1. Structural Form
Pipe: Seamless steel pipe, spiral pipe, stainless steel pipe, welded pipe, galvanized pipe, etc.
Insulation material: rigid polyurethane foam.
Leakage Alarm Line: During the manufacturing of high-temperature pre-fabricated buried insulation pipes, an alarm line is embedded in the insulation layer near the steel pipe. In the event of a leakage at any point in the pipeline, the alarm line transmits the signal, triggering an alarm on a dedicated detection instrument and displaying the exact location and extent of the leakage. This allows for prompt notification to maintenance personnel to quickly address the leaking section, ensuring the safe operation of the heating network.
Outer protective tube: Galvanized iron sheet, aluminum sheet, stainless steel, etc.

2. Application Scope
Thermal insulation and heat preservation for liquids and gases at temperatures not exceeding 150℃ and pressures not exceeding 2.5 Mpa.

3. Execution Standards: "High-Density Polyethylene Outer Sheath Polyurethane Foam Pre-fabricated Direct-Buried Insulated Pipe" (GB/T 29047-2012); "High-Density Polyethylene Outer Sheath Polyurethane Foam Pre-fabricated Direct-Buried Insulated Pipe" (CJ/T 114-2000); "Integrated Pre-fabricated Insulated Pipe System for Underground Geothermal Network — Insulated Pipe Composed of Working Steel Pipe, Polyurethane Insulation, and Polyethylene Outer Sheath" (EN253-2003)

4. Service Life
The thermal insulation pipe in this structure is a three-layer design, with the working pipe and insulation fully protected by the outer sheath; the outer sheath is coated with galvanized corrosion protection, which allows for continuous use under normal operating conditions for up to 30 years.