Heavy Duty Epoxy Coal Tar Coated SSAW Pipe 813mm OD with 3-Cloth 5-Oil Layer

Engineered for severe subterranean deployments and highly aggressive soil environments, this Heavy Duty Epoxy Coal Tar Coated SSAW Pipe represents the peak of reinforced liquid coating technology. Featuring a large 813mm outer diameter (32-inch NPS) Spiral Submerged Arc Welded (SSAW) steel base, this pipeline provides outstanding structural load-bearing capacity and pressure handling.
The exterior is protected by an industry-proven 3-Cloth 5-Oil (3-Cloth 5-Coat) reinforced anti-corrosion system. This specialized structural coating alternates five high-build coats of liquid coal tar epoxy with three layers of high-tensile glass fiber mesh. This configuration creates an exceptionally thick, rugged, and impact-resistant composite shield that completely insulates the steel from acidic clay, marsh moisture, and heavy soil stress, delivering a reliable 30+ year lifespan for heavy municipal and industrial pipeline projects.

Features & Advantages

Reinforced 3-Cloth 5-Oil Composite: Alternating glass fiber mesh and liquid coal tar epoxy layers provide superior mechanical strength, preventing rock puncture and coating shear during installation and backfilling.

Exceptional Corrosion Barrier: The extremely thick dry film thickness (DFT) offers absolute isolation from harsh underground salts, stagnant water, and anaerobic bacteria.

High-Strength SSAW Base: The 813mm OD spiral weld distributes internal and external stresses evenly, accommodating heavy overburdens and high operating pressures.

High Soil Stress Tolerance: Effectively resists soil shifting, thermal expansion, and root penetration, preventing delamination in unstable, swampy, or clay-rich terrains.

Technical Specifications

Specification Item	Detailed Description
Product Name	Heavy Duty Reinforced Epoxy Coal Tar Coated SSAW Pipe
Base Pipe Standard	API 5L (Gr. B, X42, X52), ASTM A252, or GB/T 9711 / GB/T 3091
Manufacturing Process	SSAW (Spiral Submerged Arc Welding)
Outer Diameter (OD)	32.00 inches (813.0 mm)
Wall Thickness (WT)	Typical 8.0 mm to 20.0 mm (Customizable based on project pressure requirements)
Coating Type	3-Cloth 5-Oil Reinforced Epoxy Coal Tar System (三布五油)
Coating Standards	SY/T 0447, AWWA C210, SSPC-Paint 16
Coating Structure	Primer + 5 coats of Coal Tar Epoxy Paint + 3 layers of Woven Glass Fiber Cloth
Typical Dry Film Thickness (DFT)	Minimum 0.6 mm to 0.8 mm (600 – 800 microns) or as specified
Pipe Ends	Beveled ends (30°~35°) with a factory-controlled bare steel cutback for field joint welding
Standard Length	11.8m, 12.0m, or customized

Product Applications

Severe Underground Municipal Mains: Wastewater, stormwater, and drainage mains crossing unstable, clay-rich, or swampy terrains.

Industrial Cooling Intake/Discharge: Subterranean loops in coastal power plants, chemical refineries, and heavy industrial facilities.

Regional Water Diversion Projects: High-capacity water supply mains buried in highly acidic or saline coastal soils.

Piling & Marine Foundations: High-load structural water pipelines and foundation piles in intertidal or marine zones.

Rigorous Quality Control & Manufacturing Process

Our 813mm SSAW heavy-duty pipes are manufactured and coated under strict, modern quality control protocols:

SSAW Base Inspection & Blasting: The spiral weld bead is checked, and the pipe exterior undergoes aggressive abrasive shot blasting to SA 2.5 cleanliness to ensure maximum surface grip.

Automated Multi-Pass Coating Application: The primer and first coat of liquid coal tar epoxy are applied. While wet, high-strength glass fiber cloth is wrapped under continuous tension. This sequence is repeated until three layers of cloth and five coats of epoxy are fully integrated.

Controlled Curing Process: The composite is allowed to fully cure under controlled ambient conditions to form a dense, single-body reinforced protective shell.

Non-Destructive Thickness & Spark Testing: Dry film thickness is verified using electromagnetic gauges. High-voltage Holiday testing (typically at 2kV to 5kV depending on thickness) is executed across the entire pipe surface to guarantee zero pinholes or dielectric gaps.

Frequently Asked Questions (FAQ)

Q1: What is the engineering purpose of a “3-Cloth 5-Oil” coating system?

A: Standard liquid paint coatings are relatively thin and susceptible to mechanical damage from rocks, backfill abrasion, and soil movement (soil stress). The “3-Cloth 5-Oil” system alternates five liquid epoxy coal tar coats with three layers of woven glass fiber mesh. This creates a reinforced, high-thickness composite shield that handles heavy physical impact and prevents coating shear during subterranean soil shifting.

Q2: What is the average thickness (DFT) of this reinforced system?

A: A standard 3-cloth 5-oil system achieves a robust Dry Film Thickness (DFT) of 600 to 800 microns (approximately 24 to 32 mils). This is significantly thicker than standard liquid-only applications, providing an enhanced physical barrier against moisture and chemical penetration.

Q3: Does the spiral weld seam of the 813mm SSAW pipe affect the coating uniformity?

A: No. During the automated wrapping process, the glass fiber cloth is applied under tight tension, forcing the liquid epoxy coal tar to fully encapsulate the spiral weld bead. This eliminates any risk of air voids, bridging, or thin spots along the weld profile, ensuring a continuous protective barrier.

Q4: How are the welded joints protected on-site?

A: The pipes are delivered with precision-beveled ends and a factory-controlled bare steel cutback. After field butt-welding and weld inspection, the joint area is cleaned. Technicians apply a matching “3-cloth 5-oil” hand-wrapped liquid and mesh system on-site, or utilize heavy-duty cold-applied coal tar tape to match the main pipe’s reinforced protective profile.