Polyurethane Thermal Insulation Steel Pipe

Update time：2025-04-04

I.Introduction of Polyurethane Thermal Insulation Steel Pipe 

Polyurethane insulation steel pipe has become the core energy-saving material in the field of heating, cooling and chemical pipeline by virtue of its rigid foaming polyurethane insulation layer.

It adopts high-pressure spraying technology to form a honeycomb structure with a closed cell rate of over 95%, isolating water vapor infiltration.

II.Five core advantages of polyurethane thermal insulation steel pipe

i.Extreme heat preservation, energy saving and consumption reduction 

Rigid foaming polyurethane thermal conductivity is only 1/2 of the traditional materials, seamless coverage of the thermal insulation layer, to avoid the cold bridge effect, energy saving rate of more than 30%. ii.

ii. Compression and moisture resistance, stability and durability 

compressive strength ≥ 200kPa, water absorption rate of closed-cell structure <3%, no corrosion and cracking in underground humid environment, adapt to -50℃~150℃ extreme temperature.

iii. Lightweight design, convenient construction 

40% thinner than glass wool insulation layer, saving underground space, supporting direct burial maintenance-free, shorten the construction period by more than 30%.

iv. Environmental protection and safety, long-lasting protection 

fluorine-free foaming process, in line with the national standard GB/T 31404-2015, non-toxic and non-polluting, flame retardant grade B1.

v. Low operation and maintenance cost, strong economy 

Support with temperature and pressure repair, no need to stop the pipeline, failure maintenance costs reduced by 60%.

III.4 Steps Scientific Material Selection Guide 

i. Traceability of raw materials, strict control of purity 

Black MDI purity ≥ 98%, white material should be new polyether polyol, provide SGS test report; 

Reject TDI by-products, recycled materials, to ensure that there is no irritating odor. ii.

ii. Hard indexes of product performance 

Closed cell rate ≥95% (bubble diameter on cutting surface <0.5mm); 

Water absorption rate ≤3% (weight gain test after 24 hours of immersion); 

Compressive strength ≥200kPa (under 10% deformation). iii.

iii. Enterprise qualification verification 

Choose ISO9001 certified factories with more than 10 years of engineering cases; 

Require third-party test reports (e.g. National Building Materials Testing Center). iv.

iv. Construction Supporting Services 

Priority is given to using the same manufacturer's outer protection pipe (polyethylene or FRP), with melt flow rate deviation ≤ 0.5g/10min; 

Requirements to provide standardized construction plans, including quality control processes such as weld flaw detection, layering and pressing.

IV.Comparison of Industry Application Scenarios and Benefits

V. Polyurethane Insulated Steel Pipe Export Standards 

i. International Common Standards 

(1) Pipe Standards 

Working steel pipe needs to comply with API 5L (oil pipeline pipe) or ASTM A53/A106 (seamless/SSAW steel pipe) to ensure that the chemical composition and mechanical properties are up to standard.

EN 253 is commonly used in the European market, covering the overall prefabrication requirements for the working steel pipe, polyurethane insulation and polyethylene outer protection pipe.

(2) Performance of the insulation layer 

Density ≥ 60kg/m³, closed cell rate ≥ 88%, thermal conductivity ≤ 0.033W/(m-K) (50 ℃ test conditions).

Compressive strength ≥0.3MPa (10% deformation conditions), water absorption ≤10% (boiling water immersion for 90 minutes).

(3) Requirements for outer protection pipe 

High-density polyethylene (HDPE) density ≥940kg/m³, tensile strength ≥19MPa, elongation at break ≥350%.

Anti-corrosion coating needs to comply with DIN 30678 (polyethylene anti-corrosion layer) or GB/T 23257 (domestic equivalent standard).

ii. Special Requirements for Target Markets 

(1) European Market 

EN 253 certification is mandatory, focusing on continuous operation temperature (140℃), peak temperature (150℃) and 30-year service life verification of the insulation pipe.

CE certification and proof of environmental compliance (e.g. fluorine-free foaming process) are required.

(2) North American market 

Conform to ASTM standards, such as ASTM C177 (thermal conductivity test of insulation materials), ASTM D1621 (compressive strength test).

The outer protection pipe needs to pass UL certification (flame retardant performance) and NACE anti-corrosion standard.

(3) Middle East and Southeast Asia market 

Emphasis on high temperature resistance performance (some projects require resistance to 180 ℃), need to provide third-party test reports of modified polyurethane insulation.

Adapt to high saline and alkaline environment, the outer protection pipe needs to be certified by ISO 21809-1 (anti-corrosion coating).

iii. Export Quality Control Points 

(1) Production Standard 

Adopt GB/T 29047-2012 (domestic) or EN 253 (international) for prefabrication, and ensure that the factory passes ISO 9001 quality management system certification.

The surface treatment of steel pipe needs to reach Sa2 grade descaling (GB/T 8923), with roughness R=12.5μm. 

(2) Testing and Acceptance 

Each batch of products needs to be provided with third-party testing report, containing key parameters such as axial shear strength (≥0.12MPa) and melt index (0.50~0.70g/10min).

Implementation of layered compression test: working pressure 1.5 times the steady pressure for 30 minutes without leakage.

(3) Marking and packaging 

The outer protection pipe is labeled with material, specifications, implementation standards, production date and manufacturer information, in line with the labeling regulations of the target country.

Use moisture-proof packaging during transportation, and install protective caps on the pipe ends to avoid mechanical damage to the insulation layer.

iv. Avoidance of common export risks 

Risk of poor quality raw materials: Refuse to use TDI waste or recycled materials, and ask suppliers to provide test certificates of MDI purity ≥ 98%.

Construction suitability: confirm the target country's burial depth standard (e.g. European requirement ≥1.5 meters) and welding process (e.g. ASME B16.5 flange connection) before export.