The district heating network is a network of pipes dedicated to supplying heat to an urban area from a power station. This network works in a closed loop with a steam line (heat transfer fluid) that can reach up to 950mm in diameter, and a condensation water recirculation  line towards the power station.

The pipes pass through dense urban areas with significant acessibility limitations, limited space and a high security level owing to the fact that steam circulates in the pipes at 180°C, at pressures of up to 20 bar.

Scheme district heating CPCU_SFZ
Scheme district heating CPCU_SFZ

Over the past decades, SFZ has evolved its designs to meet increasingly stringent normative and client constraints:

  • significant temperature variations

  • limited space

  • line stability

  • loads due to piping pressure thrust.

In compliance with the normative requirements:

  • PED 2014/68/UE


  • NF EN ISO 15609-01

SFZ offers a wide range of devices:

  • for steam lines: ND 80 to ND 950

  • for water recirculation lines: ND 40 to ND 450

Using bellows made of:

  • stainless steel

  • incoloy 825

  • inconel 625

District heating is one of the traditional markets of SFZ, with it having equipped the largest network in France, i.e. the one in Paris.

SFZ is one of ​the experts in this sector and can prove that it has significant experience in it. More than 1200 expansion joints are installed in the Parisian network, some of which have been in service for more than 30 years now.


Paris district heating network CPCU_SFZ