OFFSHORE PIPELINE
OFFSHORE PIPELINE – SUBSEA TRANSMISSION SYSTEMS
Outside Diameter：Φ323.9mm – 1626mm (12.75″ – 64″ )
Wall Thickness：12.7 – 40mm (0.5″ – 1.57″)
Quality Standards：API 5L PSL2、API 5LC/5LD、DNV-OS-F101、ISO 13623、ASME B31.4/B31.8
Length：12 – 24m (40′-80′), Double Joints up to 48m
Coating : 3LPP (Three-Layer Polypropylene), FBE + Concrete Weight Coating (CWC), Field Joint Coating (FJC), or as per project requirements
description
Offshore pipeline are important underwater arteries for global energy transportation, enabling the safe and efficient transport of oil, gas, and other critical resources through the marine environment. Designed with high-performance steel pipes (fabricated using a precise UOE/JCOE process), these pipes are built with advanced materials, automated welding technology, and multi-layer protection systems to withstand extreme subsea conditions, including deep-sea pressure, corrosive brine, seismic activity, and temperature fluctuations. They are designed for 30-50+ years of continuous operation, providing unmatched reliability in high-pressure, high-flow scenarios while prioritizing environmental safety and operational resiliency.
Product Name: Subsea Transmission Pipeline, Offshore Flowline
Specifications:
Outer Diameter: 323.9mm–1626mm
Wall Thickness: 12.7 — 40mm
Length: 12m / 24m (Double Joints: 24-48m)
Standard and Steel Grade:
API SPEC 5L: PSL2 X65, X70, X80, X100
DNV-OS-F101: 450, 485, 555, 625 (SMYS in MPa)
ISO 13623: L485, L555, L625
API 5LC/5LD: C90, C95, T95 (Corrosion-Resistant Alloys)
Ends: Bevelled ends with weld prep + temporary seal caps
Surface Treatment
Primary Corrosion Protection:
- 3LPP (Three-Layer Polypropylene)
- FBE + CWC (Concrete Weight Coating for stability)
Specialized Protection: - Anode Bracelets for cathodic protection
- Rock Shield for trenchless seabed sections
- Insulation Coating for hydrate prevention
Specification
Offshore pipeline Specification Range Reference Table
| Parameters | Typical range | Extreme range | Standard basis | Engineering constraints |
| Outside diameter | ⌀323.9mm\~⌀762mm | ⌀168.3mm\~⌀1524mm | API 5L / DNV-OS | >914mm requires specialized installation vessels |
| Wall thickness | 15.0mm\~30.0mm | 10.0mm\~50.0mm | DNV-OS-F101 | Thickness \>40mm requires special welding procedures |
| Water Depth | Shallow Water (<300m) | Deepwater (300m-3000m+) | DNV-OS-F101 | Ultra-deep (>1500m) requires high collapse resistance |
| Length | Double Joints (24m) | Quad Joints (48m) / Reels | Project Specific | Reel-lay limits based on vessel capacity |
Offshore pipeline Standards and Applications Comparison Table
| Classification | Standard | Positioning | Applicability |
| Material & Manufacture | API 5L PSL2 | Global standard for line pipe | Mandatory for most subsea pipelines |
| Design & Integrity | DNV-OS-F101 | Comprehensive offshore pipeline standard | Global standard, especially North Sea & deepwater |
| Safety & Operation | ASME B31.4/B31.8 | US Pipeline Safety Codes | Required for US waters / connecting infrastructure |
| Quality & Testing | ISO 3183 | International line pipe specification | Widely used globally, alternative to API 5L |
application
Extreme tolerance:
Tolerance to high sea gravity and low temperature: Can work stably in high sea gravity and low temperature.
Resistance to seawater corrosion and chemical erosion: Has excellent resistance to seawater corrosion and chemical media.
Increased stability systems:
Emphasis on the foundation ensures the stability of the seabed: the use of special weight distribution painting prevents the displacement of the pipes in the seabed.
Adaptable connections for underwater installations: The connections are specially developed for underwater infrastructures and ensure a reliable connection.
Excellent power levels:
Optimization for the transport of large fluids: The pipeline has been specially optimized for the transport of large quantities of liquids.
Pre-programmed convenient waiting tours: Pre-installed waiting tours are offered to facilitate later maintenance work.
Security and Surveillance Security:
Real-time monitoring of pipeline integrity: Provides the ability to monitor the condition of the pipeline in real-time to ensure its structural integrity.
Emergency Stop System Compatibility: The system is compatible with Emergency Stop Systems (ESD) and can quickly and safely stop supply when needed.
advantages
Unmatched Underwater Integrity
- Strict construction for compressive strength in deep water
- Quality control for non-destructive welds
- Improved Structural Reliability Testing
Superior corrosion resistance
- Multi-lag protective barrier against seawater penetration
- Long-term cathode protection
- Tailor-made coatings for hard chemicals
Deep-water plant ready
- Compatibility with all major installation methods
- Built-in safety features to prevent collapse
- Precision mechanics for rewinding
Lifecycle Economy
- Increased service life with minimal maintenance
- Reduced seabed preparation effort
- High material recyclability
Logistics efficiency
- Tailor-made lengths to minimize offshore welding
- Pre-coated options for quick installation
Optimized shipload systems
packing
End Protection
Heavy Load Seals with Moisture Barriers
Impact-Resistant Frames for Welded Ends
Pipe Body Protection
UV-resistant film coating over corrosion protection layers
Enhanced cushioning for concrete pipe jacking
Marine freight
Specialized ship carriers with anti-skid systems
Sturmfestes locking system
Internal moisture control during shipment
Storage method
Built-up stacking to avoid ground contact
Controllable Layering by Pipe Diameter
Weatherproof Overlays for Coastal Storage Facilities
Tracking System
Permanent Identification Mark
Color-coded bands for quick identification
Digital inventory tracking
Offshore pipeline Specification Range Reference Table
| Parameters | Typical range | Extreme range | Standard basis | Engineering constraints |
| Outside diameter | ⌀323.9mm\~⌀762mm | ⌀168.3mm\~⌀1524mm | API 5L / DNV-OS | >914mm requires specialized installation vessels |
| Wall thickness | 15.0mm\~30.0mm | 10.0mm\~50.0mm | DNV-OS-F101 | Thickness \>40mm requires special welding procedures |
| Water Depth | Shallow Water (<300m) | Deepwater (300m-3000m+) | DNV-OS-F101 | Ultra-deep (>1500m) requires high collapse resistance |
| Length | Double Joints (24m) | Quad Joints (48m) / Reels | Project Specific | Reel-lay limits based on vessel capacity |
Offshore pipeline Standards and Applications Comparison Table
| Classification | Standard | Positioning | Applicability |
| Material & Manufacture | API 5L PSL2 | Global standard for line pipe | Mandatory for most subsea pipelines |
| Design & Integrity | DNV-OS-F101 | Comprehensive offshore pipeline standard | Global standard, especially North Sea & deepwater |
| Safety & Operation | ASME B31.4/B31.8 | US Pipeline Safety Codes | Required for US waters / connecting infrastructure |
| Quality & Testing | ISO 3183 | International line pipe specification | Widely used globally, alternative to API 5L |
Extreme tolerance:
Tolerance to high sea gravity and low temperature: Can work stably in high sea gravity and low temperature.
Resistance to seawater corrosion and chemical erosion: Has excellent resistance to seawater corrosion and chemical media.
Increased stability systems:
Emphasis on the foundation ensures the stability of the seabed: the use of special weight distribution painting prevents the displacement of the pipes in the seabed.
Adaptable connections for underwater installations: The connections are specially developed for underwater infrastructures and ensure a reliable connection.
Excellent power levels:
Optimization for the transport of large fluids: The pipeline has been specially optimized for the transport of large quantities of liquids.
Pre-programmed convenient waiting tours: Pre-installed waiting tours are offered to facilitate later maintenance work.
Security and Surveillance Security:
Real-time monitoring of pipeline integrity: Provides the ability to monitor the condition of the pipeline in real-time to ensure its structural integrity.
Emergency Stop System Compatibility: The system is compatible with Emergency Stop Systems (ESD) and can quickly and safely stop supply when needed.
Unmatched Underwater Integrity
- Strict construction for compressive strength in deep water
- Quality control for non-destructive welds
- Improved Structural Reliability Testing
Superior corrosion resistance
- Multi-lag protective barrier against seawater penetration
- Long-term cathode protection
- Tailor-made coatings for hard chemicals
Deep-water plant ready
- Compatibility with all major installation methods
- Built-in safety features to prevent collapse
- Precision mechanics for rewinding
Lifecycle Economy
- Increased service life with minimal maintenance
- Reduced seabed preparation effort
- High material recyclability
Logistics efficiency
- Tailor-made lengths to minimize offshore welding
- Pre-coated options for quick installation
Optimized shipload systems
End Protection
Heavy Load Seals with Moisture Barriers
Impact-Resistant Frames for Welded Ends
Pipe Body Protection
UV-resistant film coating over corrosion protection layers
Enhanced cushioning for concrete pipe jacking
Marine freight
Specialized ship carriers with anti-skid systems
Sturmfestes locking system
Internal moisture control during shipment
Storage method
Built-up stacking to avoid ground contact
Controllable Layering by Pipe Diameter
Weatherproof Overlays for Coastal Storage Facilities
Tracking System
Permanent Identification Mark
Color-coded bands for quick identification
Digital inventory tracking
