Case Study

Client

Engineering Industry, UK.

Application Date

March, 2021.

Scope of work

Wedge Gate Valve Cover and Pedestals: Internal and external corrosion protection of 6″, 10″ and 14″ wedge gate valves, bodies, covers and pedestals. The valve is subject to crude oil at a maximum service temperature of 80°c.

Substrate

Ductile iron.

Products

Internal: Polyglass VEF/ Polyglass VEHA.

External: Plasmet ZF, Corrocoat Zip E, Corrothane AP1 coating system.

Coating system

• Rebated flange faces.
• Machine surfaces masked up and protected prior to abrasive blasting and coating.
• Abrasive blasted the internal surfaces with new abrasive in accordance with ISO 8501-1 to Sa2 1/2 surface finish, to achieve a surface profile of 50 microns.
• WGC body, cover, wedge and yoke: applied Polyglass VEF to wetted surfaces to achieve a minimum DFT (Dry Film Thickness) of 1250 microns.
• Thickness checked and spark tested at 17kva.
• Abrasive blasted the specified external surfaces with new abrasive in accordance with ISO 8501-1 to Sa2 surface finish, to achieve a minimum surface profile of 50 microns.
• Applied coat of Plasmet ZF primer to achieve a minimum DFT of 100 microns.
• Applied Corrocoat Zip E to achieve a DFT of between 500-700 microns.
• Applied top coat of Corrothane AP1 – coloue: RAL 1023.

Coating credentials

Polyglass VEF: A glass flake vinyl ester acrylic co-polymer, excellent in immersed environments. Excellent flexibility in immersed environments. Excellent flexibility undercutting resistance and sliding abrasion resistance.

Plasmet ZF: A two pack epoxy coating compound incorporating glass flake, ZF has passed standard Norsok testing against system 1 – use on carbon steel, with a max operating temperature of <120 structural steel, equipment exteriors, vessels, pipework  and valves including in tidal and splash zones, and Systems 3B – internal surfaces of carbon steel vessels – ballast water tanks/internal seawater filled compartments.

Corrocoat Zip E: A 2 pack flake epoxy based coating system. It offers durable protection in aggressive atmospheric and immersed environments offering excellent edge coverage.

Corrothane AP1: A polyurethane/acrylic topcoat, a high performance cosmetic topcoat to provide excellent colour retention and weathering properties. Designed for use on marine and offshore structured work in aggressive service environments.