Valve Anti-Corrosion Coating Selection Guide

Industrial valves are widely used in oil & gas, chemical plants, power generation, water treatment, and marine industries. One of the biggest challenges in valve operation is corrosion, which can lead to leakage, shorter service life, and costly replacements. To extend durability and ensure compliance with international standards, the correct anti-corrosion coating system must be applied.

This guide provides practical recommendations for selecting valve protective coatings based on operating conditions and global standards.

Why Anti-Corrosion Coatings Are Essential for Valves

• Corrosion Resistance – Prevents rust, pitting, and chemical attack.

• Extended Service Life – Protects valves from harsh weather and process media.

• Compliance – Meets EPC and end-user requirements for oil & gas and water projects.

• Reduced Maintenance Costs – Minimizes downtime and repair frequency.

Common Types of Valve Protective Coatings

1. Epoxy Coatings

• Features: Strong adhesion, excellent corrosion resistance, affordable.

• Best for: Underground pipelines, water treatment plants, buried valves.

• Note: Epoxy can chalk under UV exposure; topcoat with polyurethane if outdoor.

2. Polyurethane Coatings

• Features: High gloss, UV resistance, weather durability.

• Best for: Outdoor and offshore valves exposed to sunlight.

• Note: Usually applied as a topcoat over epoxy primer.

3. Fusion Bonded Epoxy (FBE)

• Features: Powder coating with excellent adhesion and chemical resistance.

• Best for: Drinking water valves, buried gas valves, and high-durability service.

• Note: Requires specialized application equipment.

4. Zinc-Rich Primers

• Features: Provide sacrificial protection to steel substrates.

• Best for: Harsh environments like marine and offshore applications.

• Note: Typically used as the first layer under epoxy or polyurethane.

5. Fluoropolymer Coatings (PTFE, PFA)

• Features: Excellent chemical resistance, non-stick surface.

• Best for: Chemical plants, acid service, high-purity process valves.

• Note: More expensive and requires specialized application.

6. Thermal Spray Aluminum (TSA) or Zinc (TSZ)

• Features: Extremely durable, long-term protection against seawater.

• Best for: Offshore oil & gas platforms, subsea valves.

• Note: High initial cost but provides >20 years service life.

Coating Selection by Environment

International Standards for Valve Coatings

• ISO 12944 – Corrosion protection of steel structures by protective coatings (C1 to C5 environment categories).

• NACE SP0169 – Control of external corrosion on buried valves and pipelines.

• AWWA C550 – Fusion Bonded Epoxy coatings for valves in waterworks service.

• ISO 14713 – Zinc and aluminum coatings for corrosion protection.

• API / Oil Company Standards – Project-specific coating systems (e.g., Shell DEP, Saudi Aramco SAES-H-001).

Best Practices for Applying Valve Coatings

1. Surface Preparation – Blast clean to SA 2.5 (ISO 8501-1) before coating.

2. Coating Thickness – Follow project requirements, typically 150–300 µm DFT (dry film thickness).

3. Avoid Overpainting – Protect flange faces, nameplates, stem threads from paint.

4. Environmental Control – Apply coatings in suitable humidity and temperature.

5. Inspection & Testing – Perform DFT measurement, adhesion test, and holiday test before shipment.

Conclusion

Choosing the right anti-corrosion coating is critical to valve performance in harsh environments. Epoxy and polyurethane remain the most widely used systems, while fusion bonded epoxy (FBE), fluoropolymers, and TSA are preferred for demanding applications. By following ISO, AWWA, and NACE standards, and tailoring coatings to service conditions, manufacturers and EPC contractors can ensure valves achieve long service life, reduced maintenance, and global compliance.