria for expected lifespan and resistance to thermal aging.

Another important issue is energy efficiency and calculation of thermal transmittance (U value).

Test methods for district heating pipes

EN 253: District heating pipes – Bonded single pipe systems for directly buried hot water networks – Factory made pipe assembly of steel service pipe. Polyurethane thermal insulation and casing of polyethylene.

EN 15632: District heating pipes – Factory-made flexible pipe system

Part 1: Classification, general requirements and test methods

Part 2: Bonded system with plastic service pipes; requirements and test methods

Part 3: Non bonded system with plastic service pipes; requirements and test methods

Part 4: Bonded system with metal service pipes; requirements and test methods

EN 15698: District heating pipes – Bonded twin system for directly buried hot water networks

Part 1: Factory made twin pipe assembly of steel service pipes, polyurethane thermal insulation and one casing of polyethylene