Description
Steel Pipes in Polyurethane Foam (PUR) Insulation are modern heat-insulated structures designed for underground non-channel laying of heating networks. They represent a "pipe-in-pipe" system where a steel pipe is protected by a layer of thermal insulation and an outer casing.
Production Technology

The manufacturing process includes several stages:
1.    Steel Pipe Preparation: The pipe is cleaned and undergoes anti-corrosion treatment.
2.    Centering: The carrier steel pipe is centered inside the protective casing using supporting centering elements.
3.    PUR Pouring: Polyurethane composition is poured into the cavity between the steel pipe and the casing.
4.    Polymerization: Foaming and curing of polyurethane foam occurs.
5.    LDS Installation: A Leak Detection System (LDS) is installed for monitoring the condition of the insulation.
6.    Testing: Finished products undergo quality control and hydraulic testing.

Design Features
•    Steel Carrier Pipe: Working pipe made of carbon or stainless steel.
•    Thermal Insulation: Polyurethane foam (PUR) with a thickness of 40-100 mm.
•    Protective Casing:
o    Made of polyethylene (PE) for underground laying.
o    Made of galvanized steel for above-ground laying.
•    LDS: System for monitoring moisture in the thermal insulation.

Technical Characteristics
•    Diameter Range: DN 32 - DN 1020 mm
•    Heat Carrier Temperature: up to 130°C (up to 150°C for short-term loads)
•    Insulation Thermal Conductivity: 0.033 W/m∙°C
•    Service Life: 25-30 years and more
•    Reduction of Heat Loss: up to 40% compared to traditional insulation.

Advantages
•    High Thermal Efficiency – minimal heat losses.
•    Durability – protection against corrosion and external influences.
•    Reduced Operating Costs – minimal repairs and maintenance.
•    Monitoring Capability – the LDS allows for monitoring the condition of the route.
•    Accelerated Installation – supplied as ready-made elements.
•    Construction Savings – no need to build channels.

Areas of Application
•    Heating Networks: main and distribution heat pipelines.
•    Utilities: central heating and hot water supply systems.
•    Industry: process pipelines.
•    Oil & Gas Industry: pipelines with product temperature maintenance.
•    Construction: utility networks for new residential areas.

Normative Documentation (GOST Standards)
Main standards regulating the production of PUR-insulated pipes:
GOST 30732-2020 – "Steel pipes and fittings with thermal insulation made of polyurethane foam in a polyethylene casing. Technical specifications"
•    Defines requirements for materials and design.
•    Establishes test methods and quality control.
•    Regulates thermal insulation parameters.
GOST 32415-2013 – "Thermoplastics pressure pipes and fittings for water supply and heating systems"
•    Applies to polyethylene casings.
Additional Normative Documents:
•    STO 00209968-001-2019 – Rules for the application of pipes in PUR insulation.
•    SP 124.13330.2012 – Heating networks (updated version of SNiP 41-02-2003).
Material Requirements:
•    Steel Pipe: according to GOST 10704, GOST 8731, GOST 8732.
•    PUR Insulation: density 60-80 kg/m³.
•    PE Casing: made of polyethylene PE80, PE100.