What Is Pipe Coating?

Pipe coating is an external protective layer applied to steel pipe to prevent corrosion from soil, water, and atmospheric exposure. Unprotected buried or submerged carbon steel pipe corrodes at rates of 0.1-0.5 mm/year or higher, depending on soil resistivity, moisture, and chemical content. External coating, combined with cathodic protection, is the standard corrosion prevention system for pipelines worldwide.

The coating type depends on the pipeline’s operating temperature, burial conditions, and design life.

Coating Type	Full Name	Temperature Range	Thickness	Primary Use
FBE	Fusion Bonded Epoxy	-40°C to 85°C	300-600 microns	Onshore/offshore pipelines
3LPE	3-Layer Polyethylene	-40°C to 80°C	1.8-3.2 mm	Onshore buried pipelines
3LPP	3-Layer Polypropylene	-20°C to 140°C	1.5-3.0 mm	High-temp onshore/offshore
CTE	Coal Tar Enamel	-5°C to 65°C	4-6 mm	Legacy, declining use
CWC	Concrete Weight Coating	Subsea ambient	40-150 mm	Offshore (negative buoyancy)
PP Foam	Polypropylene Foam	-20°C to 130°C	15-100 mm	Subsea insulation
PU Foam	Polyurethane Foam	-40°C to 100°C	25-100 mm	Onshore/offshore insulation

FBE Coating

Fusion Bonded Epoxy is a thermosetting powder coating applied to pipe heated to 230-245°C. The epoxy melts, flows, and cures into a hard, smooth barrier. Single-layer FBE (300-500 microns) provides excellent adhesion and chemical resistance but limited mechanical protection.

FBE is used as:

• Standalone external coating for non-aggressive soil conditions
• Primer layer in 3LPE and 3LPP systems
• Internal coating for gas pipelines (reducing friction, preventing internal corrosion)

Standards: CSA Z245.20, ISO 21809-2

3LPE and 3LPP

Three-layer polyethylene and polypropylene systems consist of:

1. Layer 1: FBE primer (150-250 microns)
2. Layer 2: Copolymer adhesive (200-400 microns)
3. Layer 3: PE or PP topcoat (1.5-3.0 mm)

3LPE is the global standard for onshore buried oil and gas pipelines. 3LPP handles higher operating temperatures (up to 140°C) for high-temperature pipelines and flowlines.

Standards: ISO 21809-1, EN 10288, DIN 30670 (3LPE), DIN 30678 (3LPP)

Pro Tip

The transition from 3LPE to 3LPP occurs around 80°C operating temperature. Polyethylene softens above 80°C, losing its mechanical properties. For pipelines operating between 80-140°C (e.g., hot oil lines, deep gas wells), always specify 3LPP.

Concrete Weight Coating (CWC)

Subsea pipelines require negative buoyancy to remain stable on the seabed. CWC adds 40-150 mm of reinforced concrete around the anti-corrosion coating. Weight and thickness are calculated based on:

• Pipe diameter and wall thickness
• Water depth and current velocity
• Installation method (S-lay, J-lay, reel-lay)
• Seabed soil conditions

For more on coating, lining, and cladding differences, see the full guide to pipe coating, lining, and cladding.

Read the full guide to pipe types