Polyurethane Foam Pre-insulated Steel Pipe

Update time：2025-04-12

Polyurethane foam pre-insulation steel pipe is made of high-function polyether polyol combination material and many times methyl polyphenyl polyisocyanate as raw material by chemical reaction foaming. 

Polyurethane foam pre-insulation steel pipe has light weight, high strength, heat insulation, sound insulation, flame retardant, cold resistance, corrosion resistance, non-absorbent, easy and fast construction and other excellent features, has become the petroleum, chemical, electric power, construction, transportation, refrigeration and other industrial sectors of the adiabatic insulation, waterproofing leakage, sealing, and other indispensable products.

I. Structure of polyurethane foam pre-insulated steel pipe 

(1) Working steel pipe layer 

Material selection: seamless steel pipe spiral seam steel pipe or straight seam steel pipe.

Surface treatment: through the process of descaling by shot blasting, the descaling grade reaches the Sa2 level of GB8923-1988 standard, and the surface roughness is R=12.5 microns.

(2) Polyurethane foam insulation layer 

Molding process: adopting “pipe-in-pipe foaming” technology, injecting polyurethane rigid foam into the cavity between the steel pipe and the outer protection layer through high-pressure foaming machine.

Core function: waterproofing, heat preservation and supporting the self-weight of the pipe network.

Temperature Adaptation: It is suitable for medium transportation of -50℃~120℃, and can resist temperature up to 180℃ through modification.

(3) High-density polyethylene outer sheath 

Material Characteristics: Prefabricated black or yellow polyethylene pipe with low-temperature resistance (-70℃~100℃), acid and alkali corrosion resistance.

Surface treatment: corona treatment of the inner wall of the outer pipe to enhance the adhesive properties with the insulation layer.

Main function: mechanical protection (impact resistance, anti-hard object damage) and anti-corrosion waterproof dual function.

Polyurethane foam pre-insulation steel pipe is a combination of high-function polyether polyol and many times methyl polyphenyl polyisocyanate as raw materials by chemical reaction foaming. 

Polyurethane foam pre-insulation steel pipe has light weight, high strength, adiabatic, sound insulation, flame retardant, cold-resistant, anticorrosive, non-absorbent, easy and fast construction and other excellent features, has become an indispensable product for the petroleum, chemical, electric power, construction, transportation, refrigeration and other industrial sectors such as adiabatic insulation, waterproofing leakage plugging, sealing and other indispensable products.

II. Polyurethane foam pre-insulated steel pipe detailed specification model list

III. Core features of polyurethane foam pre-insulation steel pipe 

(1) Excellent thermal insulation performance 

Ultra-low thermal conductivity: 0.013-0.03kcal/m-h-°C, compared with the traditional materials, the thermal insulation efficiency is improved by 4-9 times.

Significant energy-saving effect: heat loss of only 2% (international standard is 10%), 130 ℃ hot water delivery 40 kilometers after only 1 ℃ temperature drop.

Closed-cell structure support: 92% closed-cell rate to block heat convection, reducing the “wet coat” type heat loss.

(2) Dual protection system 

Chemical protection: high-density polyethylene/glass fiber reinforced plastic outer shell is resistant to acid and alkali corrosion (PH 3-11).

Physical protection: resistance to -70 ℃ low-temperature impact, direct burial tundra without the need for pipe trench, compressive strength ≥ 0.3MPa. 

Waterproof protection: closed-cell structure water absorption rate ≤ 0.2kg/m², corona treatment of the outer sheath layer to enhance the sealing.

(3) Long life 

Anti-corrosion design: Triple protection (steel pipe + polyurethane + outer sheath) to block air/water infiltration, life expectancy of 50 years.

Intelligent monitoring: Built-in leakage alarm line can precisely locate the failure point (error ≤ 0 meters).

Strong weather resistance: can withstand -50℃~180℃ extreme temperature through modified treatment.

(4) Construction Economic Advantage 

Directly buried cost saving: reduce 50% of the amount of earthwork, 90% of the amount of concrete, and shorten the construction period by 50%.

Comprehensive cost reduction: save 25% (FRP outer protection) or 10% (HDPE outer protection) than traditional trench program.

Modular installation: prefabricated pipe fittings (elbow/tee) support DN15-DN3000 pipe diameter for quick assembly.

(5)Environmentally friendly adaptability 

Green construction: reduce transportation dust and construction noise, protect tundra ecology.

Wide compatibility: adaptable to centralized heating (120℃), industrial steam (180℃ modified), Arctic water transmission (-70℃) and other scenarios.

IV. Application of Polyurethane Foam Pre-Insulated Steel Pipe

(1)Centralized heating and cooling system 

Widely used in town centralized heating and district cooling projects.

Conveying medium: hot water (≤120℃) or cold water 

Core advantage: reduce heat loss by 40%, support direct burial laying 

Typical scenario: residential heating, commercial complex air conditioning circulatory system 

(2) Oil and gas transportation 

Covering onshore pipelines, submarine pipelines and energy facilities.

Pressure-resistant and anti-corrosion: can withstand high pressure gas transportation (≤150℃) 

Special treatment: can adapt to extreme temperatures of -50℃~180℃ through modification 

Safety protection: the outer layer of polyethylene prevents chemical corrosion and mechanical damages 

(3) Water Transmission Project in High Alpine Areas 

Specially designed for tundra environment.

Anti-freezing performance: maintain the structural integrity of the pipe at -70℃ low temperature 

Direct burial advantage: no pipe trench required, burial depth 0.6-1.2 meters tundra 

Application cases: Arctic Circle water pipeline network, drinking water system in plateau area 

(4) Industrial special pipeline 

Meet the complex needs of multiple industries.

Chemical industry: conveying acid and alkali media (PH 3-11 corrosion resistance) 

Pharmaceutical industry: thermostatic drug/pure water conveyance in clean environment 

Municipal engineering: leakage prevention of sewage network, steam piping in industrial parks 

(5) Supporting engineering services 

Adapt to diversified construction scenarios.

Prefabricated pipe fittings: insulation elbows, tees and other shaped parts 

Intelligent monitoring: built-in leakage alarm system 

Special specifications: support DN15~DN3000 pipe diameter customization