Insulated Steel Pipe Dimensions Chart

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Update time : 2026-08-13 09:12:52

  Insulated Steel Pipe is a steel pipe that has undergone insulation processing to ensure that the internal temperature and surface temperature of the working steel pipe meet or reach the required usage temperature under different working environments and external media.

  1. Product Structure—Three-Layer Structure

  The heat preservation steel pipe has a three-layer integrated structure, consisting of an inner steel pipe for conveying the medium, a middle rigid polyurethane insulation layer, and an outer high-density polyethylene outer protective pipe.

  2. Standards Implemented

  GB/T 29047-2012 Pre-insulated direct-buried pipes and fittings with high-density polyethylene outer sheath and rigid polyurethane foam

  GB/T 34611-2017 Pre-insulated direct-buried pipes with rigid polyurethane spray coating and polyethylene spiral wound

  CJ/T 114-2000 Pre-insulated direct-buried pipes with high-density polyethylene outer sheath and polyurethane foam

  GB/T 9711-2017 Steel pipes for pipeline transportation systems in the oil and gas industry

  SY/T 5037-2018 Submerged arc welded steel pipes for general fluid transportation

  GB/T 3091-2015 Welded steel pipes for low-pressure fluid transportation

  GB/T 8163-2018 Seamless Steel Pipes for Fluid Transportation

  3. Product Specifications

  Nominal Diameter: DN100mm-DN1400mm

  Pipe Wall Thickness: 5mm-22mm

  Steel Grade: Can produce steel pipes of Q series, X70 and below.

  4. Product Performance

  (1) Wide range of product specifications, applicable to primary and secondary heating pipelines.

  (2) Wide applicable temperature range, can operate for extended periods at -50℃-120℃, saving significant energy and reducing energy costs.

  (3) Strong waterproof and corrosion-resistant capabilities, while also possessing excellent characteristics such as heat insulation, sound insulation, flame retardancy, cold resistance, non-absorbency, and easy and quick construction. (4) Low coefficient of linear expansion (0.012), resulting in low axial shear strength due to temperature variations. The three-layer integrated structure is stable and will not cause peeling.

  (5) Service life can reach 30-50 years. Correct installation and use can minimize pipeline maintenance costs.

  (6) An alarm system can be installed to automatically detect pipeline leaks, accurately indicate the location of the fault, and automatically trigger an alarm.

▼Main Technical Indicators of Polyurethane Insulation Layer

Project

Unit

Index

Test methods (standards)

Density

Kg/m3

≥60

GB/T 6343

Compressive strength

MPa

≥0.3

GB/T 8813

Thermal conductivity

W/(m·k)

≤0.033

GB/T 10297

Heat resistance

140

EN253

Closed porosity

%

≥88

GB/T 10799

Water absorption rate

%

≤10

CJ/T 114

  
▼Main technical specifications of thermal insulation pipes

Project

Unit

Index

Test methods (standards)

Extrusion deformation

%

≤15%

GB/T 8806

Outer diameter increase rate

%

≤2%

GB/T 8806

Impact resistance

/

No visible cracks

GB/T 14152

Axial shear strength

MPa

≤0.12(23±2)

≤0.08(140±2)

CJ/T 114


  5. Schematic diagram of thermal insulation foam production process



  6. Product Specifications and Dimensions

  Insulated Steel Pipe Specifications and Dimensions Table

Nominal diameter

mm)

outer diameter of steel pipe

mm)

Outer diameter of outer sheath × wall thickness(mm)

Average thickness of insulation layer (mm)

200

219

315×4.9

43

250

273

365×6.3

40

300

325

420×7.0

40

350

377

500×7.8

53

400

426

550×8.8

53

450

478

580×8.8

42

500

529

655×9.8

53

600

630

760×11.5

53

700

720

850×12

53

800

820

960×14

56

900

920

1054×14

53

1000

1020

1155×14

54

1200

1220

1380×15

65

1400

1420

1580×16

64

1. Straight pipe supply length: 6-12 meters.
2. Other specifications of steel pipes and outer protective pipes can be used according to user requirements.

3. Insulation layer thickness can also be customized according to user requirements.


  Insulation projects for various indoor and outdoor centralized heating pipelines, central air conditioning pipelines, chemical and pharmaceutical industrial pipelines. Suitable for media operating at -50℃-120℃ for extended periods, with occasional peak temperatures not exceeding 140℃. Email : pipe@stpipefitting.cn

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