Insulated Steel Pipe: PUR Foam, Steel-Sleeve Steam and Overhead Systems

Every degree lost between the boiler house and the end user is fuel burned for nothing. For district heating, industrial steam and buried hot-water networks, insulated steel pipe turns a thermal problem into a specification — and the right jacket choice decides whether the system lasts ten years or thirty.

Three Insulated Pipe Configurations

• Polyurethane foam (PUR) pre-insulated pipe: steel carrier + rigid PU foam + HDPE outer casing. The standard for buried district heating hot water and chilled water.

• Steel-sleeve steam insulated pipe: an inner steel steam pipe inside mineral wool or calcium silicate insulation, protected by an outer steel sleeve. Built for high-temperature buried steam and condensate return.

• Overhead galvanized sheet insulation pipe: steel pipe wrapped with mineral wool and clad in galvanized steel sheet for above-ground racks where weather resistance matters.

Insulation Material Comparison

Key Performance Parameters

• Thermal conductivity and resulting heat loss per metre at design temperature

• Design pressure and temperature of the carrier pipe

• Water tightness of the outer casing and resistance to groundwater ingress

• Optional leak detection / alarm wire embedded in the insulation

• Axial stress, anchor and expansion design for directly buried systems

Applications

• Urban district heating and cooling networks

• Industrial steam distribution and condensate return

• Oil, chemical and refinery hot process lines

• Airport, campus and hospital energy distribution

• Overhead pipe racks and utility corridors

Frequently Asked Questions

PUR or mineral wool for my steam line?

For steam, use mineral wool or calcium silicate inside a steel sleeve. PUR is limited to roughly 120–140 °C and suits hot water, not steam.

How do I detect a leak in a buried insulated line?

Specify an embedded alarm wire or a monitoring system during design; retrofitting detection after burial is expensive.

Do overhead lines need a vapour barrier?

Yes. On chilled and cold lines a vapour barrier prevents condensation inside the insulation, which is the fastest route to corrosion under insulation.

Conclusion

Insulated pipe is a system — carrier, insulation, casing and monitoring must be designed together. Zhantong supplies PUR pre-insulated pipe, steel-sleeve steam insulated pipe and overhead galvanized insulated pipe with full specification support. Send temperatures, pressures and route length for a thermal calculation and quote.