1. Structural form
Pipe: Utilizing new types of working pipes such as PERT, PPR, and PE.
Insulation: Hard polyurethane foam plastic used; Leak alarm line: During the manufacturing of high-temperature pre-fabricated buried thermal insulation pipes, an alarm line is embedded within the insulation layer near the steel pipe. In the event of a leak at any point in the pipeline, the alarm line transmits the signal, allowing for an alarm to be triggered on a dedicated detection instrument, which then displays the precise location and extent of the leak. This enables prompt notification to maintenance personnel to address the leaking section and ensure the safe operation of the heating network.
Outer sheath: High-density polyethylene or glass fiber reinforced plastic outer sheath.

2. Application Scope
Insulation for liquids and gases with medium temperatures not exceeding 120°C and pressure not exceeding 1.6 Mpa.

3. Standard of Execution
High-Density Polyethylene Extruded Foam Pre-insulated Direct Burial Pipe (GB/T 29047-2012)
High-Density Polyethylene Outer Sheath Polyurethane Foam Pre-fabricated Direct-Buried Insulation Pipe (CJ/T 114-2000)
Integrally Pre-insulated Pipe System for Underground Geothermal Networks – Insulating Pipes Comprising a Working Steel Pipe, Polyurethane Insulation, and Polyethylene Sheath (EN253-2003).

4. Service Life
The outer sheath of this structure is made of high-density polyethylene, offering excellent waterproofing, moisture-proof, and corrosion-resistant properties. The working pipe and insulation layer are fully protected by the outer sheath, allowing for continuous operation under normal working conditions for up to 30 years.