JGD District Heating is highly experienced in the design, supply, and installation of pre-insulated pipe networks for HTHW and steam networks, to include HT3 high-temperature systems with an operational temperature range of +140˚C + to 250˚C.

Buried HT3 high-temperature systems are laid as compensating sliding systems. In the HT3 system, movements caused by ground temperature fluctuations are absorbed within the system itself. The HT3 system operates on the following premise:

• 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, and axial compensators.

When being installed, the system is broken down into calculable expansion sections. Each section is thus divided from the next utilising anchors. Expansion-absorbing elements are placed within each section and should ideally be loaded from both sides equally.

A multitude of different calculations are required and incorporated into the expansion design of these systems, including:

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

Insulation

The HT3 system’s insulation consists of a PUR foam and mineral wool combination which serves to ensure that the capacities of the PUR foam and HDPE jacket are not exceeded.

All pipes and components in the HT3 system are available as standard for two different levels of maximum operating temperatures of 210˚C or 250˚C.

The combined wall thickness of mineral wool and PUR insulation is designed to maintain the temperature of the PUR foam below 140˚C.

Both systems are available from 20 – 400DN (diameter of carrier pipe) with outer casings from 26.9mm – 406.4mm on the 250˚C series, and 26.9mm-406.4mm on the 210˚C system.