Insulation steel pipe structure composition:
Polyurethane insulation steel pipe can be divided into three-layer structure, namely, working steel pipe, polyurethane foam insulation layer, high-density polyethylene outer protection pipe.
I. Working steel pipe:
The core component of the direct buried thermal insulation steel pipe, usually according to the design and customer demand for seamless steel pipe, welded steel pipe.
II. Insulation layer:
Between the working steel pipe and the external protection pipe, filled with rigid polyurethane foam to provide good thermal insulation performance and reduce heat loss.
III. HDPE External Protection Pipe:
The outermost layer, providing waterproof, anti-corrosion and mechanical protection to ensure durability and service life of polyurethane insulation steel pipe.
Polyurethane foam insulation pipe standards in various countries:
1, China:
GB / T 29047-2021 ‘high density polyethylene outer sheath rigid polyurethane foam prefabricated buried insulation pipe and pipe fittings’.
2、Europe:
EN 448:2015 ‘District heating pipes . Directly buried hot water network pre-insulated, bonded pipes’.
3、Russia:
GOST 30732-2020 ‘Steel pipes and moulded products insulated with foamed polyurethane in the protective jacket’.
Specification, parameters, test chart of insulation pipe for central heating:
| Pipe Size | Outer Pipe Size | Insulation Thickness (mm) | Length (m) |
|---|---|---|---|
| Φ60×3.0 | Φ125×2.5 | 30 | 6 |
| Φ76×3.0 | Φ140×3.0 | 29.5 | 6 |
| Φ89×4.0 | Φ160×3.0 | 32.5 | 6 |
| Φ114×4.0 | Φ200×3.2 | 39.8 | 6 |
| Φ140×4.5 | Φ225×3.5 | 39 | 6 |
| Φ165×4.5 | Φ250×3.9 | 38.6 | 6 |
| Φ219×6.0 | Φ315×4.9 | 43.1 | 12 |
| Φ273×6.0 | Φ365×5.6 | 40.4 | 12 |
| Φ325×7.0 | Φ420×7.0 | 40.5 | 12 |
| Φ377×7.0 | Φ500×7.8 | 53.7 | 12 |
| Φ426×7.0 | Φ550×8.8 | 53.2 | 12 |
| Φ478×7.0 | Φ600×8.8 | 52.2 | 12 |
| Φ529×8.0 | Φ655×9.8 | 53.2 | 12 |
| Φ630×8.0 | Φ760×11 | 53.9 | 12 |
| Φ720×9.0 | Φ850×12 | 53 | 12 |
| Φ820×10.0 | Φ960×13 | 57 | 12 |
| Φ920×10.0 | Φ1054×14 | 53 | 12 |
| Φ1020×12 | Φ1155×14 | 53.5 | 12 |
| Φ1220×12 | Φ1380×15 | 65 | 12 |
| Parameter Name | Unit | Value | Description |
|---|---|---|---|
| Thermal Conductivity | W/(m·K) | ≤0.024 | The thermal conductivity of polyurethane foam insulation is low, providing excellent thermal insulation performance. |
| Water Absorption Rate | % | ≤0.2 | The water absorption rate of polyurethane foam is low, indicating good waterproof performance. |
| Compressive Strength | MPa | ≥0.3 | The polyurethane foam layer has high compressive strength. |
| Closed-Cell Rate | % | ≥95 | The high closed-cell rate of polyurethane foam provides excellent thermal insulation and waterproof performance. |
| Density | kg/m³ | 30-80 | The density range of polyurethane foam. |
| Temperature Range | ℃ | -196~150 | Polyurethane insulation can withstand extremely low and relatively high temperatures. |
| Service Life | Years | 30-50 | Under normal use conditions, polyurethane insulated steel pipes have a long service life. |
| Corrosion Resistance | - | Good | The outer protective pipe and corrosion-resistant layer can effectively prevent steel pipe corrosion. |
| Outer Pipe Density | kg/m³ | 940-960 | The density of high-density polyethylene outer protective pipe. |
| Outer Pipe Tensile Strength | MPa | ≥19 | The tensile strength of the outer protective pipe. |
| Outer Pipe Elongation at Break | % | ≥450 | The elongation at break of the outer protective pipe. |
| Inspection Item | Inspection Content | Inspection Standard | Notes |
|---|---|---|---|
| Appearance Quality | Smooth and flat surface, free from bubbles, cracks, depressions, and impurities | Visual Inspection | Surface quality directly affects the service life of the pipe. |
| Dimensional Accuracy | Outer diameter of steel pipe, wall thickness, insulation layer thickness, outer diameter and wall thickness of outer protective pipe | GB/T 29047-2012 | Dimensional deviations must be controlled within the standard range. |
| Insulation Layer Performance |
Density ≥60 kg/m³ Closed-cell rate ≥88% Thermal conductivity ≤0.033 W/(m·K) Water absorption rate ≤10% (100℃ boiling water, 90 minutes) Compressive strength ≥0.3 MPa (at 10% deformation) |
GB/T 29047-2012 | Insulation performance is a core indicator. |
| Outer Protective Pipe Performance |
Density ≥950 kg/m³ Tensile strength ≥19 MPa Elongation at break ≥350% Longitudinal shrinkage rate ≤3% |
GB/T 13018-91 | The outer protective pipe must have good mechanical properties. |
| Corrosion Resistance | Thickness, adhesion, and corrosion resistance of the anti-corrosion layer | GB/T 8923.1 | The anti-corrosion layer protects the steel pipe from corrosion. |
| Temperature Resistance |
Continuous operating temperature ≤120℃ Peak operating temperature ≤140℃ |
GB/T 29047-2012 | Suitable for various temperature scenarios. |
| Mechanical Strength | Shear strength ≥0.12 MPa (at 23±2℃) | GB/T 29047-2012 | Ensures the pipe is not damaged during construction and operation. |
| Durability | Service life ≥30 years | GB/T 29047-2012 | Long-term stable performance. |
| Non-destructive Testing | X-ray inspection, ultrasonic testing | NB/T 47013.2-2015 | Ensures the internal quality of the pipe. |
Features of prefabricated foam insulation steel pipe:
1. Efficient thermal insulation: excellent thermal insulation performance, effectively reduce heat loss.
2. Waterproof and anticorrosion: strong waterproof and anticorrosion ability, resisting moisture and corrosion.
3. High compressive strength: sturdy structure, strong bearing capacity.
4. Convenient construction: quick installation, high construction efficiency.
5. Long service life: strong durability, long service life.
6. Environmentally friendly materials: green and pollution-free, in line with environmental requirements.
7. Wide application: suitable for a variety of scenarios, widely used.
8. Good low-temperature performance: stable performance in low-temperature environment, no degradation of quality.
9. Low maintenance cost: simple daily maintenance, low cost.
10. High reliability: stable performance, safe and reliable.
Heat insulation pipe application areas:
1. Municipal heating system
2. Oil and gas transmission
3. Chemical industry
4. Food and pharmaceutical industry
5. HVAC systems
6. Industrial Fluid Handling
7. Cryogenic Transport
8. Polyurethane Insulated Steel Pipe for the Construction Industry
9. Water Treatment & Mining
10. Geothermal and Spa Transport