After several years of field testing, CSC Services can now install a rust mitigating coating system to protect steel structures from crevice corrosion. There is huge potential for this system to extend the lifespan of structures such as bridges, metal tanks, pipework and waterpipe bridges.
Crevice corrosion refers to the attack of metal surfaces in crevices, for example around the edges of nuts and rivet heads, and beneath steel plates, side barings and fasteners. It is a form a localised corrosion typical of steel components that develop a crevice into an open atmospheric environment. When left untreated, crevice corrosion and pack rust can create serious structural problems and can seriously affect the structural stability of steel structures such as bridges.
Crevice corrosion can’t be stopped by traditional methods. The simple cleaning and painting of steel with a zinc-based coating will not work on crevice corroded structures. Abrasive blasting will not remove the corrosion products in inaccessible areas. If active corrosion cells are not neutralised with an active chemistry to displace the moisture and scavenge the oxygen, sealing up the joint will accelerate the corrosion.
Zinc-based paints or coating systems do not chemically deal with the corrosion process that exists within crevices. This type of coating system frequently fails at the joints and connections within six months to a year. The result is rust leaking from within the connections onto the exterior surfaces.
CSC Services can provide a coating system that will stop crevice corrosion and pack rust. The coating will neutralise the acid in the crevice corroded joint; and stop corrosion on the surface of the steel. The system can be applied wet-on-wet and requires only minimal surface preparation to remove only loose paint and debris. It is therefore significantly quicker to install than traditional coatings which will only mask the problem short term.
CSC Services installed this rust mitigating coating system at Hinkley Point B Power Station in 2016. Located behind the main sea wall on the Bristol Channel coast, the Gabion Wall structure was subjected to marine exposure and high chloride ingress, putting the integrity of the structure at risk. Refurbishment of the structure was required to and protect against further corrosion.
Since installation in June 2016, this coating system has prevented rust creepage and protected the surfaces in ways that more traditional coatings (non-HRCSA) would not.
It will provide protection against delaminating coatings, perforation from sand, stone and gravel and poultice rusting.
Call 0191 410 3444 today or visit www.csc-services.co.uk/coatings
Images of rust mitigating coating system being installed at Hinkley Point B Power Station :
Affected rusted area following hot wash steel preparation and de-salting
Pack rust penetrant application. Nut, bolt and crevis protection from pack rust.
Stripe coating of steel area with rust mitigating coating system
Same day wet on wet application by brush, roller or spray.
Call 0191 410 3444 today or visit www.csc-services.co.uk/coatings
