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wr@insulatedpipeline.com
wyy@insulatedpipeline.com
Published:2025-07-07 | Last Updated: 2025-07-07 Views: 1
A prefabricated insulated steam pipe is a factory-prefabricated piping system consisting of a working pipe, insulation layer, and outer casing. It is mainly used to transport high-temperature steam and is widely applied in scenarios requiring high-temperature steam transportation, such as centralized heating, industrial production, power plants, and chemical plants.
| Parameter Name | Parameter Range |
|---|---|
| Outer Diameter Range (Working Pipe) | DN50–DN1200 |
| Outer Diameter Range (Outer Sheath) | DN200–DN2000 |
| Wall Thickness Range | 3mm–20mm |
| Length | 6m, 9m, 12m |
| Standards | CJ/T 114-2000, GB/T 29047-2012 |
| Material (Working Pipe) | Q235B, Q345B, 20#, 16Mn |
| Material (Outer Sheath) | Q235B steel pipe SSAW steel pipes HDPE |
| Insulation Materials | Hard polyurethane foam, calcium silicate, rock wool, glass wool, etc. |
| Operating Temperature | ≤350°C (up to 450°C for steel-in-steel) |
| Working Pressure | 1.6MPa – 2.5MPa |
| Insulation Layer Thickness | 30mm – 150mm |
| Insulation Layer Density | 60 – 80 kg/m³ (Polyurethane Foam) |
| Thermal Conductivity | ≤0.033 W/(m·K) (Polyurethane Foam at 20°C) |
| Allowable Burial Depth | 0.6m – 2.0m |
| Service Life | 30 – 50 years |
.jpg "Prefabricated Insulated Steam Pipes")
| Component | Description |
|---|---|
| Inner Pipe (Steam Pipe) | The main pipe for steam transmission, usually made of carbon steel or alloy steel pipe with pressure resistance and high-temperature resistance. |
| Insulation Layer | Includes insulation materials such as hard polyurethane foam (PU), rock wool, glass wool, etc., used to reduce heat loss. |
| Outer Sheath (Protective Tube) | Protects the insulation layer and inner pipe from mechanical damage and environmental corrosion, usually made of steel pipe or galvanized welded steel pipe. |
| Anti-corrosion Layer | Coated on the surface of the outer sheath to prevent corrosion, commonly using anti-corrosion materials such as epoxy coating, 3PE coating, etc. |
| Protective Layer (Optional) | Sometimes a waterproof layer or protective sleeve, such as plastic film or aluminum foil, is added to prevent moisture from entering the insulation layer. |
| Component | Material Composition | Description |
|---|---|---|
| Working Pipe | Q235B, 20#, Q345B, 16Mn | The main pipe for steam transmission, with material selection based on pressure and temperature requirements. |
| Sliding Support (Guide Support) | Carbon Steel, Stainless Steel | Supports and fixes the working pipe, reduces friction, and allows for thermal expansion and contraction. |
| Insulation Layer | Calcium Silicate, Glass Wool, Rock Wool | Multilayer composite insulation with high-temperature resistance to reduce heat loss. |
| Heat Shield Layer | Aluminum Foil Reflective Layer, Stainless Steel Sheet | Enhances insulation effectiveness by reflecting radiant heat and reducing heat loss. |
| Outer Sheath (Outer Jacket) | Q235B Spiral Welded Steel Pipe or Straight Seam Welded Pipe | Protects the internal structure and withstands soil pressure and external loads. |
| Anti-corrosion Layer | Epoxy Coal Tar, 3PE Anti-corrosion, Polyurethane Coating | Prevents corrosion of the outer sheath and extends service life. |
| Drainage System | Vent Pipe, Drainage Pipe | Removes moisture and humidity from the insulation layer to maintain dryness and prevent corrosion. |
| Alarm Wire | Copper Wire, Aluminum Wire | Monitors pipeline leakage in real-time to ensure safe operation. |
| Expansion Joint | Bellows Expansion Joint, Sleeve Expansion Joint | Compensates for thermal expansion and contraction to protect the pipeline system. |
| Standard Category | Standard Number and Name | Description |
|---|---|---|
| Steel Pipe Manufacturing Standard | GB/T 8163-2008 "Seamless Steel Pipes for Fluid Conveyance" | Applicable to the manufacturing requirements and technical conditions for seamless steel pipes. |
| Steel Pipe Manufacturing Standard | GB/T 3091-2015 "Welded Steel Pipes for Low-Pressure Fluid Conveyance" | Applicable to steel pipes for low-pressure fluid conveyance, including welded steel pipes. |
| Insulation Material Standard | GB/T 17794-2008 "Rigid Polyurethane Foam Insulation Materials" | Performance and quality requirements for polyurethane insulation materials. |
| Insulation Material Standard | CJ/T 163-2008 "Technical Specification for Prefabricated Direct-Buried Steam Insulated Pipes" | Design, construction, and acceptance standards for prefabricated direct-buried insulated pipes. |
| Anti-Corrosion Coating Standard | SY/T 0318-2014 "Technical Standard for 3PE Anti-Corrosion Coating for Conveyance Pipelines" | Technical requirements for the application and inspection of 3PE anti-corrosion coatings. |
| Anti-Corrosion Coating Standard | HG/T 3600-2009 "Epoxy Powder Coating for Anti-Corrosion" | Quality and performance requirements for epoxy powder anti-corrosion coatings. |
.jpg "Prefabricated Insulated Steam Pipes")
| Inspection Item | Inspection Standard/Specification | Main Inspection Content |
|---|---|---|
| Pipe Body Inspection | GB/T 8163, GB/T 3091, etc. | Visual inspection, dimensional measurement, mechanical property testing, non-destructive testing (ultrasonic, magnetic particle inspection, etc.), chemical composition analysis |
| Insulation Layer Inspection | GB/T 17794-2008, etc. | Insulation layer thickness, density, thermal conductivity, closed-cell rate, fire resistance, compressive strength |
| Anti-Corrosion Coating Inspection | SY/T 0318, HG/T 3600, etc. | Coating thickness, adhesion testing, corrosion resistance testing (salt spray test), surface quality inspection |
| Overall Pipe Performance Inspection | CJ/T 163-2008 "Technical Specification for Prefabricated Direct-Buried Steam Insulated Pipes" | Structural integrity check, waterproof performance, pressure resistance test, insulation effect inspection, pipe joint sealability |
| Construction and Installation Acceptance | GB 50264-2013 "Code for Construction and Acceptance of Prefabricated Direct-Buried Insulated Pipe Engineering" | Construction quality, weld quality, installation position, support and fixing, on-site re-inspection |
Specific testing methods:
Non-destructive testing of steel pipes: Ultrasonic testing (UT), magnetic particle testing (MT), and radiographic testing (RT) to ensure that welds and pipes are free of defects.
Insulation layer testing: Use a thermal conductivity meter to determine the thermal conductivity; use mechanical testing to measure the compressive strength.
Corrosion protection layer testing: Adhesion is tested using the pull-off method or cross-hatch method; salt spray testing simulates a corrosive environment.
Overall inspection: Conduct hydrostatic or pneumatic pressure tests to verify pipeline sealing and pressure resistance performance.
(1) Excellent Insulation Performance
The prefabricated insulation layer uses high-efficiency thermal insulation materials (such as polyurethane foam) to effectively reduce heat loss, maintain steam temperature, and improve energy efficiency.
(2) Fast Construction Speed
Prefabricated pipes are manufactured in the factory, including the inner pipe, insulation layer, and outer protective pipe. On-site installation only requires connection and assembly, shortening the construction period and reducing on-site labor intensity.
(3) Structural Integrity and Consistent Quality
Factory-based standardized production ensures uniform quality of the insulation and corrosion-resistant layers, minimizing on-site construction errors and improving the overall performance and service life of the pipes.
(4) Strong Corrosion Resistance
The outer casing is coated with high-quality corrosion-resistant paint and features a waterproof design, effectively preventing corrosion and moisture intrusion, and adapting to complex soil and environmental conditions.
(5) Low Maintenance Costs
Due to superior insulation and corrosion resistance, heat loss and corrosion-related maintenance needs are reduced, lowering long-term operational costs.
(6) Energy-saving and environmentally friendly
Excellent insulation reduces heat loss, lowers boiler load and fuel consumption, helps reduce carbon emissions, and meets energy-saving and environmental protection requirements.
(7) High adaptability
Customizable designs can be tailored to different operating conditions, suitable for municipal central heating, industrial steam transportation, chemical plants, and other applications.
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| Aspect | Prefabricated Insulated Steam Pipe | Polyurethane Insulated Pipe |
|---|---|---|
| Definition | Mainly used for steam conveyance, it is a composite structure with a steam pipe as the inner tube, and insulation and jacket layers on the outside. | A prefabricated insulated pipe using polyurethane foam as the insulation material, suitable for the thermal insulation conveyance of various media. |
| Insulation Material | Typically uses rigid polyurethane foam (PU), rock wool, and other insulation materials. | Mainly uses polyurethane foam as the insulation layer. |
| Application Medium | Mainly used for conveying high-temperature and high-pressure steam. | Suitable for the thermal insulation conveyance of hot water, cold water, steam, and other media. |
| Structural Composition | Inner tube (steam pipe) + insulation layer + outer jacket (steel pipe) + anti-corrosion layer. | Inner tube + polyurethane insulation layer + outer jacket (steel or plastic pipe) + anti-corrosion layer. |
| Temperature Resistance | Designed to withstand high-temperature and high-pressure steam, with higher temperature resistance. | Has a wider temperature resistance range, but generally lower than that of prefabricated steam pipes, suitable for medium and low temperatures. |
| Corrosion and Mechanical Protection | The structure is more complex, with steel jackets and thicker anti-corrosion coatings, providing stronger mechanical protection. | Also has steel or plastic jackets, but relatively weaker mechanical protection. |
| Application Environment | Commonly used in industrial steam networks, heat stations, and large-scale centralized heating systems. | More widely applied, including in hot and cold water pipelines, HVAC systems, etc. |
Summary: Prefabricated insulated steam pipes are designed for high-temperature, high-pressure steam transportation, with structures and materials that are more suitable for harsh operating conditions. Polyurethane insulated pipes, on the other hand, are more versatile and have a wider range of applications, but their high-temperature resistance is slightly inferior.
(1) Central Heating Systems
In urban central heating networks, these pipes are used for long-distance, efficient transportation of steam or hot water, ensuring minimal heat loss.
(2) Industrial Steam Transportation
In industrial enterprises such as chemical plants, steel mills, and paper mills, these pipes are used for the transportation and recycling of process steam.
(3) Petroleum and Natural Gas Industry
In oil fields, refineries, and other facilities, they are used to transport high-temperature steam for oil production enhancement, refining, and other process flows.
(4) Power Industry
In thermal power plants and combined heat and power plants, they are used to transport high-temperature steam, improving energy utilization efficiency.
(5) Food Processing and Pharmaceutical Industry
Steam is used as a heat source for sterilization, drying, heating, and other process operations, ensuring stable production.
(6) Heating, Ventilation, and Air Conditioning (HVAC) Systems
In large buildings, hospitals, schools, and other facilities, steam provides thermal energy supply to achieve comfortable indoor environments.
(7) Pulp and Paper and Textile Industries
Steam is used for heating and drying in paper manufacturing and textile processing processes.
(8) Desalination and Environmental Engineering
Steam is utilized in seawater distillation or treatment processes to enhance equipment operational efficiency.
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E-mail：wr@insulatedpipeline.com
E-mail：wyy@insulatedpipeline.com
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