Direct burial pipe insulation also known as prefabricated direct-burial insulated piping-consists of a composite pipe product featuring an insulation layer and an outer protective casing that are factory-molded before being buried directly underground. These pipes are widely used in applications such as municipal district heating, district cooling, petrochemical processing, and industrial pipeline insulation. As a co-author of the industry standard GB/T 29047-2012, Xingbang Company has specialized in this field for nearly 30 years and possesses an annual production capacity of 3,000 kilometers of polyurethane prefabricated direct-burial insulated piping (ranging from DN20 to DN1600).
Product Specifications
|
Working Steel Pipe Diameter (DN) |
Insulation Layer Thickness |
Outer Casing Outer Diameter (Dc) |
Outer Casing Minimum Wall Thickness (emin) |
|
300 |
30-50 |
393-433 |
4.0 |
|
350 |
30-50 |
445-485 |
4.0 |
|
400 |
30-60 |
494-554 |
4.0 |
|
450 |
30-60 |
547-607 |
4.5 |
|
500 |
30-60 |
598-658 |
4.5 |
|
600 |
30-60 |
700-760 |
5.0 |
|
700 |
30-60 |
790-850 |
5.0 |
|
800 |
30-60 |
891-951 |
5.5 |
|
900 |
30-60 |
992-1052 |
6.0 |
|
1000 |
30-60 |
1093-1153 |
6.5 |
|
1100 |
30-60 |
1194-1254 |
7.0 |
|
1200 |
40-100 |
1316-1436 |
8.0 |
|
1400 |
50-120 |
1538-1678 |
9.0 |
|
1600 |
60-150 |
1760-1944 |
11.0 |
Core Structure
The product features a three-layer composite structure design:
Service Pipe: The inner pipe for conveying the medium; made of seamless steel or spirally welded steel pipe, with diameters ranging from DN20 to DN1600 mm.
Signal Wire: (Optional)
Insulation Layer: Rigid polyurethane foam; density ≥ 60 kg/m³, thermal conductivity ≤ 0.033 W/(m·K), closed-cell rate ≥ 88%.
Outer Casing: High-density polyethylene (HDPE) jacket; impact-resistant, corrosion-resistant, and watertight
Product Advantages
Significant energy savings and low heat loss
The polyurethane insulation layer boasts a thermal conductivity of ≤ 0.033 W/(m·K) and a closed-cell rate of ≥ 88%. Heat loss is reduced by 40%–75% compared to traditional overhead or trench-laid systems, with temperature drop controlled to within 3°C per kilometer, resulting in substantial long-term energy cost savings.
01
Waterproof, corrosion-resistant, and durable
The fully sealed HDPE outer casing effectively blocks groundwater and soil corrosion. Combined with the high-performance polyurethane insulation (closed-cell rate ≥ 88%), the design service life reaches 30–50 years-far exceeding that of traditional trench-laid systems.
02
Rapid installation and low comprehensive cost
Factory-prefabricated pipe sections allow for direct burial on-site, eliminating the need for masonry trenches. This reduces civil engineering work by approximately 70%, shortens the construction period by about 50%, and lowers the total project cost by roughly one-third.
03
Stable quality and full process control
Utilizing a "pipe-in-pipe foaming" process, the three layers are tightly integrated, ensuring a uniform insulation layer without eccentricity. Xingbang implements a "three-inspection" quality control system and operates a CNAS-accredited testing center exceeding 2,000 m²; products comply with GB/T 29047-2012 and European EN253 standards.
04
Intelligent monitoring for safety and reliability
Optional built-in leak detection wires or fiber-optic monitoring systems enable real-time monitoring of the pipeline network's operating status and rapid, precise location of leaks. This significantly reduces maintenance costs and ensures the long-term safe operation of the network.
05
Manufacturing Process
Applications
Primary and secondary main pipelines for municipal district heating
District cooling systems
Thermal insulation for chemical industry piping
Petroleum transmission pipelines
Municipal thermal network projects
Product Certifications
Xingbang's certification system for direct burial pipe insulation covers four key dimensions-management, product, industry, and international market access-ensuring compliance for global customers:
Management Systems
Integrated certification covering ISO9001, ISO14001, ISO45001, and CNPC/Sinopec HSE standards.
01
Product Standards
Strict adherence to the GB/T 29047-2021 standard (the company participated in drafting this standard); a CNAS-accredited testing center (Registration No.: CNAS L8020) capable of independently issuing authoritative test reports.
02
International Certification
Holds EU CE certification, meeting market access requirements for Europe.
03
Industry & Green Certifications
National Manufacturing Single Champion, National "Specialized, Refined, Unique, and Innovative" (SRUI) Key "Little Giant" Enterprise, National Green Design Demonstration Enterprise, Hebei Provincial Government Quality Award, and Hebei Provincial Green Factory.
04
Products can also be manufactured in accordance with the European EN253 standard to meet the technical requirements of various overseas markets. Please contact the Xingbang sales department for copies of specific certification documents or consultations regarding market access.
On-site Construction Services
Xingbang Pipeline establishes dedicated on-site professional service teams for overseas projects, providing one-on-one, point-to-point construction services throughout the process.
On-site Technical Guidance: Experienced technical personnel are dispatched to overseas project sites to supervise key procedures-such as pipe alignment and welding, joint insulation and field joint coating, and outer casing sealing-ensuring construction quality meets international standards.
Joint Construction Services: Addressing the critical concerns of joint quality and waterproofing in overseas projects, Xingbang provides on-site joint insulation services. We use insulation materials identical to those of the main pipe body for field joint coating, combined with electro-fusion sleeves or heat-shrinkable tapes for sealing, ensuring consistent insulation performance across the entire pipeline.
Construction Support: Specialized on-site vehicles are deployed based on project needs, equipped for power generation, sandblasting, and high-pressure mechanical foaming operations, ensuring that on-site joint construction quality remains uncompromised by local conditions.
Global Service Response: Leveraging overseas facilities such as its Mexico production base and Middle East subsidiary, Xingbang can rapidly respond to on-site service needs across the Americas and the Middle East.
The company has successfully serviced overseas projects in countries including Chile, Vietnam, Mongolia, and Fiji, accumulating extensive experience in handling diverse climatic conditions and construction standards.
Packaging and Transport
Export packaging and transport for direct burial pipe insulation must withstand long-distance ocean shipping, multiple transshipments, and varying climatic conditions to ensure the product arrives safely at the overseas project site:
Factory Packaging
Pipe ends are sealed with PE caps and waterproof sheeting to prevent the ingress of salt spray and moisture during ocean transit; product specifications, standard numbers, and manufacturing details are marked on the outer casing; steel frame supports or reinforced wooden pallets are used depending on the transport method.
Lifting Specifications
Nylon lifting straps with a width of ≥50mm must be used; direct binding with steel wire ropes is strictly prohibited; pipes must be lifted and placed steadily to prevent impact damage to the outer casing.
Transport Safeguards
Specialized flatbed trucks are used, with rubber pads placed between the truck bed and the pipes; loads are securely strapped to prevent shifting; the buyer is notified of arrival details in advance to facilitate on-site unloading arrangements.
Container Shipping
Small-diameter pipes can be loaded into 40-foot high-cube containers, while large-diameter pipes are transported via flat-rack containers or break-bulk vessels; cushioning materials are used to secure the pipes within the container or ship's hold.
On-site Storage
The storage area must be level, solid, and free of standing water; pipes must be placed on supports (pipe cradles) and stacked no higher than 2 meters; for outdoor storage, waterproof tarps are used for sun and rain protection, and pipe-end seals must remain intact.
Documentation
A full set of customs clearance documents-including packing lists, commercial invoices, certificates of origin, and test reports-is provided to ensure smooth clearance at the destination port.
FAQ
Q: What are the main differences between direct burial pipe insulation and above-ground insulated piping?
A: Direct burial pipe insulation features an HDPE outer casing designed for underground direct-burial installation, offering waterproof, anti-corrosive, and soil-corrosion-resistant properties; above-ground insulated piping uses a metal outer casing suitable for open-air environments and offers superior UV resistance. The difference in materials stems from the distinct installation environments.
Q: What is the minimum soil cover depth requirement for direct burial pipe insulation?
A: For sections beneath roadways, the required soil cover depth ranges from ≥1.0 m (for DN315 pipes) to ≥1.2 m (for DN500 pipes); under non-motorized vehicle lanes or green belts, this depth may be reduced but generally should not be less than 0.8 m to prevent surface loads from damaging the pipeline.
Q: How can buried pipelines be protected against damage from third-party construction?
A: Warning tapes or warning boards can be installed above the pipeline, and as-built drawings and pipeline routing data should be provided to the project owner. Xingbang products offer an optional fiber-optic monitoring system that monitors vibration signals around the pipeline in real-time, providing timely alerts and pinpointing the location of any anomalies.
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