POLYURETHANE THERMAL INSULATION STEEL PIPE

Polyurethane thermal insulation steel pipe is a high-efficiency, three-layer prefabricated composite piping system designed for underground and overhead hot medium transmission. The structure typically comprises a steel carrier pipe (inner), rigid polyurethane foam (insulation layer), and a high-density polyethylene (HDPE) outer casing (or steel outer shell). Engineered to minimize heat loss and prevent corrosion, it is widely used in district heating, hot water supply, and industrial fluid transport.

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Product Details

POLYURETHANE THERMAL INSULATION STEEL PIPE (PU Insulated Pipe / Pre-insulated Pipe)

1. Product Overview

2. Structural Composition

Inner Working Pipe: Seamless (GB/T 8163), ERW (GB/T 3091), or Spiral/LSAW (GB/T 9711 / API 5L) steel pipe. Internal surface can be coated with FBE/epoxy for anti-corrosion.

Insulation Layer: Rigid Polyurethane (PU/PUF) foam, continuously injected to ensure zero gaps. Thermal conductivity ≤ 0.033 W/(m·K).

Outer Protective Jacket: Black HDPE casing (for buried use) or galvanized steel/aluminum (for above-ground). Features excellent waterproofing and mechanical strength.

End Seal: Red/orange painted exposed insulation edges (as shown in visual references) with protective wrapping to prevent moisture ingress during storage.

3. Technical Specifications & Dimensions

Standard lengths: 6m / 12m (custom available)

Carrier Pipe OD (mm)	Outer Jacket OD (mm)	PU Insulation Thickness (mm)	Standard Length (m)	Max Temp (°C)
Φ32 – Φ89	Φ110 – Φ160	30 – 40	6 / 12	140 (Peak 150)
Φ108 – Φ159	Φ180 – Φ250	40 – 50	6 / 12	140 (Peak 150)
Φ168 – Φ325	Φ250 – Φ450	50 – 70	6 / 12	140 (Peak 150)
Φ355 – Φ630	Φ500 – Φ800	70 – 100	6 / 12	140 (Peak 150)
Φ720 – Φ1220	Φ900 – Φ1420	100 – 120	6 / 12	140 (Peak 150)
Φ1320 – Φ1620	Φ1520 – Φ1820	120+ (Custom)	6 / 12	140 (Peak 150)

(Note: Dimensions can be tailored to project requirements, including custom bend radii and tee/joint prefabrication.)

4. Key Performance Details

Thermal Insulation: Extremely low heat loss (≤0.033 W/m·K), ensuring energy efficiency over long distances.

Operating Temp: Continuous 140°C, short-term peak 150°C (Steam grade up to 350°C with modified structure).

Service Life: 30+ years for buried networks due to HDPE outer jacket and corrosion-resistant inner pipe.

Leak Detection: Optional integrated alarm wire/cable system for real-time monitoring of moisture or carrier pipe failure.

Hydrostatic Pressure: Base pipe tested per GB/T standards; composite pipe withstands designed working pressures (1.0MPa – 2.5MPa typical).

5. Executive Standards

CJ/T 114 — Polyethylene jacket prefabricated direct buried insulation pipe for municipal heating

EN 253 — District heating pipes, pre-insulated bonded pipe systems

ASTM C1055 / ASTM F1960 — Thermal insulation and installation standards

ISO 8497 — Thermal insulation determination

GB/T 8163 / GB/T 3091 / GB/T 9711 — Base steel pipe standards

GB/T 29047 — Polyurethane foam insulation technical requirements

6. Testing & Quality Control

Dimensional inspection (OD, wall thickness, insulation thickness, ovality)

Base pipe hydrostatic & flattening test

PU foam density test (typically 60–80 kg/m³)

Thermal conductivity measurement

HDPE jacket tensile strength & elongation test

Holiday/spark test for outer casing integrity

Leak detection line continuity test (if equipped)

MTC (Mill Test Certificate) and third-party inspection (SGS/BV) available

7. Applications

Central & district heating networks (hot water/return)

Cogeneration and thermal power plant pipelines

Long-distance hot oil / crude oil transport

Industrial steam distribution (special grade)

Municipal hot water supply & building heating

Cryogenic transport (with modified insulation)

8. Packing & Delivery

Stacked bundles with steel strips, end caps with red/orange anti-rust paint seal

Non-abrasive wrapping on outer jacket to prevent UV/scratches

Marking: DN/OD, insulation thickness, standard, batch no., flow direction

Container or bulk shipment; 6m standard for easy handling

9. Catalog Sales Description (Short Version)

" Supplies Polyurethane Thermal Insulation Steel Pipes (Φ32–Φ1620mm) featuring a steel carrier pipe, rigid PU foam, and HDPE outer jacket. Compliant with CJ/T 114, EN 253, and ASTM standards, our pre-insulated pipes ensure minimal heat loss and 30+ years service life for district heating and industrial hot media. Custom lengths, prefabricated fittings, and leak-detection options available. Request specs and quotation."