BS 1387 Standard Welded Steel Pipe with Epoxy Coal Tar Coating 4 Inch for Acid Environment

Engineered to provide superior durability in highly corrosive industrial and subterranean settings, this BS 1387 Standard Welded Steel Pipe with Epoxy Coal Tar Coating is the ultimate choice for acid-prone environments. Utilizing a compact 4-inch (DN100) nominal welded steel tube manufactured to strict BS 1387 specifications (available in Medium and Heavy series), this pipe offers excellent pressure containment and precise dimensions.
The exterior (and interior, if specified) is coated with a heavy-duty Coal Tar Epoxy barrier. This coating delivers exceptional chemical inertness and resistance to mineral acids, salt spray, and aggressive acidic soils. It provides a reliable, long-lasting conduit for industrial chemical drainage, acid mine runoff, and subterranean pipelines buried in highly corrosive, low-pH backfill conditions.

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Features & Advantages

Optimized Acid & Chemical Resistance: The dense coal tar epoxy matrix is highly resistant to low-concentration inorganic acids (such as sulfuric and hydrochloric acids) and organic acids, preventing metal loss.

Trustworthy BS 1387 Standard: Fully compliant with the British standard for steel tubes, ensuring uniform wall thickness, high structural integrity, and reliable performance in low-to-medium pressure applications.

Compact & Agile 4-Inch Profile: Ideal for tight process piping configurations, chemical facility drainage loops, mining runoff networks, and subterranean trenching.

Superior Underground Isolation: Provides a tough, high-dielectric shield that completely prevents cathodic disbondment and galvanic corrosion in highly saline or acidic wet soils.

Technical Specifications

Specification Item	Detailed Description
Product Name	BS 1387 Welded Steel Pipe with Epoxy Coal Tar Coating
Base Pipe Standard	BS 1387 (Specification for screwed and socketed steel tubes and tubulars)
Base Pipe Series	Medium Series or Heavy Series
Manufacturing Process	ERW (Electric Resistance Welding) / Welded
Nominal Pipe Size (NPS)	4 Inch (DN100)
Outer Diameter (OD)	114.3 mm (Min 113.1 mm – Max 114.9 mm)
Wall Thickness (WT)	Medium Series: 4.5 mm (0.177 in) Heavy Series: 5.4 mm (0.213 in)
Anti-Corrosion Coating	Liquid Epoxy Coal Tar (Coal Tar Epoxy) Paint
Coating Standards	SSPC-Paint 16, AWWA C210, SY/T 0447
Typical Dry Film Thickness (DFT)	300 to 500 microns (12 to 20 mils) or customized
Pipe Ends	Plain Ends, Beveled for welding (with cutback), or Threaded and Coupled (T&C) to BS 21
Standard Length	5.8m, 6.0m, or customized

Product Applications

Acidic Mining Runoff Lines: Transporting wastewater and tailings with high mineral acid and chemical concentrations.

Industrial Chemical Drainage: Process drainage loops in chemical manufacturing facilities handling low-concentration acidic effluents.

Acidic Soil Burial Networks: Subterranean utility lines and water loops crossing ground soils with high organic acid, swamp water, or sulfur content.

Marine & Coastal Utilities: Low-pressure conduits exposed to aggressive salt spray and continuous wet-dry marine cycles.

Rigorous Quality Control & Manufacturing Process

Our 4-inch BS 1387 pipes are manufactured and coated under strict, modern quality control protocols to ensure performance in aggressive environments:

Raw Tube Dimensional Verification: Checking the welded steel tubes to ensure compliance with BS 1387 Medium or Heavy series physical specifications.

Surface Blast Cleaning to SA 2.5: Shot blasting the steel surface to SA 2.5 cleanliness, creating a near-white metal finish with the ideal micro-roughness for paint adhesion.

High-Build Coal Tar Epoxy Application: Multi-pass liquid coal tar epoxy is applied in a dust-free environment to ensure a continuous, uniform dry film thickness.

Dielectric & Holiday Testing: 100% dry film thickness checks and low-voltage Holiday testing are executed to guarantee absolute coating continuity and eliminate any micro-pinholes or voids.

Frequently Asked Questions (FAQ)

Q1: How does the BS 1387 classification affect my piping choices?

A: BS 1387 classifies steel tubes into Light, Medium, and Heavy series. For industrial acid environments and buried utilities, Medium Series (4.5 mm wall thickness) or Heavy Series (5.4 mm wall thickness) are recommended to provide the necessary mechanical strength and safety margins against soil movement and internal pressure.

Q2: Why is epoxy coal tar highly effective in an acid environment?

A: Coal tar epoxy is a thermosetting polymer with a highly cross-linked molecular structure. This structure exhibits exceptional chemical inertness, making the coating highly resistant to dilute inorganic acids (such as sulfuric and hydrochloric acids), organic acids, saline solutions, and aggressive microbial activity found in low-pH soils.

Q3: Can these BS 1387 pipes be threaded instead of welded?

A: Yes. Under the BS 1387 specification, these pipes are designed to support screwed and socketed (threaded and coupled) connections using BS 21 pipe threads. When ordered, we leave the threaded section bare of epoxy coal tar to ensure proper mechanical sealing during installation on-site.

Q4: How do you protect the welded joints in acidic environments on-site?

A: The pipes are supplied with factory bare steel “cutbacks” at the ends. After field butt-welding and weld inspection, the joint area is thoroughly cleaned. Pipeline crews then apply cold-applied, chemical-resistant coal tar tapes or coat the joint with high-build liquid epoxy coal tar paint to match the pipeline’s high-performance protective barrier.