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Pre-insulated pipe for HTHW & Steam

Pre-insulated Pipe Systems for HTHW and Steam

PPSL is experienced in the design, supply and installation of pre-insulated pipe networks for HTHW and steam networks. HT3 High temperature systems have an operating temperature of +140˚C + to 250˚C

Directly buried HT3 high temperature systems are laid as compensating sliding systems. In the HT3 system movement caused by temperature change are absorbed within the system.

The jacket pipe is held in place by soil friction and thus does not move.

The carrier pipe moves within the insulation, with the movement absorbed by corresponding expansion absorbing elements such as L, Z or U bends or axial compensators.

When laying, the system is broken down into expansion sections that can be calculated. Each section is divided from the next using anchors. The expansion absorbing elements are placed inside each section, and should ideally be loaded equally from both sides.

A range of calculations are utilised in the expansion design of the system with a number of examples shown below.

  • Friction
  • The compensator’s spring resistance
  • The compensator’s internal resistance
  • Resistance from, L, Z and U bends
  • Internal compressive force bends
  • The compensators start force bend
  • The anchors construction/dimensions
  • Grounds elasticity which can vary per anchor


The insulation in the HT3 system consists of a combination of PUR foam and mineral wool, helping to ensure that neither the PUR foam nor the HDPE jacket temperature capability is exceeded.

All pipes and components in the HT 3 system are available as standard for two different levels of maximum operating temperature 210˚C or 250˚C.

The wall thickness of mineral wool and PUR insulation is designed to keep the temperature of the PUR foam below 140˚C Both systems are available from 20 – 400DN (Diameter of carrier pipe) and outer casing from 26.9mm – 406.4mm on the 250˚C series and 26.9mm-406.4mm on the 210˚C system.

For more information on how PPSL can support you in your HTHW or steam project please contact us for further information.

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PPSL District Heating Ltd also operates trading and co-operation agreements with industry leading businesses and specialists that are complementary to our own skill sets, such as consultants, specialist energy supply companies and financiers to ensure you have full access to the resources required to guarantee project success.

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